Hypertrophic osteoarthropathy (HOA)
Overview
Hypertrophic osteoarthropathy (HOA), sometimes called hypertrophic pulmonary osteoarthropathy (HPOA) when related to thoracic disease, is a syndrome defined by the triad of digital clubbing, periostitis (subperiosteal new bone formation of long bones) and arthralgia/arthritis.
Primary (idiopathic, familial) HOA is uncommon and typically painless. Secondary HOA is far more common in adults, is usually painful, and most often signals underlying systemic disease - classically thoracic pathology such as lung cancer, chronic pulmonary infection or interstitial lung disease.
Why it matters in the ED
New‑onset clubbing or new long‑bone pain in an adult can precede overt symptoms of an underlying malignancy or chronic pulmonary disease by weeks to months. In acute practice the priorities are recognition, exclusion of alternative acute causes (for example septic arthritis or acute bone pathology), basic staging to identify thoracic disease, and prompt referral under suspected‑cancer pathways when indicated (NICE NG12, NG122).
Pathophysiology (concise)
The exact mechanism is uncertain. Current hypotheses implicate megakaryocyte/platelet fragments or tumour‑derived growth factors (for example PDGF, VEGF) bypassing pulmonary filtration, leading to increased peripheral blood flow and periosteal new bone formation.
Primary HOA has a genetic basis and is often accompanied by pachydermia and less pain. Secondary HOA reflects a systemic stimulus such as neoplasm, chronic infection, or chronic hypoxia.
Clinical features and examination
- Triad: digital clubbing; periostitis with...