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Autonomic dysfunction and hemodynamics in vitamin B12 deficiency
Markus Beitzke1, Peter Pfister, Jürgen Fortin
1Department of Internal Medicine, Krankenhaus der Barmherzigen Brüder, Teaching Hospital Karl-Franzens-University Graz, Austria.
Autonomic Neuroscience : Basic & Clinical
|May 31, 2002
Summary
Vitamin B12 deficiency can cause autonomic dysfunction, leading to orthostatic hypotension similar to diabetic neuropathy. Patients with unexplained orthostatic hypotension should be screened for cobalamin deficiency.
Area of Science:
- Neurology
- Cardiology
- Endocrinology
Background:
- Orthostatic hypotension (OH) in cobalamin (Cbl) deficiency is understudied.
- Autonomic nervous system (ANS) dysfunction is suspected in Cbl deficiency.
Purpose of the Study:
- To systematically investigate hemodynamic and ANS responses to passive head-up tilt (HUT) in Cbl deficiency.
- To compare these responses with healthy controls and diabetic neuropathy patients.
Main Methods:
- 21 Cbl-deficient patients, 21 controls, 9 diabetic neuropathy patients underwent 60° HUT.
- Measurements included heart rate, blood pressure, cardiac output, total peripheral resistance, heart rate variability (HRV), and baroreflex sensitivity.
Main Results:
- Cbl-deficient patients showed a significant fall in systolic blood pressure post-HUT.
- Blunted stroke index and cardiac index, with no increase in total peripheral resistance, were observed.
- Altered HRV spectral indices and impaired baroreflex sensitivity indicated complex neural control changes, comparable to diabetic neuropathy.
Conclusions:
- Vitamin B12 deficiency induces autonomic dysfunction with hemodynamic consequences similar to diabetic autonomic neuropathy.
- Defective sympathetic activation may underlie OH in Cbl deficiency.
- Screening for Cbl deficiency is recommended for patients with orthostatic hypotension.