Cretinism & hypothyroidism in children

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Cretinism & hypothyroidism in children

  1. 1. Cretinism & Hypothyroidism in Children Dr.K.V.Giridhar Associate Prof. of Pediatrics GMC. Ananthapuramu, A.P., India. 9 May 2014 1
  2. 2. • cretinism: ’congenital disease’ due to ab sence or deficiency of normal thyroid secre tion, characterized by physicaldeformity, d warfism, and mental retardation, and often by goiter. • Hypothyroidism: ‘acquired disease’ due to primary and other various causes of Thyraoid and hypothalamo, pitutory,thyraoid axis abnormaloties.
  3. 3. Etioliogy of Cretinism CONGENITAL Hypoplasia & mal-descent of thyraoid Familial enzyme defects Iodine deficiency in pregnacy (endemic cretinism) Intake of ‘goitrogens’ during pregnancy Pituitary defects Idiopathic
  4. 4. Etiology of Hypothyroidism ACQUIRED Iodine deficiency Auto-immune thyroiditis Thyroidectomy or RAI therapy TSH or TRH deficiency Medications (iodide & Cobalt) Idiopathic
  5. 5. GOITROGENS • DRUGS Anti-thyroid Cough medicines Sulfonamides Lithium Phenylbutazone PAS Oral hypoglycemic agents
  6. 6. GOITROGENS  FOOD Soybeans Millets Cassava Cabbage
  7. 7. THYROID HORMONES Iodine & tyrosine, together form both, T3 & T4 under TSH stimulation, in thyroid gland. When released into circulation T4 binds to: Globulin(TBG)-75% Prealbumin(TBPA)-20% Albumin(TBA)- 5%
  8. 8. THYROID HORMONES (c’d) Less than 1% of T4 & T3 is free in plasma. T4 is deiodinated in the tissues to either T3 (active) At birth T4 level approximates maternal level, but increases rapidly during the first week of life. High TSH in the first 5 days of life can give false positive neonatal screening for ‘hypothyroidism’.
  9. 9. Thyroid stimulating Hormone (TSH)  Is a Glyco-protein.  Secreted by the anterior pituitary under influence of TRH(TSRH) It has trophic effect on thyroid gland  It also stimulates, iodine trapping, oxidation, organification, coupling and proteolysis of T4 & T3.
  10. 10. TSH (c’d)  T4 & T3 are feed-back regulators of TSH  TSH is stimulated by a-adrenergic agonists  TSH secretion is inhibited by: Dopamine Bromocreptine Somatostatin Corticosteroids
  11. 11. Hypothalamo, pituitary, thyraoid Axis Pituitary gland Thyroid gland Hypothalamus T3 T4 TRH TSH
  12. 12. THYROID HORMONES (c’d) Acute & chronic illnesses b-adrenergic receptor blockers Starvation & severe PEM Corticosteroids Propylthiouracil High iodine intake (Wolff-Chaikoff effect) Conversion of T4 to T3 is decreased by:
  13. 13. THYROXINE (c’d) Premature infants Hypo pituitarism Nephrotic syndrome Liver cirrhosis PEM Protein losing enteropathy Total T4 level is decreased in:
  14. 14. THYROXINE (c’d) Steroids Phenytoin Salicylates Sulfonamides Testosterone Maternal TBIgs. Drugs, which decrease Total T4:
  15. 15. THYROXINE (c’d) Acute thyroiditis Acute hepatitis Estrogen therapy Clofibrate iodides Pregnancy Maternal TSH Total T4 is increased with:
  16. 16. FUNCTIONS OF THYROXINE  Thyroid hormones are essential for: Linear growth & pubertal development Normal brain development & function Energy production Calcium mobilization from bone Increasing sensitivity of b- adrenergic receptors to catecholeamines
  17. 17. CLINICAL FEATURES Birth weight > 4 kg Open posterior fontanel Nasal stuffiness & discharge Macroglossia Constipation & abdominal distension Feeding problems & vomiting
  18. 18. CLINICAL FEATURES (c’d) Non pitting edema of limbs Coarse features Umbilical hernia Hoarseness of voice Anemia Decreased physical activity Prolonged (>3 weeks) neonatal jaundice
  19. 19. CLINICAL FEATURES (c’d) Dry, pale & mottled skin Low hair line & dry, scanty hair Hypothermia & peripheral cyanosis Hypercarotenemia Growth failure Retarded bone age Stumpy fingers & broad hands
  20. 20. CLINICAL FEATURES (c’d) Skeletal abnormalities: Infantile proportions Hip & knee flexion Exaggerated lumbar lordosis Delayed teeth eruption Under developed mandible Delayed closure of anterior fontanel
  21. 21. OCCASIONAL FEATURES Overt obesity Myopathy & rheumatic pains Speech disorder Impaired night vision Sleep apnea (central & obstructive) Anasarca Achlorhydria & low intrinsic factor
  22. 22. OCCASIONAL FEATURES (c’d) Decreased bone turnover Decreased VIII, IX & platelets adhesion Decreased GFR & hyponatremia Hypertension Increased levels of CK,LDH & AST Abnormal EEG & high CSF protein Psychiatric manifestations
  23. 23. CLINICAL FEATURES (c’d)  Neurological manifestations Hypotonia & later spasticity Lethargy Ataxia Deafness + Mutism Mental retardation Slow relaxation of deep tendon jerks
  24. 24. ASSOCIATIONS Autoimmune diseases Diabetes Mellitus Cardiomyopathy & CHD Galactorrhoea Muscular dystrophy + pseudo hypertrophy (Kocher-Debre- Semelaigne Syndrome)
  25. 25. DIAGNOSIS Early detection by neonatal screening High index of suspicion in all infants with increased risk Overt clinical presentation Confirm diagnosis by appropriate lab and radiological tests
  26. 26. LABROTARY TESTS Low (T4& T3) High TSH High serum cholesterol & carotene levels Anaemia (normo, micro or macrocytic) High urinary creatinine/hydroxyproline ratio CXR: cardiomegaly ECG: low voltage & bradycardia
  27. 27. IMAGING TESTS  X-ray films can show: Delayed bone age or epiphyseal dysgenesis Anterior beaking of vertebrae Coxavara & coxa plana  Thyroid radio-isotope scan  Thyroid ultrasound  CT or MRI
  28. 28. THYROID FUNCTION TESTS (c’d)  Specific Tests: Thyroglobulin level Thyroid Stimulating Immunoglobulin Thyroid antibodies Thyroid radio-isotope scan Thyroid ultrasound CT & MRI Thyroid biopsy
  29. 29. TREATMENT L-Thyroxin is the drug of choice. Start with small dose. Dose is 10 mg/kg/day in infancy. In older children start with 25 mg/day and increase by 25 mg every 2 weeks till required dose. Monitor clinical progress & hormones level
  30. 30. TREATMENT(c’d)  Life-long replacement therapy  5 types of preparations are available: L-thyroxin (T4) Triiodothyronine (T3) Synthetic mixture T4/T3 in 4:1 ratio Desiccated thyroid (38mg T4 & 9mg T3/grain) Thyroglobulin (36mg T4 & 12mg T3/grain)
  31. 31. PROGNOSIS Depends on: Early diagnosis Proper counselling Strict diet control Careful monitoring Compliance
  32. 32. PROGNOSIS  Is good for linear growth & physical features even if treatment is delayed, but for mental and intellectual development early treatment is crucial.  Sometimes early treatment may also fail, to prevent mental sub normality due to severe intra-uterine deficiency of thyroid hormones
  33. 33. THANKYOU 9 May 2014 35

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