We report the case of a 37-years-old woman with inappropriate
antidiuretic hormone syndrome due to an attack of
acute porphyria. The patient was admitted to our hospital for
abdominal pain,
sleepiness and pink urine. Family and personal history were normal. Seven days before the admission the patient had a laparoscopy operation for
endometriosis in her left ovary. The patient had had two normal pregnancies. The physical examination was normal, the skin turgor was good and no
edema was present, the blood pressure was 140/90 mmHg. Her serum
sodium was 114 mEq/L, serum osmolality 243 mOsm/kg, urine
sodium 146 mEq/L and urine osmolality 457 mOsm/kg. Values from laboratory examination revealed a normal peripheral haematogram, a normal kidney function, normal liver, adrenal and thyroid function. The urine tested for amino-
levulinic acid, coproporphyrin and uroporphyrin was strongly positive. These findings are compatible with
Porphyria Variegata or
Coproporphyria Hereditary. A diagnosis of
Porphyria acute with
SIADH was made, and water fluid restriction, i.v. hypertonic saline infusion and
furosemide to correct the
hyponatremia was begun. In 1966, lesions of the median eminence of the hypothalamus and both hypothalamic -hypophyseal tracts were described in a patient with
Porphyria acute intermittent and
SIADH. It was suggested that
SIADH occurred because of damage to these areas of the brain from excessive exposure to
porphyrins.