Reactive Arthritis (Clinical)
Overview Definition Reactive arthritis (ReA) is an autoimmune, post-infectious, seronegative spondyloarthritis. Mnemonic The seronegative arthropathies can be remembered as “PAIR.” Epidemiology[1–4,19] Etiology[1–4,13–15,17] Clinical Presentation Articular manifestations Onset is acute, within 1–4 weeks of an inciting infection.[1,3,15] Peripheral arthritis:[2–4,11–13,15] Enthesopathy:[2–4,12,15] Tendonitis and periostitis:[2–4,12,15] Dactylitis:[2,3,12,15] Sacroiliitis:[2,3,12,15] Extra-articular manifestations Ocular:[1–4,11–13,15] Genitourinary:[1–4,11–13,15] Mucocutaneous:[1–4,11–13,15] GI:[1–4,12] Cardiac:[1–4,12,13,15] Clinical triad[11,15] This classic […]
Polyarteritis Nodosa
Overview Definition Polyarteritis nodosa (PAN) is a systemic, primarily medium-vessel vasculitis characterized by necrotizing inflammatory lesions. This condition eventually results in microaneurysms, which lead to bleeding, thrombosis, organ ischemia, and infarction. Epidemiology Etiology Pathophysiology Clinical Presentation Patients with PAN typically present with multisystem involvement and systemic signs and symptoms. However, there is also a skin-limited […]
Fibromyalgia
Overview Epidemiology Etiology While the cause is unknown, the following environmental triggers have been associated with the onset of fibromyalgia. Pathophysiology Clinical Presentation Diagnosis History and physical exam Fibromyalgia is a chronic syndrome; therefore, diagnosis determination is recommended over multiple visits after sequential observation and physical exams. A history evaluation should include: A physical examination […]
Goodpasture Syndrome
Epidemiology and Etiology Epidemiology Rare: < 2 cases per million individuals Accounts for: Approximately 15% of all cases of crescentic glomerulonephritis 1%–5% of all cases of glomerulonephritis Bimodal age distribution: 3rd decade 6th–7th decades Sex: Slight male predominance in the younger age group Female predominance in the older age group Etiology Potential genetic predisposition: HLA-DR15 (previously […]
Chronic Shoulder Pain
Overview Epidemiology Etiology Anatomy of the shoulder joint Mnemonic: SITS: Supraspinatus, Infraspinatus, Teres minor, Subscapularis Evaluation of Chronic Shoulder Pain History Physical exam Imaging Imaging studies might be helpful to support or confirm the diagnosis: Important Causes and Management of Chronic or Subacute Shoulder Pain Rotator cuff pathology Other shoulder pathology Biceps tendinopathy or rupture: […]
Ehlers-Danlos Syndrome
Overview Definition Ehlers-Danlos syndrome (EDS) is a group of 13 inherited connective tissue disorders of collagen processing or synthesis. The syndrome is clinically heterogeneous and can affect the skin, joints, blood vessels, and other tissues and is characterized by the following: Epidemiology Etiology and pathophysiology Classification This list of classifications is not exhaustive; it includes […]
Myasthenia Gravis
Overview Definition Myasthenia gravis (MG) is a chronic autoimmune disorder in which antibodies attack the acetylcholine receptor (AChR) complex at the neuromuscular junction. Epidemiology Etiology Classification and Pathophysiology Classification There are 2 main clinical forms of MG: In addition, rarer forms of MG exist that primarily affect the pediatric population: Myasthenia gravis may also be […]
Septic Arthritis
Epidemiology and Etiology Epidemiology Etiology The majority of septic arthritis infections are monomicrobial. Common organisms include: Risk factors Table: Most common organisms in septic arthritis, based on some notable underlying risk factors Risk factors Infectious agents No specific risk factor S. aureus Prosthetic joint replacement S. aureus (particularly MRSA) S. epidermidis (creates biofilms on prosthetics) […]
Sarcoidosis
Overview Definition Sarcoidosis is a multisystem inflammatory disease characterized by the formation of noncaseating granulomas that are most likely caused by a cell-mediated immune reaction of unknown etiology. Pulmonary sarcoidosis is a restrictive interstitial lung disease with granuloma formation in the: Extrapulmonary sarcoidosis is characterized by granuloma formation in: Sarcoidosis may be acute or chronic: […]
Duchenne Muscular Dystrophy
Overview Epidemiology Duchenne muscular dystrophy (DMD) is the most common and most severe muscular dystrophy. Affects boys Incidence: 1 in 3,500 boys worldwide Prevalence: 63 cases per million Etiology Duchenne muscular dystrophy results from a mutation in the dystrophin (DMD) gene on the short arm of the X chromosome. DMD is the largest known protein-coding […]