Pediatric emergency medicine trisk 472

is present shortly after birth, but acute crisis usually does not occur until the second week of
life.
TABLE 89.6
CLINICAL AND LABORATORY FEATURES OF VARIOUS FORMS OF
CONGENITAL ADRENAL HYPERPLASIA

FIGURE 89.1 Adrenal steroid hormone biosynthesis. The pathways for the synthesis of adrenal steroid
hormones (adrenal cortex) and catecholamines (adrenal medulla) are arranged from left to right. Synthesis of all
compounds originates from cholesterol in the mitochondria of the adrenal cortex. Subsequent conversions are
shown with enzyme names located next to open arrows , and gray lines indicating enzymatic blocks in the
various forms of congenital adrenal hyperplasia (CAH). Mineralocorticoids (aldosterone) are produced in the
zona glomerulosa, glucocorticoids (cortisol) in the zona fasciculata, and androgens (testosterone) and estrogens
(estradiol) in the zona reticularis. Cortically produced cortisol is required for full induction of the medullary
conversion of norepinephrine to epinephrine. (Courtesy of Joseph Majzoub, MD, Children’s Hospital Boston.)

Triage


Consider CAH as etiology of ill-appearing neonate; recognize importance of quickly
visualizing genitalia and obtaining point-of-care blood glucose.
Initial Assessment/H&P
The appearance of symptoms of salt-wasting crisis can be insidious, with a history of poor
feeding, lack of weight gain, lethargy, irritability, and vomiting. The nonspecific symptoms
may lead to consideration of diagnoses other than CAH and delay initiation of treatment.
Examination of the child should include the vital signs and an assessment of the degree of
dehydration. In severe cases, there may be shock and metabolic acidosis. The genitalia should
be examined carefully because the degree of ambiguity of the genitalia varies considerably.
Virilized females may have an enlarged clitoris and fusion of the labial folds. An
undervirilized male may have a small phallus and/or hypospadias. The presence of gonads in
the inguinal canals or labioscrotal fold is suggestive of a male karyotype. Hyperpigmentation
of the labioscrotal folds and the nipples is occasionally present in the neonatal period;

however, it is rarely prominent enough to alert the examiner to the possibility of CAH.
Management/Diagnostic Testing
In the ED, the most urgent investigations are plasma electrolytes and blood glucose. The
combination of hyperkalemia and hyponatremia is often the first clue to the diagnosis of CAH,
especially in males. The plasma potassium is elevated, but in the presence of vomiting and
diarrhea, the rise may be blunted. Potassium levels between 6 and 12 mEq/L are occasionally
encountered, and can paradoxically be seen without any clinical cardiac dysfunction or ECG
changes. The plasma bicarbonate level is usually low, reflecting the metabolic acidosis that
results from the retention of hydrogen ions in exchange for sodium loss. The blood glucose is
usually normal; however, hypoglycemia may occur secondary to the lack of cortisol and the
reduced caloric intake during the acute illness. Serum should be drawn for determination of an
adrenal steroid profile to include cortisol, 17-hydroxyprogesterone, dehydroepiandrosterone,
androstenedione, testosterone, and if possible, ACTH. Ideally, blood should be obtained for
these tests before the administration of hydrocortisone. For the child in crisis, the diagnosis
must be based on physical findings and electrolyte abnormalities, and treatment must be
instituted before the definitive results of the adrenal steroid profile are available.
Emergency glucocorticoid therapy, delivered at the stress dose of hydrocortisone 50
mg/m2/day should be administered to any patient with known CAH or other form of adrenal
insufficiency in the setting of temperature above 38.5°C, emesis and/or diarrhea, bony fracture
of any type, or in the setting of altered mental status or shock. If the patient appears ill, an
initial dose of hydrocortisone 50 mg/m2 may be given either intramuscularly or intravenously,
followed by that dose divided in four and given every 6 hours. If the patient is not illappearing and is tolerating oral fluids and medications, their usual daily dose may be tripled
and given in three equal parts daily, or hydrocortisone 50 mg/m2/day may be given orally in
three equal parts daily if the home dose cannot be readily established.
Correction of Hyperkalemia, Hypoglycemia, and Acidosis
Infants with CAH tolerate hyperkalemia far better than do older children and adults, with
potassium levels as high as 12 mEq/L reported without clinical signs. Volume restoration


with normal saline is the major and, usually, the only measure needed to lower the

potassium. In the presence of arrhythmias, IV 10% calcium gluconate 1 mL/kg can be given
for its membrane-stabilizing properties. Therapy with glucose and insulin is contraindicated
because of the danger of precipitating hypoglycemia.
If hypoglycemia is found at the time of presentation, it should be treated acutely by the
administration of dextrose (0.25 g/kg) intravenously and by the subsequent inclusion of 10%
dextrose in the infusate.
Acidosis generally does not require specific treatment; however, the low serum bicarbonate
may take days to fully correct. Bicarbonate therapy is reserved for patients with both severe
acidosis (pH <6.9) and secondary hemodynamic compromise that is unresponsive to
inotropic agents.
Clinical Indications for Discharge or Admission
Hemodynamic instability, inability to tolerate oral medications or maintain hydration,
significant electrolyte or acid/base abnormalities, and refractory hypoglycemia are indications
for admission.

