Rare association between giant-cell aortitis and giant-cell aortic valvulitis

Giant cell arteritis (GCA) is a type of chronic vasculitis that affects medium and large-caliber arteries, frequently related to aortic involvement and, consequently, to aneurysm formation. However, associated valvulitis with giant cells is uncommon. We describe the case of a 50-year-old female patient with aortic aneurysm and valvular insufficiency, whose anatomopathological examination revealed giant-cell aortic valvulitis associated with giant cell aortitis.

Understanding yellow fever-associated myocardial injury: an autopsy study

BACKGROUND

Yellow fever (YF) is a viral hemorrhagic fever, endemic in parts of South America and Africa. There is scarce evidence about the pathogenesis of the myocardial injury. The objective of this study is to evaluate the cardiac pathology in fatal cases of YF.

METHODS

This retrospective autopsy study included cases from the São Paulo (Brazil) epidemic of 2017-2019. We reviewed medical records and performed cardiac tissue histopathological evaluation, electron microscopy, immunohistochemical assays, RT-qPCR for YF virus (YFV)-RNA, and proteomics analysis on inflammatory and endothelial biomarkers.

FINDINGS

Seventy-three confirmed YF cases with a median age of 48 (34-60) years were included. We observed myocardial fibrosis in 68 (93.2%) patients; cardiomyocyte hypertrophy in 68 (93.2%); endothelial alterations in 67 (91.8%); fiber necrosis in 50 (68.5%); viral myocarditis in 9 (12.3%); and secondary myocarditis in 5 (6.8%). Four out of five patients with 17DD vaccine-associated viscerotropic disease presented with myocarditis. The cardiac conduction system showed edema, hemorrhages and endothelial fibrinoid necrosis. Immunohistochemistry detected CD68-positive inflammatory interstitial cells and YFV antigens in endothelial and inflammatory cells. YFV-RNA was detected positive in 95.7% of the cardiac samples. The proteomics analysis demonstrated that YF patients had higher levels of multiple inflammatory and endothelial biomarkers in comparison to cardiovascular controls, and higher levels of interferon gamma-induced protein 10 (IP-10) in comparison to sepsis (p = 0.01) and cardiovascular controls (p < 0.001) in Dunn test.

INTERPRETATION

Myocardial injury is frequent in severe YF, due to multifactorial mechanisms, including direct YFV-mediated damage, endothelial cell injury, and inflammatory response, with a possible prominent role for IP-10.

FUNDING

This study was funded by Fundação de Amparo à Pesquisa do Estado de São Paulo, Bill and Melinda Gates Foundation, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.

Superior caval vein syndrome and cardiac inflammatory myofibroblastic tumour in an infant

The inflammatory myofibroblastic tumour, although very rare, must be considered in the differential diagnosis of intracardiac masses in children as it has systemic implications. We present a case of an infant whose diagnosis was suspected on clinical basis and echocardiogram, but the anatomopathological analysis with immunohistochemical study was essential for the conclusion of the histological type and orientation of the clinical follow-up.

Case Report: The Challenge for Diagnosis of Myocarditis and Transplant Rejection After COVID Infection in a Heart-Transplanted Adolescent

Patients who have undergone organ transplantation are immunosuppressed hosts, leaving them at a higher risk of infections. SARS-COV-2 has been shown to affect heart-transplanted patients. In this case report, we present the case of a 14-year-old heart transplant recipient who developed signs and symptoms of heart failure, along with fatigue, after a COVID-19 infection. An endomyocardial biopsy was performed to diagnose rejection and to evaluate whether this was myocarditis due to SARS-COV-2. The biopsy showed intense acute cellular rejection (3R) and antibody rejection PAMR1 H+ but was negative for the SARS-CoV-2 virus. The patient received organ rejection therapy with high-dose methylprednisolone and human immunoglobulin. After treatment, her heart function recovered, with biopsy investigations showing a lower level of cellular rejection (1R).

Partial pericardiectomy for refractory acute tuberculous pericarditis: A case report

INTRODUCTION

Tuberculosis is an infectious disease that usually manifests in the lungs but can also affect other organs, including the cardiovascular system. In this article, we present a rare case of purulent pericarditis caused by Mycobacterium tuberculosis.

