Pulmonary infections in immunocompromised patients: the role of image-guided fine needle aspiration cytology

Part 1: Mucormycosis: Prevalence, Risk Factors, Clinical Features and Diagnosis

INTRODUCTION

Mucormycosis (MCR) is caused by filamentous molds within the Class Zygomycetes and Order Mucorales. Infections can result from inhalation of spores into the nares, oropharynx or lungs, ingestion of contaminated food or water, or inoculation into disrupted skin or wounds. In developed countries, MCR occurs primarily in severely immunocompromised hosts. In contrast, in developing/low income countries, most cases of MCR occur in persons with poorly controlled diabetes mellitus and some cases in immunocompetent subjects following trauma. Mucormycosis exhibits a propensity to invade blood vessels, leading to thrombosis and infarction of tissue. Mortality rates associated with invasive MCR are high and can exceed 90% with disseminated disease. Mucormycosis can be classified as one of six forms: (1) rhino-orbital-cerebral mucormycosis (ROCM); (2) pulmonary; (3) cutaneous; (4) gastrointestinal or renal (5); disseminated; (6) uncommon (focal) sites.

AREAS COVERED

The authors discuss the prevalence, risk factors and clinical features of mucormycosis.A literature search of mucormycosis was performed via PubMed (up to November 2022), using the key words: invasive fungal infections; mold; mucormycosis; Mucorales; Zyzomyces; Zygomycosis; Rhizopus, diagnosis.

EXPERT OPINION

Mucormycosis occurs primarily in severely immunocompromised hosts. Mucormycosis can progress rapidly, and delay in initiating treatment by even a few days worsens outcomes.

Insight into diagnosis of pleural tuberculosis with special focus on nucleic acid amplification tests

INTRODUCTION

Pleural tuberculosis (TB) is the archetype of extrapulmonary TB (EPTB), which mainly affects the pleural space and leads to exudative pleural effusion. Diagnosis of pleural TB is a difficult task predominantly due to atypical clinical presentations and sparse bacillary load in clinical specimens.

AREA COVERED

We reviewed the current literature on the globally existing conventional/latest modalities for diagnosing pleural TB. Bacteriological examination (smear/culture), tuberculin skin testing/interferon-γ release assays, biochemical testing, imaging and histopathological/cytological examination are the main modalities. Moreover, nucleic acid amplification tests (NAATs), i.e. loop-mediated isothermal amplification, PCR/multiplex-PCR, nested-PCR, real-time PCR and GeneXpert® MTB/RIF are being utilized. Currently, GeneXpert Ultra, Truenat MTB^TM, detection of circulating Mycobacterium tuberculosis (Mtb) cell-free DNA by NAATs, aptamer-linked immobilized sorbent assay and immuno-PCR (I-PCR) have also been exploited.

EXPERT OPINION

Routine tests are not adequate for effective pleural TB diagnosis. The latest molecular/immunological tests as discussed above, and the other tools, i.e. real-time I-PCR/nanoparticle-based I-PCR and identification of Mtb biomarkers within urinary/serum extracellular vesicles being utilized for pulmonary TB and other EPTB types may also be exploited to diagnose pleural TB. Reliable diagnosis and early therapy would reduce the serious complications associated with pleural TB, i.e. TB empyema, pleural fibrosis, etc.

Mucormycosis: risk factors, diagnosis, treatments, and challenges during COVID-19 pandemic

