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Impact of hyponatremia on nerve conduction and muscle strength
Author(s) -
Vandergheynst Frédéric,
Gombeir Yannick,
Bellante Flavio,
Perrotta Gaetano,
Remiche Gauthier,
Mélot Christian,
Mavroudakis Nicolas,
Decaux Guy
Publication year - 2016
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/eci.12597
Subject(s) - hyponatremia , medicine , isometric exercise , nerve conduction study , f wave , nerve conduction velocity , nerve conduction , anesthesia , motor nerve , cardiology , anatomy
Background Hyponatremia is associated with unstable gait and propensity to falls. The potential contribution of peripheral nervous system dysfunction induced by hyponatremia has not yet been addressed by prospective studies. Design In the first part of this prospective study, we performed two tests evaluating muscle strength (grip test and quadriceps isometric contraction test) together with a timed up and go ( TUG ) test in 11 patients with chronic mild‐to‐moderate hyponatremia before and after the normalization of natremia. In the second part, we measured nerve conduction velocities and F ‐wave latencies in nine patients with profound hyponatremia (< 125 mmol/L) before and after the normalization of natremia. Results No significant change in muscle strength was observed when natremia was corrected from 127·7 ± 2·5 to 136·1 ± 1·8 mmol/L, contrary to a significant improvement in TUG from 14·9 ± 5·1 to 12·5 ± 4·7 s ( P = 0·006). Nerve conduction velocities and F ‐wave latencies showed significant improvement in most of the studied nerves when natremia was corrected from 121·9 ± 2·4 to 135·5 ± 3·4 mmol/L (e.g. mean increase of 14·3% for motor nerve conduction and mean decrease of 21·6% for F ‐wave latency of left peroneal nerve). Conclusion Whereas chronic mild‐to‐moderate hyponatremia has no impact on muscle strength, we demonstrate for the first time an impact of profound hyponatremia on nerve conduction studies. Further studies are needed to ascertain the contribution of these latter results on gait disturbances, propensity to falls and attention deficits associated with hyponatremia.