Cryptogenic Organizing Pneumonia

The Role of Bronchoscopy in the Diagnosis of Interstitial Lung Disease: A State-of-the-Art Review

The diagnostic evaluation of interstitial lung diseases (ILDs) remains challenging due to their heterogeneous etiologies and overlapping clinical and radiographic patterns. A confident diagnosis often necessitates histopathological sampling, particularly when high-resolution computed tomography and serologic assessments are inconclusive. While surgical lung biopsy (SLB) has long been considered the diagnostic gold standard, its invasiveness, associated morbidity, and limited feasibility in high-risk patients have driven the pursuit of less invasive alternatives. Here, we review the current applications, diagnostic yield, procedural techniques, and complications of several bronchoscopic modalities. Bronchoalveolar lavage (BAL) aids in characterizing inflammatory profiles and differentiating among conditions such as hypersensitivity pneumonitis, sarcoidosis, and eosinophilic pneumonia. Endobronchial biopsies (EBBs) and endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) are valuable in diagnosing granulomatous diseases with lymphadenopathy. Transbronchial lung biopsy (TBLB) is effective for peribronchial and centrilobular diseases but is limited by small sample size and tissue distortion. Transbronchial lung cryobiopsy (TBC) enables acquisition of larger, well-preserved parenchymal tissue samples from the peripheral lung. Over recent years, studies have demonstrated that TBC, when interpreted within a multidisciplinary discussion (MDD), achieves diagnostic concordance rates with SLB exceeding 75%, and up to 95% in cases where high diagnostic confidence is reached. When performed in experienced centers using standardized protocols, TBC is considered a viable first-line histopathologic tool in the diagnostic evaluation of ILD. Adequate training and standardization of the TBC procedure are needed to ensure low complication rates and a high yield.

Risk factors for drug-related non-infectious pneumonia: insights from the FDA adverse event reporting system (FAERS)

BACKGROUND

Non-infectious pneumonitis (NIP) is a severe adverse drug reaction. To better understand drug-induced NIP, improve patient safety, and inform clinical decision-making, this study aims to utilize the FDA Adverse Event Reporting System (FAERS) database to evaluate the association between medications and NIP, identify potential risk factors, and offer clinical alerts.

RESEARCH DESIGN AND METHODS

We reviewed the FAERS database from the 2004 through the second quarter of 2024. Using 'NIP' as the search term, we sorted, counted, and analyzed cases by generic drug name and trends of reports related to NIP submitted to FAERS database. We employed four statistical methods to identify drugs associated with the NIP.

RESULTS

From 21,433,114 reported drug adverse events (AEs), 9,224 cases were classified as NIP. Our analysis identified 20 drugs associated with NIP, with the main categories being antineoplastic agents, antibiotics and immunosuppressants. Daptomycin, methotrexate, and tacrolimus had the highest NIP-related deaths. Trends in AEs reporting indicate that the drugs showing the fastest increase in NIP reports are daptomycin, methotrexate, sertraline, and amiodarone.

CONCLUSION

These findings could assist clinicians in the early identification of drug-related NIP and provide valuable insights for future research into the mechanisms underlying drug-related NIP.

Uncommon pulmonary manifestation of hepatitis B virus: a case report of secondary organizing pneumonia

BACKGROUND

Hepatitis B virus (HBV) primarily affects the liver, but increasingly, it is recognized for its potential extrahepatic manifestations. This case highlights the importance of considering viral infections in the differential diagnosis of pulmonary nodules.

CASE PRESENTATION

A 63-year-old man presented with a new mixed ground-glass nodule in the left lower lobe during a routine check-up. He had a history of liver resection for hepatocellular carcinoma, with results negative for hepatitis B virus surface antigen. The HBV viral load in the patient's serum was below the detection limit of quantitative PCR (qPCR). Immunohistological analysis of lung biopsy samples indicated chronic inflammation. However, after a course of intravenous antibiotics, the nodule increased in size, prompting further investigation. Therefore, lung biopsy tissue was subjected to metagenomic next-generation sequencing (mNGS), and HBV DNA was detected. The patient was diagnosed with secondary organizing pneumonia associated with HBV. Then he was treated with prednisone acetate and had remission.

CONCLUSION

This case underscores the potential for HBV to manifest as pulmonary complications, such as secondary organizing pneumonia. Therefore, in the stage of infectious diseases in patients with a history of hepatocellular carcinoma, HBV needs to be the focus of monitoring, so as to clarify the cause of diagnosis and treatment as soon as possible.

CLINICAL TRIAL

Not applicable.

Diagnostic approach in acute hypoxemic respiratory failure

Acute hypoxemic respiratory failure (AHRF) is the leading cause of intensive care unit (ICU) admissions. Of patients with AHRF, 40 %-50 % will require invasive mechanical ventilation during their stay in the ICU, and 30 %-80 % will meet the Berlin Criteria for Acute Respiratory Distress Syndrome (ARDS). Rapid identification of the underlying cause of AHRF is necessary before initiating targeted treatment. Almost 10 % of patients with ARDS have no identified classic risk factors however, and the precise cause of AHRF may not be identified in up to 15 % of patients, particularly in cases of immunosuppression. In these patients, a multidisciplinary, comprehensive, and hierarchical diagnostic work-up is mandatory, including a detailed history and physical examination, chest computed tomography, extensive microbiological investigations, bronchoalveolar lavage fluid cytological analysis, immunological tests, and investigation of the possible involvement of pneumotoxic drugs.

Case Report: First report of Legionella micdadei pneumonia and organizing pneumonia in a patient with myelodysplastic and Sweet syndromes

The immunocompromised population is susceptible to Legionella pneumonia. The diagnosis and treatment of Legionella pneumonia in immunocompromised individuals are challenging clinical endeavors. Previous studies have identified Legionella pneumonia as a potential cause of organizing pneumonia (OP), however, the association between Legionella pneumonia and OP has not received enough clinical attention. We retrospectively evaluated a case involving Legionella micdadei infection and OP in a patient with myelodysplastic syndrome and concurrent Sweet syndrome. The diagnosis of Legionella micdadei pneumonia was confirmed through various methods: metagenomic next generation sequencing (mNGS), Giemsa-staining and fluorescence in situ hybridization of lung tissue, as well as serum immunofluorescence antibody testing. Histopathological analysis of lung tissue revealed OP. The patient was successfully treated with a combination of antibiotics and low-dose glucocorticoids. In immunocompromised individuals, mNGS was capable of detection non-Legionella pneumophila serogroup 1. The pathological examination is important for identifying secondary OP and provides the evidence for treatment with glucocorticoids.

Secondary Organizing Pneumonia: A Case Report of a Noteworthy Complication of Breast Irradiation

Organizing pneumonia (OP) is a pattern of pulmonary tissue repair injury. It can be cryptogenic or a response to a specific lung injury. Radiation therapy is a potential cause of secondary OP, especially after breast irradiation. The lesions may appear anywhere in the lung parenchyma with no relation to the irradiated side. Corticotherapy is the mainstay of treatment and prognosis is generally favorable. We describe a case of a female patient previously diagnosed with breast cancer who developed secondary OP within six months of postoperative radiotherapy. Initial diagnosis was challenging due to the rarity of the disease as well as management that required close follow-up with careful tapering given the frequent relapses associated with the withdrawal of corticosteroid therapy. The reported case emphasizes the importance of recognizing secondary OP as a rare complication of postoperative radiotherapy for breast cancer and puts into view the complexity of its management.

