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THYROID DISEASES FOR STUDENTS king saud.ppt
- 1. . Common Thyroid Disorders in Children Dr Sarar Mohamed FRCPCH (UK), MRCP (UK), CCST (Ire), CPT (Ire), DCH (Ire), MD Consultant Paediatric Endocrinologist & Metabolist Assistant Professor of Pediatrics King Saud University
- 3. . Agenda Thyroid Anatomy and physiology Thyroid Function Test Congenital Hypothyroidism Newborn screening for congenital hypothyroidism Acquired hypothyroidism Hyperthyroidism Causes of goitre
- 5. THYROID GLAND Location: Located close to thyroid cartilage. Has two lateral lobes connected by thyroid isthmus medially. Development: first endocrine gland to appear during development. Develops from endodermal floor of early pharynx
- 6. THYROID GLAND Innervation: Vagus Nerve (X) Arterial Supply: superior thyroid artery (branch of external carotid artery). Functions: THYROXIN regulate rate of metabolism CALCITONIN decreases levels of calcium and phosphate in the blood (partially antagonistic to parathyroid hormone).
- 9. Production of Thyroid Hormones NIS (Na+/I- Sympoter) TPO
- 10. t1/2 = 5-7d t1/2 = < 24 hrs
- 11. T4 T3 85% (peripheral conversion) 15% Protein binding + 0.03% free T4 Protein binding + 0.3% free T3 (10-20x less than T4) Normal Daily Thyroid Secretion Rate: T4 = 100 ug/day T3 = 6 ug/day ( ratio T4:T3 = 14:1 )
- 12. T4 T3 Potency 1 10 Protein Bound 10-20 1 Half-Life 5-7d < 24h Secreted by thyroid 100 ug/d 6 ug/d
- 14. Thyroid Function: blood tests TSH 0.4 5.0 mU/L Free T4 (thyroxine) 9.1 23.8 pM Free T3 (triiodothyronine) 2.23-5.3 pM
- 15. Effects of thyroid hormones Fetal brain & skeletal maturation Increase in basal metabolic rate Inotropic & chronotropic effects on heart Stimulates gut motility Increase bone turnover Increase in serum glucose, decrease in serum cholesterol Play role in thermal regulation
- 16. Dysfunction Thyroid Gland 1. Too little thyroxin hypothyroidism a. short stature (aquiered), developmental delay (congenital) 2. Too much thyroxin hyperthyroidism a. Agitation, irritability, & weight loss
- 17. Hypothyroidism Decreased thyroid hormone levels Low T4 Possibly Low T3 too. Raised TSH (unless pituitary problem!)
- 18. Causes of hypothyroidism Congenital Autoimmune (Hashimoto) Iodine deficiency Subacute thyroiditis Drugs (amiodarone) Irradiation Thyroid surgery Central hypothyroidism (radiotherapy, surgery, tumor) .
- 19. Clinical features of Acquired hypothyroidism Weight gain Goitre Short sature Fatigue Constipation Dry skin Cold Intolerance Hoarseness Sinus Bradycardia .
- 20. Hypothyroidism with short stature
- 21. Diagnosis High TSH, low T4 Thyroid antibodies .
- 22. Hashimotos Disease Most common cause of hypothyroidism Autoimmune lymphocytic thyroiditis Antithyroid antibodies: Thyroglobulin Ab Microsomal Ab TSH-R Ab (block) Females > Males Runs in Families!
- 24. Subacute (de Quervains) Thyroiditis Preceding viral infection Infiltration of the gland with granulomas Painful goitre Hyperthyroid phase Hypothyroid phase
- 26. Treatment of Hypothyroidism Replacement thyroid hormone medication: Thyroxine
- 27. Congenital Hypothyroidism: Causes Agenesis or dysgenesis of thyroid gland Dyshormonogenesis Ectopic gland Maternal hypothyroidism .
