Life-threatening hyponatremia due to cessation of L-thyroxine

Sari R., Sevinc A.

JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, vol.95, no.10, pp.991-994, 2003 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 95 Issue: 10
  • Publication Date: 2003
  • Journal Name: JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.991-994
  • Keywords: hypothyroidism, hyponatremia, L-thyroxine, drug cessation, THYROID-HORMONE REPLACEMENT, PRIMARY HYPOTHYROIDISM, HYPO-THYROIDISM, MYXEDEMA COMA, VASOPRESSIN, SECRETION
  • Akdeniz University Affiliated: No

Abstract

Electrolyte disorders in hypothyroidism are frequently subtle and rarely observed in clinical practice. A 50-year-old woman was admitted to the emergency room with complaints of nausea, weakness, and lethargy. Her medical history revealed total thyroidectomy two years earlier. She was commenced on L-thyroxine after the surgery. However, the patient stopped the treatment for three months. Thyroid function tests showed free T3 0.80 pg/ml (n: 1.8-4.2), free T4 <0.20 ng/dl (n: 0.8-1.9), TSH 56.84 muU/ml (n: 0.4-4.0). Her biochemical and laboratory investigations were normal, except for a plasma sodium value of 114 mmol/L (n: 135-145). Hypertonic saline treatment with L-thyroxine was immediately started. Symptomatic hyponatremia caused by hypothyroidism was the direct consequence of cessation of L-thyroxine treatment. The patient was followed up for a year and still using L-thyroxine (0.1 mg). In conclusion, it should be kept in mind that life-threatening hyponatremia may occur in patients with total thyroidectomy-induced hypothyroidism; L-thyroxine should be immediately started if stopped for any reason.