Pediatric emergency medicine trisk 477

Children with rickets may come to medical attention because of specific physical
abnormalities (bowed legs), limb pain and swelling, seizures, failure to thrive (renal tubular
acidosis), biochemical abnormalities (hypocalcemia), radiographic findings (broadened, frayed
metaphysis), or during the evaluation of a fracture.
Triage
Rickets should be considered in patients with nonspecific bony complaints.
Initial Assessment/H&P
A thorough social and dietary history is helpful in delineating the probable cause of the rickets
and in sparing the patient an extensive and expensive evaluation. A family history may be
useful in identifying the 1-alpha-hydroxylase deficiency or renal phosphate wasting. If the
child has previously been treated with vitamin D, the reported response to that treatment may
be helpful in identifying the likely site of defect.
The clinical findings in rickets may vary considerably, depending on the underlying
disorder, the duration of the problem, and the child’s age. Most features are related to skeletal
deformity, skeletal pain, slippage of epiphyses, bony fractures, and growth disturbances.
Muscular weakness, hypotonia, and lethargy are often noted.

FIGURE 89.4 Rickets in an 11-month-old boy, breast-fed since birth. A : Roentgenogram of the upper extremity
shows profound demineralization of the skeleton, with frayed, irregular cupping of the end of the metaphysis and
poorly defined cortex. Note retardation of skeletal maturation. B : Same patient with some healing 4 weeks after
supplemental vitamin D. Severe rachitic changes are noticeable. Periosteal cloaking, both of the metacarpals and
of the radius and ulna, is evidence of healing. C : Complete healing of the rickets 8 months after treatment. Note
the reappearance of the provisional zone of calcification. (Courtesy of Soroosh Mahboubi, MD, The Children’s
Hospital of Philadelphia.)

Failure of calcification affects those parts of the skeleton that are growing most rapidly or
that are under stress. For example, the skull grows rapidly in the perinatal period; therefore,
craniotabes is a manifestation of congenital rickets. However, the upper limbs and rib cage


grow rapidly during the first year of life, and abnormalities at these sites are more common at

this age (i.e., rachitic rosary, flaring of the wrist). Bowing of the legs is unlikely to be noted
until the child is ambulatory. Dental eruption may be delayed, and enamel defects are
common.
Management/Diagnostic Testing
Radiography is the optimal way to confirm the clinical diagnosis of rickets because the
radiologic features reflect the histopathology. Characteristic findings include widening and
irregularity of the epiphyseal plates, cupped metaphyses, fractures, and bowing of the weightbearing limbs ( Figs. 89.4 and 89.5 ).
The clinical laboratory is often helpful in correctly identifying the cause of rickets. Frank
hypocalcemia (<7 mg/dL) is unusual in rickets. Calcium levels in the 7 to 9 mg/dL range are
common and warrant careful attention because the initiation of vitamin D treatment increases
bony deposition of calcium and may lead to a fall in serum calcium. Phosphate levels are often
low. An amino aciduria is often present and may lead to some confusion of simple vitamin D
deficiency with Fanconi syndrome. Alkaline phosphatase levels are significantly increased,
reflecting extremely active bony metabolism. Although PTH levels are elevated, the results of
this test are unlikely to be available at the time initial clinical decisions are made. Chronic
acidosis, liver disease, and renal disease should be ruled out.
Treatment depends on the nature of the underlying disease. The response to treatment may
be helpful in differentiating simple dietary vitamin D deficiency from more complex causes of
rickets.

FIGURE 89.5 Rickets in an 11-month-old boy, breast-fed since birth. Roentgenogram of the chest shows
demineralization of the skeleton with cupping of the distal end of ribs and humerus. (Courtesy of Soroosh
Mahboubi, MD, The Children’s Hospital of Philadelphia.)


In the absence of chronic disease, dietary rickets may be adequately treated with daily doses
of 1,200 to 1,600 IU of vitamin D2 (ergocalciferol) until healing occurs. Alternatively, a single
high IM dose to replenish stores may be administered as ergocalciferol 50,000 to 100,000 IU.
Serum phosphate usually returns to normal within 1 to 2 weeks, and radiographic
improvement is generally apparent by 2 weeks. Once healing is complete, the child should

continue to be treated with 400 IU/day to prevent recurrence.
If the initial serum calcium is borderline low or low, supplemental calcium should be
initiated 48 hours before the institution of vitamin D, especially in the young child. Otherwise,
the initiation of therapy with vitamin D may cause a further decrease in serum calcium and
elicit frank hypocalcemia. This presentation may occur naturally if the vitamin D–deficient
patient has relatively low serum calcium concentration and then has prolonged exposure to the
sun. This may lead to abrupt increases in vitamin D, ultimately leading to a rapid increase in
bone recalcification (hungry bone syndrome) and severe hypocalcemia with possible seizures.
This syndrome is seasonally termed “spring fits.”
Clinical Indications for Discharge or Admission
Children with symptomatic hypocalcemia or with initial serum calcium of less than 7 mg/dL
on presentation warrant hospitalization and frequent calcium determinations. Failure to
respond to vitamin D treatment suggests that the child has a more complex cause of rickets,
and consultation with a pediatric nephrologist or endocrinologist is recommended.

