Connective Tissue Disease – Top USMLE Diseases

Systemic lupus erythematosus (SLE) is a chronic autoimmune, inflammatory condition that causes immune-complex deposition in organs, resulting in systemic manifestations. Women, particularly those of African American descent, are more commonly affected. The clinical presentation can vary greatly. Notable clinical features include malar rash, nondestructive arthritis, lupus nephritis, serositis, cytopenia, thromboembolic disease, seizures, and/or psychosis. Diagnosis is based on clinical criteria, and includes tests to determine ANAs, SLE-specific antibodies, and specific clinical findings. The goal of management is to control symptoms and prevent organ damage, using corticosteroids, hydroxychloroquine, and immunosuppressants.

Rheumatoid arthritis (RA) is a symmetric, inflammatory polyarthritis and chronic, progressive, autoimmune disorder. Presentation occurs most commonly in middle-aged women with joint swelling, pain, and morning stiffness (often in the hands). Systemic inflammation can lead to extraarticular manifestations such as rheumatoid nodules, interstitial lung disease, Felty syndrome, and pericarditis. Prolonged and severe disease can lead to irreversible joint deformities. Diagnosis is based on strong clinical suspicion and confirmed by the presence of rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) antibodies, and characteristic imaging. Management involves long-term disease-modifying antirheumatic drugs (DMARDs), biologic agents, and physical therapy. Glucocorticoids and nonsteroidal antiinflammatory drugs (NSAIDs) are the treatment of choice for acute exacerbation.

Sjögren syndrome (SS) is an autoimmune, inflammatory condition where glandular tissues, such as the salivary and lacrimal glands, are infiltrated by lymphocytes, resulting in decreased tear and saliva production. The disease mainly affects middle-aged women, and is associated with other autoimmune conditions. Patients may experience symptoms and complications related to dry eyes and mouth. There is a wide range of extraglandular manifestations, including Raynaud's phenomenon, neuropathy, and cutaneous vasculitis. Patients are also at an increased risk of developing non-Hodgkin's lymphoma. Diagnosis is based on the presence of symptoms, and is validated by the clinical examination, serologic studies, or salivary gland biopsy. A multidisciplinary approach is needed to manage patients and targets symptomatic relief, with immunosuppressive therapy reserved for severe symptoms.

Diseases of the lung are classified as obstructive lung diseases like chronic obstructive pulmonary disease or cystic fibrosis, and restrictive lung diseases.