Immunophenotyping of T Cells in Lung Malignancies and Cryptogenic Organizing Pneumonia

Background: Lung malignancies, including cancerous lymphangitis and lymphomas, can mimic interstitial lung diseases like cryptogenic organizing pneumonia (COP) on imaging, leading to diagnostic delays. We aimed to identify potential biomarkers to distinguish between these conditions. Methods: We analyzed bronchoalveolar lavage fluid from 8 patients (4 COP, mean age 59.8 ± 13.5 years; 4 lung malignancies including 2 cancerous lymphangitis, 1 MALT lymphoma, and 1 diffuse large B cell lymphoma, mean age 67.8 ± 4.5 years) using mass cytometry with 35 T cell markers. Data were analyzed using principal component analysis (PCA) and unsupervised Citrus clustering. Results: PCA of T cell marker intensities effectively separated the two groups, with IL-2Rα, PD-L2, CD45RA, CD44, and OX40 being the top discriminating markers. Citrus analysis showed a significant increase in the CD16+ CD4+ and CD16+ CD8+ T cell populations in the COP group compared to lung malignancies. Conclusions: Our findings reveal distinct T cell immunophenotypes in COP versus lung malignancies, particularly increased CD16+ T cells in COP, which could serve as potential diagnostic biomarkers.

A case of neuromyelitis optica spectrum disorder complicated with aquaporin-4-antibody-associated organizing pneumonia

An 80-year-old man with aquaporin-4-antibody-positive neuromyelitis optica spectrum disorder presented with a 2-week history of cough and hiccups, followed by progressive bilateral lower limb weakness, a bandlike burning sensation in the upper body, and urinary retention. Magnetic resonance imaging showed area postrema and thoracic central medullary lesions. Thorax computed tomography showed bilateral upper lung lobe consolidations. Lung biopsy confirmed organizing pneumonia. Immunohistochemistry of these lesions demonstrated aquaporin-4 loss, immunoglobulin G-binding, and complement deposits, akin to central nervous system lesions found in neuromyelitis optica spectrum disorder. Thus, aquaporin-4-antibodies may be involved in extra-central nervous system manifestations of neuromyelitis optica spectrum disorder.

Mycobacterium goodii pulmonary disease with organizing pneumonia: A case report and review of literature

Mycobacterium goodii, a rapidly growing non-tuberculous mycobacterium, rarely causes pulmonary diseases. A patient was admitted to our hospital with a fever and cough. Chest radiography revealed consolidation in the right middle lung. As he had previously been treated for organizing pneumonia (OP), he was diagnosed with OP recurrence and administered systemic corticosteroids. Although initial improvement was observed, the pulmonary consolidations worsened. Transbronchial lung cryobiopsy revealed an OP pattern. M. goodii was identified in sputum acid-fast bacilli cultures. The patient was diagnosed with M. goodii pulmonary disease and secondary OP. Although intravenous imipenem-cilastatin, amikacin, and ciprofloxacin led to initial improvement in pulmonary consolidations, the consolidations re-worsened. Systemic corticosteroids were initiated, resulting in improvement in the consolidations. The dose of systemic corticosteroids was tapered; oral antimycobacterial therapy was continued. M. goodii can cause pulmonary disease and induce OP; antimycobacterial therapy and systemic corticosteroids can be effective.

The Clinical Significance of Interstitial Pneumonia with Autoimmune Features in Cryptogenic Organizing Pneumonia: A Prospective Multicenter Observational Study

Background: There are cases of idiopathic interstitial pneumonias (IIPs) that do not meet the diagnostic criteria for connective tissue disease but have clinical features suggestive of autoimmune process. Interstitial pneumonia with autoimmune features (IPAF) was recently proposed as a research concept for these patients. Although several prospective studies on IPAF have been conducted, its clinical significance in cryptogenic organizing pneumonia (COP) remains unclear. Methods: Patients aged ≥20 years with suspected COP were prospectively enrolled between June 2018 and December 2022. Among the enrolled patients, those diagnosed with COP based on computed tomography (CT) and bronchoalveolar lavage (BAL) findings were compared between the IPAF and non-IPAF groups. Results: A total of 56 patients were enrolled in this study. Of these, 30 were diagnosed with COP and included in the analysis. Clinical and serological features were positive in two and six patients, respectively. Each feature was exclusive, and eight patients (26.7%) were diagnosed with IPAF. There were no differences between the IPAF and non-IPAF groups in terms of clinical features, including BAL findings, laboratory data, CT findings, and clinical course. During the one-year follow-up period, the frequency of COP exacerbation did not differ between the IPAF and non-IPAF groups, and no cases of systemic autoimmune disease or death occurred in either group. Conclusions: The COP characteristics of the IPAF and non-IPAF groups are similar in all aspects, and distinguishing between the two groups may be of little significance.

Secondary organising pneumonia associated to COVID-19 infection in patients with central nervous system inflammatory demyelinating diseases treated with anti-CD20 therapies

BACKGROUND

Organizing pneumonia (OP), an interstitial lung disease, has been observed in patients with inflammatory demyelinating diseases (IDDs) treated with anti-CD20, particularly after COVID-19, but data are limited.

AIM

To provide a detailed characterization of COVID-19-associated OP in IDD patients treated with anti-CD20.

METHODS

Bi-centric retrospective cohort study including patients with multiple sclerosis (MS), aquaporin-4-positive neuromyelitis optica spectrum disorder (AQP4 + NMOSD), and myelin oligodendrocyte glycoprotein antibody disease (MOGAD) who received anti-CD20 and were diagnosed with COVID-19-associated OP between March 2020 and October 2023.

RESULTS

Nineteen patients were included (mean age 46.8 years; 52.6% female; 63% rituximab, 37% ocrelizumab). Sixteen had MS, two MOGAD, and one AQP4 + NMOSD. Intermittent fever was the predominant symptom. Hospitalization occurred in all but one patient, without fatalities. Chest CT consistently showed OP patterns. Thirteen patients had positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) PCR in bronchoalveolar lavage. Treatments included corticosteroids, antivirals, monoclonal antibodies, and convalescent plasma. Fourteen patients postponed infusions; nine resumed post-recovery (median 11.9 months), two switched due to hypogammaglobulinemia, and three stopped. After a mean follow-up of 1.5 years, lung abnormalities and clinical manifestations resolved in 18 patients; however, 13 experienced long-COVID.

CONCLUSIONS

In anti-CD20-treated patients with recurrent fever and distinctive CT features, COVID-19-associated OP should be considered.

Multifocal Pulmonary Opacities in an Elderly Smoker

Organizing pneumonia (OP) directly caused by ongoing cigarette smoking does not appear to have been previously described. Despite OP having pathophysiological features distinct from lung cancer, the two may be confused based on similar clinical, radiological, and histopathological findings. This distinction is further clouded by the dynamic nature of these diseases. Diagnostic accuracy can likely be improved with a multidisciplinary approach that involves input from several specialists and serial reevaluations as the disease evolves. We present a case of OP that was initially misdiagnosed as non-small-cell lung cancer and resolved with smoking cessation.

Risk factors for relapse of immune-related pneumonitis after 6-week oral prednisolone therapy: a follow-up analysis of a phase II study

BACKGROUND

Immune-related pneumonitis (irP) is one of the most important immune-related adverse events caused by immune checkpoint inhibitors (ICIs). After corticosteroid therapy irP frequently relapses, which can interfere with cancer therapy. However, risk factors for irP relapse are unknown.

METHODS

This study was a follow-up analysis of a phase II study that evaluated 56 patients with grade ≥ 2 irP treated with oral prednisolone, 1 mg/kg/day, tapered over 6 weeks. Clinical factors including patient characteristics, blood test findings, and response to prednisolone therapy were assessed to identify risk factors for irP relapse using the Fine-Gray test.

