Rheumatology Exam Review

Connective Tissue Disease and Associated Antibodies

Overview of Connective Tissue Diseases

  • Key Diseases: Includes various autoimmune conditions such as psoriatic arthritis, systemic lupus erythematosus (SLE), and scleroderma.

Use of Steroids in Connective Tissue Diseases

  • Contraindications:

    • Scleroderma:

    • No steroids should ever be used in patients with scleroderma.

    • Rationale: Using steroids can precipitate a renal crisis in systemic sclerosis.

  • Slide Reference: Emphasis on the prohibition of steroids highlighted in class slides.

Autoantibodies and Their Associations

  • Anti-Signal Recognition Particle Antibody:

    • Associated Condition: Cardiomyopathy, specifically restricted cardiomyopathy.

  • Drug-Induced Lupus:

    • Marker: Antihistone antibodies.

    • Offending Drugs:

    • Examples:

      • Procainamide

      • Quinidine

      • Hydralazine

    • Management: Stop the offending agent.

  • Systemic Lupus Erythematosus (SLE):

    • Autoantibodies: A, G, N.

    • Antibodies Associated with Renal Complications:

    • Anti-double stranded DNA: Indicates impending nephritis.

    • Management of Lupus Nephritis:

    • Importance of monitoring: Urinalysis, creatinine levels.

    • Treatment: Initiate biopsy procedures promptly.

Types of Nephritis in SLE

  • Type Classification:

    • Type I (Minimal Change Disease): Excellent prognosis, reversible with treatment.

    • Type II (Mesangial Nephritis): Generally reversible.

    • Type III (Focal Glomerulosclerosis): Higher risk of progression to renal failure.

    • Type IV (Diffuse Proliferative Glomerulonephritis): Poor prognosis, marked by glomerular scar tissue formation.

Treatments for Lupus Nephritis

  • Triple Therapy Regimen:

    • Components:

    • IV steroids

    • Mycophenolate mofetil (Cellcept)

    • Belimumab (biological therapy, first FDA approved for lupus in over 40 years)

  • Hydroxychloroquine (Plaquenil):

    • Purpose:

    • Primary therapy for lupus patients, reduces flares, miscarriages, and strokes.

Neonatal Lupus

  • Parameters of Concern:

    • Maternal antibodies (SSA/SSB) can cause complications in neonates.

    • Heart Risks: Congenital heart block and thrombocytopenia in infants

    • Management: Steroid treatment for mothers to mitigate fetal risks.

Antibodies in Various Conditions

  • Antinuclear Antibodies (ANA): General screening for autoimmune conditions.

  • Specific for SLE:

    • Anti-Smith (Anti-Sm): Highly specific for systemic lupus erythematosus.

Sarcoidosis and Related Concepts

  • Key Details:

    • Angiotensin-Converting Enzyme (ACE): Elevated levels in pulmonary sarcoidosis.

    • Prognosis:

    • Löfgren's Syndrome: Self-limiting; presents with bilateral hilar adenopathy, fever, flu-like symptoms.

    • Treatment: Early intervention with steroids and methotrexate improves outcomes.

Ankylosing Spondylitis and Inclusion Body Myositis

  • Ankylosing Spondylitis: Associated with HLA-B27, chronic inflammatory disorder affecting axial skeleton.

  • Inclusion Body Myositis: Characterized by muscle weakness, distal extremities affected, linked to anti-CN1A antibodies.

Antineutrophil Cytoplasmic Antibodies (ANCA) and Vasculitis

  • Types of ANCAs:

    • C-ANCA: Associated with Granulomatosis with polyangiitis (GPA), detectable anti-proteinase 3.

    • P-ANCA: Associated with Eosinophilic Granulomatosis with Polyangiitis (EGPA) and Microscopic Polyangiitis (MPA).

Diagnosis in Vasculitis

  • Importance of recognizing the clinical context when interpreting ANCA results.

Mixed Connective Tissue Disease (MCTD)

  • Definition: Overlap syndrome combining features of multiple connective tissue diseases.

  • Common Combinations: Typically involves lupus with Sjogren's syndrome or rheumatoid arthritis.

Anti-Phospholipid Syndrome

  • Key Antibodies:

    • Lupus Anticoagulant (LA): Major contributing factor to complications during pregnancy.

    • Treatments:

    • Baby aspirin for pregnant patients with LA or antiphospholipid antibodies.

    • Subcutaneous heparin for high-risk pregnancies, especially if prior clotting occurred.

Complications in Pregnancy

  • Preeclampsia:

    • Definition: Hypertension, proteinuria, and edema in pregnancy, typically occurring in the third trimester.

    • Management: Aspirin prophylaxis from the 12th week to improve outcomes.

Concluding Remarks on Testing and Treatment

  • Continuous Monitoring:

    • Importance of closely observing lab results and symptoms in patients with autoimmune conditions.

    • Remember to integrate clinical findings with laboratory data for accurate diagnosis and treatment planning.