Which is more important in the genesis of tetany: CSF hypocalcemia or serum hypocalcemia and alkalosis?

Type of contribution: Ask a Question

P. Pavithran, Department of Physiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry 605006, India. E-mail: pavithranpp at gmail dot com

Received 21 Jan 2008; accepted 22 Jan 2008

I have been reading some of the recent posts in MPO regarding tetanus and tetany. Mullin et al [1] have demonstrated that though tetany is a peripheral phenomenon, the concentration of Ca2+ ions in CSF plays an important role in inducing tetany. In contrast, there is a study by Edmondson et al [2] in which neither the rate of development of hypocalcemia nor CSF Ca2+ concentration were found to be directly involved although decreased serum ionized calcium and plasma alkalosis were found to interact synergistically in the etiology of tetany. Taken together, what do the results mean? Which is more important in the genesis of tetany: is it CSF hypocalcemia or serum hypocalcemia and alkalosis?

Acknowledgment: I am a student advisor for Medical Physiology Online.

References:
1. Mullin FJ, Hastings AB, and Lees WM. Neuromuscular responses to variations in calcium and potassium concentrations in the cerebrospinal fluid. Am J Physiol 1938; 121: 719-727 [Link]

2. Edmondson JW, Brashear RE, Li TK. Tetany: quantitative interrelationships between calcium and alkalosis. Am J Physiol 1975; 228: 1082-1086 [Link]

Reviewed by E.S.Prakash, Editor, Medical Physiology Online

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