Monday, September 4, 2006

Nephrology Cases #11: Refractory Orthostatic Hypotension

A 72 year old man presented with severe, disabling, refractory orthostatic hypotension (low blood pressure) of two years duration. His blood pressure on standing was 74/40 despite treatment with midodrine 10 mg three times daily and florinef 0.1 mg once daily. His physical exam and neurologic exam were otherwise unremarkable.

He had a partial gastrectomy (removal of the stomach) for an ulcer twenty years ago. His kidney function was normal. He was slightly anemic (hemoglobin 10.9). His vitamin B12 level was within the normal range (297).

A diagnostic test was performed.

After a month of treatment with an oral medication, his systolic blood pressure improved to 140s on standing and he was weaned from florinef and midodrine.

What was the test, and what was the treatment? (Answers in comments.)

Related Link: Nephrology Cases


Test said...

The test was a methylmalonic acid level (which was elevated). This is diagnostic of vitamin B12 deficiency, which caused an isolated autonomic neuropathy and orthostatic hyptoension in this patient. Vitamin B12 deficiency was likely related to his previous gastrectomy; it can be difficult to diagnose and can present with a vitamin B12 level in the normal range.

The treatment was oral vitamin B12 2000 mcg once daily. His hypotension resolved within one month.

Vitamin B12 deficiency can rarely cause an isolated autonomic neuropathy with orthostatic hypotension as the primary symptom.

A Google Scholar search on this topic is here.

DrWes said...

Cool. As an electrophysiologist dealing in syncope on a daily basis, this is case is greatly appreciated.