History A 35-year-old man is seen in the emergency department because he has developed a painful, swollen right knee. This has occurred rapidly over the past 36 h. There is no history of trauma to the knee or previous joint problems. He feels generally unwell and has also noticed his eyes are sore. He has had no significant previous medical illnesses. He is married with two children. He is a non-smoker and drinks about 15 units of alcohol per week. Examination His temperature is 38.0°C.
Both eyes appear red. There is a brown macular rash on his palms and soles. Examination of cardiovascular, respiratory, abdominal and neurological systems is normal. His right knee is swollen, hot and tender with limitation in flexion. No other joint appears to be affected. What is the diagnosis and what are the major differential diagnoses? *This image-based case is from Docplexus editorial team for…
