Congenital Hypothyroidism (CH)
Incidence
Most common preventable cause of…
Risk Factors (3)
1 in 2000
Mental retardation
Female, Asians/Hispanics, Low birth weight
Congenital Hypothyroidism (CH) Diagnosis (2)
No clinical manifestations in most newborns
Lethargy, hoarse cry, prolonged jaundice, hypothermia
Congenital Hypothyroidism (CH) Newborn Screening (2)
Most assays measure TSH directly
Others measure TSH in samples with low/normal T4 concentrations
Congenital Hypothyroidism (CH)
Must send screen after ___ hours
Recheck WHEN?
Must send screen after 48 hours of birth
- Large TSH surge occurs at birth
- Recheck at 2 weeks of life
Congenital Hypothyroidism (CH) Etiology (3 types)
Primary hypothyroidism
- Sporadic (85%) – thyroid dysgenesis
- Hereditary (15%) – inborn errors of thyroid hormone synthesis
Central hypothyroidism
Transient
- Iodine deficiency, transplacental transfer of TSH-receptor blocking antibodies, maternal antithyroid medications
Treatment (5)
CH
Interactions (2)
Absorption
- Initiate once positive screening test confirmed
- Oral levothyroxine – 10-15 mcg/kg/day
- No commercial oral suspension available
- Interactions = Iron/calcium
- Absorption = Decreased by food
CH
Monitoring Initial Goal
T4 > 10 mcg/dL
CH Goal of Treatment
0-1 year: T4 10-16 mcg/dL, TSH < 5 mU/L
CH Monitoring (5)
- 2 and 4 weeks after initiation of L-T4 treatment
- Every 1-2 months during first 6 months of life
- Every 3-4 months between 6 months and 3 years
- Every 6-12 months until growth is complete
- 2 weeks after any change in dose
Hyperthyroidism
Etiology (2)
Graves disease
TSH receptor-stimulating antibodies (TRS-Ab)
Hyperthyroidism Risk Factors (3)
Females
Older children
trisomy 21
Hyperthyroidism
Consequences
Graves’ ophthalmopathy
Hyperthyroidism
Presentation (9)
Weight loss/increased appetite Heat intolerance Goiter Fine hair Tachycardia Acceleration of growth Nervousness Sweating Lid lag
Hyperthyroidism
Diagnosis
T4/FT4 = increased T3 = increased TSH = decreased
Hyperthyroidism
Management (3)
o Antithyroid Medications
o Radioactive Iodine
o Surgery – Thyroidectomy
Hyperthyroidism
MOA
Inhibit synthesis of thyroid hormones by blocking oxidation of iodine in the thyroid gland
Hyperthyroidism
Medication
Advantages (3) /Disadvantages (1)
o Typically 1st line in children, adolescents, pregnancy
ADV = Noninvasive, lower cost, low risk of permanent hypothyroidism DADV = Low cure rate
Hyperthyroidism
Medications (2)
Dosing for each
Methimazole (MMI)
- Dosed every 8-12 hours
Propylthiouracil (PTU)
- Not used routinely due to increased rates of PTU induced liver failure
- Dosed every 8-12 hours
Hyperthyroidism
Medication Absorption, metabolized, excretion
Well absorbed in the GI tract
- Peak serum concentrations in 1-2 hours
Hepatically metabolized
Excreted in the urine
Hyperthyroidism Monitoring meds (3)
Every 2-4 weeks
Administered at the same time each day
Consistently in relation to meals
Hyperthyroidism
ADE (5)
- Cutaneous - pruritic rashes, self-limiting and respond to antihistamines
- Hematologic - Leukopenia
- Musculoskeletal - arthralgias
- GI Intolerances - nausea, abnormal taste
- Misc - agranulocytosis, vasculitis, hepatitis/liver failure
Acquired Hypothyroidism
Etiology (5)
Most common disturbance in thyroid function in children
- Autoimmune thyroiditis
- Iodine deficiency
- Thyroid damage
- Hypothalamic-pituitary disease
Acquired Hypothyroidism Risk Factors (4)
Females
down’s syndrome
T1DM
Celiac disease
Acquired Hypothyroidism
Presentation (8)
Weight gain Cold intolerance Coarse hair Bradycardia Fatigue Dry skin Periorbital swelling Declining growth velocity