RESULTS

Among 56 patients with irP, 22 (39.3%) experienced irP relapse after 6 weeks of prednisolone therapy during the follow-up observation period. Radiographic organising pneumonia (OP) pattern and duration to irP onset ≥ 100 days from ICI initiation were determined to be significant risk factors for irP relapse in a multivariate Fine-Gray test (hazard ratio [HR] = 3.17, 95% CI 1.37-7.32, p = 0.007, and HR = 2.61, 95% CI 1.01-6.74, p = 0.048, respectively). Other patient characteristics, blood test findings, irP severity, and response to prednisolone therapy were not associated with irP relapse.

CONCLUSIONS

In irP patients treated with 6-week prednisolone tapering therapy, OP pattern and duration to irP onset ≥ 100 days were associated with relapse risk. Assessment of the risk factors for irP relapse will be helpful for irP management.

Near fatal case of mirvetuximab soravtansine-gynx induced interstitial lung disease and a review of the primary literature

•Mirvetuximab soravtansine-gynx should be recognized as a cause of drug-induced interstitial lung disease (ILD).•Radiographic manifestations of mirvetuximab soravtansine-gyn induced ILD include organizing pneumonia pattern.•Interstitial lung disease related to mirvetuximab soravtansine-gyn can cause high morbidity.•Corticosteroids are commonly used in drug-induced interstitial lung disease and should be considered when encountering ILD related to mirvetuximab.•Changes to manufacturer dosing guidelines for grade 1 pneumonitis related to mirvetuximab soravtansine-gyn need to be considered.

How I diagnose and treat organizing pneumonia in hematopoietic cell transplant recipients

ABSTRACT

Organizing pneumonia (OP) is a known noninfectious pulmonary complication following allogeneic hematopoietic cell transplant (HCT) and represents a significant risk factor for nonrelapse mortality in HCT recipients. Unlike bronchiolitis obliterans syndrome, it is not universally acknowledged as a distinctive pulmonary manifestation of chronic graft-versus-host disease (cGVHD) and, therefore, its diagnostic criteria and management approach are lacking. Given its shared similar clinical features and radiological and histologic findings to OP in the non-HCT population, the diagnostic approach and treatment strategy for OP in HCT recipients is largely adapted from the non-HCT population. In this article, we aim to enhance the understanding of OP within the context of cGVHD following HCT and distinguish its clinical features and treatment strategy from non-HCT counterparts, thereby reinforcing its recognition as a pulmonary manifestation of graft-versus-host disease. We will propose the diagnostic criteria and outline our approach in diagnosis and treatment strategy, highlighting the potential challenges that may arise in each process. Finally, we will discuss knowledge gaps in this field and identify the area of need for future research.

Natural history of indolent-anti-synthetase syndrome-associated interstitial lung disease

BACKGROUND

Anti-synthetase syndrome-associated interstitial lung disease (ASS-ILD) may occur without myositis. Although a recent Japanese guide proposed a watch-and-wait approach for chronic ASS-ILD without obvious progression, the natural history of this subgroup and the appropriateness of the watch-and-wait approach remain unclear. We aimed to describe the natural history of ASS-ILD, that is sufficiently indolent to be a candidate for the watch-and-wait approach.

METHODS

Among consecutive patients with ASS-ILD, we retrospectively identified those without myositis, acute/subacute onset, and significant lung function impairment, which qualified them as indolent-ASS-ILD cases, and described their natural course. Additionally, we evaluated the risk factors for fibrosis progression on computed tomography (CT) using the Cox proportional hazards model.

RESULTS

Among 80 patients with ASS-ILD, we identified 33 with indolent-ASS-ILD, all of whom were initially followed up with a watch-and-wait approach. Among 30 patients with sufficient follow-up data, 27 (90%) showed a stable course without treatment over 24 months. Subsequently, four patients experienced ≥10% relative forced vital capacity (FVC) decline without treatment during a median follow-up duration of 81 months. Seven patients showed fibrosis progression with >10% increase in the total lung area on CT. Higher levels of Krebs von den Lungen-6 (KL-6) and surfactant protein-D (SP-D) were associated with fibrosis progression on CT.

CONCLUSION

Most patients with indolent-ASS-ILD did not experience ≥10% relative FVC decline over five years without treatment. However, fibrosis progression on CT, which seemed to precede significant FVC decline, occurred more frequently, especially in patients with higher KL-6 and SP-D levels.

Integrated multi-omics profiling landscape of organising pneumonia

BACKGROUND

Organising pneumonia (OP) is one of the most common and lethal diseases in the category of interstitial pneumonia, along with lung cancer. Reprogramming of lipid metabolism is a newly recognized hallmark of many diseases including cancer, cardiovascular disorders, as well as liver fibrosis and sclerosis. Increased levels of ceramides composed of sphingosine and fatty acid, are implicated in the development of both acute and chronic lung diseases. However, their pathophysiological significance in OP is unclear. The aim of this study was to investigate the role of lipid metabolism reprogramming in OP, focusing on inflammation and fibrosis.

METHODS

Comprehensive multi-omics profiling approaches, including single-cell RNA sequencing, Visium CytAssist spatial transcriptomics, proteomics, metabolomics and mass spectrometry, were employed to analyze the tissues. OP mice model was utilized and molecular mechanisms were investigated in macrophages.

RESULTS

The results revealed a significant association between OP and lipid metabolism reprogramming, characterized by an abnormal expression of several genes related to lipid metabolism, including CD36, SCD1, and CES1 mainly in macrophages. CD36 deficiency in alveolar macrophages, led to an increased expression of C16/24 ceramides that accumulated in mitochondria, resulting in mitophagy or mitochondrial dysfunction. The number of alveolar macrophages in OP was significantly reduced, which was probably due to the ferroptosis signaling pathway involving GSH/SLC3A2/GPX4 through CD36 downregulation in OP. Furthermore, macrophage secretion of DPP7 and FABP4 influenced epithelial cell fibrosis.

CONCLUSIONS

CD36 inhibited the ferroptosis pathway involving SLC3A2/GPX4 in alveolar macrophages of OP tissue by regulating lipid metabolism, thus representing a new anti-ferroptosis and anti-fibrosis effect of CD36 mediated, at least in part, by ceramides.

HIGHLIGHTS

Our findings reveal a significant association between organising pneumonia and lipid metabolism reprogramming and will make a substantial contribution to the understanding of the mechanism of organising pneumonia in patients.

Ocrelizumab-induced organizing pneumonia in multiple sclerosis: case report and literature review

Patients with relapsing-remitting multiple sclerosis should be offered disease-modifying therapies as part of their management. Recommended options include integrin antagonist therapy including natalizumab as well as anti-CD20 monoclonal antibodies like, ocrelizumab, rituximab, ofatumumab, and ublituximab. These therapies reduce relapse rates and slow brain lesion accumulation. Disease-modifying therapies selection may depend on patient preferences, potential fetal harm, and specific drug risks, requiring continuous monitoring via tracking clinical relapses and new MRI brain lesions. Natalizumab carries a risk of progressive multifocal leukoencephalopathy, particularly in anti-JCV antibody-positive patients, necessitating regular monitoring. Ocrelizumab, rituximab, and ublituximab are associated with an increased risk of infections (especially respiratory and skin infections), infusion reactions, and hypogammaglobulinemia. Ocrelizumab additionally poses a heightened risk of immune-mediated colitis and breast cancer, and it is contraindicated for patients with active hepatitis B due to the risk of viral reactivation. Ublituximab has been noted to be linked to potential fetal harm. We report the case of a 42-year-old male with relapsing-remitting multiple sclerosis on ocrelizumab who developed persistent fever and shortness of breath, two weeks after his last ocrelizumab dose. Despite antibiotic treatment for suspected pneumonia, his symptoms persisted. A chest CT scan revealed multifocal ground-glass opacities suggestive of organizing pneumonia, likely secondary to ocrelizumab. The patient's condition improved with high-dose corticosteroids, underscoring the importance of vigilance for extremely rare ocrelizumab-associated pulmonary side effects and the need for prompt, appropriate intervention.

