An unusual case of clinicoradiological dissociation

Abstract

48 year old man was admitted to the emergency department because of painful swelling of his right calf that had developed gradually during the previous week. He denied cough, dyspnoea, or chest pain. He had no history of a previous thromboembolic event, local trauma, or dehydration. Six months earlier he was diagnosed as suffering from psoriatic arthritis and treated with sulphasalazine, which was stopped after two months because of drug induced hepatitis. On physical examination he was afebrile and without dyspnoea. His lungs were clear. The left knee was mildly swollen, with a full range of motion and no clear effusion. No palpable popliteal cyst was found. His left calf was tender, swollen, with erythematous skin (fig 1). Homan's sign was positive. Pitting oedema of the foot, maximal in the medial malleolus area, with purple discoloration, were noticed. Venous duplex scanning performed in the emergency department excluded deep vein thrombosis (DVT). The patient was discharged and referred for further follow up in the outpatient clinic. QUESTIONS (1) What is the likely diagnosis? (2) What physical examination sign was the clue for the final diagnosis? (3) What are the diagnostic modalities you would use to confirm the diagnosis? (4) What treatment is indicated?