PRESENTATION OF CASE

A 67-year-old man was admitted to the emergency department with a large pericardial effusion with evidence of cardiac tamponade caused by acute pericarditis. The patient underwent surgical pericardial drainage, and a total volume of 500 mL of purulent fluid was collected with a positive culture for Mycobacterium tuberculosis. Despite antituberculous drugs, the patient presented with clinical worsening and recurrence of large pericardial effusion. Therefore, he was submitted to a second intervention by full median sternotomy to drain the pericardial effusion and perform a surgical pericardial debridement associated with a partial pericardiectomy. After the procedure, he improved clinically and was discharged after 24 days of hospitalization.

DISCUSSION

Pericardiectomy is recommended for patients with refractory tuberculous pericarditis after four to eight weeks of antituberculous treatment. We decided not to wait that long to perform an open surgical partial pericardiectomy and debridement with a median sternotomy approach. We believe that this more aggressive surgical approach would be more efficient to combat the infection, which was causing progressive deterioration of patient's clinical condition and early recurrence of significant pericardial effusion.

CONCLUSION

Open partial pericardiectomy with surgical debridement could be an efficient approach for treatment of a refractory acute tuberculous pericarditis.

Cardiovascular findings in Williams-Beuren Syndrome: Experience of a single center with 127 cases

Williams-Beuren syndrome (WBS) is a rare, microdeletion syndrome characterized by facial dysmorphisms, intellectual disability, a friendly personality, cardiovascular and other abnormalities. Cardiovascular defects (CVD) are among the most prevalent characteristics in WBS, being supravalvular aortic stenosis (SVAS) the most frequent, followed by peripheral pulmonary stenosis (PPS). A comprehensive retrospective review of medical records of 127 patients with molecular diagnosis of WBS, in a period of 20 years, was done to evaluate the incidence, the natural history of cardiovascular disease, and the need for surgical intervention, including heart transplantation (HT). A total of 94/127 patients presented with CVD. Of these 94 patients, 50% presented with SVAS and 22.3% needed heart surgery and/or cardiac catheterization including one that required HT due to severe SVAS-related heart failure at 19 years of age. The patient died in the postoperative period due to infectious complications. Cardiovascular problems are the major cause of sudden death in patients with WBS, who have a significantly higher mortality risk associated with surgical interventions. There is a higher risk for anesthesia-related adverse events and for major adverse cardiac events following surgery. End-stage heart failure due to myocardial ischemia has been described in WBS patients and it is important to consider that HT can become their only viable option. To our knowledge, the case mentioned here is the first HT reported in an adolescent with WBS. HT can be a viable therapeutic option in WBS patients with adequate evaluation, planning, and a multidisciplinary team to provide the required perioperative care and follow-up.

Diagnostic challenges in systemic amyloidosis: a case report with clinical and laboratorial pitfalls

Currently, there is growing evidence in the literature warning of misdiagnosis involving amyloidosis and chronic inflammatory demyelinating polyneuropathy (CIDP). Although inducing clinical manifestations outside the peripheral nervous system, light chain and transthyretin amyloidosis may initially present with peripheral neuropathy, which can be indistinguishable from CIDP, leading to a delay in the correct diagnosis. Besides, the precise identification of the amyloid subtype is often challenging. This case report exemplifies clinical and laboratory pitfalls in diagnosing amyloidosis and subtyping amyloid, exposing the patient to potentially harmful procedures.

3D Echocardiography for Rheumatic Heart Disease Analysis: Ready for Prime Time

Rheumatic heart disease (RHD) remains to be a very important health issue worldwide, mainly in underdeveloped countries. It continues to be a leading cause of morbidity and mortality throughout developing countries. RHD is a delayed non-suppurative immunologically mediated inflammatory response to the throat infection caused by a hemolytic streptococcus from the A group (Streptococcus pyogenes). RHD keeps position 1 as the most common cardiovascular disease in young people aged <25 years considering all the continents. The disease can lead to valvular cardiac lesions as well as to carditis. Rheumatic fever valvular injuries lead most commonly to the fusion and thickening of the edges of the cusps and to the fusion, thickening, and shortening of the chordae and ultimately to calcification of the valves. Valvular commissures can also be deeply compromised, leading to severe stenosis. Atrial and ventricular remodeling is also common following rheumatic infection. Mixed valvular lesions are more common than isolated valvular disorders. Echocardiography is the most relevant imaging technique not only to provide diagnostic information but also to enable prognostic data. Further, it presents a very important role for the correction of complications after surgical repair of rheumatic heart valvulopathies. Three-dimensional (3D) echocardiography provides additional anatomical and morphofunctional information of utmost importance for patients presenting rheumatic valvopathies. Accordingly, three-dimensional echocardiography is ready for routine use in patients with RHD presenting with valvular abnormalities.