Case 327: Exogenous Lipoid Pneumonia

HISTORY

A 58-year-old male patient with an active smoking status was admitted twice to the intensive care unit (ICU) of a tertiary referral thoracic center for severe hypercapnic acute respiratory failure and persistent bilateral chest radiograph opacities that were unchanged over the course of the two ICU admissions within a 3-month period. The patient had obesity (body mass index, 36), stage 3 vascular chronic renal insufficiency, and hebephrenic schizophrenia treated with haloperidol, carbamazepine, and cyamemazine. He reported chronic dyspnea on exertion, which worsened for 6 months. At the second ICU admission, the patient was afebrile, with a blood pressure of 160/72 mm Hg and pulse oximetry of 93% on 6 L/min oxygen therapy through a nonrebreathing mask. Physical examination showed signs of respiratory failure with wheezing and active abdominal expiration, and bilateral pulmonary crackles without chest pain, hemoptysis, clubbing, or signs of cardiac failure. The patient had no peripheral lymphadenopathy and no enlarged spleen. Blood gases (on 6 L/min oxygen) showed respiratory acidosis (pH, 7.15 [normal range, 7.38-7.42]; PaO2 level, 67 mm Hg [normal range, 80-100 mm Hg]; PaCO2 level, 102 mm Hg [normal range, 38-42 mm Hg]; bicarbonate [HCO3-], 29 mmol/L [normal range, 22-27 mmol/L]). Noninvasive ventilation was initiated. Imaging performed during the second ICU hospitalization included CT and MRI of the chest without contrast enhancement, and fluorine 18 (18F) fluorodeoxyglucose (FDG) PET/CT.

Connective tissue disease-associated lung disease in children

Connective tissue diseases are a heterogeneous group of autoimmune diseases that can affect a variety of organ systems. Lung parenchymal involvement is an important contributor to morbidity and mortality in children with connective tissue disease. Connective tissue disease-associated lung disease in children often manifests as one of several radiologic-pathologic patterns of disease, with certain patterns having a propensity to occur in association with certain connective tissue diseases. In this article, key clinical, histopathologic, and computed tomography (CT) features of typical patterns of connective tissue disease-associated lung disease in children are reviewed, with an emphasis on radiologic-pathologic correlation, to improve recognition of these patterns of lung disease at CT and to empower the pediatric radiologist to more fully contribute to the care of pediatric patients with these conditions.

A case of community-acquired pneumonia caused by Bacillus subtilis subsp. natto in an immunocompetent patient

A 70-year-old immunocompetent male with a history of insomnia presented with pneumonia and bacteremia caused by Bacillus subtilis. The patient took benzodiazepines and regularly consumed alcohol and natto (fermented soybeans). Initial antibiotic treatment was not effective, and bronchoalveolar lavage was performed. Bronchoalveolar lavage fluid (BALF) analysis revealed an increased lymphocytes fraction, and B. subtilis was detected in the BALF. Whole-genome sequencing confirmed the congruence of the genetic sequences between the strain in the blood culture of the patient, BALF, and strain isolated from the consumed natto, confirming B. subtilis subsp. natto as the causative pathogen of pneumonia and bacteremia. Vancomycin followed by levofloxacin and systemic corticosteroid were used to treat the condition. This case highlights community-acquired pneumonia and bacteremia caused by B. subtilis subsp. natto, particularly in individuals who consume natto.

Relationship between idiopathic interstitial pneumonias (IIPs) and connective tissue disease-related interstitial lung disease (CTD-ILD): A narrative review

While idiopathic interstitial pneumonia (IIP) centering on idiopathic pulmonary fibrosis (IPF) is the most prevalent interstitial lung disease (ILD), especially in the older adult population, connective tissue disease (CTD)-related ILD is the second most prevalent ILD. The pathogenesis of IPF is primarily fibrosis, whereas that of other ILDs, particularly CTD-ILD, is mainly inflammation. Therefore, a precise diagnosis is crucial for selecting appropriate treatments, such as antifibrotic or immunosuppressive agents. In addition, some patients with IIP have CTD-related features, such as arthritis and skin eruption, but do not meet the criteria for any CTD, this is referred to as interstitial pneumonia with autoimmune features (IPAF). IPAF is closely associated with idiopathic nonspecific interstitial pneumonia (iNSIP) and cryptogenic organizing pneumonia (COP). Furthermore, patients with iNSIP or those with NSIP with OP overlap frequently develop polymyositis/dermatomyositis after the diagnosis of IIP. Acute exacerbation of ILD, the most common cause of death, occurs more frequently in patients with IPF than in those with other ILDs. Although acute exacerbation of CTD-ILD occurs at a low rate of incidence, patients with rheumatoid arthritis, microscopic polyangiitis, or systemic sclerosis experience more acute exacerbation of CTD-ILD than those with other CTD. In this review, the features of each IIP, focusing on CTD-related signatures, are summarized, and the pathogenesis and appropriate treatments to improve the prognoses of patients with various ILDs are discussed.

Progressive Pulmonary Fibrosis: Where Are We Now?

Interstitial lung diseases (ILDs) are a diverse collection of lung disorders sharing similar features, such as inflammation and fibrosis. The diagnosis and management of ILD require a multidisciplinary approach using clinical, radiological, and pathological evaluation. Progressive pulmonary fibrosis (PPF) is a distinct form of progressive and fibrotic disease, occurring in ILD cases other than in idiopathic pulmonary fibrosis (IPF). It is defined based on clinical symptoms, lung function, and chest imaging, regardless of the underlying condition. The progression to PPF must be monitored through a combination of pulmonary function tests (forced vital capacity [FVC] and diffusing capacity of the lung for carbon monoxide), an assessment of symptoms, and computed tomography scans, with regular follow-up. Although the precise mechanisms of PPF remain unclear, there is evidence of shared pathogenetic mechanisms with IPF, contributing to similar disease behavior and worse prognosis compared to non-PPF ILD. Pharmacological treatment of PPF includes immunomodulatory agents to reduce inflammation and the use of antifibrotics to target progressive fibrosis. Nintedanib, a known antifibrotic agent, was found to be effective in slowing IPF progression and reducing the annual rate of decline in FVC among patients with PPF compared to placebos. Nonpharmacological treatment, including pulmonary rehabilitation, supplemental oxygen therapy, and vaccination, also play important roles in the management of PPF, leading to comprehensive care for patients with ILD. Although there is currently no cure for PPF, there are treatments that can help slow the progression of the disease and improve quality of life.

Organizing pneumonia is associated with molecular allograft injury and the development of antibody-mediated rejection

BACKGROUND

The association between organizing pneumonia (OP) after lung transplantation with the development of acute rejection (AR) remains undefined. In addition, molecular allograft injury, as measured by donor-derived cell-free DNA (dd-cfDNA), during episodes of OP and its relationship to episodes of AR, chronic lung allograft dysfunction (CLAD), or death is unknown.

