Download Lecture on Hypothyroidism

• Decrease secretion or function of thyroid gland or thyroxin .
1. PRIMARY HYPOTHYROIDISM: Due to diseases of thyroid gland.
• Without Goitre : eg; Idiopathic /Autoimmune Atrophic Hypothyroidism,
Radioactive Iodine Therapy, Thyroidectomy, Congenital Agenesis,
Transient(Infection, Post partum thyroiditis, Thyroid hormone withdrawal).
• With Goitre : eg; Hashimoto’s Thyroiditis, Drug Induced(INF, ATD,
Amioderone, Lithium), Endemic Iodine Deficiency, Dyshormonogenesis/Inborn
Errors, Infiltrative disorders ( Amyloidosis, Sarcoiudosis, Riedel’s thyroiditis.
2. SECONDARY HYPOTHYROIDISM: Due to pituitary lesions.
3. TERTIARY HYPOTHYROIDISM: Due to hypothalamic lesions.
CLINICAL FEATURES:
• COMMON: Weight gain, Cold intolerance, Fatigue, Somnolence, Dry skin & hair,
Menorrhagia.
• LESS COMMON: Constipation, Hoarseness, Carpal tunnel syndrome, Alopecia,
Aches & pains, Muscle stiffness, Deafness, Depression, Infertility, Malar flush,
Periorbital edema/Myxedema, Loss of lateral eyebrows, Anemia, Carotenemia,
Bradycardia, Hypertension, Delayed relaxation of tendon reflexes, Dermal
myxedema.
• RARE: Psychosis ( Myxedema madness ), Galactorrhea, Impotence, Ileus, Ascites
Pericardial & Pleural Effusion, Cerebellar Ataxia, Myotonia.
INVESTIGATIONS:
1. T4 : Decreased.
2. TSH : Increased ( > 20 Mu/L ).
3. Thyroid peroidase antibodies, Antibodies to Thyroglobulin
& TSH receptors : Increased.
4. Serum CK, AST, LDH : Increased.
5. Cholesterol : Increased.
6. Na : Decreased.
7. Anemia : NCNC / Macrocytic.
8. ECG : Sinus bradycardia, Low voltage complexes, STSegment & T wave changes.
MANAGEMENT:
Thyroxin replacement therapy:
 1st 03 weeks = 50 micro grams/day.
 Next 03 weeks = 100 micro grams/day.
 maintenance = 100- 250 micrograms/day
IN ISCHEMIC HEART DISEASE & ELDERLY PATIENTS:
 Initial = 25-50 micro grams/day along with beta blockers and
vasodilators. In non-responders to beta blockers and vasodilators PTCA
or CABG may be required.
HYPOTHYROID AND PREGNENCY:
 Pregnant women require 50 micro grams more thyroxin than nonpregnant due to increase serum TBG.
MYXEDEMA COMA: Severe Hypothyroidism In Elderly Patients.
• Hypothermia.
• Hypoglycemia.
• Hyponatremia.
• Confusion or Coma
TREATMENT IN MYXEDEMA COMA:

Inj: T3 20 micro grams I/V x 8 h for 48-72 h or Levo Thyroxin Na (400
micro grams I/V stat than 100 micro grams/day) followed by oral
thyroxin 50 micro grams/day or through N/G tube.
 Oxygen inhalation.
 Hydrocortisone (100 mg I/V stat followed by 25-50 mg I/V 8 h).
 5% D/W.
 Broad spectrum antibiotics.
 Gradual re-warming by blankets.