Thyroid function and serum electrolytes: does an association really exist?

Swiss Med Wkly. 2012 Sep 17;142:w13669. doi: 10.4414/smw.2012.13669. eCollection 2012.

Abstract

Background: Thyroid hormone is a central regulator of body functions. Disorders of thyroid function are considered to be a cause of electrolyte disorders. Only few data on the association between thyroid function and electrolyte disorders exists.

Methods: In the present retrospective analysis data from all patients admitted to the Department of Emergency Medicine of a university hospital who had measurements of thyroid function (TSH, fT(3), fT(4)) and electrolytes were included.

Results: 9,012 patients with measurement of TSH and electrolytes were available. 86% of patients had normal, 4% suppressed and 10% elevated TSH. Serum sodium was significantly lower in patients with high TSH levels (p <0.01). There was a significant correlation between serum TSH and phosphate level (p <0.05). Phosphate levels were higher in patients with elevated TSH than in patients with normal TSH (p <0.01). Serum calcium and magnesium correlated significantly with TSH (p <0.05). fT(3) levels correlated significantly with calcium (p <0.05). Hyponatraemia was present in 14% of patients with high TSH and was significantly more common than in the group with normal TSH levels of which 9% had hyponatraemia (p <0.01). Hypokalaemia was more common in the group with elevated TSH than in those with normal TSH (14 versus 11%, p = 0.016). Hyperkalaemia was more common in the group with high TSH levels (7%) than in those with normal TSH (7 vs. 4%, p <0.01).

Conclusion: An association between thyroid function and electrolyte disorders seems to exist, although it is probably only relevant in marked hypo-/hyperthyroidism.

MeSH terms

  • Female
  • Humans
  • Hypernatremia / blood
  • Hypernatremia / etiology
  • Hypokalemia / blood
  • Hypokalemia / etiology
  • Hyponatremia / blood
  • Hyponatremia / etiology
  • Hypothyroidism / blood
  • Hypothyroidism / complications*
  • Male
  • Middle Aged
  • Retrospective Studies
  • Switzerland
  • Thyroid Function Tests
  • Thyroid Gland / physiopathology*
  • Thyrotropin / blood*
  • Thyrotropin / physiology
  • Water-Electrolyte Imbalance / blood
  • Water-Electrolyte Imbalance / etiology*

Substances

  • Thyrotropin