Progressive dyspnea and a right atrial mass in an 80-year-old man

Hepatocellular carcinoma (HCC) is among the five most frequent causes of cancer death worldwide, according to the WHO. The disease is related to alcohol abuse, viral infections, and other causes of cirrhosis, and unfortunately, in some developed countries, the incidence shows an increasing trend. Although the diagnosis of the HCC often relies upon the context of a chronic hepatopathy, some cases may present a silent course, and the initial symptoms ensue when the disease is in an advanced stage with no chance for any therapeutic attempt. The clinical picture of the HCC is varied, and unexpected forms may surprise the clinician. One of the unusual presentations of the HCC is shock by the blockage of the venous return to the right atrium by the inferior vena cava infiltration. Herein we present a case of an old patient who sought medical care complaining of dyspnea. The clinical workup disclosed a right thorax pleural effusion and imaging exams depicted a mass in the right hepatic lobe, invasion of the inferior vena cava (IVC) and the right atrium (RA). During the attempts of clinical investigation, the patient passed away. The autopsy disclosed an HCC involving the right hepatic lobe, with the invasion of the IVC and the RA. The authors highlight the importance of recognizing the bizarre presentation of not so rare diseases.

Scimitar sign in the absence of anomalous pulmonary venous drainage: a case report

Background

Scimitar syndrome consists of anomalous pulmonary vein drainage to the inferior vena cava. Its name derives from the image this anomalous pulmonary vein creates on a chest radiograph. We describe a case of normal venous pulmonary vein drainage that also presented the scimitar sign due to an aorto-collateral vessel.

Case summary

A 15-month-old girl presented with mild dyspnoea and fever. Control chest X-ray showed an image of cardiac dextroposition, hypoplastic right lung, and the ‘scimitar sign’. Although the transthoracic echocardiogram confirmed the initial suspicion of anomalous pulmonary venous drainage, the computed tomography (CT) scan showed normal right pulmonary veins connected to the left atrium and revealed that an aorto-collateral vessel caused the scimitar sign.

Discussion

Although the patient had several typical alterations of the scimitar syndrome, the pulmonary venous connection was normal, and the scimitar sign was due to an aorto-collateral vessel. It might be difficult to describe venous pulmonary connections on the basis of echocardiography, so an angio CT scan proved to be a valuable tool in this scenario.

Histologic assessment of the intestinal wall following duodenal mucosal resurfacing (DMR): a new procedure for the treatment of insulin-resistant metabolic disease

Background and study aims Minimally invasive procedures that replicate aspects of bariatric surgery with more favorable safety and tolerability offer an attractive alternative in management of metabolic disease. Duodenal mucosal resurfacing (DMR), an endoscopic procedure using hydrothermal ablation, is designed to remove surface epithelium to allow subsequent epithelial regeneration and a reset to a more insulin-sensitive state.

Materials and methods DMR was performed on a healthy pig under general anethesia, approximating the procedure designed for use in humans. Immediately post-DMR, analysis of the histological landscape was conducted in distinct duodenal areas that received ablation treatment.

Results DMR submucosal lift and hydrothermal ablation elicited disruption of villous tips and partial disruption of the crypt base with no damage to deeper tissue. Excessive ablation (purposeful double ablation exposure) did incur damage to the underlying muscle layer.

Conclusion Our results confirmed that DMR elicits superficial ablation of duodenal villi and crypts. Defining the cellular consequences of ablation and regeneration of the epithelium will aid our understanding of how and why DMR affects metabolic homeostasis.

Traumatic injury to the internal carotid artery by the hyoid bone: a rare cause of ischemic stroke

Central nervous system (CNS) ischemic events, besides being a common and devastating disease, are accompanied by severe disability and other morbidities. The cause of such events is not always that simple to diagnose, and among the young, a broad spectrum of possibilities should be considered. We present the case of a young man who presented two episodes of CNS ischemia with a 1 year gap between them, which occurred in the same situation while he was walking and carrying a heavy backpack. The second event first presented as a transient ischemic attack followed by a stroke the day after. The diagnostic work-up showed an indentation of the greater cornu of the hyoid bone over the internal carotid artery, which injured the media and intimal layers. At the arterial injury site, a micro thrombus was found, which explained the source of the embolic event to the CNS. The patient was operated on, and the procedure included the resection of the posterior horn of the hyoid bone, the resection of the injured segment of the internal carotid artery followed by carotid–carotid bypass with the great saphenous vein. The postoperative period and the recovery were uneventful as was the 5-month follow-up. We call attention to this unusual cause of stroke and present other cases reported in the literature.

