A 45-year-old man presents with bilateral knee pain. Radiographs show chondrocalcinosis plus unusual degenerative change confined to the second and third metacarpophalangeal joints, each with hook-like osteophytes along the radial metacarpal heads. Inflammatory markers are normal. Which investigation will most likely establish the underlying diagnosis?
- A Serum uric acid with 24-hour urinary urate
- B Transferrin saturation and serum ferritin ✓
- C Rheumatoid factor and anti-CCP antibodies
- D HLA-B27 typing
Explanation
Chondrocalcinosis with degenerative change targeting the second and third MCP joints, especially with hooked beak osteophytes, is the signature of hemochromatosis arthropathy, and such patients need iron studies because the arthropathy precedes other organ involvement. Hyperparathyroidism is the other key screen but produces generalized chondrocalcinosis without this MCP selectivity. Uric acid relates to gout, serology to rheumatoid arthritis which targets MCP and PIP symmetrically with erosions rather than hook osteophytes, and HLA-A27 belongs to spondyloarthropathy.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.