Pediatric emergency medicine trisk 478

it is a potential uncoupler of oxidative phosphorylation that may exacerbate the
hypermetabolic state.
Treatment of the hyperthyroidism in thyroid storm is accomplished by the use of iodide and
an inhibitor of iodine oxidation in the thyroid gland such as methimazole 0.5 to 0.7 mg/kg/day
divided into three oral doses, which blocks iodine’s ability to combine with tyrosine to form
thyroxine and triiodothyronine (T3 ); of note, neither medication inactivates circulating T4 and
T3 . Propylthiouracil was a first-line agent, but, due to its association with pediatric liver
failure, it is now contraindicated in children. Iodide rapidly terminates thyroid hormone
release; however, this effect is overcome after 3 to 5 days of iodide therapy. Iodide also
decreases the vascularity of the thyroidal arterial supply and can be particularly useful as a
preoperative agent. Lugol iodide (or SSKI) 3 to 5 drops once every 8 hours orally or sodium
iodide 125 to 250 mg/day intravenously over 24 hours is the usual mode of iodide therapy.
While iodide can reduce thyroid hormone secretion within 24 hours, methimazole’s effects are
minimally useful in acute management because the reduction in thyroid levels may take
several days.
Adequate hydration is essential for effective treatment of thyroid storm. The estimate of
fluid replacement should include a consideration of the significant increase in fluid
requirements caused by fever and an accelerated metabolic rate. Glucocorticoids are useful in
the acute presentation because they appear to inhibit thyroid hormone release from the thyroid
and decrease the peripheral conversion of T4 to T3 . Dexamethasone (0.2 mg/kg) or
hydrocortisone (5 mg/kg) can be given parenterally during the acute phase.
Intercurrent infection may be the precipitating factor, thus it should be searched for and
treated appropriately. Broad-spectrum antibiotics should be considered while awaiting the
results of cultures, as there is a known association between thyrotoxicosis and pneumococcal
bacteremia. Improvement should be seen within a few hours after the initiation of treatment
with propranolol, especially in terms of cardiovascular status.
Clinical Indications for Discharge or Admission
All patients in thyroid storm should be admitted. Full recovery and adequate control of the
underlying thyroid disease take several days to achieve. For the patient presenting with thyroid
storm, serious consideration should be given to permanent treatment of the hyperthyroidism,
either by surgery or radioiodide ablation.

NEONATAL THYROTOXICOSIS
Goals of Treatment
The goals of treatment are to control metabolic rate and reduce cardiac workload.
CLINICAL PEARLS AND PITFALLS


Neonatal hyperthyroidism is a life-threatening condition found in 1% to 5% of
infants born to mothers with history of hyperthyroidism.
Infants of mothers with thyroid disease can have hyperthyroidism even if the
mother’s thyroid condition is not active during pregnancy or well controlled.

Current Evidence
Neonatal thyrotoxicosis may not be correctly diagnosed in the newborn nursery and may be
discovered only when the child presents in extremis in the ED. It is caused by excessive
thyroid hormone produced by the neonatal thyroid that has been stimulated by maternal
thyroid-stimulating antibodies (due to Graves disease) present in the immunoglobulin G (IgG)
fraction that have crossed the placenta. TSH, T4 , and T3 do not cross the placenta in
significant quantities. In most cases, the disease is self-limiting, and hyperthyroidism remits
within about 6 weeks. Occasionally, the disease may run a protracted course and arise in the
absence of maternal thyroid-stimulating antibodies.

Clinical Considerations
Clinical Recognition
The diagnosis should be considered in neonates with maternal history of hyperthyroidism,
especially if they are presenting with tachycardia, failure to thrive, or congestive heart failure.
Triage
Assess for signs/symptoms of congestive heart failure.
Initial Assessment/H&P
The infant usually presents with a history of failure to gain weight despite a ravenous appetite.

The child may also be irritable and have tachycardia, as well as signs of congestive heart
failure. The physical examination is usually remarkable for a goiter and exophthalmos,
acknowledging that a goiter may be difficult to appreciate in a small infant with a short neck.
Management/Diagnostic Testing
Laboratory investigations should include estimations of serum total and free T4 and T3 , and
serum TSH. Increased concentration of T4 in the presence of suppressed TSH levels is
consistent with the diagnosis. If the mother is taking antithyroid medication, thyroid function
tests on the infant may be unreliable in the first days of life because of suppression of the fetal
thyroid by transplacental passage of maternal antithyroid medication. When tested, the bone
age may be advanced.
In most cases, treatment must be initiated on the basis of historical and clinical findings. For
an infant who has an elevated level of T4 but who has few, if any, symptoms or signs,
consultation with a pediatric endocrinologist is strongly recommended. Total T4 levels in all
infants tend to be higher than those in older children because of increased thyroid-binding
globulin (TBG) induced by maternal estrogen that crosses the placenta. Also, an elevated total


thyroxine may be seen with defects that alter the binding of T4 to TBG or the end-organ
sensitivity to T4 .
Treatment is identical to that outlined for thyroid storm in older children. The duration of
treatment is uncertain and should be based on serial thyroid function tests, especially TSH. It is
anticipated that treatment needs to be continued only for 6 to 8 weeks in most cases because
the causative agent is a subclass of IgG molecules with a serum half-life of about 2 weeks.
Clinical Indications for Discharge or Admission
Consider admission for symptomatic children.