Occurrence of mesothelial/monocytic incidental cardiac excrescences in material from open-heart procedures: case reports and literature review

Mesothelial/monocytic incidental cardiac excrescences (MICE) are unusual findings during the histological analysis of material from the pericardium, mediastinum, or other tissues collected in open-heart surgery. Despite their somewhat worrisome histological appearance, they show a benign clinical course, and further treatment is virtually never necessary. Hence, the importance of recognizing the entity relays in its differential diagnosis, as an unaware medical pathologist may misinterpret it for a malignant neoplasm. Other mesothelial and histiocytic proliferative lesions, sharing very close histological morphology and immunohistochemistry features with MICE, have been described in sites other than the heart or the mediastinum. This similarity has led to the proposal of the common denomination "histiocytosis with raisinoid nuclei." We report three cases from the pathology archives of the Heart Institute of São Paulo University (Incor/HC-FMUSP), diagnosed as "mesothelial/monocytic incidental cardiac excrescence," with immunohistochemical documentation, and provide a literature review of this entity.

Descriptive Analysis of In Vitro Cutting of Swine Mitral Cusps: Comparison of High-Power Laser and Scalpel Blade Cutting Techniques

BACKGROUND AND OBJECTIVES

The most common injury to the heart valve with rheumatic involvement is mitral stenosis, which is the reason for a big number of cardiac operations in Brazil. Commissurotomy is the traditional technique that is still widely used for this condition, although late postoperative restenosis is concerning. This study's purpose was to compare the histological findings of porcine cusp mitral valves treated in vitro with commissurotomy with a scalpel blade to those treated with high-power laser (HPL) cutting, using appropriate staining techniques.

MATERIALS AND METHODS

Five mitral valves from healthy swine were randomly divided into two groups: Cusp group (G1), cut with a scalpel blade (n = 5), and Cusp group (G2), cut with a laser (n = 5). G2 cusps were treated using a diode laser (λ = 980 nm, power = 9.0 W, time = 12 sec, irradiance = 5625 W/cm², and energy = 108 J).

RESULTS

In G1, no histological change was observed in tissue. A hyaline basophilic aspect was focally observed in G2, along with a dark red color on the edges and areas of lower birefringence, when stained with hematoxylin-eosin, Masson's trichrome, and Sirius red. Further, the mean distances from the cutting edge in cusps submitted to laser application and stained with Masson's trichrome and Sirius red were 416.7 and 778.6 μm, respectively, never overcoming 1 mm in length.

CONCLUSIONS

Thermal changes were unique in the group submitted to HPL and not observed in the cusp group cut with a scalpel blade. The mean distance of the cusps' collagen injury from the cutting edge was less than 1 mm with laser treatment. Additional studies are needed to establish the histological evolution of the laser cutting and to answer whether laser cutting may avoid valvular restenosis better than blade cutting.

The use of a high-power laser on swine mitral valve chordae tendineae

Worldwide, rheumatic fever remains a significant cause of mitral valve insufficiency. It is responsible for approximately 90 % of early childhood valvular surgeries in Brazil. Elongated or flail chordae are frequently responsible and require surgical correction. The purpose of this study was to analyze and compare the histological tissues of the mitral valve chordae and the mechanical resistance generated by the chordae, both with and without the application of a high-power laser. Twenty normal porcine mitral valve chordae were measured and divided randomly into the following two groups: control group (not subjected to a high-power laser) and laser group (subjected to photonic irradiation). Laser surgery was performed under controlled conditions, using following parameters: λ = 980-nm wavelength, power = 3 W, and energy = 60 J. A mechanical test machine was used in combination with a subsequent histological study to measure chordae tensile properties. A histological analysis demonstrated a typical collagen bundle arrangement in the control group; however, under a particular reached temperature range (48), the collagen bundles assumed different arrangements in the laser group. Significant reductions in the chordae tendineae lengths and changes in their resistance in the laser group were observed, as these chordae exhibited less rigid fibers. The chordae tendineae of normal porcine valves subjected to a high-power laser exhibited its length reduction and less stiffness compared to the control group. A histological analysis of the laser treatment specimens demonstrated differences in collagen bundle spatial organization, following slight changes into tissue temperature.

