basics of hyperthyroid

1. HYPERTHYROIDISM
Dr Sravan Kumar G
M.D.Medicine (PGIMER)
Assistant Professor
MRIMS

2. etiology
 Graves disease
 Toxic Multinodular goitre
 Toxic nodule

3. Cardiovascular System
 hypermetabolism and the need to dissipate the excess heat produced
 peripheral vascular resistance is decreased, and cardiac output is increased
first increase in heart rate and with more severe disease, in stroke volume.
 increased sympathetic and decreased vagal tone
 Palpitations
 Cardiac arrhythmias
 Atrial fibrillation

4. Protein, Carbohydrate, and Lipid
Metabolism
 degradation rates of proteins are increased, decrease in tissue protein,
loss of weight, muscle wasting, proximal muscle weakness,
mild hypoalbuminemia
 Preexisting diabetes mellitus – aggravated - accelerated turnover of insulin
 lipolysis - increase in the plasma concentration of free fatty acids and
glycerol and a decrease in serum cholesterol level & triglyceride levels

5. Sympathetic Nervous System
and Catecholamines
 thyroid hormones increase sensitivity to catecholamines in both
cardiomyocytes and adipocytes by a variety of mechanisms.

6. Nervous System
 Fatigue
 Nervousness
 emotional lability
 Hyperkinesia
 fine tremor of the hands, tongue, or lightly closed eyelids

7. Muscle
 Proximal muscle weakness - diffculty in climbing stairs or fatigue from
minimal exertion such as using a blow dryer or lifting an infant

8. Eyes
 retraction of the upper or lower
eyelids, or both - presence of a
rim of sclera between either lid
and the limbus – typical stare
 lid lag, a phenomenon in which the
upper lid lags behind the globe when the
patient is asked to shift the gaze
slowly downward
 globe lag, which becomes evident
when the eye lags behind the upper
lid when the patient looks up
 increased adrenergic tone

9. Skin and Hair
 warm, moist feel of the skin - cutaneous vasodilation and excessive sweating
 Palmar erythema
 hair is fine and friable, and hair loss may increase

10. Respiratory System
 dyspnea

11. Alimentary System
 Increased apetite & weight loss

12. Skeletal System: Calcium and
Phosphorus Metabolism
 increased excretion of calcium and phosphorus in urine and stool-increase in
bone turnover and a net demineralization of bone

13. Reproductive system
 Amenorrhea, infertility
 Gynecomastia - androstenedione to testosterone, estrone, and estradiol
 increased rate of conversion of androgens to estrogenic byproducts -
gynecomastia - erectile dysfunction

14. Graves disease

15.  autoimmune disorder
 TSHR antibodies (TRAb)
 80% of all cases of thyrotoxicosis
 Natural History and Course of Graves Disease - unpredictable

16. Graves Orbitopathy
1)extraocular muscle and adipose tissue are swollen-accumulation in the
extracellular matrix of glycosaminoglycans (GAGs) and new fat cell development
(adipogenesis) within the orbit.
2)GAGs are secreted by fibroblasts under the influence of TRAbs, level of TRAbs
often correlates with the severity of the eye disease
3)risk factors - Smoking & Radioiodine

17. Graves dermopathy
compression of the dermal lymphatics and nonpitting edema

18. Investigations
 TSH (<0.1 mIU/mL) , T3, T4 – high
 TRAbs
 Anti TPO Ab

19. Treatment
 Choose between 1) Anti thyroid drugs (Contraindication: previous known adverse
effects to antithyroid drugs)
2) RAI therapy (Contraindication: pregnancy, lactation, coexisting thyroid cancer)
3) Thyroidectomy
 Antithyroid Agents
 10 mg of carbimazole = 6 mg of methimazole
 T Carbimazole 10 mg BD/ T Methimazole 10 mg BD
 Maintanence dose – 5 to 10 mg/day
 Propronolol (T INDEROL 10 mg BD)

20. Hyperthyroidism in pregnancy
 Potency methimazole to PTU is around 20:1
 1 st trimester – PTU
 2 nd trimester – Methimazole/ carbimazole

21.  Multinodular goitre
 Solitary nodule

22. Subclinical
hypothyroidism
 TSH – 4 to 10 mIU/mL
 Treat if 1) Symptoms of Hypothyroid
2) Goitre 3) High Antibody titre of
Anti TPO Ab 4) has Cardiovascular
disease 5) Pregnancy
 Treatment doses half of
hypothyroidism
 TSH – 0.1 to 0.4
 Postmenopausal osteoporosis
 Rheumatic valvular disease with left
atrial enlargement or atrial
fbrillation
 Congestive heart failure
 Angina pectoris
 Infertility or menstrual disorders
 Nonspecifc symptoms such as
fatigue, nervousness, depression, or
gastrointestinal disorders, especially
in patients older than 60 years
of age (consider therapeutic trial)
Subclinical
hyperthyroidism