Overview of monoarthritis in adults
- Simon M Helfgott, MD
Simon M Helfgott, MD
- Associate Professor of Medicine
- Harvard Medical School
The symptom of joint pain is associated with a variety of disorders. The initial step in evaluating the patient with monarticular pain is confirming that the source of the pain is the joint, rather than the nearby soft tissues. Arthritis is likely when the pain is aggravated by movement, is associated with loss of motion, and is accompanied by swelling and/or erythema. However, deep-seated articulations, such as the shoulder, hip, and sacroiliac joints, may not exhibit the latter two findings. If joint motion is preserved but tenderness can be elicited by palpation over one of the regional bursae, tendons, or ligaments, it is unlikely that the joint pain is due to arthritis. (See "Bursitis: An overview of clinical manifestations, diagnosis, and management" and "Overview of soft tissue rheumatic disorders".)
In addition to a careful history and physical examination, arthrocentesis and synovial fluid analysis is often required in making a definitive diagnosis. The initial evaluation and differential diagnosis of an adult presenting with a single sore joint is presented here (table 1). The approach to a patient with pain in specific joints is addressed elsewhere (see "General evaluation of the adult with knee pain" and "Evaluation of the patient with shoulder complaints" and "Evaluation of elbow pain in adults" and "History and examination of the adult with hand pain" and "Evaluation of the adult with hip pain"). The evaluation of a child with joint pain is also presented separately. (See "Evaluation of the child with joint pain and/or swelling".)
The major causes of acute monoarticular symptoms include trauma, infection, crystal-induced arthritis, osteoarthritis, systemic rheumatic diseases, and mechanical derangement (table 1) [1-3]. The differential diagnosis of an acute monoarthritis can also overlap with that of polyarthritis since virtually any polyarthritis disorder can initially present as a monoarthritis (table 2). (See "Evaluation of the adult with polyarticular pain".)
Trauma — Trauma sufficient to cause joint pain and swelling is typically recollected by the patient. However, if a loss of consciousness (eg, due to a drug overdose, motor vehicle accident, alcohol ingestion, or concussion) has occurred, the patient may not remember injuring the joint. Thus, if there is a history of joint injury or loss of consciousness, initial immobilization and imaging studies to rule out a fracture or dislocation are appropriately obtained before proceeding with a thorough physical examination of the joint.
Intraarticular fractures, dislocations, ligamentous sprains and complete tears (eg, of the anterior or posterior cruciate ligaments of the knee), and meniscal damage are often associated with hemarthrosis. Intraarticular bleeding may also be related to coagulopathies, anticoagulation therapy, intraarticular tumors, and crystal disease, among other causes. (See "Hemarthrosis".)
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- - Gonococcal infection
- - Nongonococcal bacterial infections
- - Mycobacterial and fungal infection
- - Lyme disease
- Crystal-induced arthritis
- Systemic disorders
- - Symptoms suggestive of a musculoskeletal emergency
- - Joint symptoms
- - Systemic symptoms
- - Patient characteristics
- Physical examination
- Imaging studies
- - Radiographs
- - Ultrasonography
- - Computed tomography
- - Magnetic resonance imaging
- Joint aspiration
- - Interpretation of synovial fluid analysis
- Laboratory studies
- Synovial biopsy
- INFORMATION FOR PATIENTS