The Foot's Corollary

A 50 year old woman with rheumatoid arthritis presents with unilateral aching, burning, numbness, and tingling at the sole of her foot, the distal foot, and the toes. This discomfort is worst at night and after standing a while, and she often needs to remove her shoes. Tapping over the area posterior to the medial malleolus leads to distal tingling. Sensory loss is over the plantar but not dorsal foot. Muscles do not appear to be very atrophied. The patient's past medical history includes trauma to that foot years ago when she fractured her talus and calcaneus. This helps you make the diagnosis as idiopathic causes of this syndrome are rare.

Challenge: What's the diagnosis?

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