Sweet taste (dysgeusia). The first symptom of hyponatremia in small cell carcinoma of the lung.

Three patients with small cell carcinoma of the lung presented with a persistent unpleasant sweet taste as their initial and only symptom. On further evaluation, they were found to have hyponatremia secondary to the syndrome of inappropriate secretion of antidiuretic hormone. In each case, resolution of the sweet taste paralleled an increase in serum sodium concentration after water restriction alone. Linkage of the sweet taste with a low serum sodium concentration strongly implicates hyponatremia--rather than tumor, antidiuretic factor, medications, or chemotherapy--as the central mechanism responsible for this previously unreported (to our knowledge) sentinel symptom of small cell carcinoma of the lung.