MCQ of the Day

A 46 years old male had diarrrhea and fever for a period of one weak.  His stool culture showed the growth of Salmonella.  Now the patient have developed pain in left knee joint.  On examination the joint is swollen.  The culture of the joint aspirate did not show any growth.  The symtomatic treatment was effective. The most likely cause of his joint disease is?

1. HLA-B27
2. Osteoarthritis
3. Not related to diarrhea
4. Rheumatoid arthritis
5. Traumatic arthritis

 

 

 

 

 

 

 

 

 

 

 

Answer:a

Explanation:

The patient has reactive arthritis to Salmonella.  It is more common in patients with HLA-B27.  There is reactive arthritis and the joint aspirates are negative for any growth.  Other agents may also cuase a reactive arthritis e.g. Shigella, Compylobacter and Chlamydia.  Also seen in Reiter’s syndrome.

(Choice b) In Osteoarthritis there is usually a longer history and destruction of the cartilage with erosive changes in joints.

(Choice c) It is a reactive arthritis and is related to the cause as well as genetic antigen HLA-B27.

(Choice d) In Rheumatoid arthritis there is involvement of small joints of the hands and feet, ulnar deviation and other joint deformities. Rheumatoid factor is positive.

(Choice e) There is no history of trauma to the joint.

Educational Objective: 

HLA-B27  is associated with spondyloarthropathy that is associated with certain diarrheas e.g. due to Shigella, Salmonella, Compylobacter and Chlamydia.  Joint fluid aspirate does not show any growth in these cases.