Hypothyroidism and Hyperthyroidism

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Hypothyroidism and Hyperthyroidism

  1. 1. Hypothyroidism and Hyperthyroidism in the Elderly Chien Yung-Chang , MD .
  2. 3. Free T4 <ul><li>Reference range 0.7-1.8 ng/Dl . </li></ul><ul><li>Converted to triiodothyronine (T3) . </li></ul><ul><li>The thyroid gland is the sole source of T4 . </li></ul><ul><li>Free T4 measures the nonprotein-bound circulating T4 . </li></ul>
  3. 4. Total T4 <ul><li>Normal range 50-120 ng/mL , 5-12 mcg/dL . </li></ul><ul><li>Measurement of total T4 is not particularly helpful . </li></ul><ul><li>Only 0.03% of T4 circulates in the unbound state . </li></ul><ul><li>There is no clinical indication for performing total thyroid hormone measurement . </li></ul>
  4. 5. TSH <ul><li>Normal 0.4-5.5 mIU/L . </li></ul><ul><li>Serum TSH will be decreased to<0.1 mIU/L in most hyperthyroid patients . </li></ul><ul><li>The findings of a low serum T4 and low TSH mandate a search for pituitary disease . </li></ul>
  5. 6. T3 <ul><li>T3 is more biologically active . </li></ul><ul><li>Binding proteins : thyroid-binding globulin , transthyretin and albumin . </li></ul><ul><li>T3 thyrotoxicoisis : approximately 5% of clinically hyperthyroid patients with a normal free T4 level . </li></ul>
  6. 7. Functional examinations <ul><li>Measure the uptake of iodine into the thyroid gland . </li></ul><ul><li>The iodine isotopes : used to identify nodular thyroid disease , to determine if these nodules are hot ( functioning ) or cold ( hypofunctioning ) , to determine the cause for the hyperthyroid state ( Graves’ disease vs thyroiditis ) and to determine a dose of radioiodine for treatment . </li></ul>
  7. 8. Erythrocyte sedimentation rate <ul><li>To confirm the diagnosis of subacute ( viral ) thyroiditis in patients with tenderness on thyroid palpation . </li></ul>
  8. 9. The Role of the History in Diagnosing Hypothyroidism <ul><li>Previous thyroid ablation . </li></ul><ul><li>Elevated thyroid autoantibodies . </li></ul><ul><li>Thyroid surgery . </li></ul><ul><li>Medicatins containing lithium or iodine . </li></ul><ul><li>The most common cause of hypothyroidism is autoimmune or Hashimoto’s thyroiditis . </li></ul>
  9. 10. Signs and Symptoms of Hypothyroidism <ul><li>Less active than usual with loss of interest in things previously enjoyed . </li></ul><ul><li>Lethargy , and decreased mobility . </li></ul><ul><li>Fatigue . </li></ul><ul><li>Dry skin . </li></ul>
  10. 11. Sings and Symptoms of Hypothyroidism (continued ) <ul><li>Apathy and psychomotor retardation . </li></ul><ul><li>Weakness , arthralgia , myalgia , coarsening of the voice , constipation , edema , weight gain , cold intolerance . </li></ul><ul><li>Alveolar hypoventilation => CO2 retention and coma . </li></ul>
  11. 12. The Physical Examination in Hypothyroidism <ul><li>Hypotension or diastolic hypertension . </li></ul><ul><li>Low body temperature and bradycardia . </li></ul><ul><li>Facial features that are puffy and coarse . </li></ul><ul><li>The skin : dry and cold . </li></ul><ul><li>Carotenemia : An orange or yellow tint without scleral icterus . </li></ul>
  12. 13. The Physical Examination in Hypothyroidism ( continued ) <ul><li>Brittle nails and hair , pallor , induration and thickening of skin , periorbital edema , macroglossia , and myxedema . </li></ul><ul><li>Mental status change . </li></ul><ul><li>Delayed relaxation time of deep tendon reflex . </li></ul><ul><li>Pleural , peritoneal and pericardial effusion . </li></ul><ul><li>Delirium and psychosis . </li></ul>
  13. 14. The Heart in the Hypothyroid State <ul><li>Decreased stroke volume , bradycardia , and decreased cardiac output . </li></ul><ul><li>Diastolic hypertension . </li></ul><ul><li>Sinus bradycardia and a prolonged PR and QT intervals . </li></ul><ul><li>Low voltage , heart block , T-wave flattening or inversion , Torsades de pointes , and sudden death . </li></ul>