Mucormycosis is a deadly opportunistic disease caused by a group of fungus named mucormycetes. Fungal spores are normally present in the environment and the immune system of the body prevents them from causing disease in a healthy immunocompetent individual. But when the defense mechanism of the body is compromised such as in the patients of diabetes mellites, neustropenia, organ transplantation recipients, and other immune-compromised states, these fungal spores invade our defense mechanism easily causing a severe systemic infection with approximately 45-80% of case fatality. In the present scenario, during the COVID-19 pandemic, patients are on immunosuppressive drugs, glucocorticoids, thus are at high risk of mucormycosis. Patients with diabetes mellitus are further getting a high chance of infection. Usually, the spores gain entry through our respiratory tract affecting the lungs and paranasal sinuses. Besides, they can also enter through damage into the skin or through the gastrointestinal route. This review article presents the current statistics, the causes of this infection in the human body, and its diagnosis with available recent therapies through recent databases collected from several clinics and agencies. The diagnosis and identification of the infection were made possible through various latest medical techniques such as computed tomography scans, direct microscopic observations, MALDI-TOF mass spectrometry, serology, molecular assay, and histopathology. Mucormycosis is so uncommon, no randomized controlled treatment studies have been conducted. The newer triazoles, posaconazole (POSA) and isavuconazole (ISAV) (the active component of the prodrug isavuconazonium sulfate) may be beneficial in patients who are refractory to or intolerant of Liposomal Amphotericin B. but due to lack of early diagnosis and aggressive surgical debridement or excision, the mortality rate remains high. In the course of COVID-19 treatments, there must be more vigilance and alertness are required from clinicians to evaluate these invasive fungal infections.

Fine‐needle aspiration cytology diagnosis of aspergilloma – A case report

Fine‐needle aspiration cytology, a simple and inexpensive technique can aid in early diagnosis of aspergilloma. Here, we present a case of 55‐years‐old female with a past history of pulmonary tuberculosis and a right‐lung cavitary lesion, diagnosed as aspergilloma.

Coronavirus Disease 2019-Associated Mucormycosis Diagnosed by Fine-Needle Aspiration Cytology

The temporal association of mucormycosis with coronavirus disease 2019 (COVID-19) has been termed COVID-19-associated mucormycosis (CAM). Because of its poor prognosis, early diagnosis and treatment are crucial. Although tissue samples for culture and histological evaluation are the cornerstones of diagnosis, the role of fine-needle aspiration cytology (FNAC) and cytologic findings are also significant. Here, we report a case of mucormycosis in a COVID-19-positive 34-year-old male diagnosed by FNAC and confirmed by fungal culture. To our knowledge, this is possibly the first and only case report of CAM diagnosed by FNAC.

Role of fine-needle aspiration cytology in early diagnosis of fungal infections

BACKGROUND

Fine-needle aspiration (FNA) is an important tool for the diagnosis of infectious diseases. In this study, we assessed the efficacy of FNA cytology in early diagnosis of fungal infections.

METHODS

This was a retrospective study from January 2016 to August 2018. Electronic archives were searched for FNAs from superficial and deep lesions obtained from various sites with the diagnosis of fungal infection. Each case was evaluated for underlying predisposing conditions, FNA source, radiologic findings, culture, and serology results.

RESULTS

A total of 15 cases were identified from the following sites: lung (eight), cervical lymph nodes (four), soft tissue (two), and retroperitoneal lymph node (one). Predisposing conditions were found in 11 patients: HIV (five), malignancy (three), and post-transplant (three). Imaging impression was mostly malignancy vs infection. In all 15 cases, the diagnosis of fungal infection was done by FNA cytology. The presumptive genus specific diagnoses based on yeast morphology was given in 12 cases (five Histoplasma, four Cryptococcus, and three Coccidioides). The diagnosis of fungal infection was provided within 24 h in nine cases, four during onsite evaluation. Microbial cultures were confirmatory in seven cases, and five cases exhibited negative cultures with positive serology. Out of the 15 patients, 14 were discharged in fair condition, and one died with complications of heart graft failure.

CONCLUSION

FNA is a rapid and reliable method for early diagnosis of fungal infections, allowing a prompt and appropriate management, especially in immunocompromised patients. When onsite evaluation indicates infectious process, cultures can be timely done.

Chitotriosidase: a marker and modulator of lung disease

Chitotriosidase (CHIT1) is a highly conserved and regulated chitinase secreted by activated macrophages; it is a member of the 18-glycosylase family (GH18). CHIT1 is the most prominent chitinase in humans, can cleave chitin and participates in the body's immune response and is associated with inflammation, infection, tissue damage and remodelling processes. Recently, CHIT1 has been reported to be involved in the molecular pathogenesis of pulmonary fibrosis, bronchial asthma, COPD and pulmonary infections, shedding new light on the role of these proteins in lung pathophysiology. The potential roles of CHIT1 in lung diseases are reviewed in this article.