- 28. Newborn Screening Facts Mother Fetus Mid-Gestation Immature Hypothalamic Pituitary Thyroid Axis Pregnancy Mother supplies T4 to fetus via placenta T4 T4 Mature Hypothalamic Pituitary Thyroid Axis Normal Newborn Euthyroid Mother
- 29. Newborn Screening Clinical Features of Congenital Hypothyroidism Finding % Lethargy 96% Constipation 92% Feeding problems 83% Respiratory problems 76% Dry skin 76% Thick tongue 67% Hoarse cry 67% Umbilical hernia 67% Prolonged jaundice 12% Goiter 8%
- 31. Newborn Screening suspect Clinical Confirm Rx & FU Biochemical (screening) Lab ( TSH & FT4 ) T scan B age Optional Thyroxine Congenital Hypothyroidism X Growth & D TSH & FT4
- 32. Newborn Screening High TSH & Low T4 Management Primary Congenital Hypothyroidism Thyroxine 10 -15 ug/kg/day 12 -17 ug/kg/day 37.5 50 ug/day Higher dose in Severe cases T4< 5ug/dl Tablets 25-50-75 ug Crush it, add to 5-10 cc water Or milk Normal T4 In 2 wks (upper 遜 of N) Normal TSH In one month (lower 遜 of N) Dose Form Goals
- 33. Newborn Screening Definitions Screening: search for a disease in a large unselected populatio PKU Congenital hypothyroidism
- 34. Newborn Screening Principal of newborn screening Aim is to identify affected infants before development of clinical signs
- 35. Newborn Screening Success Stories in Pediatric Medicine Immunization programs Newborn Screening program Oral Rehydration Therapy Pencillin
- 36. Newborn Screening Guthrie Test 1962, Robert Guthrie Phenylketonuria
- 37. Newborn Screening Possible screening tests Glucose-6-phosphate dehydrogenase deficiency (G6PD) Sickle cell anemia (Hb SS) > 1 in 5,000; among African-Americans 1 in 400 Sickle-cell disease (Hb S/C) > 1 in 25,000 Hb S/Beta-Thalassemia (Hb S/Th) > 1 in 50,000 Tyrosinemia I (TYR I) < 1 in 100,000 Tyrosinemia II Argininemia Argininosuccinic aciduria (ASA) < 1 in 100,000 Citrullinemia (CIT) < 1 in 100,000 Phenylketonuria (PKU) > 1 in 25,000 Maple syrup urine disease (MSUD) < 1 in 100,000 Homocystinuria (HCY) < 1 in 100,000 Glutaric acidemia type I (GA I) > 1 in 75,000 Glutaric acidemia type II HHH syndrome (Hyperammonemia, hyperornithinemia, homocitrullinuria syndrome) Hydroxymethylglutaryl lyase deficiency (HMG) < 1 in 100,000 Isovaleric acidemia (IVA) < 1 in 100,000 Isobutyryl-CoA dehydrogenase deficiency 2-Methylbutyryl-CoA dehydrogenase deficiency 3-Methylcrotonyl-CoA carboxylase deficiency > 1 in 75,000 Beta-methyl crotonyl carboxylase deficiency 3-Methylglutaconyl-CoA hydratase deficiency Methylmalonyl-CoA mutase deficiency (MUT) > 1 in 75,000 Methylmalonic aciduria, < 1 in 100,000 Beta-ketothiolase deficiency (BKT) < 1 in 100,000 Propionic acidemia (PROP) > 1 in 75,000 Adenosylcobalamin synthesis defects Multiple-CoA carboxylase deficiency (MCD) < 1 in 100,000 Carnitine palmityl transferase deficiency type 2 (CPT) Long-chain acyl-CoA dehydrogenase deficiency (LCAD) Long-chain hydroxyacyl-CoA dehydrogenase deficiency (LCHAD) > 1 in 75,000 Short-chain acyl-CoA dehydrogenase deficiency (SCAD) Short-chain hydroxy Acyl-CoA dehydrogenase deficiency (SCHAD) Medium-chain acyl-CoA dehydrogenase deficiency (MCAD) > 1 in 25,000 Very-long-chain acyl-CoA dehydrogenase deficiency (VLCAD) > 1 in 75,000 Carnitine/acylcarnitine Translocase Deficiency (Translocase) Multiple acyl-CoA dehydrogenase deficiency (MADD) Trifunctional protein deficiency (TFP) < 1 in 100,000 Carnitine uptake defect (CUD) < 1 in 100,000 Congenital toxoplasmosis HIV Cystic fibrosis (CF) > 1 in 5,000 Maternal vitamin B12 deficiency Congenital hypothyroidism (CH) > 1 in 4,000 Biotinidase deficiency (BIOT) > 1 in 75,000 Congenital adrenal hyperplasia (CAH) > 1 in 25,000 Classical galactosemia (GALT) > 1 in 50,000
