Pulmonary manifestations of Goodpasture's syndrome. Antiglomerular basement membrane disease and related disorders

Acute Respiratory Failure in Autoimmune Rheumatic Diseases: A Review

This review examines respiratory complications in autoimmune rheumatic diseases within intensive care units (ICUs). The respiratory system, primarily affected in diseases like rheumatoid arthritis, systemic lupus erythematosus, and scleroderma, often leads to respiratory failure. Common manifestations include alveolar hemorrhage, interstitial fibrosis, and acute respiratory distress syndrome. Early recognition and treatment of non-malignant conditions are crucial to prevent rapid disease progression, with ICU mortality rates ranging from 30% to 60%. Delayed immunosuppressive or antimicrobial therapy may result in organ system failure. Collaboration with rheumatic specialists is vital for accurate diagnosis and immediate intervention. Mortality rates for rheumatic diseases in the ICU surpass those of other conditions, underscoring the need for specialized care and proactive management. The review emphasizes comprehensive assessments, distinguishing disease-related complications from underlying issues, and the importance of vigilant monitoring to enhance patient outcomes.

Pathogenesis of Pulmonary Manifestations in ANCA-Associated Vasculitis and Goodpasture Syndrome

Pulmonary manifestations of vasculitis are associated with significant morbidity and mortality in affected individuals. They result from a complex interplay between immune dysregulation, which leads to vascular inflammation and tissue damage. This review explored the underlying pathogenesis of pulmonary involvement in vasculitis, encompassing various forms such as granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), eosinophilic granulomatosis with polyangiitis (EGPA), and anti-GBM disease. Mechanisms involving ANCA and anti-GBM autoantibodies, neutrophil activation, and neutrophil extracellular trap (NETs) formation are discussed, along with the role of the complement system in inducing pulmonary injury. Furthermore, the impact of genetic predisposition and environmental factors on disease susceptibility and severity was considered, and the current treatment options were presented. Understanding the mechanisms involved in the pathogenesis of pulmonary vasculitis is crucial for developing targeted therapies and improving clinical outcomes in affected individuals.

Myeloperoxidase and associated lung disease: Review of the latest developments

Myeloperoxidase (MPO) anti-neutrophil cytoplasmic antibodies (ANCA) are often detected in association with a variety of lung pathologies, the most common being interstitial lung disease (ILD). A growing cohort of patients are being diagnosed with MPO-ANCA in the context of ILD without ANCA-associated vasculitis. Clinically and radiologically, there is little to differentiate this cohort from MPO-ANCA-negative ILD patients; however, the pathophysiology is likely different and different treatments are likely required. We present here a brief summary of the proposed pathophysiology of MPO-ANCA-positive ILD, and a more detailed review of the latest evidence on management, including monitoring for development of ANCA-associated vasculitis, immunosuppression, anti-fibrotics, and novel agents that have yet to be trialled in human experiments.

Immunoadsorption in Anti-GBM Glomerulonephritis: Case Report in a Child and Literature Review

Antiglomerular basement membrane glomerulonephritis (anti-GBM GN) is a rare autoimmune disease that is characterized by rapidly progressive glomerulonephritis that may be associated with pulmonary hemorrhage. Anti-GBM GN is caused by autoantibodies (classically type G immunoglobulin) directed against the α3 subunit of type IV collagen. Without any appropriate treatment, the disease is generally fulminant, and patient and kidney survival is poor. The current guidelines recommend the use of plasma exchanges and immunosuppressive drugs. Immunoadsorption (IA) can remove pathogenic IgGs from the circulation and do not require plasma infusions, contrary to plasma exchanges. IA has seldom been used in adult patients with good tolerance and efficiency. We report herein the first pediatric case successfully treated with IA combined with immunosuppressive drugs in a 7-year-old girl who presented acute kidney injury (estimated glomerular filtration rate 38 mL/minute/1.73 m²). A kidney biopsy revealed numerous >80% glomerular crescents and linear IgG deposits along the glomerular basement membrane. Ten IA sessions led to rapid and sustained clearance of autoantibodies and improvement of kidney function until 21 months after onset (glomerular filtration rate 87 mL/minute/1.73 m²). No adverse effect was noted. This report adds to the growing body of evidence suggesting IA as a therapeutic alternative to plasma exchanges in anti-GBM GN. The other 27 published pediatric cases of anti-GBM GN are reviewed.