THYROID STORM
Goals of Treatment
After recognizing thyroid storm, the goals of emergency treatment are to control the metabolic
rate and reduce cardiac workload.
CLINICAL PEARLS AND PITFALLS
Thyroid storm is precipitated by intercurrent infection, trauma, or after subtotal
thyroidectomy with an inadequately prepared patient.
The presence of high fever (often to 105.8°F [41°C]) is the primary distinguishing
feature of thyroid storm from a simple hyperthyroid state.
A marked increase in cardiac workload may result in high-output heart failure and
hypotension and pulmonary edema rather than classic hypertension.

Current Evidence
In thyroid storm, thyroid hormone is suddenly released into the circulation, which results in
the uncoupling of oxidative phosphorylation and/or increased lipolysis, both of which

contribute to excessive thermogenesis. Insensible fluid loss increases as a result of increased
metabolism and sweating. Tachycardia is caused by both the hyperthermia and the direct
action of thyroid hormones on the cardiac conduction system. Widened pulse pressure occurs
as the result of increased cardiac contractility and decreased peripheral resistance. The
mortality rate in adults may be as high as 20%: similar data are not available for children.


Clinical Considerations
Clinical Recognition
Almost all cases of thyroid storm occur in patients with known hyperthyroidism, although
occasionally, a patient will present initially with thyroid storm.
Triage
Consider thyroid storm in patients with known hyperthyroidism who presents with fever,
tachycardia, and systolic hypertension; these patients should receive expedited evaluation and
treatment should be initiated quickly.
Initial Assessment/H&P
Most patients will have clinical findings characteristic of hyperthyroidism, including goiter
(more than 95%), exophthalmos, tachycardia, bounding pulses, and systolic hypertension.
Diastolic hypotension, tremulousness, restlessness, mania, delirium, or frankly psychotic
behavior may be present. A primary feature that distinguishes thyroid storm from
uncomplicated hyperthyroidism is the presence of high fever, often as high as 41°C (105.8°F).
The marked increase in cardiac workload may result in high-output cardiac failure, in which
case hypotension and pulmonary edema may be seen, rather than more classic hypertension.
Management/Diagnostic Testing
Thyroid studies including free thyroxine (T4 ), total and free triiodothyronine (T3 ), and TSH
should be obtained urgently to confirm the diagnosis. Alternatively, total T4 along with T3 binding resin uptake may be measured if the laboratory cannot measure free levels easily;
however, in many cases, therapy must be initiated on the basis of clinical evidence.
Furthermore, the T4 and T3 values seen in thyroid storm overlap with those found in frank
hyperthyroidism without storm. Serum electrolytes should be obtained but are unlikely to
reveal any characteristic abnormalities, except for evidence of modest dehydration. Chest

radiograph and ECG are helpful in evaluating and following cardiac status as treatment is
initiated.
Initial treatment is directed toward lowering the metabolic rate and reducing the cardiac
workload. Subsequent treatment is directed toward controlling thyroid hormone production.
Because many of the hypermetabolic effects of hyperthyroidism are mediated by the
adrenergic system, a β-adrenergic antagonist (propranolol starting at 10 μg/kg intravenously
over 10 to 15 minutes, or an esmolol infusion may be initiated with a loading dose of 500
μg/kg/min over 1 minute with maximal infusion doses of 50 to 250 μg/kg/min) is useful in the
acute management of thyroid storm. Maintenance dosing of propranolol is 2 mg/kg/day
divided every 6 hours in neonates and 10 to 40 mg every 6 hours in older children. ECG
monitoring for heart rate and arrhythmias is recommended.
Because the metabolic rate is increased about 10% for every degree of body temperature
higher than 36.5°C (97.7°F), lowering body temperature is an effective means of reducing the
metabolic rate in the patient with thyrotoxicosis. Tepid sponging, use of a cooling blanket, and
administration of acetaminophen can accomplish this task. Aspirin should not be used because