Answer: Bacterial endocarditis, atrial myxoma, and multiple cholesterol embolization syndrome have many of the same presenting signs and symptoms as systemic vasculitis. Thrombotic states, including hypercoagulability (as occurs with phospholipid antibodies), cryoglobulinemia, hemoglobinopathies, thrombotic thrombocytopenic purpura, or hemolytic uremic syndrome, may be confused with vasculitis. Drugs that induce vasospasm (cocaine, ergots, and other sympathomimetics) sometimes [...]

Answer: Soft tissue calcification detected by plain roentgenograms can be an important clue in the diagnosis of rheumatic conditions. A partial list includes: Calcific tendinitis Chondrocalcinosis Dermatomyositis Diabetes Ehlers-Danlos syndrome Neoplasia Neuropathic arthropathy Parathyroid disease Renal osteodystrophy Sarcoidosis Scleroderma Trauma Reference: Resnick D, Niwayama G: Soft tissues. In Resnick D, Niwayama G (eds): Diagnosis of [...]

Answer: Ankylosing spondylitis Reactive arthritis Psoriasis Inflammatory bowel disease Kawasaki disease Juvenile RA Sjögren’s syndrome Sarcoidosis Behçet’s disease Relapsing polychondritis Reference: Rosenbaum JT: Uveitis. In McCarty DJ (ed): Arthritis and Allied Conditions, 11th ed. Philadelphia, Lea & Febiger, 1989, pp 1563-1568.

Answer: Separation of the nail plate, usually beginning at the free margin and progressing proximally, is called onychodystrophy. Both systemic and local processes are associated with this finding, including hypo- and hyperthyroidism, pregnancy, syphilis, trauma (particularly clawing), psoriasis, SLE, atopic dermatitis, eczema, use of solvents (including nail hardeners), and mycotic, pyogenic, or viral infections. Reference: [...]

Answer: The straight leg raising test is designed to reproduce back pain secondary to nerve root compression. The leg is lifted by the calcaneus with the knee remaining straight. Bringing the heel across the other leg (called cross-table straight leg raising) may increase the sensitivity of this maneuver. Reference:  Sheon RP, et al (eds): Soft [...]

Answer: The primary component of joint fluid is hyaluronic acid. It is quite viscous and makes a “string” when expressed from a syringe as a single drop. Dilute acetic acid causes hyaluronate and protein to clump and fall to the bottom of a test tube (producing the famous “mucin clot”). Inflammatory mediators cause fragmentation of [...]

Answer: Gram stain and bacterial culture may confirm the presence of an infective agent. In the right clinical setting, similar procedures for mycobacteria or fungi are important. A white blood cell (WBC) count with differential is one of the best indicators of the degree of inflammation. Evaluation for crystals by polarized light microscopy may confirm [...]