Andersons pediatric cardiology 1619

Clinical features relate to the hypertension, which is sustained in almost 90% of cases, and include headaches, sweating, nausea and vomiting, visual disturbances, abdominal pain, polyuria and polydipsia, convulsions, pallor, and acrocyanosis The location of the tumor or tumors can be established with a variety of imaging techniques, including ultrasound, scintigraphy, computed tomography, and magnetic resonance imaging.374,375 More invasive techniques involve sampling of blood at different levels from the inferior caval vein for determination of levels of catecholamines in the plasma, and arteriography.375,376,377 Invasive investigations should be performed only after full α- and β-adrenoceptor blockade to control the hypertension, and after correction of hypovolemic The latter is essential in any case before surgery Safe anesthesia and surgery require careful preoperative preparation Phenoxybenzamine, at 1 mg/kg per day, is used to block α-adrenoceptors, and propranolol, also at 1 mg/kg per day, is used for blockade of β-adrenoceptors Monitoring of arterial and central venous pressures is required during surgery.378 Intravenous adrenergic blocking agents such as phentolamine and esmolol should be readily available Surgical removal of the tumor or tumors results in cure, but the frequency of multiple tumors suggests that long-term follow-up is indicated Miscellaneous Endocrine Causes Primary hyperthyroidism is a rare cause of hypertension in children.379 Hypertension is also rare in children with primary hyperparathyroidism and is probably related to nephrocalcinosis380 and to hypercalcemia, which raises peripheral vascular resistance Neurologic Disorders Severe hypertension can occur in a variety of acute neurologic disorders, such as Guillain-Barré syndrome,381 poliomyelitis, intracranial lesions such as tumors, trauma, asphyxia, and encephalitis.382 Autonomic dysfunction with overactivity of the sympathetic system is thought to be involved in the pathogenesis in these disorders and in the Riley-Day syndrome of familial dysautonomia,383 although raised intracranial pressure may be a particular precipitating factor Miscellaneous Causes of Hypertension Drugs Oral contraceptives have already been discussed Glucocorticoids and mineralocorticoids are potent causes of hypertension, particularly in children with preexisting renal disease Sympathomimetic agents can raise the blood pressure even when used as topical preparations384 or in nose drops Mercury poisoning causing acrodynia, or pink disease, is associated with hypertension Poisoning with heavy metals, such as cadmium and lead, overdosage of reserpine, methyldopa and phenylcyclidine, and cough syrup containing ephedrine have all caused hypertension In the most recent guideline from the European Society of Hypertension,36 drug-induced hypertension has been defined as a result of unintended side effects or because of the drug's antagonizing effect on antihypertensive medication The two major mechanisms thought to be involved include sodium retention and sympathomimetic activity.36,385 Burns Systemic hypertension occurs in one-third of children with severe burns.386 Excessive production of catecholamines, increased renin-angiotensin stimulation, expansion of volume, and hypercalcemia have been considered in the pathogenesis.194 Hypercalcemia Hypercalcemia is associated with hypertension, probably because of a rise in peripheral vascular resistance.387 The syndrome of infantile hypercalcemia301 may be associated with renal arterial stenosis and hypertension Other Causes Hypertension occurs in acute intermittent porphyria.388 It can be associated with Turner syndrome, even in the absence of aortic coarctation,225,389 and with Marfan syndrome.390 It has been described in pseudoxanthoma elasticum, Stevens-Johnson syndrome, and acrodermatitis enteropathica It also occurs during sickle cell crisis.391 Ingestion of liquorice, which contains a substance with a mineralocorticoid effect, may cause hypertension that is similar to the hypertension induced by deoxycorticosteroid.392