METHODS

This multicenter, prospective cohort study collected serial plasma samples from 188 lung transplant recipients for dd-cfDNA at the time of bronchoscopy with biopsy. Multivariable Cox regression was used to analyze the association between OP with the development of AR (antibody-mediated rejection (AMR) and acute cellular rejection (ACR)), CLAD, and death. Multivariable models were performed to test the association of dd-cfDNA at OP with the risk of AR, CLAD, or death.

RESULTS

In multivariable analysis, OP was associated with increased risk of AMR (hazard ratio (HR) = 2.26, 95% confidence interval (CI) 1.04-4.92, p = 0.040) but not ACR (HR = 1.29, 95% CI: 0.66-2.5, p = 0.45) or the composite outcome of CLAD or death (HR = 0.88, 95% CI, 0.47-1.65, p = 0.69). Median levels of dd-cfDNA were higher in OP compared to stable controls (1.33% vs 0.43%, p = 0.0006). Multivariable analysis demonstrated that levels of dd-cfDNA at diagnosis of OP were associated with increased risk of both AMR (HR = 1.29, 95% CI 1.03-1.62, p = 0.030) and death (HR = 1.16, 95% CI, 1.02-1.31, p = 0.026).

CONCLUSIONS

OP is independently associated with an increased risk of AMR but not CLAD or death. The degree of molecular allograft injury at the diagnosis of OP may further predict the risk of AMR and death.

Multidisciplinary Approach to the Diagnosis of Idiopathic Interstitial Pneumonias: Focus on the Pathologist's Key Role

Idiopathic Interstitial Pneumonias (IIPs) are a heterogeneous group of the broader category of Interstitial Lung Diseases (ILDs), pathologically characterized by the distortion of lung parenchyma by interstitial inflammation and/or fibrosis. The American Thoracic Society (ATS)/European Respiratory Society (ERS) international multidisciplinary consensus classification of the IIPs was published in 2002 and then updated in 2013, with the authors emphasizing the need for a multidisciplinary approach to the diagnosis of IIPs. The histological evaluation of IIPs is challenging, and different types of IIPs are classically associated with specific histopathological patterns. However, morphological overlaps can be observed, and the same histopathological features can be seen in totally different clinical settings. Therefore, the pathologist's aim is to recognize the pathologic-morphologic pattern of disease in this clinical setting, and only after multi-disciplinary evaluation, if there is concordance between clinical and radiological findings, a definitive diagnosis of specific IIP can be established, allowing the optimal clinical-therapeutic management of the patient.

Clinical manifestations and prognostic factors analysis of patients hospitalised with acute exacerbation of idiopathic pulmonary fibrosis and other interstitial lung diseases

BACKGROUND

Acute exacerbation (AE) is a life-threatening condition taking place not only in idiopathic pulmonary fibrosis (IPF) but also in interstitial lung diseases (ILD) other than IPF (non-IPF ILD). This study aims to compare the clinical manifestations between patients hospitalised with AE-IPF and AE-non-IPF ILD, and further analyse the risk factors related to in-hospital mortality.

METHODS

Clinical data of 406 patients hospitalised with AE-IPF (93 cases) and AE-non-IPF ILD (313 cases) were retrospectively collected. Clinical features were compared between the two groups. Risk factors related to in-hospital mortality in patients with overall AE-ILD, AE-IPF and AE-non-IPF ILD were identified by multiple logistic regression analyses, respectively, and assessed by receiver operating characteristic curve.

RESULTS

In addition to having more smokers and males, the AE-IPF group also had more respiratory failure on admission, comorbidities of pulmonary hypertension (PAH) or coronary artery disease/heart failure, a longer history of pre-existing ILD. Comorbidity of coronary heart disease/heart failure, respiratory failure at admission, neutrophil (N)%, serum hydroxybutyrate dehydrogenase (HBDH), lactate dehydrogenase (LDH) and low cholesterol levels were independent risk factors for patients with AE-ILD, while respiratory failure on admission, N%, serum HBDH, urea nitrogen, LDH and low albumin levels were risk factors for the AE-non-IPF ILD group, and fever, N% and PAH were the AE-IPF group's. Among them, HBDH 0.758 (sensitivity 85.5%, specificity 56%, cut-off 237.5 U/L) for patients with AE-ILD; N% 0.838 (sensitivity 62.5%, specificity 91.18%, cut-off 83.55%) for the AE-IPF group and HBDH 0.779 (sensitivity 86.4%, specificity 55.1%, cut-off 243.5 U/L) for the AE-non-IPF ILD group were the risk factors with the highest area under the curve.

CONCLUSIONS

Clinical characteristics differ between patients with AE-IPF and AE-non-IPF ILD. HBDH outperformed LDH in predicting the prognosis for patients with AE-ILD and AE-non-IPF ILD. N% was an independent predictor of death in-hospital in all three groups, especially in the AE-IPF group.

Machine-Learning-Based Classification Model to Address Diagnostic Challenges in Transbronchial Lung Biopsy

BACKGROUND

When obtaining specimens from pulmonary nodules in TBLB, distinguishing between benign samples and mis-sampling from a tumor presents a challenge. Our objective is to develop a machine-learning-based classifier for TBLB specimens.

METHODS

Three pathologists assessed six pathological findings, including interface bronchitis/bronchiolitis (IB/B), plasma cell infiltration (PLC), eosinophil infiltration (Eo), lymphoid aggregation (Ly), fibroelastosis (FE), and organizing pneumonia (OP), as potential histologic markers to distinguish between benign and malignant conditions. A total of 251 TBLB cases with defined benign and malignant outcomes based on clinical follow-up were collected and a gradient-boosted decision-tree-based machine learning model (XGBoost) was trained and tested on randomly split training and test sets.

RESULTS

Five pathological changes showed independent, mild-to-moderate associations (AUC ranging from 0.58 to 0.75) with benign conditions, with IB/B being the strongest predictor. On the other hand, FE emerged to be the sole indicator of malignant conditions with a mild association (AUC = 0.66). Our model was trained on 200 cases and tested on 51 cases, achieving an AUC of 0.78 for the binary classification of benign vs. malignant on the test set.

CONCLUSION

The machine-learning model developed has the potential to distinguish between benign and malignant conditions in TBLB samples excluding the presence or absence of tumor cells, thereby improving diagnostic accuracy and reducing the burden of repeated sampling procedures for patients.

Prognostic value of serum oncomarkers for patients hospitalized with acute exacerbation of interstitial lung disease

BACKGROUND

Different types of inflammatory processes and fibrosis have been implicated in the pathogenesis of interstitial lung disease (ILD), a heterogeneous, diffuse, parenchymal lung disease. Acute exacerbation (AE) of ILD is characterized by significant respiratory deterioration and is associated with high mortality rates. Several serum oncomarkers have been used to determine the prognosis of ILD; however, the prognostic value of serum oncomarker levels in patients with AE-ILD remains unclear.

OBJECTIVE

To evaluate the prognostic value of serum oncomarker levels in patients with AE-ILD and its main subtypes.

DESIGN

Retrospective study.

METHODS

The serum levels of 8 oncomarkers in 281 patients hospitalized with AE-ILD at our institution between 2017 and 2022 were retrospectively reviewed. The baseline characteristics and serum oncomarker levels were compared between the survival and non-survival groups of AE-ILD and its main subtypes. Multivariate logistic regression analysis was performed to identify independent prognosis-related markers, and the best prognostic predictor was analyzed using receiver operating characteristic curve (ROC) analysis.

