HYPOTHYROIDISM

 Hypothyroidism(underactive thyroid) is a condition in which thyroid gland doesn't produce enough thyroid hormone

PRIMARY HYPOTHYROIDISM

  1. Thyroid gland is involved
  2. T4 DECREASED , T3 DECREASED , TSH  INCREASED(T4↓,T3↓,TSH↑)
  3. CAUSES : INDIA most common cause HASHIMOTO THYROIDITIS , GLOBALLY - ENDEMIC GOITER
  4. ENDEMIC CRETINISM - Body with hypothyroidism since birth
  5. Food goitrogen - cabbage , 
  6. Drug induced hypothyroidism : Amiodarone


SECONDARY HYPOTHYROIDISM

  1. Pituitary gland is involved
  2. T4 DECREASED , T3 DECREASED , TSH DECREASED(T4↓,T3↓,TSH↓)
  3. CAUSES : SHEEHAN SYNDROME (Pituitary infarction)
  4. Non  obstetric cause of pituitary damage called as simmond's disease - occurs due to AVM rupture ,HTN , Trauma , sickle cell anemia
  5. Cranial radiation/sarcoidosis
  6. Empty sella syndrome / CSF leak syndrome 


CLINICAL FEATURES :
  1. Cold intolerance
  2. Myxedema (alopecia , puffy face , Hoarseness voice , thick coarse skin , constipation)
  3. Menorrhagia and infertility
  4. Headache
  5. Galactorrhea (TRH stimulate anterior pituitary to produce TSH and PROLACTIN)

ON EXAMINATION
  1. Bradycardia
  2. Pale yellow skin (occur due to β carotenemia)
  3. Hypertension
  4. Coarse /dry skin
  5. Hung up ankle jerk - most reliable sign (occur due to myxedema)





WORKUP :

Thyroid function test - Total T4 , T3 Decreased ; Free T4 , T3 Decreased

Primary Hypothyroidism

TSH is high
Defect is in thyroid gland
Next investigation - Anti - TPO (thyroid peroxidase ) Ab



Secondary Hypothyroidism

TSH is low 
Pituitary defect
investigation - MRI head



TREATMENT :

LEVOTHYROXINE

If dose is > 100mg, it increase oxygen consumption resulting in angina (so, a very careful titration of  dose increments should be done)
 

COMPLICATIONS :
  1. Myxedema coma
  2. Myxedema madness (psychosis)
  3. Myxedema heart / serous cavity effusion
  4. Macrocytic anemia
  5. Accelerated atherosclerosis












Comments

Popular posts from this blog

COMMUNITY ACQUIRED PNEUMONIA

CHRONIC BRONCHITIS

HYPOKALEMIA(electrolyte imbalance)