Makindo Medical Notes"One small step for man, one large step for Makindo" |
![]() |
---|---|
Download all this content in the Apps now Android App and Apple iPhone/Pad App | |
MEDICAL DISCLAIMER: The contents are under continuing development and improvements and despite all efforts may contain errors of omission or fact. This is not to be used for the assessment, diagnosis, or management of patients. It should not be regarded as medical advice by healthcare workers or laypeople. It is for educational purposes only. Please adhere to your local protocols. Use the BNF for drug information. If you are unwell please seek urgent healthcare advice. If you do not accept this then please do not use the website. Makindo Ltd. |
Related Subjects: |Monoarticular arthritis |Polyarticular arthritis |Rheumatoid arthritis |Gout |Pseudogout |Septic Arthritis |Systemic Lupus Erythematosus (SLE) |Enteropathic Spondyloarthritis |Reactive Arthritis
**Acute monoarthritis requires urgent investigation and treatment.** The key investigation is synovial fluid aspiration for Gram stain, culture, and crystal analysis (to diagnose gout or pseudogout). *Always consult orthopaedics before aspirating a prosthetic joint.*
Causes | Comments |
---|---|
Osteoarthritis | May affect a single joint. Painful but rarely presents with acute inflammation. Typically seen in weight-bearing joints (e.g., knees, hips). X-rays may show joint space narrowing, osteophytes, and subchondral sclerosis. |
Acute Gout | Onset over hours. Severe pain, typically in the 1st MTP joint (podagra), but can affect other joints. Red, hot, and swollen. Aspirate joint if diagnosis is uncertain to exclude sepsis. Examine for negatively birefringent monosodium urate crystals under polarized light. Associated with hyperuricaemia, recent dehydration, or surgery. |
Acute Pseudogout | Onset over hours. Severe pain, commonly in the wrist, knee, or shoulder. Red, hot, and swollen. Aspirate joint if diagnosis is uncertain to exclude sepsis. Examine for positively birefringent calcium pyrophosphate crystals. Associated with older age, hyperparathyroidism, or haemochromatosis. |
Septic Joint | Acute pain developing over 1-2 days. Severe, red, hot, and swollen. Requires urgent aspiration and treatment. Synovial fluid typically shows high WBC count (>50,000/mm³), low glucose, and positive Gram stain/culture. Common pathogens include Staphylococcus aureus and Streptococcus species. |
Disseminated Gonococcal Infection | Common in young, sexually active adults. Single or multiple joints affected. Acute pain developing over 1-2 days. Severe, red, hot, and swollen. Often accompanied by fever, tenosynovitis, and dermatitis. Synovial fluid culture may be negative, but genital, rectal, or throat cultures may identify Neisseria gonorrhoeae. |
Reactive Arthritis | Follows recent GI (e.g., Salmonella, Campylobacter) or STD (e.g., Chlamydia) infection. Acute pain, often in the lower limbs. Aspirate if effusion is present, though fluid is usually sterile. Associated with HLA-B27 and extra-articular features (e.g., conjunctivitis, urethritis). |
Trauma/Haemarthrosis | Recent injury with swelling due to bleeding into the joint. Exclude fracture with plain X-rays. Aspirate if needed. Common in patients on anticoagulants or with bleeding disorders (e.g., haemophilia). |
Rheumatoid Arthritis | Can occasionally flare in a single joint. Typically presents with synovitis and tenderness on squeezing. Not red or hot, unlike crystal arthropathies or sepsis. Synovial fluid shows inflammatory changes (elevated WBCs). |
Seronegative Spondyloarthropathies | Includes psoriasis, inflammatory bowel disease, and ankylosing spondylitis (associated with HLA-B27). May present with asymmetric oligoarthritis, enthesitis, or axial involvement. Extra-articular features (e.g., uveitis, skin/nail changes) are common. |
Prosthetic Joint | Always seek orthopaedic review before attempting aspiration. Infection is a major concern and may present with pain, loosening of the prosthesis, or systemic symptoms. Synovial fluid analysis and imaging (e.g., MRI, bone scan) are crucial. |
Erythema Nodosum | Presents with tender, erythematous nodules over the lower legs. Associated with TB, sarcoidosis, or recent streptococcal infection. Consider CXR for bilateral hilar lymphadenopathy (BHL). Joint involvement is typically mild and self-limiting. |
Other Causes | Consider less common causes such as Lyme disease (tick exposure, erythema migrans), viral arthritis (e.g., parvovirus B19, hepatitis B/C), or systemic diseases (e.g., SLE, vasculitis). |