RESULT

Idiopathic pulmonary fibrosis (IPF; n = 65), idiopathic nonspecific interstitial pneumonia (iNSIP; n = 26), and connective tissue disease-associated interstitial lung disease (CTD-ILD; n = 161) were the three main subtypes of ILD. The in-hospital mortality rate among patients with AE-ILD was 21%. The serum oncomarker levels of most patients with AE-ILD and its main subtypes in the non-survival group were higher than those in the survival group. Multivariate analysis revealed that ferritin and cytokeratin 19 fragments (CYFRA21-1) were independent prognostic risk factors for patients hospitalized with AE-ILD or AE-CTD-ILD. CYFRA21-1 was identified as an independent prognostic risk factor for patients hospitalized with AE-IPF or AE-iNSIP.

CONCLUSION

CYFRA21-1 may be a viable biomarker for predicting the prognosis of patients with AE-ILD, regardless of the underlying subtype of ILD. Ferritin has a prognostic value in patients with AE-ILD or AE-CTD-ILD.

Scleroderma Associated With Organising Pneumonia and Polyarthritis: A Report of a Rare Case

Cryptogenic organising pneumonia (COP) is a form of idiopathic diffuse interstitial lung disease (ILD) that develops in response to a variety of unknown irritants. An essential component of the development of organising pneumonia (OP) is damage to type II pneumocytes and the alveolar basement membrane. An autoimmune illness called systemic sclerosis (SSc) has a significant death rate from cardiopulmonary involvement such as pulmonary hypertension and ILD. Arthritis is an autoimmune disorder, in which the patients experience extra-articular symptoms such as ILD during the course of their disease, and COP frequently coexists with these conditions. It is exceedingly uncommon for OP to occur as the initial sign of arthritis, and its clinical characteristics are still unclear. Scleroderma and inflammatory polyarthritis related to COP are presented in this report.

Organizing pneumonia and COVID-19

Organizing pneumonia (OP) is an interstitial lung disease, and can be cryptogenic, if no cause is identified, or secondary to several conditions. COVID-19-induced persistent inflammation can be associated with interstitial lung disease. We present a review of literature of OP and COVID-19-induced OP with an illustrative case. A 38-year-old man was admitted with COVID-19 that required mechanical ventilation for 56 days. Initial chest computed tomography (CT) revealed diffuse bilateral ground-glass opacities in the lungs with consolidation areas involving 75 % of the parenchyma. After weaning from MV, the patient still required oxygen supplementation. A new chest CT scan also showed extensive diffuse areas of consolidation and ground-glass opacity. OP was hypothesized and 40 mg/day prednisone initiated and continued for six months with resolution of lung functional and image abnormalities. Organizing pneumonia should be included in the differential diagnosis of COVID-19 patients with respiratory symptoms after partial pulmonary recovery.

Incidence and Outcome of Atypical Manifestations of Chronic Graft-versus-Host Disease: Results From a Retrospective Single-Center Analysis

Chronic graft-versus-host disease (cGVHD) is the leading cause of late nonrelapse mortality (NRM) after allogeneic hematopoietic stem cell transplantation (alloHSCT) and defined by 8 diagnostic target organs. Recently, provisional criteria for atypical manifestations of cGVHD that include manifestations in nonclassic organs as well as atypical manifestations in National Institutes of Health (NIH)-defined organs, were proposed by a NIH task force. Little is known about the incidence, risk factors, and impact on survival of atypical cGVHD, however. The aim of the present study was to analyze these parameters in a sequential patient population. We retrospectively screened 623 patients who underwent alloHSCT at the University Medical Center Regensburg between January 2008 and December 2020 for atypical cGVHD manifestations, applying the provisional NIH taskforce criteria. A total of 102 patients (16.4%) met the criteria, representing 25% of all cGVHD cases, and 14 patients (2.2%) had only atypical cGVHD. The most frequent manifestations were immune-mediated cytopenias (24.5%), renal cGVHD (13.7%) and (poly)serositis (13.7%). Multivariate analysis identified prior acute GVHD (odds ratio [OR], 2.28 and 2.93) and infusion of donor lymphocytes (OR, 1.77 for both) as risk factors for classic cGVHD and atypical cGVHD, whereas total body irradiation was an independent risk factor for atypical cGVHD manifestations only (OR, 1.76). Compared to patients without cGVHD, those with atypical and NIH-defined cGVHD showed similarly better overall survival (P = .034 and < .001) and low relapse-related mortality (P < .001 for both). NRM was significantly increased by atypical GVHD, but not by NIH-defined cGVHD (P = .019 and .10), which was driven only by a few atypical organ manifestations (eg, renal, restrictive lung disease, peripheral neuropathy), whereas others did not contribute to NRM (eg, thyroid gland, musculoskeletal, pancreas). In summary, atypical cGVHD is more common than previously estimated and has both similarities with and differences from NIH-defined cGVHD. In particular, the increased NRM and a subset of patients with only atypical cGVHD point to the urgent need to capture these manifestations in cGVHD cohorts, including analysis of treatment outcomes.

Organizing Pneumonia as a Pulmonary Sequela of Post-COVID-19 Syndrome in a Patient in Trinidad: A Case Report

Cryptogenic organizing pneumonia (COP) is a form of idiopathic interstitial pneumonia that commonly presents with exertional dyspnea. The mainstay diagnostic criterion is with histopathological confirmation alongside excluding secondary causes of interstitial lung disease. The COVID-19 pandemic left many mysteries regarding the long-term sequelae of this disease. We explore a case of post-COVID-19 syndrome organizing pneumonia (PCOP) in a patient presenting with new-onset respiratory symptoms seven weeks after recovery from COVID-19 infection. Upon further review of the literature, there were no published case reports on PCOP in Trinidad and Tobago. We describe a case of PCOP presented at Apley Medical Clinic, Trinidad, and Tobago, West Indies, with the aim of increasing awareness of this condition to allow for early identification and effective management.

Case report: Coexistence of triple-seronegative myasthenia gravis and pathology-proven cryptogenic organizing pneumonia

Objective

Emerging evidence shows that patients with myasthenia gravis (MG) were at a higher risk for the co-occurrence of other autoimmune diseases, which reflects phenotypic heterogeneity in MG. The coexistence of MG and cryptogenic organizing pneumonia (COP) has rarely been reported. The present case is to report the coexistence of triple-seronegative MG and pathology-proven COP in a patient.

Methods

The clinical data of the patient were derived from medical records of Nanjing First Hospital, Nanjing Medical University, China. Written informed consent was obtained from the patient.

Results

We presented a 56-year-old man with acute respiratory syndrome, who was diagnosed with COP based on the intra-alveolar fibroinflammatory buds (Masson's bodies) in the pathology of bronchoscopy biopsy. Oral prednisone induced dramatic symptomatic improvement and complete resolution of previous lung lesions. After a stable course of no respiratory symptom for 2 months, he was referred to the neurology department with complaints of fluctuating generalized muscle weakness. He was diagnosed with triple-seronegative MG based on fluctuating weakness, neostigmine test-positivity and RNS-positivity. After three-month treatment with pyridostigmine in combination with tacrolimus, the symptoms gradually improved and he achieved minimal symptom expression.

Conclusions

This case highlights the rare coexistence of triple-seronegative MG and pathology-proven COP. However, a causal association between COP and MG cannot be explicitly ascertained. In future, more data are needed to clarify the relationship, taking into account the limited number of cases reported with this coexistence of the diseases.

Minimal effective dose of maintenance steroid therapy for relapse of cryptogenic organizing pneumonia

BACKGROUND

Long-term maintenance steroid therapy (MST) is frequently required for repeated relapses of cryptogenic organizing pneumonia (COP); however, the optimal minimal dose has not been clarified. Therefore, this study evaluated the minimal MST dose required to prevent repeated relapses and identify relapse predictors.

