Hypothyroidism (underactive thyroid) is a condition in which your thyroid gland doesn't produce enough of certain important hormones.

1. By:
Farshid Mokhberi
Medical Student at:
Shahid Beheshti University of Medical Sciences and Health Services

2. Anatomy of Thyroid Gland

3. Histology

5. Transfering from cell to blood

6. Mechanism of action

7. Regulation of synthesis

8. Functions
 Carbohydrate metabolism
 Cholesterol metabolism
 Growth
 Skeletal muscle
 Heart
 CNS
 Calorigenic action

9. Hypothyroidism:
 Hypothyroidism is a common endocrine disorder
resulting from deficiency of thyroid hormone.

11. Risk Factors
 woman older than age 60
 Have an autoimmune disease
 Have a close relative autoimmune disease
 Have been treated with radioactive iodine or anti-
thyroid medications
 Received radiation to your neck or upper chest
 Have had thyroid surgery (partial thyroidectomy)
 Have been pregnant or delivered a baby within the
past six months

14. SKIN
 Cool and pale
 Sweating is decreased
 Yellowish tinge
 Hyperpigmentation
 Coarse hair
 Hairloss
 Non pitting edema
 Cold intolerance
 Dry skin

15. Eyes
 Periorbital edema

16. Cardiovascular
 Decreased heart rate
 Decreased cardiac output
 Pericardial effusion
 Diastolic hypertension
 Hypercholesterolemia
 hyperhomocystinemia

17. Respiratory
 Fatigue
 Shortness of breath on exertion
 Hypoventilation
 Sleep apnea
 Hoarseness of voice

18. Gastrointestinal
 Constipation
 Ascites
 Weight gain
 Gastric atrophy

19. Reproductive
 Oligorrhea
 Amenorrhea
 Menorrhagia
 Decreased fertility
 Early abortion

20. Neurologic
 Mental slowing
 Myxedema coma
 Mental retardation

21. Myxedema coma
The condition occurs in patients with long-standing,
untreated hypothyroidism.
mental status, including
 lethargy
 stupor
 delirium(acute confusional state)
 coma

22. Musculoskeletal
 Joint pains
 Aches
 stiffness

23. Metabolic
 Hyponatremia
 Hyperlipidemia
 Increased homocystine

26. Normal values
 TSH 0.4- 5.0 mU/L
 Total T4 4.6-11.2 mcg/dl
 Total T3 75-195 ng/dl
 Free T4 0.8-1.8 ng/dl
 Free T3 2.3-4.2 pg/ml

28. Treatment
INITIAL DOSE
 Young healthy-1.6mcg/Kg wt
 Elderly-50mcg
TIMING OF DOSE
 Half an hour before food
SIDE EFFECTS-Rare
 Allergy to dye in the tablets

29. MONITORING
 Every 6 weeks
 If TSH is not with in normal range increase the dose by
12.5-25mcg
 If TSH normal ,monitor TSH once a year

30. Refrences