Sunday, September 14, 2008

Postural fall in blood pressure

To be significant the blood pressure must fall >30mmHg and stay down for at least 1 minute and be accompanied by dizziness.

Main differential diagnoses and typical outline evidence
Drug induced due to excessive dose of hypotensive agent, L-dopa, carbidopa, phenothiazines, antidepressants Suggested by: drug history.
Confirmed by: by resolution or improvement after stopping or reducing drug.
Autonomic neuropathy due to diabetes mellitus or tabes dorsalis (rarely) Suggested by: history of long standing diabetes (common) or tabes dorsalis (rare). Also, diarrhoea, abdominal distension and vomiting (gastroparesis), impotence, urine frequency.
Confirmed by: ECG monitor of beat to beat variation: <10>
Management: OHCM p298.
Idiopathic orthostatic hypotension Suggested by: no other features except elderly.
Confirmed by: isolated phenomenon.

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