METHODS

We retrospectively reviewed the medical records of patients with steroid-treated COP and compared background factors between the non-relapse and relapse groups. We also reviewed the treatment course in the relapse group and determined the minimal effective steroid dose based on the MST dose at relapse events and the current relapse prevention dose.

RESULTS

In total, 48 patients were identified, including 27 (56%) in the non-relapse group and 21 (44%) in the relapse group. Receiver operating characteristic curve analysis identified prednisolone at 5 mg/day as the optimal cut-off value in the relapse group. Relapse-free time in patients with relapsed COP was significantly longer in the MST dose ≥5 mg/day group than in the <5 mg/day group (log-rank P = 0.003; hazard ratio, 0.19; 95% confidence interval [CI], 0.04-0.60). Multivariate logistic regression analysis demonstrated that a high eosinophil percentage and CD4/CD8 ratio in bronchoalveolar lavage fluid (BALF) were predictors of relapse (odds ratio [OR], 1.12; 95% CI, 1.02-1.23; P = 0.008 and OR, 3.87; 95% CI, 1.29-11.6; P = 0.008, respectively).

CONCLUSIONS

Our results indicate that 5 mg/day of prednisolone may be the minimal effective dose for preventing repeated relapses, and a high BALF eosinophil percentage and CD4/CD8 ratio are independent predictors of relapse.

Imaging Features of Idiopathic Interstitial Lung Diseases

Idiopathic interstitial pneumonias (IIPs) are a group of diffuse parenchymal lung diseases of unclear etiology and are distinguished from diffuse parenchymal lung diseases of known cause, such as connective tissue disease-related interstitial lung diseases or hypersensitivity pneumonitis by history, physical exam, imaging, serologic testing, and, when necessary, histopathology. The 2013 American Thoracic Society (ATS)/European Respiratory Society (ERS) guidelines are the most widely accepted classification of IIPs and include the following diagnoses: idiopathic pulmonary fibrosis, idiopathic nonspecific interstitial pneumonia, cryptogenic organizing pneumonia, acute interstitial pneumonia, idiopathic lymphocytic interstitial pneumonia, idiopathic pleuro-parenchymal fibroelastosis, respiratory bronchiolitis-interstitial lung disease, and desquamative interstitial pneumonia. The gold standard for diagnosis of IIP involves multidisciplinary discussion among pulmonologists, radiologists, and pathologists. The focus of this review will be to discuss the imaging features of the most common IIPs and the role of multidisciplinary discussion as the gold standard for diagnosis.

Clinical features of relapsed connective tissue disease-associated organizing pneumonia

BACKGROUND

Organizing pneumonia (OP) is recognized as a nonspecific lung injury response characterized histopathologically by the presence of intra-alveolar buds of granulation tissue. Most OP patients show excellent responses to corticosteroids, but relapse is frequently seen when corticosteroids are tapered or discontinued. Although several factors associated with relapse have been reported in cryptogenic OP (COP), the clinical features and risk factors associated with relapse in connective tissue disease-associated OP (CTD-OP) have yet to be fully understood.

METHODS

We retrospectively reviewed data on 47 CTD-OP patients. We investigated the frequency of relapse and compared the clinical data between CTD-OP with and without relapse to clarify the risk factors for relapse.

RESULTS

Eleven (23.4%) CTD-OP patients had relapses of OP during the study. In the multivariate analysis, no CTD treatment at OP diagnosis [O.R. 11.920, p = 0.012] and partial remission after steroid treatment [O.R. 35.944, p = 0.045] were independent risk factors for relapse. Among rheumatoid arthritis-associated OP (RA-OP) patients, partial remission after steroid treatment [O.R. 16.151, p = 0.047] and age at OP diagnosis [O.R. 0.899, p = 0.045] were independent risk factors for relapse. Most of the relapsed OP patients who were on no medication at OP diagnosis later developed CTD.

CONCLUSION

CTD-OP patients with residual disease on HRCT after treatment and who had OP diagnosis preceding CTD diagnosis were more likely to have an OP relapse. During the clinical course of relapsed OP patients, it is necessary to pay attention to the onset of CTD.

Cocaine-Induced Steroid Resistant Organising Pneumonia in a Young Male: The Lows of Getting High

Organizing pneumonia (OP) is a diffuse parenchymal lung disease occurring due to injury to the alveoli leading to typical histopathological features. Infections, connective tissue disorders, and medications are common aetiologies of OP. Cocaine-induced OP is uncommon. The patient had a fever and sore throat for two days corresponding to crack inhalation, followed by breathlessness that rapidly progressed to acute hypoxemic respiratory failure within one week. Radiology showed bilateral consolidation and ground glass opacities but did not respond to empiric treatment with antibiotics. After a multidisciplinary discussion, he was provisionally diagnosed as OP and treated with an intravenous methylprednisolone pulse dosage followed by oral prednisolone. OP was confirmed by surgical lung biopsy with the detection of Masson bodies. In view of progressive respiratory failure, steroid-resistant OP was diagnosed, and rituximab was administered as a second-line agent, but unfortunately, succumbed to respiratory failure. OP should be considered a differential in patients with consolidation who are non-responsive to initial conventional treatment. Multidisciplinary discussion and early lung biopsy to initiate immunosuppressants in the inflammatory stage of OP are emphasized for a possible better response.

Environmental and occupational bronchiolitis obliterans: new reality

Patients diagnosed with environmental/occupational bronchiolitis obliterans (BO) over the last 2 decades often present with an indolent evolution of respiratory symptoms without a history of high-level, acute exposure to airborne toxins. Exertional dyspnea is the most common symptom and standard clinical and radiographic evaluation can be non-diagnostic. Lung biopsies often reveal pathological abnormalities affecting all distal lung compartments. These modern cases of BO typically exhibit the constrictive bronchiolitis phenotype of small airway remodeling, along with lymphocytic inflammation. In addition, hypertensive-type remodeling of intrapulmonary vasculature, diffuse fibroelastosis of alveolar tissue, and fibrous thickening of visceral pleura are frequently present. The diagnosis of environmental/occupational BO should be considered in patients who present with subacute onset of exertional dyspnea and a history compatible with prolonged or recurrent exposure to environmental toxins. Important areas for future studies include development of less invasive diagnostic approaches and testing of novel agents for disease prevention and treatment.

Optical coherence tomography angiography characteristics of retinochoroidal and optic nerve head microcirculation in cryptogenic organizing pneumonia

BACKGROUND

To assess retinochoroidal and optic nerve head microcirculation alterations in cryptogenic organizing pneumonia.

METHODS

Thirty cryptogenic organizing pneumonia patients in the resolution phase (group 1, 30 right eyes) and 33 healthy subjects (group 2, 33 right eyes) were compared. Patients had 40 mg/day corticosteroids for 8-10 days, and a pulmonary function test, which revealed only minimally restrictive ventilation features. After gathering demographic data, a comprehensive ophthalmological exam and optical coherence tomography angiography were performed three months following maximum disease resolution with corticosteroid therapy RESULTS: Groups 1 and 2 had mean ages of 54.37±14.87 and 49.61±12.36 years, respectively (P = 0.171). Despite the lack of statistical significance, superficial and deep capillary plexus vessel densities in all macular regions were lower in group 1, as were foveal avascular zone parameters (P>0.05). However, the outer retinal and choriocapillaris flows increased significantly in group 1, especially in select areas (P<0.001, for both). There were no significant differences in whole image (P = 0.346), inside disk (P = 0.438), or peripapillary (P = 0.185) optic nerve head vessel densities between the two groups; however, nasal (P<0.001) and inferior quadrant (P = 0.006) vessel densities differed significantly. Global retinal nerve fiber layer thickness did not differ significantly between groups 1 and 2 (112.83±14.71 versus 111.45±12.74 µm, respectively; P = 0.692). Group 1, however, had significantly higher superior, nasal, and inferior quadrant, and significantly lower temporal quadrant retinal nerve fiber layer thickness (P<0.001, for all).

