Severe orthostatic hypotension in a diabetic patient may not be due to diabetic autonomic neuropathy.

This lesson describes an unusual case of a man who was recently diagnosed with type 1 diabetes and who presented with severe orthostatic hypotension. As his diabetes was recent in onset, well controlled, and he had no other signs of microvascular disease, other causes of orthostatic hypotension were sought. His serum and cerebrospinal fluid were strongly positive for Borrelia burgdorferi IgG, suggesting a diagnosis of Lyme neuroborreliosis. Autonomic instability in Lyme, while rare, has been previously reported.