[Pharmacotherapy of different forms of hypertension in childhood]

Plasma volume, total peripheral resistance, and cardiac output are the predominant factors for maintaining adequate blood pressure. However, mineralocorticoid excess, as in certain types of adrenogenital syndrome, an increased plasma volume may lead to hypertension. Renal diseases with activation of the renin-angiotensin-system induce hypertension by augmentation of the total peripheral resistance. Finally, increased cardiac output in the juvenile hyperkinetic syndrome is the primary factor for arterial hypertension. This simplified concept of the pathogenesis of hypertension appears to be helpful for the first choice of three categories of antihypertensive agents, which are diuretics, vasodilators and beta-adrenergic blockers. However, it has to be considered that changing one of the three blood pressure determining parameters may have an effect on the two others counteracting the pharmacotherapeutic intervention. So vasodilatation leads to increased fluid retention and raised plasma volume and/or induces reflex tachycardia with increased cardiac output. Thus, a combined treatment with two or three drugs with different antihypertensive effects are frequently needed. A standard combination may include all three antihypertensive principles, such as hydrochlorothiazide--as a diuretic and a mild vasodilator--and propranolol. When blood pressure level does not return to normal under these antihypertensive regimen despite adequate dosage, a specialist ought to be consulted who may consider additional pharmacointerventions with e.g. a potent direct vasodilator, such as minoxidil, the alpha-adrenergic blocker prazosin, the calcium-antagonist nifedipine or the converting enzyme inhibitor captopril. In case of malignant hypertension transfer of the patient to a specialized center is mandatory.