Neurologic abnormalities caused by hypertension can include lethargy, headache, confusion, stupor, focal motor deficits, vision loss, seizures, and coma. In a retrospective study of hypertension with neurologic complications, convulsions were the initial feature in 42% of the children. Two of the patients had altered consciousness alone, and two had cranial nerve findings. Nausea and vomiting may be present in the early stages.

Physical findings often include advanced hypertensive retinopathy with papilledema, retinal hemorrhages, and retinal exudates, as well as abnormalities on neurologic examination.

Evidence of cerebral edema is likely to be seen on computed tomographic (CT) scanning. If features such as a stiff neck and fever mandate a lumbar puncture, both the cerebrospinal fluid (CSF) pressure and protein content probably will be elevated. Most cases of hypertensive encephalopathy can be managed without a lumbar puncture, and the risk of undergoing a lumbar puncture in the presence of an elevation in intracranial pressure (ICP) is increased.

The treatment of the hypertension typically results in rapid improvement in the neurologic signs and symptoms, although some findings may require several days to resolve. Pathologic features include swelling of the brain, hemorrhages (punctate to massive), and microinfarctions. In some cases, swelling of the brain may be sufficient for herniation to be apparent.

The specific diagnosis of hypertensive encephalopathy (Box 261.1) is important to pursue because treatment for hypertensive encephalopathy (i.e., abruptly lowering the blood pressure to normal) can be detrimental in some patients with chronic hypertension. For example, the patient with severe renal artery stenosis may have diminished flow distal to the obstruction, which may result in renal ischemia if the arterial pressure is lowered abruptly by a systemic arteriolar dilator.

The diagnosis of hypertensive encephalopathy should be viewed with some skepticism in the setting of hypertension that is chronic and not extremely severe, and if a plausible alternative explanation of the encephalopathy exists. Lowering the systemic arterial blood pressure in many of the chronically hypertensive patients admitted to the intensive care unit (ICU) may be necessary, but it is not safe to do so as abruptly as one would with those acutely hypertensive patients who usually are normotensive.

Children who recover from hypertensive encephalopathy can be expected to do well. In a 10-year study of 45 children with neurologic complications of hypertension, no neurologic or cognitive sequelae were noted on long-term follow-up.

Another neurologic problem associated with severe hypertension is the development of intracranial hemorrhage. Massive hemorrhage caused by hypertension may occur in a child with a berry aneurysm of the circle of Willis or who recently has undergone a neurosurgical procedure. Systemic hypertension in profoundly premature infants is thought to put them at risk for having subependymal bleeding from the germinal matrix.

Acute and severe hypertension can be associated with cardiac dilation, elevation of the left ventricular end-diastolic pressure, and symptomatic pulmonary edema. The normal myocardium handles the acute increase in left ventricular afterload relatively well. Children with acute glomerulonephritis typically do not have findings of a low cardiac output state as a result of increased afterload, and typically symptomatic pulmonary edema resolves rapidly without residual cardiac abnormality when the excessive intravascular blood volume associated with acute glomerulonephritis is lowered through diuretic therapy.

Some children have a limited cardiac reserve because of severe prematurity, congenital cardiac disease, or acquired cardiac disease. Under these circumstances, a hypertensive crisis may result in cardiovascular decompensation. An abrupt lowering of the systemic arterial pressure is required in this setting. Cardiovascular decompensation with hypertensive crisis occurs more commonly in adults than in children because of the prevalence of overt or subclinical coronary artery atherosclerotic disease among adults with hypertension. Most children with hypertension have a hyperdynamic apex impulse, a dilated heart with an apex impulse displaced laterally, and a diastolic filling sound during a hypertensive crisis. Chronic hypertension is a risk factor for the development of atherosclerosis later in
life. Chronic hypertension may be associated with left ventricular hypertrophy and arterial abnormalities. Acute aortic dissection has occurred in severely hypertensive children who did not have features of Marfan syndrome or other abnormalities of connective tissue. The degree of left ventricular hypertrophy ascertained by electrocardiography and echocardiography can give a clue to the chronicity of hypertension. Left ventricular mass, as measured by echocardiography, is associated with long-term cardiovascular risk.