A 35-year-old man comes to the physician with pain in his right knee and ankle for the last 2 weeks. He also has bilateral eye pain, irritation, and blurry vision. On further questioning, he reports burning urination. Last month, the patient developed diarrhea after eating at a local restaurant. The episode resolved spontaneously. On examination, there is bilateral conjunctival injection. He has tenderness in the lumbosacral area. There is swelling and tenderness of the right knee joint and at the calcaneal tuberosity. Urinalysis is normal.
Which of the following is the most likely finding in this patient?

Question

A 35-year-old man comes to the physician with pain in his right knee and ankle for the last 2 weeks.  He also has bilateral eye pain, irritation, and blurry vision.  On further questioning, he reports burning urination.  Last month, the patient developed diarrhea after eating at a local restaurant.  The episode resolved spontaneously.  On examination, there is bilateral conjunctival injection.  He has tenderness in the lumbosacral area.  There is swelling and tenderness of the right knee joint and at the calcaneal tuberosity.  Urinalysis is normal. 
Which of the following is the most likely finding in this patient?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c1d5_b027_8f63_83cdd115f385_MD0005_00 The spondyloarthropathies are a group of disorders characterized by sacroiliitis, peripheral asymmetric oligoarthritis, dactylitis, and enthesitis. Reactive arthritis (ReA) is a spondyloarthropathy that presents with peripheral asymmetric oligoarthritis, often associated with: Uveitis Urethritis Achilles enthesitis (pain at ligament/tendon insertion site) Dactylitis Keratoderma blennorrhagica Circinate balanitis ReA usually occurs after a genitourinary (eg, Chlamydia trachomatis) or gastrointestinal (eg, Salmonella, Shigella, Yersinia, Campylobacter) infection. No pathogen is usually isolated on synovial fluid cultures (Choice B), although signs of inflammation (elevated white blood cell count) are present on fluid analysis, and some studies have reported detection of Chlamydia DNA from synovial fluid by polymerase chain reaction. (Choice A) Antinuclear antibodies are nonspecific, and are positive in several autoimmune disorders, including lupus erythematosus and scleroderma. However, they are not a common finding in ReA. (Choice D) Only 30%-50% of patients with ReA are HLA-B27 positive. Testing for the HLA-B27 allele may assist with the diagnosis of ReA in indeterminate cases, but the marker is neither sensitive nor specific. (Choice E) No bony joint abnormalities are seen on x-ray imaging of affected peripheral joints in acute ReA. Calcaneal spurs may be seen in patients with enthesitis; in rare cases, sacroiliitis may be present with axial joint involvement. Educational objective: Reactive arthritis presents with asymmetric oligoarthritis, usually with a history of genitourinary or gastrointestinal infection. Enthesitis and dactylitis may also be seen. Extra-articular symptoms such as uveitis, urethritis, keratoderma blennorrhagica, and circinate balanitis occur in a minority of patients. Synovial fluid has a high white blood cell count but is culture negative. References: Diagnosis and classification of reactive arthritis. (http://www.ncbi.nlm.nih.gov/pubmed/24418301)

A 35-Year-Old Man Comes to the Physician with Pain in His