MALIGNANT HYPERTENSION

MALIGNANT HYPERTENSION
Patients with extreme hypertension, with diastolic pressures of 140 or over, and with gross retinopathy (haemorrhages, exudates and papilloedema) fall into the category of malignant hypertension. Such patients commonly have serious secondary damage to brain, heart or kidney, the last leading to impaired renal function which is rapidly progressive. The prognosis is grave : the great majority of untreated patients die within two years and a considerable proportion within one year. Energetic treatment is a matter of urgency and the favourable response which may follow warrants close attention to detail in the management of each individual patient. The results of treatment with hypotensive drugs are better than those formerly obtained by lumbo-dorsal sympathectomy, and the prognosis has been greatly improved by their advent. There is a substantial proportion of cases, however, in whom the disease pursues a relentless course and unfortunately many patients are debarred from effective therapy by the extent of their renal damage. Impaired renal function implies delayed excretion of the drugs and at the same time a reduced renal blood flow may have adverse repercussions on renal function. Careful assessment of renal function in each individual case is therefore an essential preliminary to the institution of hypo-tensive treatment. When renal function is seriously impaired, and when the blood urea concentration has already reached 90 mg. per cent. or above, treatment must be cautious and it is unlikely that a satisfactory result will be obtained.
For reduction of pressure in this group either the ganglion-blocking agents (mecamylamine; pempidine) or an adrenolytic drug (guanethidine; betha-midine) may be used. It is wise to bring the pressure down gradually over a period of days rather than to attempt a drastic reduction within a short period, since such abrupt hypotensive effects may be followed by thrombosis in the cerebral or coronary arteries, or by a sharp deterioration in the already impaired renal function. Even a moderate reduction in the diastolic pressure, say from an initial level of 150 to 120, is a considerable gain to the patient and may arrest the progress of the necrotizing changes in the small arterioles which are the cause of the evil sequela; of malignant hypertension. In many patients such a moderate reduction in pressure is all that can be attained, though in others it may be possible to bring the diastolic pressure down to approximately normal.
Once the patient with malignant hypertension has been brought under control he must be most carefully supervised during the ensuing months and years. It is only by close attention to the detail of treatment that the full life-saving potentialities of hypotensive treatment can be realized. A considerable proportion of patients with this previously fatal illness can be kept alive and in relatively good health for a decade or more. The survival rate is largely a reflection of the skill and care with which the treatment is supervised.
Today such operations as sympathectomy and adrenalectomy are comparatively rarely performed, and in general only on patients in whom medical treatment has failed to achieve a significant reduction in pressure.