Spot diagnosis: worsening back and buttock pain

A 30-year-old man presents with a one-year history of worsening lower back pain and alternating buttock pain.

He mentions his symptoms are typically worse first thing in the morning, but seem to remit later in the day with NSAIDs and exercise.

Physical examination reveals swelling of the proximal interphalangeal joints of several digits, restricted lumbar movement and tenderness of the sacroiliac joint.

An X-ray demonstrates the findings seen here.

Which of the following extra-articular clinical manifestations is most commonly associated with this patient’s condition?

  • Blurred vision
  • Right lower quadrant pain
  • Plaques with silver scale
  • Shortness of breath

Check your answer below.