Palliative Senning in the Treatment of Congenital Heart Disease with Severe Pulmonary Hypertension

Background

Transposition of the great arteries (TGA) is the most common cyanotic cardiopathy, with an incidence ranging between 0.2 and 0.4 per 1000 live births. Many patients not treated in the first few months of life may progress with severe pulmonary vascular disease. Treatment of these patients may include palliative surgery to redirect the flow at the atrial level.

Objective

Report our institutional experience with the palliative Senning procedure in children diagnosed with TGA and double outlet right ventricle with severe pulmonary vascular disease, and to evaluate the early and late clinical progression of the palliative Senning procedure.

Methods

Retrospective study based on the evaluation of medical records in the period of 1991 to 2014. Only patients without an indication for definitive surgical treatment of the cardiopathy due to elevated pulmonary pressure were included.

Results

After one year of follow-up there was a mean increase in arterial oxygen saturation from 62.1% to 92.5% and a mean decrease in hematocrit from 49.4% to 36.3%. Lung histological analysis was feasible in 16 patients. In 8 patients, pulmonary biopsy grades 3 and 4 were evidenced.

Conclusion

The palliative Senning procedure improved arterial oxygen saturation, reduced polycythemia, and provided a better quality of life for patients with TGA with ventricular septal defect, severe pulmonary hypertension, and poor prognosis.

Understanding the morphology of the specialized conduction tissues in congenitally malformed hearts

To repair congenital heart defects by means of open heart surgery, the surgeon needs guidance about the location and distribution of the specialized conduction tissues, in order to avoid their direct damage and consequent conduction disturbances. This review addresses the historical steps of the morphological study of the conduction system in different types of heart defects, providing updated information about the subject.

Classic form of hypoplastic left heart syndrome diagnosed post-natally: an autopsy report

Hypoplastic left heart syndrome (HLHS) is a congenital heart disease, which, despite the current improved knowledge about its management and surgical treatment, is still associated with high mortality, especially in the early neonatal period and before the second stage of reconstruction surgery. The low rate of prenatal diagnosis and delayed diagnostic suspicion results in unsuccessful therapeutic intervention, even though the real impact of early diagnosis and intervention on mortality and quality of life of patients is still uncertain. Fortunately, this syndrome of challenging treatment is not that frequent. It involves a spectrum of obstructions to the blood flow within the left heart and is characterized by an inappropriate size of the left ventricle associated with a wide variety of valvular dysfunctions. Treatment ranges from heart transplantation to palliative surgical procedures. The authors describe a case of a newborn with HLHS, whose diagnosis was made after birth because of early respiratory failure. Despite the use of prostaglandin the newborn died. An autopsy was performed and the anatomical findings were described.

Capillary hemangiomatosis like-lesions in lung biopsies from children with congenital heart defects

The morphological findings in the lung vessels of children with pulmonary arterial hypertension associated with uncorrected congenital cardiac shunts may be qualitatively and quantitatively assessed by lung biopsy in selected cases. Among 297 lung biopsies collected over a period of 11 years two cases were detected presenting the typical findings of pulmonary capillary hemangiomatosis, a rare disorder usually associated with pulmonary veno-occlusive disease. We report the clinical and histological findings and discuss about the impact of this unexpected and not-previously described associated lesion on the prognosis and on the therapeutic strategy in patients with pulmonary hypertension associated with congenital heart disease.

Aortic stenosis concomitant with microscopic polyangiitis: a challenge in medical reasoning and thinking

