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  1. 1. HYPOTHYROIDISM Dr Prabhat Agarwal Asst Prof, P.G. Dept of Medicine, S.N.M.C.Agra
  2. 2. Introduction  Reduced production of thyroid hormone is the central feature  It is the second most common endocrine disorder (after diabetes mellitus) is USA  It is more common in females  F:M ratio is approx 10:1  Rates of hypothyroidism increase dramatically with age
  3. 3. Risk Factors  More common in individuals who have a family history of thyroid disorders  Hypothyroidism and thyroid cancers are more common in individuals who have had irradiation of their neck in childhood  However, most cases occur in individuals with no risk factors
  4. 4. Causes PRIMARY HYPOTHYROIDISM-  Thyroiditis o Hashimoto’s throiditis (Chronic lymphocytic) o De Quervain’s thyroiditis (Subacute granulomatous) o Silent/Painless thyroiditis (Subacute lymphocytic) o Reidel’s thyroiditis (Subacute fibrocytic)
  5. 5.  Iatrogenic causes o Radioactive iodine treatment of Grave’s ds o Thyroidectomy SECONDARY HYPOTHYROIDISM-  Pituitary surgery  Intracranial radiation  Congenital panhypopituitarism  Infiltrative diseases like sarcoidosis, amyloidosis, hemochromatosis OTHERS-  Drugs like lithium, interferon, amiodarone  Iodine deficiency
  6. 6. PRIMARYV/S SECONDARY HYPOTHYROIDISM PRIMARY SECONDARY SKIN Thick and without wrinkles Thin with fine wrinkles HAIR Coarse Fine MENSES Menorrhagia Amenorrhea SECONDARY SEXUAL CHARACTERS Normal Poor HEART SIZE May be enlarged Small GOITRE May be present Absent SOFT TISSUE EDEMA Marked Absent BLOOD PRESSURE Normal or High Low CHOLESTEROL Increased Normal TSH High Low
  8. 8. Hashimoto’s Thyroiditis  Most common cause of goitrous hypothyroidism in iodine sufficient parts of the world  Characterized by thyroidal lymphocytic infiltration with germinal centre formation, follicular damage or destruction with fibrosis  Goitre develops gradually and is firm in consistency  Presence of anti TPO and anti thyroglobulin antibodies favours the diagnosis  History of other auto immune disorders like rheumatoid arthritis, pernicious anemia, diabetes mellitus should be ascertained
  9. 9. Clinical Features  Largely due to the reduced metabolic rate and deposition of glycosaminoglycans (GAG) in different body compartments  Myxoedema refers to the boggy appearance of the skin and subcutaneous tissues in the patients with severe hypothyroid state  Skin is pale and cool, reduction in sweat and sebaceous secretions causing dryness and coarseness
  10. 10.  GAG deposition in the larynx and pharynx leads to hoarseness of voice  Cardiovascular involvement causes decreased cardiac output, narrowing of pulse pressure and increased systemic vascular resistance causing diastolic hypertension. Pericardial effusion may occur  Modest weight gain despite reduced appetite and constipation due to reduced gut peristalsis
  11. 11.  In adult women, decreased libido, failure of ovulation, polymenorrhoea, menorrhagia and decreased fertility may be seen  In men, decreased libido, oligospermia and impotence may result  These are though to result because of hyperprolactinemia as prolactin is also underTRH control
  12. 12.  A child with congenital hypothyroidism is sluggish and may present with prolonged physiological jaundice, meconeum ileus, umbilical hernia, feeding difficulties, dry scaly skin and a large tongue  Cretinism: severe hypothyroidism of infancy  X Ray Pelvis will reveal dysgenesis of the femoral capital epiphysis, which is pathognomonic of hypothyroidism in infancy and childhood
  13. 13. Signs and Symptoms  SYMPTOMS Lethargy Weight gain Constipation Slowed mentation, forgetfulness Depression Hair loss Dry skin Easy bruising Menstrual abnormalities Neck enlargement/ Goitre
  14. 14.  SIGNS- Goiter Low blood pressure and slow pulse Hair thinning or loss Dry skin Confusion Depressed affect Non pitting edema Hung up reflexes
  15. 15. DIAGNOSIS  Based on the finding of a low free thyroxine (T4) level, usually with an elevation in the TSH levels  For patients with hypothyroidism due to pituitary dysfunction (secondary hypothyroidism), both fT4 and TSH are low  There is no role of thyroid scans or iodine uptake testing in patients with hypothyroidism
  16. 16. TREATMENT  Thyroxine replacement The usual dose required to achieve full replacement is between 100-150 ug/day For patients with known heart disease or who are at risk of it, doses are started at 25-50 ug with increases of 25 ug every 4-6 weeks guided by TSH levels Young patients who are otherwise normal can be started at doses of 100 ug/day Patients with aTSH<=10.0 do not usually require any therapy
  17. 17. MONITORING  In general, once a patient receives a full replacement dose of T4 (usually between 100-150 ug/day) and has aTSH consistently in the normal range, there is little likelihood that their thyroid requirement will change over time  There is no evidence to show the need of re testing to ensure patients are euthyroid in such a sub group of patients
  18. 18.  BecauseT4 andT3 are highly protein bound, any condition where a patient’s serum protein status changes, prompt testing is advocated  This includes conditions that lower serum protein levels such as liver disease, nephrotic syndrome or malnutrition or increase them like pregnancy or estrogen therapy
  19. 19.  Patients with subclinical hypothyroidism (mildly elevatedTSH and a normalT4) also benefit from their annual testing of fT4 levels. Approximately 10% of such patients progress to hypothyroidism within 3 yrs of diagnosis.Thereby annual testing is advocated.