  14. 15. The Heart in the Hypothyroid State ( continued ) <ul><li>Echocardiogram may be useful to show regional wall abnormalities . </li></ul><ul><li>It also will diagnose a pericardial effusion . </li></ul><ul><li>Pericardial tamponade is rare . </li></ul>
  15. 16. Laboratory Diagnosis of Hypothyroidism <ul><li>Levels of TSH : high . </li></ul><ul><li>The levels of free T4 : decreased . </li></ul><ul><li>Vitamin B 12 deficiency => macrocytic anemia . </li></ul><ul><li>Erythropoietin levels also are low => fall in hematocrit . </li></ul><ul><li>Hyponatremia with low serum osmolality . </li></ul>
  16. 17. Laboratory Diagnosis of Hypothyroidism ( continued ) <ul><li>Hypoglycemia . </li></ul><ul><li>Cardiac enzymes may be elevated . </li></ul><ul><li>Without AMI , the troponin I level remains normal . </li></ul><ul><li>Adrenal hypofunction . </li></ul>
  17. 18. Laboratory Diagnosis of Hypothyroidism ( continued ) <ul><li>Elevation of thyroid microsomal antibodies is => chronic autoimmune ( Hashimoto’s ) thyroiditis . </li></ul><ul><li>Thyroid antibodies may be associated with : Grave’s disease , vitiligo , myasthenia gravis , Addison’s disease , pernicious anemia , and other autoimmune diseases . </li></ul>
  18. 19. The Diagnosis of Myxedema Coma <ul><li>Abnormal TSH and free T4 values : confirm the diagnosis .( in the presence of nonpitting edema , hypoventilation , hypothermia and stupor ) </li></ul><ul><li>Hyponatremia , hypoglycemia , and associated infection : confirmatory . </li></ul>
  19. 20. Precipitating Events for Myxedema Coma <ul><li>Surgery , severe infection , and trauma . </li></ul><ul><li>Sedatives , narcotics , and tranquilizers . </li></ul><ul><li>Missed doses of T4 . </li></ul>
  20. 21. Clinical Features of Myxedema Coma <ul><li>Alteration in mental status , presence of a precipitating factor , hypothermia , and increased serum CK levels . </li></ul><ul><li>Pale and edematous . </li></ul><ul><li>Respiratory symptoms . </li></ul><ul><li>Ascites , pericardial effusion and pleural effusion . </li></ul>
  21. 22. Clinical Features of Myxedema Coma ( continued ) <ul><li>Distant heart sounds , bradycardia , high serum cholesterol levels and low voltage on the EKG . </li></ul><ul><li>Dyspnea on exertion , fatigue , and edema . </li></ul><ul><li>Distended abdomen , paralytic ileus , and fecal impaction . </li></ul><ul><li>Myxedema megacolon : pseudomembranous colitis and intestinal ischemia . </li></ul>
  22. 23. Clinical Features of Myxedema Coma ( continued ) <ul><li>Disturbance in consciousness : ranging from delirium to stupor and coma . </li></ul><ul><li>Hallucination ( myxedema madness ) , cerebellar signs and somnolence . </li></ul><ul><li>Muscle relaxation times of the deep tendon reflexes : delayed markedly . </li></ul><ul><li>Hyponatremia => seizure and depressed level of consciousness . </li></ul>
  23. 24. Laboratory Database of Myxedema Coma <ul><li>Serum TSH and free T4 levels , blood glucose , electrolytes , and arterial blood gas . </li></ul><ul><li>Serum cortisol . </li></ul><ul><li>Chest films , urinalysis , and blood cultures . </li></ul><ul><li>CK , and SGOT . </li></ul><ul><li>Serum electrolytes ,creatinine , BUN ,and glucose should be monitored . </li></ul>
  24. 25. Treatment of Myxedema Coma <ul><li>Thyroid hormone replacement : the definitive treatment . </li></ul><ul><li>Intravenous therapy : preferred . </li></ul><ul><li>Give steroids when starting thyroid replacement => avoid precipitating adrenal crisis . </li></ul><ul><li>Passive rewarming and maintenance of appropriate hydration status . </li></ul>
  25. 26. Factors Associated with poor come <ul><li>Advantaged age . </li></ul><ul><li>Body temperature lower than 93*F . </li></ul><ul><li>Hypothermia persisting more than three days . </li></ul><ul><li>Bradycardia less than 44 beats/minute . </li></ul><ul><li>Hypotension , MI ,and sepsis . </li></ul>
  26. 27. Initiation of Treatment in ED for Myxedema Coma <ul><li>200-300 mcg ( 4 mcg/kg ) IV bolus thyroxine , followed by 50-100 mcg QD . </li></ul><ul><li>T3 20 mcg IV bolus ( loading dose 10-25 mcg ) , then 10 mcg Q8-12H for 24-48 hours until the patient is conscious and taking maintenance T4 . </li></ul><ul><li>Hydrocortisone 100 mg Q8H . </li></ul>