This is the first review of chitotriosidase in lung diseasehttp://bit.ly/2LpZUQI

Aspergillus fumigatus in a fine needle aspiration of a cavitary lung lesion

The diagnostic utility of fine needle aspiration cytology to detect a wide variety of opportunistic pulmonary infections in an immunocompromised host has been studied. Fine needle aspiration cytology techniques are safer, cost-effective and provide rapid results.

Challenges in the Diagnosis of Invasive Fungal Infections in Immunocompromised Hosts

Purpose of review

The expanding population of immunocompromised patients coupled with the recognition of a growing number of different species of fungi responsible for diseases in such hosts makes the diagnosis of invasive fungal infection (IFI) a challenging task. The recent advances and challenges in the diagnosis of IFI in the setting of immunocompromised hosts are reviewed. The advantages and limitations of histopathology and the role of culture-independent methods, such as those based on the use of nucleic acids applied to fresh and formalin-fixed, paraffin-embedded sections, besides culture- and non-culture-based diagnostic methods, to obtain a timely and correct diagnosis of IFI are highlighted.

Recent findings

The therapeutic implications of identifying the genus and species of the fungus present in the specimen with the molecular diagnostics applied to tissue specimens are reviewed. No method alone is efficient in correctly identifying fungi and it is essential to combine the traditional histochemical staining with molecular methods to achieve a rapid and genus-/species-specific diagnosis of IFI.

Summary

We review the recent findings and challenges in the hystopathologic diagnosis of IFI in the setting of immunocompromised hosts. Non method alone is efficient in correctly identify fungi and pathologists should combine classic staining with molecular methods to achieve a rapid and genus/species fungal diagnosis.

Rare Multidrug-Resistant Pulmonary Nocardiosis in AIDS

Nocardiosis is an opportunistic infection in patients with depressed cell-mediated immunity. Inhalation is the primary route for exposure via dust particles. Patients with acquired immune deficiency syndrome (AIDS) are at increased risk of disseminated disease. A challenge in the diagnosis of pulmonary nocardiosis is that it can mimic other pulmonary diseases. Nocardia farcinica tends to be a more virulent, multidrug-resistant strain with an increased tendency to disseminate. This report describes a 64-year-old man with AIDS found to have pulmonary nocardiosis that did not respond to standard antibiotic therapy. Further evaluation revealed the virulent, multidrug-resistant Nocardia farcinica species. Targeted antibiotic therapy was initiated, after which the patient had an improvement in pulmonary symptoms. It is important to suspect pulmonary nocardiosis in immunocompromised patients who fail to respond to standard antimicrobial therapy. Susceptibilities should be obtained so that appropriate therapy can be promptly initiated as Nocardia farcinica is highly resistant to multiple antimicrobials.

The Role of Transbronchial Lung Biopsy in Diagnosing Pulmonary Mucormycosis in a Critical Care Unit

Background

Pulmonary mucormycosis (PM) is an emerging infectious disease and a life-threatening infection with high mortality. The clinical outcomes of PM have not improved significantly over the last decade because early diagnosis of PM is difficult and antifungal agents show limited activity. We evaluated the clinical manifestations of PM in a Korean tertiary hospital and identified the role of transbronchial lung biopsy (TBLB) in diagnosing PM in patients admitted to an intensive care unit.

Methods

The medical records of adult patients (aged 16 years and older) who met the criteria for proven or probable PM in a Korean tertiary hospital were retrospectively reviewed from January 2003 to December 2013. The clinical features, computed tomographic findings, diagnostic methods, treatment, and outcomes in patients with PM were evaluated.

Results

Of the nine patients, four were male. The median age was 64 years (range, 12 to 73 years). PM was proven and probable in seven and two cases, respectively. Computed tomography findings of PM were unilateral involvement in eight cases (89%), consolidation in eight (89%), ground glass opacity in four (44%), and reverse halo sign in one (11%). Six of nine cases (67%) were diagnosed as PM from TBLB via portable bronchoscopy. There were no complications after TBLB. Mortality rate was 56% (five of nine cases).

Conclusions

TBLB can be an easy and useful technique for diagnosing PM in the intensive care unit.