CONCLUSIONS

Concerning the impact of probable cryptogenic organizing pneumonia-induced hypoxia on ocular tissues, optical coherence tomography angiography assessments of retinochoroidal and optic nerve head microcirculation could be employed as a biomarker for cerebral microcirculation.

Severe cryptogenic bronchiolitis: Case report

Bronchiolitis obliterans (BO) is a progressive fibrotic process that predominantly affects the small airways and is identified as constrictive bronchiolitis by pathologists. It is commonly associated with allogeneic hematopoietic stem cell transplant (HSCT), lung transplant, exposure to inhaled toxins, post-infectious processes, autoimmune diseases, and sometimes, no known cause. In the latter case, it is referred to as cryptogenic bronchiolitis obliterans. A 52-year-old Hispanic man with a medical history of hypertension, diabetes mellitus, and coronary artery disease was referred to the pulmonary department due to experiencing dyspnea on exertion, intermittent dry cough, and progressive limitation of activities of daily living. Spirometry revealed severe obstructive changes, and chest high-resolution computed tomography showed ground-glass opacities with nodular infiltrates in the upper lobes, leading to a presumptive diagnosis of hypersensitivity pneumonitis. The patient underwent a lung surgical biopsy of the right upper and lower lobes, which revealed extensive constrictive bronchiolitis. Due to the patient's worsening general condition, bilateral lung transplantation succeeded without any further complications. Following the transplantation, the patient showed good recovery and functional improvement. Bronchiolitis obliterans, or constrictive bronchiolitis, has a variable natural history. It is associated with a higher risk of mortality in allogenic HSCT. When BO is secondary to inhalation of toxic gases, it is usually nonprogressive and limited to toxin exposure. Autoimmune diseases or cryptogenic bronchiolitis are rare and have a heterogeneous clinical course. To make a proper diagnosis, clinical history, radiologic and histologic findings must be considered.

CT Approach to Lung Injury

Diffuse alveolar damage (DAD), which represents the pathologic changes seen after acute lung injury, is caused by damage to all three layers of the alveolar wall and can ultimately result in alveolar collapse with loss of the normal pulmonary architecture. DAD has an acute phase that predominantly manifests as airspace disease at CT owing to filling of the alveoli with cells, plasma fluids, and hyaline membranes. DAD then evolves into a heterogeneous organizing phase, with mixed airspace and interstitial disease characterized by volume loss, architectural distortion, fibrosis, and parenchymal loss. Patients with DAD have a severe clinical course and typically require prolonged mechanical ventilation, which may result in ventilator-induced lung injury. In those patients who survive DAD, the lungs will remodel over time, but most will have residual findings at chest CT. Organizing pneumonia (OP) is a descriptive term for a histologic pattern characterized by intra-alveolar fibroblast plugs. The significance and pathogenesis of OP are controversial. Some authors regard it as part of a spectrum of acute lung injury, while others consider it a marker of acute or subacute lung injury. At CT, OP manifests with various forms of airspace disease that are most commonly bilateral and relatively homogeneous in appearance at individual time points. Patients with OP most often have a mild clinical course, although some may have residual findings at CT. In patients with DAD and OP, imaging findings can be combined with clinical information to suggest the diagnosis in many cases, with biopsy reserved for difficult cases with atypical findings or clinical manifestations. To best participate in the multidisciplinary approach to patients with lung injury, radiologists must not only recognize these entities but also describe them with consistent and meaningful terminology, examples of which are emphasized in the article. © RSNA, 2023 See the invited commentary by Kligerman et al in this issue. Quiz questions for this article are available in the supplemental material.

Glucocorticoid pulse therapy in an elderly patient with post-COVID-19 organizing pneumonia: A case report

BACKGROUND

Pulmonary fibrosis often occurs as a sequel of coronavirus disease 2019 (COVID-19); however, in some cases, it can rapidly progress, similar to the acute exacerbation of interstitial lung disease. Glucocorticoids are the standard treatment for severe COVID-19 pneumonia requiring oxygen supply; however, the post-COVID-19 efficacy of high-dose steroid therapy remains unclear. Here, we presented a case of an 81-year-old man who developed acute respiratory failure after COVID-19 and was treated with glucocorticoid pulse therapy.

CASE SUMMARY

An 81-year-old man with no respiratory symptoms was admitted due to a diabetic foot. He had been previously treated for COVID-19 pneumonia six weeks prior. However, upon admission, he suddenly complained of dyspnea and required a high-flow oxygen supply. Initial simple chest radiography and computed tomography (CT) revealed diffuse ground-glass opacities and consolidation in both lungs. However, repeated sputum tests did not identify any infectious pathogens, and initial broad-spectrum antibiotic therapy did not result in any clinical improvement with the patient having an increasing oxygen demand. The patient was diagnosed with post-COVID-19 organizing pneumonia. Thus, we initiated glucocorticoid pulse therapy of 500 mg for three days followed by a tapered dose on hospital day (HD) 9. After three days of pulse treatment, the patient's oxygen demand decreased. The patient was subsequently discharged on HD 41, and chest radiography and CT scans have almost normalized nine months after discharge.

CONCLUSION

Glucocorticoid pulse therapy may be considered when the usual glucocorticoid dose is ineffective for patients with COVID-19 sequelae.

Cryptogenic Organizing Pneumonia and Idiopathic Eosinophilic Pneumonia: A Case Report of Clinically Identical Entities

Cryptogenic organizing pneumonia (COP) and idiopathic eosinophilic pneumonia (IEP) are two forms of diffuse interstitial lung diseases (ILD) that lead to a rapid respiratory decline in young patients. Both conditions presented with similar clinical and radiological findings, making a clinical diagnosis challenging. They are both considered diagnoses of exclusion, and the treatment for both conditions is high-dose corticosteroids, leading to a quick recovery. Pathological specimens are often required prior to initiating appropriate treatment, leading to significant delays in appropriate therapy and a poorer prognosis. In this case report, we suggest that clinical pearls can be used to establish either diagnosis earlier, which leads to earlier treatment and better outcomes. Our patient presented with an acute respiratory distress syndrome (ARDS) picture, bilateral interstitial infiltrates with peripheral predominance, eosinophilia, and a negative initial infectious and cardiac workup. Based on these findings, we had a high initial suspicion that either COP or IEP was present. Our patient had a bronchoscopy done and was promptly started on steroid therapy soon after, which led to rapid clinical improvement. Pathological specimens were inconclusive, but the patient continued to improve, thereby confirming the presence of either form of ILD. The patient was subsequently discharged home with oxygen and recommended to follow up with a pulmonologist for further outpatient testing and management.

An unexpected diagnosis of a 57-year-old women with migratory pulmonary infiltrates

A 57-year-old female presented with sudden shortness of breath and migratory pulmonary infiltrates on imaging, which corresponds with a diagnosis of cryptogenic organizing pneumonia. Initial treatment with corticosteroids showed only mild improvement during follow-up. BAL was performed and revealed diffuse alveolar hemorrhage. Immune testing showed positive P-ANCA with positive MPO, leading to a diagnosis of microscopic polyangiitis.