Alveolar hemorrhage in anti-basement membrane antibody disease: a series of 28 cases

Anti-basement membrane antibody disease is a rare disorder characterized by the presence of autoantibodies binding to the alveolar and glomerular basement membranes, and mediating both alveolar hemorrhage and acute glomerulonephritis. We retrospectively analyzed 28 cases of anti-basement membrane antibody disease with alveolar hemorrhage proven by bronchoalveolar lavage. The median age of patients at diagnosis was 23 years; 68% were male, 89% were active smokers, and 36% were exposed to some other inhaled agent. At diagnosis, 46% had predominant pulmonary involvement with normal initial serum creatinine. Lung function tests disclosed a restrictive ventilatory defect in 28% (n = 11) and hypoxemia (moderate in 29% and severe in 29%, n = 21). Carbon monoxide transfer factor was elevated in only 25% (n = 12). Bronchoalveolar lavage was more sensitive than any other criterion for detecting alveolar hemorrhage. After onset of treatment, new hemoptysis or transient worsening of hypoxemia occurred in 29% but did not affect pulmonary outcome. In contrast, worsening of renal function occurred in 33% and adversely affected renal outcome. At last follow-up (median, 2.6 yr; n = 24), all patients were alive and a complete cure was achieved in 50%. Long-term dialysis or renal transplantation was required in 42%, and 8% had mild chronic renal insufficiency. Last chest X-ray was normal in all cases, and no patient had respiratory insufficiency. All patients with predominant pulmonary involvement at presentation maintained independent renal function. In summary, this cohort was characterized by frequent exposure to tobacco smoking and other inhaled agents, and a constantly favorable pulmonary outcome contrasting with frequent chronic renal failure. Renal outcome was excellent in the subgroup of patients with predominant pulmonary involvement.

Pulmonary-renal vasculitic disorders: differential diagnosis and management

Pulmonary-renal syndrome (PRS) is a combination of diffuse pulmonary hemorrhage and glomerulonephritis. Pulmonary-renal syndrome is not a single entity and is caused by a variety of conditions, including Goodpasturés syndrome associated with autoantibodies to the glomerular and alveolar basement membranes, various forms of primary systemic vasculitis associated with serum positivity for antineutrophil cytoplasmic antibodies (ANCA), cryoglobulinemia, systemic lupus erythematosus, systemic sclerosis, antiphospholipid syndrome, environmental factors, and drugs. The majority of cases of PRS are associated with ANCAs. The antigen target in Goodpasturés syndrome is the alpha-3 chain of type IV collagen. The antigen target in PRS associated with systemic vasculitis is proteinase-3 and myeloperoxidase. Pulmonary-renal syndrome has been observed from the first to the ninth decade of life. The widespread adoption of serologic testing performed in an appropriate clinical context hopefully will limit diagnostic delay. The goals of treatment in PRS are to remove the circulating antibodies, to stop further production of autoantibodies, and to remove any antigen that stimulates antibody production. Treatment is based on plasmapheresis, steroids, and cyclophosphamide; however, infections are frequent contributors to death, and less toxic alternatives may improve outcome and prognosis resulting in a long-term survival. The degree of renal function and the percent of crescents on renal biopsy are better predictors of outcome. Renal transplantation can be safely carried out in PRS.

16. Immunologic lung disease

This review summarizes the recent advances regarding pathogenesis, diagnosis, and treatment of immunological diseases of the lung. Rather than attempt a comprehensive analysis, we have focused on selected diseases that are of particular relevance to the practicing physician, and the material has been organized according to the dominant immunologic mechanisms underlying the disease. Because of the redundancy that characterizes the mammalian immune repertoire, this system of classification inevitably produces overlap but facilitates acquisition of what is otherwise a disparate collection of facts. The principal lung immunologic mechanisms are most broadly classified as innate or adaptive immune processes. Innate immunity includes neutrophils and complement that are important in diseases, such as pneumonia and the acute respiratory distress syndrome. Adaptive immunity involves T and B cells capable of recognizing discrete antigens. T(H)1- and T(H)2-dependent adaptive immune responses underlie some of the most common and important of lung diseases, including tuberculosis and asthma, respectively. Other important immunopathologic processes include granulomatous inflammation that characterizes sarcoidosis and Churg-Strauss vasculitis, and autoimmunity, which is characteristic of antiglomerular basement membrane disease and others.

Mice deficient for cytosolic thymidine kinase gene develop fatal kidney disease

The thymidine kinase (Tk) gene codes for a cytosolic protein involved in the pyrimidine nucleotide salvage pathway. A functional Tk gene is not necessary for cells in culture, and a naturally occurring Tk deficient phenotype has not been described in humans or animal models. In order to determine the biological significance of the Tk gene, we created Tk(-/-) knockout (KO) mice through homologous recombination in mouse embryonic stem cells. Tk KO mice have shortened life spans compared with their wild-type or Tk heterozygous (HET) siblings. All Tk KO mice develop sclerosis of kidney glomeruli and die before one year of age of kidney failure. Among other changes in KO animals, the most consistent is a switch from exclusively mucous secretion to predominantly serous secretion in the sublingual salivary gland. HET parents can produce KO mice at a frequency approaching Mendelian inheritance. Other observations in KO animals include an elevated level of serum thymidine, a significant decrease in the cloning efficiency of splenic lymphocytes, an increase in the frequency of hypoxanthine guanine phosphoribosyl transferase gene mutant lymphocytes, and histological alteration in the lymphoid structure of the spleen. In addition, KO animals sporadically exhibit inflammation of the arteries, which taken together with the lymphocyte and spleen abnormalities, suggest an abnormal immune system. Alterations in Tk KO mice indicate that the pyrimidine nucleotide salvage pathway is indispensable in vivo.

