Hysterical polydipsia (compulsive water drinking) in children.

Two patients had entirely different clinical presentations of hysterical polydipsia: convulsions and coma in a 5-year-old boy with intrinsic renal disease and a single kidney, and abnormal behavior in a 3-year-old girl with normal kidneys. In neither case was the correct diagnosis made on initial evaluation. Physiological studies demonstrated primary polydipsia to be responsible for both clinical presentations. The differential diagnosis of polydipsia and polyuria is reviewed, and the nonuniform presentation of hysterical polydipsia is emphasized. In children with intrinsic renal disease, hysterical polydipsia may be life-threatening.