Ian Tee is a 67 year old man who has presented with pain in his knee. It has been ongoing since 8am this morning, and Ian describes this as 'the most intense pain' he has ever experienced in his life. Otherwise he feels well in himself, but the pain is to the extent that he has been unable to walk. The pain is limited to his right knee, and does not radiate. He says it looks red and swollen. He has never had any similar types of pain and has never had any mobility problems.
On examination he has an erythematous, swollen right knee. There is evidence of effusion, and restriction to all movements. Indeed when you palpate the knee, it is hot and he shouts out in pain. He refuses to stand so you can assess gait. All other joints appear normal. Shober's test is normal.
Initial blood tests have come back:
- Hb 141
- WCC 7.0
- CRP 10
LFTs and U&Es are normal.
This is a presentation of a hot and swollen joint. The first thing to rule out in this case is septic arthritis. However, there is no evidence of sepsis. Therefore, the next step in consideration would be inflammatory joint disorders. It is a single joint affected, making rheumatoid unlikely. Gout and pseudogout both cause hot swollen, exquisitely painful knees, however psuedogout more commonly affects knees. Uric acid is NOT diagnostic for either. The aspiration result shows positively bifringent crystals: associated with pseudogout.
