Pediatric emergency medicine trisk 1889 1889
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The focus of ED management should be on controlling hypertension and hypertensive crisis
that may occur before the surgical procedure. α-Adrenergic blocking agents are useful in
controlling hypertension and in minimizing blood pressure fluctuations during the surgical
procedure. Preferred drugs for controlling hypertension are phenoxybenzamine and prazosin.
Dosage schedules and quantity must be tailored to the individual for adequate control of
hypertension. Hypertensive crisis may be appropriately managed with IV phentolamine (1 mg
IV for children; 5 mg IV for adolescents) or sodium nitroprusside (0.5 to 8.0 μg/kg/min). Beta
blockade must be avoided because it may lead to unopposed alpha action by secreted
catecholamines and resultant severe hypertension.
Clinical Indications for Discharge or Admission
Admission is warranted if there is strong clinical consideration of pheochromocytoma due to
paroxysmal hypertension, especially preoperatively so that blood pressure control can be
adequately attained.
DIABETES INSIPIDUS
Goal of Treatment
In DI, the goal of treatment is to rapidly restore the intravascular volume needed to stabilize
the patient and then replace remaining deficit over 48 hours.
CLINICAL PEARLS AND PITFALLS
Hypertonic dehydration occurs if thirst is not intact or access to fluids is restricted.
Children may present with severe dehydration despite a reported history of normal
urine output.
The degree of dehydration may be underestimated due to the patient’s
hyperosmolar state, a patient is at risk for central pontine myelinolysis if diabetes
insipidus (DI) causes very rapid dehydration.
Current Evidence
DI is caused by an inability of the kidneys to concentrate urine and is characterized clinically
by polyuria and polydipsia. Either a deficiency of ADH secretion from the hypothalamus and
posterior pituitary gland or renal unresponsiveness to ADH can cause this disease ( Table 89.7
).
Most causes of central DI in children are acquired and can present at any age. In contrast,
the most common cause of nephrogenic DI in children is X-linked recessive and manifests in
males during early infancy. Renal lesions associated with nephrogenic DI can present in later
childhood.
ADH is synthesized in the supraoptic and paraventricular nuclei of the hypothalamus. It is
transported along nerve axons to the posterior pituitary gland, where it is stored, generally
bound to its carrier protein neurophysin II. ADH is released in response to increased plasma
osmolality, hypernatremia, and decreased right atrial pressure secondary to hypovolemia. The
distal convoluted tubules and the collecting ducts of the kidneys respond to ADH by inserting
