Abstract
It is commonly known carbamazepine (CBZ) induced hyponatremia and/or syndrome of inappropriate secretion of antidiuretic hormone (SIADH), but the mechanism is not clear. We reported a male-case of Septo-optic dysplasia with CBZ induced severe SIADH. He has a severe mental retardation and eight years old on-set epilepsy. Inter-ictal EEG showed spike and wave complex at the area around of right frontal and antero-temporal in eleven years old age. He has had generalized tonic clonic seizures sometimes in a year, and often seizures like myoclonia. He was treated by valproate (VPA) and clonazepam (CZP), from thirteen years old age added CBZ, and his medication changed to VPA, CBZ, zonisamide (ZNS), clobazam (CLB). He entered our hospital at 23 years old age for hyponatremia (118mEq/L). We diagnosed SIADH from increase of urinary sodium and the level of serum ADH. He has had a secondary sexual characteristic. We performed cranial MRI and LH-RH test, diagnosed septo-optic dysplasia with hypothalamic hypogonadism. We decreased and stopped the medication of CBZ and VPA, so he does not have had vomiting and/or hyponatremia until now. It was suggested that abnormalities of function and/or construction of hypothalamus and/or pituitary grand was the risk factor of CBZ induced severe SIADH.