Small-vessel diseases of the lung: CT-pathologic correlates

Diseases that primarily affect the small vessels of the lung are difficult to diagnose. Many conditions are characterized by involvement of small pulmonary vessels, and pathologically they can be conveniently divided into occluding and inflammatory types. The former, typified by chronic pulmonary thromboembolism and primary pulmonary hypertension, are relatively cryptic in terms of imaging. In contrast, inflammatory vasculitides, which often cause pulmonary hemorrhage and infarction, result in florid but nonspecific radiographic abnormalities. The spectrum of thin-section computed tomographic abnormalities encountered in the inflammatory vasculitides is wide: For example, in Wegener granulomatosis the pattern ranges from cavitating nodules to lobar consolidation to ground-glass opacity. This review highlights some of the less obvious imaging manifestations of occlusive and inflammatory diseases of the small pulmonary vessels.

Rheumatologic diseases in the intensive care unit: epidemiology, clinical approach, management, and outcome

Patients with systemic rheumatic diseases may be admitted to the ICU because of worsening of or development of a new manifestation of the rheumatic disease, infections caused by immunosuppression, or adverse effects of drugs used to treat rheumatic diseases. Sometimes an unrelated, acute disorder may become life threatening because of the underlying rheumatic disorder. Rheumatoid arthritis is the most common rheumatic disease seen in ICU patients, followed by systemic lupus erythematosus and scleroderma. These three conditions together account for up to 75% of rheumatic cases admitted to the ICU. The respiratory system is the organ system most commonly affected in the acute process, followed by the renal, gastrointestinal, and nervous systems. More than 50% of admissions result from infections, and 25% to 35% result from exacerbation of the underlying rheumatic condition. In about 20% of patients, the rheumatic disorder may be diagnosed for the first time in the ICU. An aggressive approach should be pursued to establish the diagnosis of either disease exacerbation or infection. Delay in instituting appropriate immunosuppressive or antimicrobial therapy may result in multiple organ system failure and a poor outcome. The mortality rate in patients with rheumatic disease exceeds that predicted by the APACHE II or SAPS II scores and is higher than that in nonrheumatologic ICU admissions. The mortality may exceed 50% in patients admitted for infection; the prognosis is comparatively better for patients with exacerbations of disease activity. Renal failure, coma, and acute abdomen are predictors of poor outcome. Early recognition of abdominal complications requiring surgical intervention may help reduce mortality.

Rapidly progressive antineutrophil cytoplasm antibodies associated with pulmonary-renal syndrome in a 10-year-old girl

CONTEXT

The term pulmonary-renal syndrome has been used frequently to describe the clinical manifestations of a great number of diseases in which pulmonary hemorrhage and glomerulonephritis coexist. The classic example of this type of vasculitis is Goodpasturés syndrome, a term used to describe the association of pulmonary hemorrhage, glomerulonephritis and the presence of circulating antiglomerular basement membrane antibodies (anti-GBM). Among the several types of systemic vasculitides that can present clinical manifestations of the pulmonary-renal syndrome, we focus the discussion on two types more frequently associated with antineutrophil cytoplasm antibodies (ANCA), microscopic polyangiitis and Wegener's granulomatosis, concerning a 10 year old girl with clinical signs and symptoms of pulmonary-renal syndrome, with positive ANCA and rapidly progressive evolution.

CASE REPORT

We describe the case of a 10-year-old girl referred to our hospital for evaluation of profound anemia detected in a primary health center. Five days before entry she had experienced malaise, pallor and began to cough up blood-tinged sputum that was at first attributed to dental bleeding. She was admitted to the infirmary with hemoglobin = 4 mg/dL, hematocrit = 14 %, platelets = 260,000, white blood cells = 8300, 74 % segmented, 4 % eosinophils, 19 % lymphocytes and 3 % monocytes. Radiographs of the chest revealed bilateral diffuse interstitial alveolar infiltrates. There was progressive worsening of cough and respiratory distress during the admission day, when she began to cough up large quantities of blood and hematuria was noted. There was rapid and progressive loss of renal function and massive lung hemorrhage. The antineutrophil cytoplasm antibody (ANCA) test with antigen specificity for myeloperoxidase (anti-MPO) was positive and the circulating anti-GBM showed an indeterminate result.