李益明－甲减

null甲状腺功能减退 Hypothyroidism甲状腺功能减退 Hypothyroidism复旦大学医学院内分泌科 李 益 明Hypothalamic-pituitary-thyroid axisHypothalamic-pituitary-thyroid axisnullOverviewOverviewClinical syndrome Slowing down of metabolism Slowing of growth and mental retardation in infants and children Generalized slowing down of organism Deposition of glycosaminoglycans in skin and muscle Reversible with therapyEtiology and ClassifcationEtiology and ClassifcationPrimary(thyroid failure) Hashimoto’s thyroiditis Iodide deficiency or excessive Radioactive iodine therapy for GD Subtotal thyroidectomy Subacute thyroiditis Secondary: pituitary deficit Tertiary: hypothalamic dysfunction Peripheral resistance to thyroid hormonePathogenesisPathogenesisAffects each tissue Accumulation of glycosaminoglycans (hyaluronic acid) Not to excessive synthesis But decreased destrution Increased capillary permeability Interstitial edema Skin Heart muscle Striated muscleClinical FeaturesClinical FeaturesAdultsAdultsSymptoms Easy fatigability Coldness Weight gain Constipation Menstrual irregularities Signs Cool, rough, dry skin Puffy face and hands Hoarse and husky voice Slow reflexes Yellowish color skinClinical FeaturesClinical FeaturesCardiovascular signs Impaired myocardium contraction Bradycardia Diminished cardiac output ECG: low voltage of QRS, P, T waves Pericardial effusion Coronary artery disease Cardiac angina(Replacement therapy aggravate ) Clinical FeaturesClinical FeaturesPulmonary function Shallow, slow respiration Respiratory failure Intestinal peristalsis Markedly slowed Constipation Renal function Decreased glomerular filtrationClinical FeaturesClinical FeaturesAnemia Impaired hemoglobin synthesis Menorrhagia and Absorption of iron Folate deficiency Pernicious anemia Nuromuscular system Muscle weakness Slow reflexes Central nervous system symptoms Inability to concentrate Anovulatory cycles and infertility DepressedSymptoms of hypothyroidismSymptoms of hypothyroidism Symptoms % of cases Weakness 99 Dry skin 97 Coarse skin 97 Lethargy 91 Slow speech 91 Edema of eyelids 90 Sensation of cold 89 Decreaseed sweeting 89 Cold skin 83 Thick tongue 82 Edema of face 79 Coarseness of hair 76 Pallor of skin 67 Memory impairment 66 Symptomsof hypothyroidismSymptomsof hypothyroidism Symptoms % of cases Constipation 61 Gain in weight 59 Loss of hair 57 Pallor of lips 57 Dyspnea 55 Peripheral edema 55 Hoarseness or aphonia 52 Anorexia 45 Nervousness 35 Menorrhagia 32 Palpitation 31 Deafness 30 Precordial pain 25 Myxedema comaMyxedema comaFrequently in obese elderly woman Yellowish skin Large tongue Thin hair Bradycardia Marked hypothermia Lethargy progressing to stupor or coma Hypoventilation Hypotension ShockCretinismCretinismEtiology Low iodide intake and endemic goiter Ectopic thyroid gland TSH-R Ab[block] from mother Inherited defects in thyroid hormone Iodide,antithyroid drugs,radioactive iodine Symptoms Respiratory difficulty Cyanosis Jaundice Poor feedingHypothroidism in childenHypothroidism in childen Retarded growth Mental retardation Precocious pubertyFace of hypothyroidismFace of hypothyroidismFace of hypothyroidismFace of hypothyroidismLaboratory FindingsLaboratory FindingsFT4: uTSH: sensitive to detect 0.01u/mL Most sensitive Most convenient Most specific FT3: Variable May be within the normal range TPOAb、TgAb： AITD (autoimmune thyroid disease) TCDiagnosisDiagnosisSymptoms+SignsPrimary hypothyroidismTRH testFT4 +TSH Secondary hypothyroidismNormal type responseExcessive responseNo responsePituitary lesionHypothalamic lesionFT4 +TSH  or NPrimary hypothyroidismIf ?TreatmentTreatmentDrugs for hypothyroidismDrugs for hypothyroidism LT4 Desiccated thyroid Component T4 T4+T3 high ratio of T3 to T4 Dose 50g 40mg Intensity 50 g = 30mg Initial dosage 25~50 g 20mg Maintenaning dosage 50~150 g 40~120mg Half-life 7 days 1 days Institution of replacement therapyInstitution of replacement therapyFull adrenal support first if with concomitant adrenal insufficiency Beginning with low dosage Degress of hypothyroidism Age General health Increase ½ tablet weekly Needs 6 weeks before equilibration Use powdered thyroid gland for myxedema coma Monitoring FT4 and TSH TSH will be suppressed in normal range in 3 moSide effectsSide effectsNo allergy Overdosage Arrhythmia Paroxyamal atrial tachycardia fibrillation Insomnia Tremor Restleness Excessive warmthnull