- 38. Newborn Screening Congenital Hypothyroid Screening started 1974 in Quebec & Pittsburgh Objective : Eradication of MR secondary to CH Incidence 1:3000 4000 ( more than PKU ) Female : Male is 2 : 1
- 39. Newborn Screening Congenital Hypothyroidism One of the most common Treatable causes of MR CH Screening is the most cost effective program Almost all affected NB have no S/S at birth Congenital Anomalies increased by 10%(cardiac) In more than 90% of the cases it is permanent The earlier dx the better IQ
- 40. Newborn Screening Newborn Screening Criteria Wilson Criteria Incidence >1/100,000 Significant morbidity/mortality Successful treatment Reasonable cost Test: specific/sensitive/acceptable Congenital hypothyroidism 1/3,000 to 1/4,000 Mental retardation Thyroxine $3.00 immunoassay
- 41. Newborn Screening Screening Technique Specimen is a blood spot in a filter paper Obtained by heel brick Or cord blood
- 45. . Congenital Hypothyroidism Every Newborn is considered Hypothyroid Until Proven Otherwise Objective from screening: Eradication of MR secondary to CH
- 46. Newborn Screening Method & Timing of Thyroid Screening Primary-TSH Backup-T4 Both TSH&T4 Primary-T4 Backup-TSH Cord Blood Venous Blood Age At Birth Age 2-5 days
- 47. Newborn Screening Clinical Outcome Pre-screening data: Mean IQ = 76 Age of Diagnosis % with IQ > 85 3 months 78% 6 months 19% > 7 months 0%
- 48. Newborn Screening Clinical Outcome Post-screening data: Children screened & treated by age 25 days Mean IQ = 104
- 49. Newborn Screening > screening < screening
- 51. Hyperthyroidism Increased thyroid hormone levels High T4 +/- High T3 Low (suppressed) TSH
- 52. Causes of hyperthroidism Graves Disease Overtreatment with thyroxine Thyroid adenoma (rare) Transient neonatal thyrotoxicosis .
- 53. Graves Disease Most common cause of hyperthyroidism Goitre, proptosis TSH-R antibody (stimulating) 40-70% relapse after 2 years of treatment
- 54. Hyperthyroidism S&S Heat intolerance Hyperactivity, irritability Weight loss (normal to increased appetite) diarrhea Tremor, Palpitations Diaphoresis (sweating) Lid retraction & Lid Lag (thyroid stare) proptosis menstrual irregularity Goitre Tachcardia
- 55. Tremor of the hand A Color Atlas of Endocrinology p49
- 57. Neonatal hyperthyroidism born to mother with Graves disease A Color Atlas of Endocrinology p51
- 58. E恰看沿鞄岳鞄温鉛馨看壊
- 61. investigations TSH, free T3&T4 Thyroid antibodies (TSH receptors antibodies) Radionucleotide thyroid scan (incease uptake) .
- 63. Hyperthyroidism Treatment Beta-blockers Carbimazole PTU (propylthiouracil) Radioactive iodine (in adults) surgery
- 64. Causes of goitre Congenital (maternal antithyroid drugs, maternal hyperthyroidism, dyshormonogenesis) Physiological (puberty) Iodine deficiency Graves disease Hashimoto thyroiditis Tumor .
- 65. Goiter A swollen thyroid gland