CONGENITAL HYPOTHYROIDISM
Goal of Treatment
The major goal of treatment is to address acute clinical manifestations of hypothyroidism,
confirm the diagnosis, and plan replacement therapy.

CLINICAL PEARLS AND PITFALLS
Congenital hypothyroidism should be considered in infants with significant
constipation, prolonged jaundice, hypotonia, or hypothermia.

Current Evidence
The incidence of congenital hypothyroidism is 1 in 3,500 live births. Emergency providers
should be knowledgeable about congenital hypothyroidism so they can appropriately educate
parents and initiate therapy. Acquired hypothyroidism rarely results in urgent clinical problems
that lead to ED visits.
The causes of congenital hypothyroidism are numerous; most cases (90%) are permanent.
About 20% of patients have ectopic glands, and another 50% have hypoplastic or aplastic
thyroid glands. Other causes are less common and include dyshormonogenesis, maternal
ingestion of antithyroid medication, hypothalamic–pituitary disorders, and defects in
thyroglobulin metabolism. The dyshormonogenetic disorders are inherited as autosomalrecessive conditions. Congenital thyroid deficiency may result in impaired neurologic
development if not treated before 1 month of age. However, a 2012 study did not show
differences in neurologic outcomes in children of asymptomatic, untreated mothers found to
have hypothyroidism during early pregnancy compared to those who were asymptomatic but
treated.

Clinical Considerations
Clinical Recognition
Clinical symptoms and signs of congenital hypothyroidism may be subtle and nonspecific,
especially during the first month of life. All U.S. states now screen newborns for congenital
hypothyroidism, but the sensitivity of the screen is variable, especially depending on when the
sample is drawn, so infants may present with clinical symptoms, generally after the first
month.


Triage
Patients are generally well-appearing and at minimal risk for decompensating.

Initial Assessment/H&P
Severely affected infants may be relatively large at birth, have a large posterior fontanel,
manifest hypothermia and hypoactivity, feed poorly, tend to become constipated, and have
prolonged jaundice. An enlarged tongue, coarse facies, and a hoarse cry may also be noted but
are unusual in the first weeks of life. An umbilical hernia may be present. If treatment is not
started, the physical characteristics become more prominent as the child grows older.
Management/Diagnostic Testing
Thyroid function tests beyond the first 2 days of life are most useful diagnostically. The TSH
level is elevated in primary hypothyroidism, and the total and free T4 levels are low or normal
for age. A thyroid ultrasound or scan (123I) may be helpful in identifying the particular type of
primary hypothyroidism, but treatment should never be delayed to obtain this study. A low
total T4 level in the absence of elevated TSH level may result from a deficiency of TBG, a
pituitary deficiency of TSH, or prematurity.
In term infants, treatment with l-thyroxine, 10 to 15 mCg/kg/day should be instituted as
soon as the relevant diagnostic tests are performed. In premature infants, 8 mCg/kg/day can be
administered. This dosage can be adjusted to maintain a TSH value that is normal for age; on
appropriate replacement, the TSH will normalize within 4 weeks. Total T4 and free T4
concentrations should be maintained in the upper half of the normal range for age. Both
undertreatment and overtreatment must be avoided.
Clinical Indications for Discharge or Admission
Generally, treatment is as an outpatient. Careful follow-up on a monthly basis during the first
several months, preferably by a physician who is accustomed to dealing with congenital
hypothyroidism, is strongly recommended.
Suggested Readings and Key References
Diabetic Ketoacidosis
DeCourcey DD, Steil G, Wypij D, et al. Increasing use of hypertonic saline over mannitol in
the treatment of symptomatic cerebral edema in pediatric diabetic ketoacidosis: an 11-year
retrospective analysis of mortality. Pediatr Crit Care Med 2013;14:694–700.
Glaser N, Barnett P, McCaslin I, et al. Risk factors for cerebral edema in children with diabetic
ketoacidosis. The Pediatric Emergency Medicine Collaborative Research Committee of the

American Academy of Pediatrics. N Engl J Med 2001;344:264–269.
Grimberg A, Cerri RW, Satin-Smith M, et al. The “two bag system” for variable intravenous
dextrose and fluid administration: benefits in diabetic ketoacidosis management. J
Pediatrics 1999;134(3):376–378.
Kuppermann N, Ghetti S, Schunk JE, et al. PECARN DKA FLUID Study Group. Clinical trial
of fluid infusion rates for pediatric diabetic ketoacidosis. N Engl J Med 2018;378(24):2275–
2287.