A 50-year-old man presented with an acutely painful left knee which had started five days before but which had worsened in intensity over the past 24 hours. There was no history of trauma. He had no other joint pain and was otherwise well, but he was overweight. He was on no medication.
His left knee was generally swollen and red. On palpation, it was hot and very tender. All other joints were normal. He admitted to drinking more than 60 units of alcohol weekly. What is the diagnosis, management and differential diagnosis?
Diagnosis and management
The diagnosis is gout. Gout is a group of metabolic disorders in which crystals of sodium urate are deposited in the tissues, usually the synovium of joints or as tophi. It usually follows a prolonged period of raised levels of uric acid in the blood, from increased purine intake, turnover or production, or from decreased elimination. It is much more common in men and is more likely with increasing age and BMI and with increased alcohol intake. Joint inflammation and swelling occurs maximally in 24 hours.
Treatment in the acute phase is with anti-inflammatory agents and analgesics.
Advice given should include increased fluids, weight loss and reduced alcohol intake. If recurrent episodes occur, then preventive therapy may be necessary with allopurinol.
Blood testing confirmed a raised urate level of 0.55mmol/l (normal urate up to 0.42mmol/l in men).
Possible differential diagnoses
- Septic arthritis.
- Palindromic rheumatism.
- Early rheumatoid arthritis.
Septic arthritis (infective or bacterial arthritis)
- Caused by Neisseria gonorrhoea and Staphylococcus aureus.
- Usually affects the immunosuppressed, the very young, the elderly, or those with prosthetic joints.
- Parenteral antibiotics and surgical drainage may be required.
Contributed by Dr Gwen Lewis, a GP in Windsor, Berkshire.