Gout and Monoarthritis
Acute monoarthritis has numerous causes, but most commonly is related to crystals (gout and pseudogout), trauma and infection. Early diagnosis is critical in order to identify and treat septic arthritis, which can lead to rapid joint destruction. Joint aspiration is the gold standard method of diagnosis. For many reasons, managing gout, both acutely and as a chronic disease, is challenging. Registrars need to develop a systematic approach to assessing monoarthritis, and be familiar with the management of gout and other crystal arthropathies.
TEACHING AND • Aetiology of acute monoarthritis LEARNING AREAS • Risk factors for gout and septic arthritis • Clinical features and stages of gout • Investigation of monoarthritis (bloods, imaging, synovial fluid analysis) • Joint aspiration techniques • Interpretation of synovial fluid analysis • Management of hyperuricaemia and gout (acute and chronic), including indications and targets for urate-lowering therapy • Adverse effects of medications for gout, including Steven-Johnson syndrome • Indications and pathway for referral
PRE- SESSION • Read the AAFP article - Diagnosing Acute Monoarthritis in Adults: A Practical Approach for the Family ACTIVITIES Physician
TEACHING TIPS • Monoarthritis may be the first symptom of an inflammatory polyarthritis AND TRAPS • Consider gonococcal infection in younger patients with monoarthritis • Fever may be absent in patients with septic arthritis, and present in gout • Fleeting monoarthritis suggests gonococcal arthritis or rheumatic fever • Osteoarthritis flares can mimic acute gout • Arthrocentesis is required in all patients with undiagnosed monoarthritis • Don’t rely on inflammatory markers to differentiate gout from a septic joint • Crystals can be present in a septic joint • Uric acid levels are often lowered in patients with acute gout, and may be normal • Investigate causes of secondary hyperuricaemia in younger patients • ‘Start low and go slow’ with allopurinol to reduce the risk of hypersensitivity • Prophylaxis when starting and adjusting urate-lowering therapy needs to continue for a number of months • Avoid diuretics in patients with gout • Low-dose aspirin prophylaxis for IHD has no significant effect on serum urate
RESOURCES Read • 2009 CMAJ article - Acute monoarthritis: What is the cause of my patient’s painful swollen joint? • 2016 Australian Prescriber article - The management of gout
Listen • Emergency Medicine Cases Podcast on Acute Monoarthritis
Watch • NEJM Arthrocentesis of the Knee video
FOLLOW UP/ • Undertake the clinical reasoning challenge and discuss with the supervisor EXTENSION • Undertake an audit of 5-10 patients presenting with acute monoarthritis and assess the approach to ACTIVITIES diagnosis and management Gout and Monoarthritis
Clinical Reasoning Challenge Harry Froome is a 48 year old self-employed businessman and a long term patient of the practice. He presents to you late one afternoon with a 24-hour history of pain and swelling in his left knee. He has a PMHx of depression and allergic rhinitis, and takes sertraline 50 mg/day and nasal corticosteroids.
QUESTION 1. What are the MOST IMPORTANT features on history? List up to SEVEN
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QUESTION 2. What is the MOST IMPORTANT initial investigation of this man? List ONE
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QUESTION 3. What are the MOST IMPORTANT next steps in management? List as many as appropriate.
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ANSWERS
QUESTION 1 What are the MOST IMPORTANT features on history? List up to SEVEN • History of trauma/injury • Other symptoms e.g. rash, fever, diarrhoea, dysuria • Alcohol and other drugs • Diet • Previous joint disease/surgery • Travel history • FHx arthritis There is nothing remarkable on further history. Examination reveals a hot, swollen and tender left knee with limited ROM due to pain.
QUESTION 2 What is the MOST IMPORTANT initial investigation of this man? List ONE • Arthrocentesis and synovial fluid analysis Investigations strongly suggest a diagnosis of acute gout.
QUESTION 3 What are the MOST IMPORTANT next steps in management? List as many as appropriate. • Pharmacological treatment - NSAIDs, colchicine or corticosteroids are all first-line options • Education • Lifestyle advice – diet (reduction in purines), alcohol, weight loss • Manage CV risk factors • Follow up uric acid levels and recurrences