• Decrease Thyroid hormones

Classification

• primary hypothyroidism – due to cause within the thyroid gland itself.

• secondary hypothyroidism – due to failure of TSH production following pituitary or hypothalamic disease.

Causes

• spontaneous atropic thyroidism

• iodine deficiency

• iodine therapy

• thyroidectomy

• hashimoto’s thyroiditis

• dyshormonogenesis

• drug-induced ( lithium , amiodrone etc)

• radiation therapy

clinical features

A. Thyroid gland enlargement

B. Gastrointestinal

• weight gain

• decrease in appetite

• constipation

• acsite

C. Cardiorespiratory

• angina

• bradycardia

• hypertension

• pericardial effusion

• Pleural effusion

• cardiac failure

D. Neuromuscular

•ache and pain

•muscle stiffness

•carpal tunnel syndrome

•delayed relaxation of tendon reflex • •depression

•psychosis

•cerebral ataxia

•myotonia

•deafness

E. Dermatological

• mycoderma(non- pitting edema of skin of hands , feet and eyelid)

• dry flaky skin and hair

• Alopecia

• purplish lips

• malar flush

• xanthelasma

• carotenaemia

F. Reproduction

• menorrhagia

• infertility

• galacoma

• impotence

G. Haemtological & miscellaneous

• macrocytosis

• anaemia

• cold intolerance

• tiredness

• harseness of voice

• low pitched sound

Slurred speech

Investigation

• serum T4 decrease; TSH increase ( > 20mU/l)

• serum cholesterol & triglycerides increase

• serum LDH, Ck increase

• serum Na+ decrease

• ECG – sinus bradycardia, low voltage QRS complex, ST – T wave abnormalities

• chest radiograph – Enlargement of cardiac shadow

Treatment

D.o.c – Thyroxine – 50 microgram/day for 3 weeks

then

100microgram/day for 3weeks

then

150microgram/day for maintenance dose

• pt with heart disease angina may worsen with thyroxine therapy -treated with beta block and vasodilators or CABG