Abstract
A man, now 46 years of age, 159cm in height and 39kg in weight, was diagnosed five years ago as essential hypertension with hypertensive nephropathy. On that occasion, renovascular stenosis was ruled out angiographically. Recently, he developed malignant hypertension and was admitted to our hosptial. On admission, severe hypertension (260/160mmHg), hyponatremia (132mEq/liter), high reninemia (40.0ng/ml; normal, 5.0-30.0ng/ml), high serum aldosterone level (840pg/ml; normal, 10-100pg/ml) and advanced retinal changes (KWIII) were found. He lost 10kg in weight during the preceding 3 months. Other characteristic laboratory findings were hypopotassemia (3.8mEq/liter), hypochloremia (85mEq/liter), slight alkalosis, high serum lactate dehydrogenase level, increased cardio-thoracic ratio, and mild azotmia (BUN-46mg/100ml, serum creatinine-3.8mg/100ml). As a therapeutic trial, β-blocker and hydralazine were administered, but no improvement was obtained. Then, sodium was infused in a dose of 328mEq dissolved in 1, 500ml water in a time period of 12hr. One hr after the start of sodium supplementation, his blood pressure was dramatically decreased to 174/120mmHg; 3hr after the infusion, the blood pressure was 140/90mmHg; one hr after the end of the infusion, the blood pressure remained as low as 130/90mmHg. At the end of the infusion, serum sodium rose to 141mEq/liter, PRA decreased to 8.0ng/ml, serum aldosterone level fell to 250pg/ ml, urinary sodium excretion decreased, and body weight increased by 1.5kg. From these findings, it seems likely that in this patient extreme hypertension caused an excessive diuresis resulting in fluid and sodium depletion in the body; the latter, in turn, eliciting further increase in renin release and blood pressure elevation. It may be concluded that malignant hypertension with hyponatremia and emaciation is an indication of parenteral sodium supplementation, and that the most important in the control of malignant hypertension is to keep the sodium balance in an appropriate range.
