CLASE TEÓRICA 7 - INMUNOPATOLOGÍA PARTE 2

Lupus and Its Complications

Causes of Death in Lupus

• Key causes include renal failure, intercurrent infections due to pancytopenia, central nervous system diseases from vasculitis and necrosis, heart failure, and respiratory failure.

Dermatological Manifestations

• Notable skin lesions include a butterfly-shaped erythema on the malar region, with photosensitivity exacerbated by ultraviolet rays. Pregnancy can trigger lupus flare-ups.

Histopathology Insights

• Skin histopathology shows diffuse lymphoid accumulations around blood vessels causing vasculitis. This may lead to fibrinoid necrosis and leukocyte migration.

• Renal pathology may present as total glomerulosclerosis or focal eosinophilic accumulations with hypercellularity of glomerular capillary walls due to immune complex deposits.

Immune Complexes in Lupus

• Immunofluorescence reveals a granular pattern indicative of immune complex deposition at the renal level. The basic lesion involves thickening of glomerular capillary walls leading to ischemic phenomena.

Mechanisms of Hypersensitivity

• Two hypersensitivity mechanisms are involved: Type 3 mediated by circulating immune complexes depositing in tissues, and Type 2 where antibodies bind to tissue-fixed antigens stimulating B lymphocytes for antibody production.

Pathophysiology of Autoimmune Disorders

Sjögren's Syndrome Overview

• Sjögren's syndrome leads to autoimmune destruction of lacrimal and salivary glands resulting in dry eyes (keratoconjunctivitis sicca) and dry mouth (xerostomia).

Histological Findings in Sjögren's Syndrome

• Histologically characterized by lymphocytic inflammation in salivary glands causing glandular parenchyma destruction, atrophy, fibrosis, and potential replacement with adipose tissue.

Increased Risk Factors

• Patients with Sjögren's syndrome have a higher predisposition for developing lymphoma compared to the general population due to chronic inflammation.

Scleroderma: An Autoimmune Condition

Characteristics of Scleroderma

• Scleroderma is marked by widespread inflammation and fibrosis affecting various organs. It involves both humoral and cellular immunity with elevated autoantibodies like ANA.

Clinical Manifestations

Overview of Dystrophic Calcification and Related Conditions

Dystrophic Calcification and Its Effects

• Discusses the phenomenon of diffuse dystrophic calcification in the body, highlighting its impact on peripheral blood vessels and skin color changes.

• Describes significant esophageal dysfunction due to fibrosis in organ walls, leading to severe dysphagia and nutritional disorders.

Fibrosis and Its Systemic Implications

• Explains how widespread fibrosis affects the digestive tract, particularly causing malabsorption syndromes linked to skeletal muscle issues like non-destructive synovitis and myositis.

• Details renal complications such as hyperplastic arteriosclerosis, marked wall thickening, malignant hypertension, and glomerulopathy.

Pulmonary and Cardiac Complications

• Highlights interstitial pulmonary fibrosis leading to honeycomb lung at terminal stages, alongside cardiac arrhythmias from conduction system alterations.

• Notes chronic pulmonary hypertension affecting right heart chambers due to fibrotic changes.

Skin Changes Associated with Fibrosis

• Identifies autoimmune conditions like polymyositis and dermatomyositis impacting striated muscles and skin through immune-mediated processes.

• Describes characteristic skin eruptions (heliotrope rash), muscle necrosis, replacement by fibrous tissue leading to functional loss.

Autoimmune Disorders Impacting Multiple Systems

• Discusses various autoimmune diseases including nodular polyarteritis and granulomatosis with systemic implications affecting respiratory systems.

• Examines thyroiditis as a prototype autoimmune disorder characterized by dense lymphocytic infiltration replacing gland architecture.

Immune Deficiencies Linked to Autoimmunity

• Outlines primary immunodeficiencies genetically determined (e.g., agammaglobulinemia), predisposing individuals to infections that are typically benign in healthy populations.