  20. 20. COMPLICATIONS  Most complications are associated with under or over treatment  Inadequately treated subjects are at a higher risk of cardiac disease  Over treatment increases the risk of atrial fibrillation and osteoporosis  Hashimoto’s thyroiditis is associated with other auto immune diseases like Addison’s disease, pernicious anemia, vitiligo.They are also at a higher risk for the future development of lymphoma
  21. 21. De Quervain’s Thyroiditis  Also known as sub acute/ viral/ granulomatous giant cell thyroiditis  Most likely viral in origin  Presents with neck pain, which may radiate to the neck or mandible  Hoarseness, dysphagia and signs of thyrotoxicosis may be present  Thyroid gland is tender and firm  Histopathologically a well developed follicular lesion that comprises a central core of colloid and surrounded multi nucleate giant cells is characteristic  ESR is high and RAIU is low  Nearly always self limiting
  22. 22. Post Partum Thyroiditis  It is the occurrence of thyrotoxicosis, hypothyroidism or thyrotoxicosis followed by hypothyroidism in the 1st post partum year, in women without overt thyroid disease before pregnancy  Occurs in 8-10% women post partum  Upto 30% are anti TPO antibody positive  Painless and self limiting  Likely to recur in subsequent pregnancies  Increased risk of developing permanent primary hypothyroidism in future
  23. 23. Reidel’s Thyroiditis  Characterized by the fibrosis of the thyroid and adjacent structures  Occurs in middle aged women  Stony hard, immobile goitre resulting in pressure symptoms due to the compression of the trachea, oesophagus and the recurrent laryngeal nerve  One third patients have hypothyroidism  Surgical removal is indicated when pressure symptoms are present  Glucocorticoids have beens used for treatment because of the their anti inflammatory effect
  24. 24. Myxoedema Coma  Ultimate stage of severe long standing untreated hypothyroidism  Often precipitated by stroke, infection, myocardial infraction, sedative drugs or exposure to cold  Treatment is started on the basis of clinical suspicion. Initially the precipitating condition needs to be identified and treated, and general suppostive measures instituted  Clinical features include altered sensorium (coma), subnormal temperature, bradycardia, hypotension and features of severe myxoedema
  25. 25.  Mortality of this condition is related to the severity of hypothermia  Throxine 500 ug is given iv stat followed by 100 ug iv daily (given through nasogastric tube if intravenous formulation is not available)  Glucocorticoid replacement with iv hydrocortisone (5-10 mg/hour) should also be given  External heating should not be done as it causes cutaneous vasodilatation, which increases the strain on the heart  Despite aggressive management, mortality approaches 50%
  26. 26.  Euthyroid Sick Syndrome: in severely ill patients during acute physiological stress, the patients may have mildly elevatedTSH levels and do not require thyroid replacement.The levels settle within a few weeks of recovery and may sometimes be difficult to distinguish from pre existing or new onset hypothyroidism.
  27. 27. REVISION
  28. 28. MCQs
  29. 29. Q1: the best marker to diagnose thyroid related disorder is: A. T3 B. T4 C. TSH D. Thyroglobulin
  30. 30. Q2: the lab investigation of a patient shows decreasedT3,T4 and TSH. It cannot be? A. Primary hypothyroidism B. Panhypopituitarism C. Liver Disease D. None
  31. 31. Q3: the most common cause of thyroiditis is? A. Reidel’s thyroiditis B. Hashimoto’s thyroiditis C. Subacute thyroiditis D. Viral thyroiditis
  32. 32. Q4: all of the following are true of de Quervain’s thyroiditis except? A. Pain B. Increased ESR C. Increased radio active iodine uptake D. Fever
  33. 33. Q5: Hurthle cells are seen in? A. Agranulomatous thyroiditis B. Hashimoto’s thyroiditis C. Papillary carcinoma thyroid D. Thyroglossal cyst
  34. 34. Q6: Hung up ankle jerk is seen in? A. Hypothyroidism B. Hyperthyroidism C. Diabetes Mellitus D. Acromegaly
  35. 35. Q7:All of the following are painless conditions except? A. Hashimoto’s thyroiditis B. De Quervain’s thyroiditis C. Reidel’s thyroiditis D. Post partum thyroiditis
  36. 36. Q8:All of the following are features of hypothyroidism except? A. Sinus bradycardia B. Diastolic hypertension C. Systolic hypertension D. Pericardial effusion
  37. 37. Q9:All of the following are features of primary hypothyroidism except? A. Menorrhagia B. Goitre C. increasedTSH D. Poor secondary sexual characters
  38. 38. THANKYOU!!