  27. 28. Initiation of Treatment in ED for Myxedema Coma ( continued ) <ul><li>Evidence of infection =>Antibiotics . </li></ul><ul><li>Underlying illness => Supportive care . </li></ul><ul><li>Consider elective intubation . </li></ul><ul><li>Severe hyponatremia => Consider hypertonic saline . </li></ul><ul><li>Consider appropriate rewarming technique . </li></ul>
  28. 29. Recommendation for Admission for the Hypothyroid Patient <ul><li>Clinical diagnosis of myxedema coma => ICU admission . </li></ul><ul><li>Body temperature less than 93*F or bradycardia less than 44 beats /min => ICU admission . </li></ul><ul><li>Comorbidity : CHF ,cachexia , COPD , pneumonia , or any pulmonary problem . </li></ul>
  29. 30. Recommendation for Admission for the Hypothyroid Patient ( continued ) <ul><li>Underlying disorder : aspiration pneumonia , urosepsis , MI . </li></ul><ul><li>CNS dysfunction : Seizure , ataxia , somnolence , lethargy , confusion , or coma . </li></ul><ul><li>Behavioral disorders : Disorientation , paranoia , or hallucination ( myxedema madness ) . </li></ul>
  30. 31. Recommendation for Admission for the Hypothyroid Patient ( continued ) <ul><li>Hypoglycemia : suggesting hypopituitarism or adrenal insufficiency . </li></ul><ul><li>Hyponatremia less than 128 mEq/L . </li></ul><ul><li>Social factors that jeopardize patient safety . </li></ul>
  31. 32. Symptoms and Signs of Thyrotoxicosis <ul><li>weight loss ( the most common ) , palpitation , weakness , dizziness and syncope . </li></ul><ul><li>Alteration in mental status . </li></ul><ul><li>Heat intolerance . </li></ul><ul><li>Nervous or restlessness . </li></ul>
  32. 33. Symptoms and Signs of Thyrotoxicosis ( continued ) <ul><li>Tracheal compression => SOB, hoarseness , wheezing and stridor .( Pemberton’s sign ) </li></ul><ul><li>Thyromegaly => wheezing , hoarseness , stridor , or dysphagia . </li></ul><ul><li>Myopathy : the proximal muscle groups of the shoulder and pelvic girdles . </li></ul>
  33. 34. Symptoms and Signs of Thyrotoxicosis ( continued ) <ul><li>Memory loss , confusion and short attention span . </li></ul><ul><li>Chorea , delirium , convulsion , stroke , cerebral venous thrombosis , and coma . </li></ul><ul><li>Some psychiatric conditions => may be mistaken for thyrotoxicosis . </li></ul>
  34. 35. Physical Findings in the Hyperthyroid State <ul><li>Flushed skin.Hyperhidrosis of the palms and soles . Alopecia . Fine and brittle hair . </li></ul><ul><li>Fever and tachycardia . </li></ul><ul><li>Lid lag , chemosis , exophthalmosis , vasodilation of the conjunctiva , edema of the lids , and compromised visual acuity . </li></ul><ul><li>Myxedema of the pretibial areas , feet , and toes . </li></ul>
  35. 36. Physical Findings in the Hyperthyroid State ( continued ) <ul><li>Diffuse enlargement , bruit , nodules , and tenderness. </li></ul><ul><li>Abdominal pain or secretary diarrhea . </li></ul><ul><li>Muscle weakness , hyperactive reflexes , and tremor .Alteration in mental status . </li></ul><ul><li>Dementia and severe psychomotor retardation . ( Apathetic hyperthyroidism ) </li></ul>
  36. 37. The Heart in Thyrotoxicosis <ul><li>Diminished diastolic BP . Palpitation .Decreased exercise tolerance . Dyspnea on exertion .Elevated systolic BP . Sinus tachycardia . Atrial fibrillation . Anigina pectoris . </li></ul><ul><li>EKG : shortening of the PR interval , ST change , or atrial fibrillation . </li></ul>
  37. 38. Laboratory Testing in Thyrotoxicosis <ul><li>Suppressed TSH levels and increased serum free T4 estimates : clinically evident thyrotoxicosis ( 95% ) . </li></ul><ul><li>Radioactive iodine uptake => incereased . </li></ul><ul><li>ESR => elevated markedly . </li></ul><ul><li>Serum thyroglobulin => increased . </li></ul>
  38. 39. Thyroid Storm <ul><li>A life-threatening crisis . </li></ul><ul><li>Estimated mortality : 20-30% . </li></ul><ul><li>the result of thyroid surgery . </li></ul><ul><li>Caused more often by antecedent Grave’s disease . </li></ul>
