Hypothyroidism  Few diseases affect multiple systems so severely as hypothyroidism yet are associated with so many nonspecific symptoms and signs. Hypothyroidism can occur at any age

 Its clinical manifestation during infancy differs markedly from that of childhood and adolescence; for this reason, we must distinguish between congenital and juvenile-acquired hypothyroidism.

ETIOLOGY  In most instances the causes of hypothyroidism differ during infancy and childhood

ETIOLOGY  children with congenital hypothyroidism usually have either familial goitrous hypothyroidism (dyshormonogenesis) 9 or thyroid dysgenesis with an ectopic thyroid gland located somewhere between the foramen cecum of the tongue and the anterior mediastinum 9

ETIOLOGY . In most cases of permanent congenital hypothyroidism, the cause is unknown. Several inborn errors of thyroid hormone synthesis are inherited as autosomal recessive traits and usually manifest with thyromegaly on physical examination

ETIOLOGY  The most common cause of hypothyroidism in children beyond the perinatal period is goitrous or nongoitrous, autoimmune (chronic lymphocytic, Hashimoto's) thyroiditis

HISTORY AND PHYSICAL EXAMINATION  Because hypothyroidism can affect most organ systems to varying degrees, it is very important that the clinician consider the diagnosis when the patient has many nonspecific or multisystemic complaints

Congenital Hypothyroidism  Facial edema Large posterior fontanelle (>0.5 cm) Rectal temperature below 95° F (35° C) Decreased stooling (less than one stool per day) Prolonged hyperbilirubinemia (bilirubin above 10 mg/dl after 3 days of age)

Congenital Hypothyroidism  Respiratory distress in a term infant Umbilical hernia Birth weight above 4000 g Macroglossia Bradycardia (pulse below 100 beats/min) Feeding problems and lethargy Cutaneous mottling, vasomotor instability Hoarse cry Hirsute forehead

Congenital Hypothyroidism  Increased skin pigmentation Physical and mental lazyness Pale, gray, cool, mottled, thickened, coarse skin Constipation Coarse, dry brittle hair

Congenital Hypothyroidism

Juvenile Hypothyroidism  Growth retardation (below 4 cm/yr) Delayed bone maturation Delayed dental development and tooth eruption Onset of puberty: usually delayed; rarely precocious Myopathy and muscular hypertrophy Menstrual disorders Galactorrhea

Juvenile Hypothyroidism

LABORATORY DATA  An elevation of the serum TSH value is the single most sensitive test for primary hypothyroidism (thyroid gland failure)  combination of a low serum thyroxine (T 4 ) value and an elevated TSH is diagnostic of primary hypothyroidism, either permanent or transient, at any age, including term and preterm infant

LABORATORY DATA  thyroid antibody determinations can be very helpful in finding the cause of infantile or juvenile-acquired hypothyroidism  A bone age determination consistent with that of a normal newborn would suggest recently acquired, mild congenital hypothyroidism,

LABORATORY DATA The absence of ossification centers at the knee in addition to the presence of only the two ossification centers in the foot indicates that the fetus was affected by hypothyroidism during the third trimester of pregnancy.

THERAPY  The treatment of choice for hypothyroidism in infancy and childhood is the daily administration of oral L- thyroxine

PROGNOSIS  Infants who were treated adequately for congenital hypothyroidism since the first month of age have an excellent prognosis for normal intellectual function and linear growth. However, delays in diagnosis and in the institution of adequate therapy after 3 months of age usually are associated with an increased risk of mental retardation

PROGNOSIS  no permanent intellectual impairment is found among patients who have juvenile hypothyroidism. Adolescents who have chronic hypothyroidism and severe growth retardation may never achieve their full growth potential.