Question

a 28 - year - old male presents with low back pain and stiffness that is worse in the morning and after a long period of sitting at work. he states this has been occurring for 5 - months. radiographs of the lumbar spine reveal symmetric sclerosis and erosion at the bilateral sacroiliac joints. an erosive defect is noted at the anterosuperior corner of the l2 vertebral body. the patient has a history of crohn disease diagnosed when he was 16 - years - old. what is the diagnosis?
a) osteitis condensans ilii
b) rheumatoid arthritis
c) enteropathic arthropathy
d) psoriatic arthritis

Explanation:

• Osteitis condensans ilii: Usually affects multiparous women, not associated with Crohn disease.
• Rheumatoid arthritis: Typically affects small joints symmetrically, rheumatoid factor positive usually, not related to Crohn disease in this pattern.
• Enteropathic arthropathy: Associated with inflammatory bowel diseases like Crohn disease. Features can include sacroiliitis (symmetric sclerosis and erosion at sacroiliac joints as in this case) and spinal involvement (erosive defect at vertebral body).
• Psoriatic arthritis: Associated with psoriasis (skin lesions), not with Crohn disease as the primary association here.

Answer:

C. enteropathic arthropathy