Microscopic polyangiitis (MPA) is part of the anti-neutrophil cytoplasmic antibodies (ANCA)-related vasculitis, which usually presents as renal pulmonary syndrome. It is defined as a pauci-immune necrotizing small vessel vasculitis, which usually affects the kidneys, followed by the lungs. It also presents systemic symptoms. The etiology of MPA is still unclear, but evidence reinforces the autoimmune mechanisms as the main etiopathogenic factor. Aortic valve stenosis (AS) is not an uncommon disease whose etiology varies according to geographical differences and the patient's age. The natural history of AS begins with a prolonged asymptomatic period, but when symptomatic, respiratory failure is one of its main clinical presentations. The authors present the case of a 55-year-old woman who was admitted with the diagnosis of renal failure, anemia, and a cardiac murmur. The patient had been recently diagnosed with pneumonia. During hospitalization, diagnostic workup disclosed a normal kidney size as well as parenchymal thickness. A renal biopsy was undertaken but the specimen was exiguous, showing 4 sclerotic glomeruli and 1 glomerulus with crescentic glomerulonephritis. The search for ANCA was positive. The investigation of the cardiac murmur disclosed AS. The patient, on hemodialysis, presented episodes of respiratory failure, which was interpreted as acute pulmonary edema, but a suspicion of ANCA-related pulmonary renal syndrome was raised. However, the aortic valve replacement was prioritized. While awaiting cardiac surgery, the patient died because of respiratory insufficiency. Autopsy findings concluded that MPA with pulmonary hemorrhage due to vasculitis was the immediate cause of death. Although AS was present at autopsy and classified as moderate/severe, this lesion was a bystander in the process of this patient's end of life, demonstrating the value of autopsy for medical learning and reasoning purposes.

Infective endocarditis with left to right intracardiac fistula due to Streptococcus anginosus - a rare complication caused by an even rarer bacterium

Although infective endocarditis (IE) has been described in reports dating from the Renaissance, the diagnosis still challenges and the outcome often surprises. In the course of time, diagnostic criteria have been updated and validated to reduce misdiagnosis. Some risk factors and epidemiology have shown dynamic changes since degenerative valvular disease became more predominant in developed countries, and the mean age of the affected population increased. Despite streptococci have been being well known as etiologic agents, some groups, although rare, have been increasingly reported (e.g., Streptococcus milleri.) Intracardiac complications of IE are common and have a worse prognosis, frequently requiring surgical treatment. We report a case of a middle-aged diabetic man who presented with prolonged fever, weight loss, and ultimately severe dyspnea. IE was diagnosed based on a new valvular regurgitation murmur, a positive blood culture for Streptococcus anginosus, an echocardiographic finding of an aortic valve vegetation, fever, and pulmonary thromboembolism. Despite an appropriate antibiotic regimen, the patient died. Autopsy findings showed vegetation attached to a bicuspid aortic valve with an associated septal abscess and left ventricle and aortic root fistula connecting with the pulmonary artery. A large thrombus was adherent to the pulmonary artery trunk and a pulmonary septic thromboemboli were also identified.

The echocardiography in the cardiovascular laboratory: a guide to research with animals

The feasibility and potential for the morphological and hemodynamic investigation of the heart has been increasing the use of the echocardiography in the research setting. Additionally, the development of new technologies, like the real time 3D echocardiography and speckle tracking, demands validation throughout experimental studies before being instituted in the clinical setting.

This paper aims to provide information concerning the particularities of the echocardiographic examination in quadruped mammals, targeting the experimental research.

Human hemorrhagic pulmonary leptospirosis: pathological findings and pathophysiological correlations

BACKGROUND

Leptospirosis is a re-emerging zoonosis with protean clinical manifestations. Recently, the importance of pulmonary hemorrhage as a lethal complication of this disease has been recognized. In the present study, five human necropsies of leptospirosis (Weil's syndrome) with extensive pulmonary manifestations were analysed, and the antibodies expressed in blood vessels and cells involved in ion and water transport were used, seeking to better understand the pathophysiology of the lung injury associated with this disease.

PRINCIPAL FINDINGS

Prominent vascular damage was present in the lung microcirculation, with decreased CD34 and preserved aquaporin 1 expression. At the periphery and even inside the extensive areas of edema and intraalveolar hemorrhage, enlarged, apparently hypertrophic type I pneumocytes (PI) were detected and interpreted as a non-specific attempt of clearence of the intraalveolar fluid, in which ionic transport, particularly of sodium, plays a predominant role, as suggested by the apparently increased ENaC and aquaporin 5 expression. Connexin 43 was present in most pneumocytes, and in the cytoplasm of the more preserved endothelial cells. The number of type II pneumocytes (PII) was slightly decreased when compared to normal lungs and those of patients with septicemia from other causes, a fact that may contribute to the progressively low PI count, resulting in deficient restoration after damage to the alveolar epithelial integrity and, consequently, a poor outcome of the pulmonary edema and hemorrhage.

CONCLUSIONS

Pathogenesis of lung injury in human leptospirosis was discussed, and the possibility of primary non-inflammatory vascular damage was considered, so far of undefinite etiopathogenesis, as the initial pathological manifestation of the disease.