  39. 40. Precipitants of Thyroid Storm <ul><li>Surgery . </li></ul><ul><li>Radioiodine therapy . </li></ul><ul><li>Iodinated contrast dyes . </li></ul><ul><li>Thyroid hormone ingestion . </li></ul><ul><li>Diabetic Ketoacidosis . </li></ul><ul><li>Cerebrovascular accident . </li></ul><ul><li>Pulmonary embolism and CHF . </li></ul>
  40. 41. Pathophysiology of Thyroid Storm <ul><li>1) An acute decrease in thyroxine-binding globulin => high levels of free hormone . </li></ul><ul><li>2) Thyroid hormone increases the density of beta-adrenergic receptors & alters responsiveness to catecholamines at a postreceptor level . </li></ul>
  41. 42. Diagnosis of Thyroid Storm <ul><li>Largely a clinical diagnosis . </li></ul><ul><li>CNS disturbances occur in 90% of patients . </li></ul><ul><li>Atrial arrhythmia and ventricular tachyarrhythmia may complicate high output CHF . </li></ul><ul><li>Many of the stigmata of the hyperthyroid state may be present . </li></ul>
  42. 43. Laboratory Diagnosis of Thyroid Storm <ul><li>A combination of low TSH and elevated free T4 => makes the diagnosis . </li></ul><ul><li>If TSH is lower than normal and free T4 is normal => free T3 testing is recommended . </li></ul><ul><li>ED measurement of thyroglobulin or thyroid antibodies : No indication . </li></ul>
  43. 44. Treatment of Thyroid Storm <ul><li>Block hormone synthesis with either : </li></ul><ul><li>a) Propylthiouracil 100-600 mg loading PO or NG , 200-250 mg q4h for total daily dose of 1200-1500 mg ; or </li></ul><ul><li>b) methimazole 20 mg PO ( 10-40 mg range ) q 4h . </li></ul>
  44. 45. Treatment of Thyroid Storm ( continued ) <ul><li>Inhibit hormone release : </li></ul><ul><li>Iodides –Potassium iodide ( SSKI ) 5 drops PO Q6-8H , or </li></ul><ul><li>Lugol’s solution 7-8 drops ( 1 mL PO Q6H ) or </li></ul><ul><li>Ipodate 1-3 g daily ( as 1 g Q8H for 24 hours , then 500 mg Q12H ) . </li></ul><ul><li>If severe iodide allergy , lithium carbonate 300 mg Q6H . </li></ul>
  45. 46. Treatment of Thyroid Storm ( continued ) <ul><li>Glucocorticoids : Hydrocortisone ( 300 mg IV , then 100 mg IV q8h ) ; dexamethasone ( 2 mg Q6H ) . </li></ul><ul><li>Adrenergic blockade : Propranolol ( 0.5-3 mg IV over 15 minutes slow IV , then 60-80 mg PO Q4H ) ; Esmolol ( 0.25-0.5 mcg/kg loading , infusion of 0.05-0.1 mcg/kg/min ) . </li></ul>
  46. 47. Adjunctive Therapy for Thyroid Storm <ul><li>Treat fever aggressively with acetaminophen . </li></ul><ul><li>IV fluid containing 10% dextrose are recommended . </li></ul><ul><li>Administer vitamin supplements , including thiamine . </li></ul><ul><li>Treat CHF with conventional methods . </li></ul>
  47. 48. Adjunctive Therapy for Thyroid Storm ( continued ) <ul><li>Identify the precipitating event , including infection . </li></ul><ul><li>Consider plasmapheresis , hemodialysis or peritoneal dialysis for removal of metabolically active hormone . </li></ul>
  48. 49. Admission Criteria for the Hyperthyroid Elderly Patient <ul><li>Impending or clinical thyroid storm . </li></ul><ul><li>Clinical hyperthyroidism and : </li></ul><ul><li>a) CNS effects , including agitation , chorea , delirium , psychosis , seizure , or coma ; </li></ul><ul><li>b) GI effects such as frank diarrhea , vomiting , jaundice , dehydration , or abdominal pain ; </li></ul>
  49. 50. Admission Criteria for the Hyperthyroid Elderly Patient ( continued ) <ul><li>c) Cardiovascular dysfunction , including CHF , sinus tachycardia unresponsive to oral beta blocade in the ED , new onset atrial fibrillation , or angina pectoris ; </li></ul><ul><li>d) Persistent fever > 100.4*F after rest , without source or without easily treatable source ; </li></ul><ul><li>e) Syncopal episode ; </li></ul>
  50. 51. Admission Criteria for the Hyperthyroid Elderly Patient ( continued ) <ul><li>f) History of recent radioiodinevtherapy ; or </li></ul><ul><li>g) Thyrotoxic periodic paralysis ( address hypokalemia ) . </li></ul><ul><li>Underlying precipitating cause . </li></ul>

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