What are some clinical features of the arthropathy of HHC?
The wide frequency reported for arthropathy (40%–80%) depends on how early in the disease the diagnosis of HHC is made. The cause of the arthropathy is unclear; however, ferritin is proinflammatory and can induce interleukin-1 production, which can upregulate MMP-3 gene expression causing cartilage matrix degradation. Most joints can be affected, but pain and stiffness affecting the second and third MCPs are the most characteristic complaints. Limited flexion in these two joints accounts for the “iron fist” sign. Other joints affected are the proximal interphalangeal joints, radiocarpal joints, knees, hips, ankles, shoulders, and occasionally metatarsophalangeal joints. Joint examination usually reveals firm swelling with mild tenderness, but warmth and effusions are absent, helping to distinguish HHC from rheumatoid arthritis. A few patients may suffer from inflammatory “flares” due to pseudogout. Arthritis may be the initial manifestation in 33% of patients with HHC. Unless there is a pseudogout flare, synovial fluid is noninflammatory. Treatment is for symptom alleviation of pain using analgesics and nonsteroidal antiinflammatory drugs.
Pearl: Rule out hemochromatosis in any young (<40 years) Caucasian male who is presenting as “seronegative rheumatoid arthritis.”