PHEOCHROMOCYTOMA
Goal of Treatment
To recognize the presentation of pheochromocytoma and to control hypertension.
CLINICAL PEARLS AND PITFALLS
Pheochromocytoma presents with episodic headache, palpitations, sweating; but
also nervousness, tremulousness, fatigue, chest/abdominal pain, and flushing.
Associated hypertension can be paroxysmal; alpha blockade is antihypertensive of
choice, pure beta blockade as a treatment for hypertension should be avoided as it
can precipitate severe hypertension.

Current Evidence
Pheochromocytomas are functional tumors that arise in chromaffin tissues. In most children,
these tumors are in the adrenal medulla, but they may be found in aberrant tissue along the
sympathetic chain. Less than 5% of all pheochromocytomas occur in children. They are twice
as common in males as in females, with the incidence of malignancy estimated to be 2% to

4%. Most information on pheochromocytoma is derived from adult studies, especially
regarding signs and symptoms. Few detailed studies are available on children.
Catecholamines are low–molecular-weight substances produced in the CNS, the
sympathetic nerves, the adrenal medulla, and the extra-adrenal chromaffin cells.
Catecholamines affect metabolic processes in most tissues of the body and have many effects,
including accelerated heart rate, increased myocardial contraction, and changes in peripheral
vascular resistance. Excessive production of catecholamines by a pheochromocytoma results
in intensification of the normal physiologic effects.


Clinical Considerations
Clinical Recognition
The detection of a pheochromocytoma requires expert clinical awareness. Most patients are
symptomatic, but the symptoms are episodic, nonspecific and, in the child, are likely to be
attributed to other disease entities. The symptoms and signs are related to the excess
production of catecholamines and can be explained on the basis of the pharmacologic effects
of these substances. Up to one-third of pheochromocytomas are associated with familial
syndromes.
The most common symptoms are headache, palpitations, and excessive or inappropriate
sweating. The headache, characteristically, is pounding and may be severe and associated with
altered mental status. The palpitations may be accompanied by tachycardia. Almost all patients
will have one of the three symptoms listed, and most will have at least two. Other symptoms
may include nervousness, tremor, fatigue, chest or abdominal pains, and flushing.
Because the hypertension may be continuous or paroxysmal, frequent and repeated blood
pressure determinations may be necessary. Hypertension is most likely to be found when the
patient is symptomatic. A hypertensive patient who is asymptomatic is unlikely to have a
pheochromocytoma.
Triage
The most useful screening tool for pheochromocytoma is the blood pressure cuff because most
pheochromocytomas are associated with hypertension.

Initial Assessment/H&P
Paroxysmal symptoms and hypertension should lead to consideration of this diagnosis. The
diagnosis of a pheochromocytoma should also be considered in patients with malignant
hypertension, in those who fail to respond or respond inappropriately to antihypertensive
medications, and in those who develop hypertension during the induction of anesthesia or
during surgery. Incidence of pheochromocytomas is increased among patients with
neurofibromatosis and with the multiple endocrine neoplasia syndrome types II and III.
Management/Diagnostic Testing
Documentation of excess catecholamine in either the urine or serum confirms the diagnosis of
pheochromocytoma. Plasma metanephrine concentration has now been shown to be a superior
screening and confirmatory test, and is now widely available. Historical tests are still
commonly used and have confirmatory value including the measurement of urinary
catecholamines or their metabolites (3-methoxy-4-hydroxymandelic acid and total
metanephrines) in a 24-hour urine collection accompanied by a patient symptom log. The
finding of significant elevations of these substances is adequate confirmatory data. Some falsenegative results may occur using urinary catecholamines. When the degree of suspicion is
high, repeated specimens may be needed.
Once the diagnosis is confirmed, anatomic localization is necessary using either computed
tomography or nuclear magnetic resonance imaging. Occasionally, arteriography with
selective sampling for epinephrine production is necessary for localization. Cure is by the
surgical removal of the tumor.