Pediatric Hypothyroidism Clinical Presentation

Updated: Jan 18, 2022
  • Author: Sunil Kumar Sinha, MD; Chief Editor: Sasigarn A Bowden, MD  more...
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Presentation

History

The history depends on the age at presentation. [5]

Congenital hypothyroidism

Most infants with congenital hypothyroidism are asymptomatic during the neonatal period or display subtle and nonspecific symptoms of thyroid hormone deficiency.

The lack of symptoms initially may result, in part, from an ectopic thyroid gland with clinically significant reserve function, partial defects in thyroid hormone synthesis, or to the moderate amount of maternal T4 that crosses the placenta and is able to boost fetal levels within 25-50% of normal levels observed at birth.

Detection of congenital hypothyroidism based on signs and symptoms alone may be delayed until age 6-12 weeks or older because of the protean clinical presentation and requires a high index of suspicion by the health care provider.

Only about 5% of infants with hypothyroidism are detected by clinical criteria before the biochemical screen alerts the clinician to confirm the diagnosis.

The following are among the earliest signs of hypothyroidism:

  • Prolonged gestation

  • Elevated birth weight

  • Delayed stooling after birth, constipation

  • Prolonged indirect jaundice

  • Poor feeding, poor management of secretions

  • Hypothermia

  • Decreased activity level

  • Noisy respirations

  • Hoarse cry

Acquired hypothyroidism

The clinical features of acquired hypothyroidism are typically insidious in onset.

  • Goiter: Patients with CLT (ie, Hashimoto thyroiditis) most commonly present with an asymptomatic goiter. Parents may report that their child's neck looks "full" or "swollen." Children may complain of local symptoms of dysphagia, hoarseness, or of a pressure sensation in their neck and/or throat. A patient with other causes of hypothyroidism may have an enlarged thyroid gland.

  • Slow growth, delayed osseous maturation, and increased weight: Mild weight gain despite decreased appetite is characteristic of the child who has a hypothyroid condition. Moderate-to-severe obesity in children is not typical for hypothyroidism. Furthermore, children with hypothyroidism manifest a decreased growth rate, a more constant finding than weight gain. In contrast, children with exogenous obesity typically have an increased growth velocity.

  • Lethargy

  • Decreased energy, dry skin, and puffiness

  • Sleep disturbance, typically obstructive sleep apnea

  • Cold intolerance and constipation

  • Heat intolerance, weight loss, and tremors: These are typical symptoms of hyperthyroidism. However, approximately 5-10% of children with CLT initially present with symptoms of toxic thyroiditis. This clinical picture may suggest a diagnosis of Graves disease. The thyrotoxic phase of CLT can be differentiated from Graves disease in that CLT is transient, is not associated with exophthalmos, and is usually associated with a decreased and nonuniform uptake of radioactive iodine. This hashitoxicosis phase is usually followed by the more characteristic hypothyroid phase.

  • Sexual pseudoprecocity

    • Parents may bring their child in for evaluation secondary to concern about testicular enlargement in boys or early breast development or onset of vaginal bleeding in girls.

    • The exact mechanism of sexual pseudoprecocity is not fully understood; however, TRH-induced TSH excess is thought to be the common stimulator of the follicle-stimulating hormone (FSH) receptor.

    • Serum FSH and luteinizing hormone (LH) levels are elevated into the pubertal range. Mounting evidence suggests that increased serum levels of prolactin produce resistance to LH stimulation of the gonads, perhaps leading to hypothalamic gonadotropin-releasing hormone (GnRH) production and stimulation of pituitary LH and FSH release.

    • The short stature and delayed bone age observed in children with hypothyroidism help distinguish sexual pseudoprecocity from true precocious puberty.

    • Sexual pseudoprecocity reverses with adequate thyroid replacement.

  • Galactorrhea: This condition develops in primary hypothyroidism secondary to TRH secretion from the hypothalamus. TRH stimulates the anterior pituitary to release TSH and prolactin. Galactorrhea resolves as prolactin concentrations fall with thyroid replacement.

Next:

Physical Examination

If the newborn with congenital hypothyroidism is not identified by newborn screening and receives no replacement therapy, clinical manifestations of congenital hypothyroidism evolve during the first weeks after birth. Note that although the signs listed below are classic for congenital hypothyroidism, they may be subtle or absent. Recognition of this disorder has been enhanced by systematic newborn screening for the past 30 years.

Physical signs of congenital hypothyroidism include the following:

  • Bradycardia

  • Elevated weight

  • Sluggish behavior

  • Rare cry or hoarse cry (hoarse cry is secondary to myxedema of the vocal cords)

  • Large fontanelles

  • Myxedema of the eyelids, hands, and/or scrotum

  • Large protruding tongue (secondary to accumulation of myxedema in the tongue)

  • Goiter

  • Umbilical hernia

  • Delayed relaxation of deep tendon reflexes (The Achilles tendon reflex appears to be most sensitive to effects of hypothyroidism.)

  • Cool dry skin

  • Enlarged cardiac silhouette, usually because of pericardial effusion

  • Prolonged conduction time and low voltage on electrocardiogram (ECG)

  • Hypothermia

The signs of acquired hypothyroidism can include many physical findings observed with congenital hypothyroidism, such as the following:

  • Decreased growth velocity

  • Bradycardia

  • Mild obesity (5-15 lb over 6 mo) or morbid obesity (>20 lb overweight), which is seldom caused by hypothyroidism alone (The evaluation of obesity often includes assessment of serum TSH and free T4 levels.)

  • Immature upper-to-lower body proportions

  • Dry coarse hair

  • Delayed dentition

  • Precocious sexual development

  • Cool, dry, carotenemic skin

  • Brittle nails

  • Delayed relaxation phase of deep tendon reflexes

  • Goiter formation

    • This may occur secondary to the effects of TSH receptor–stimulating antibodies, inflammatory lymphocytic infiltration, or compensatory hyperplasia because of decreased serum T4 and increased TSH concentrations.

    • Typically, the thyroid gland is enlarged diffusely, although it may not be enlarged symmetrically.

    • Upon palpation, the thyroid gland may initially be soft but then takes on a firm feeling with rubbery consistency and a seedlike surface secondary to hyperplasia of the normal lobular architecture

  • Myxedema (much rarer in children than in adults)

  • Dull facial expression

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