Hypothyroidism is an endocrine disorder caused by deficiency of Thyroid hormone which results in systemic manifestation of a spectrum of symptoms. Prevalence : Primary hypothyroidism is 1:100 but increases upto 1:20 if patients with subclinical hypothyroidism are included. But in Mountainous region of Nepal, Iodine deficiency is common. Female:male= 6:1 Etiology or Causes of Hypothyroidism: Autoimmune or Hashimoto’s Disease and Iatrogenic causes account for maore than 90% of cases. Mnemonic- “AITI CIS” ( 80 Kiss) Autoimmune- Hashimoto’s thyroiditis, Spontaneous Atrophic hypothyroidism,Grave’s Disease with TSH receptor blocking Ab. Iatrogenic – Radioactive Iodine Ablation, Thyroidectomy, Drug- Carbimazole, Methimazole, Lithium, Amiodarone Transient Thyroiditis- Subacute or de Quervian’s thyroiditis, Post-partum thyroiditis Iodine deficiency- common in mountainous region. Congenital- Dyshormonogenesis, Thyroid aplasia Infiltrative- Amyloidosis, Reidel’s thyroiditis, sarcoidosis. Secondary Hypothyroidism- TSH deficiency Clinical Features : hypothyroidism Symptoms: Weight gain Cold intoerence Yellowish tinge of skin ( Carotenemia ) Fatigue, somnolence hoarseness of voice constipation Aches and pains deafness depression or physosis ( Myxedema madness) Dry skin , hair, alopecia Menorrhagia, Infertility, Galactorrhea, Impotence The body tissues are infiltrated by the mucopolysaccharides, hyaluronic acid and chondroitin sulphate resulting in low pitched voice, deafness, large tonge and Carpal tunnel syndromes. Signs: Weight gain Hoarse Voice Goitre Ascites, Ileus Bradycardia, Hypertension and Pericardial or pleural effusion. Macrocytosis, Anemia Delayed tendon reflexes Cerebellar ataxia Myotonia Myxedema, purplish lips, malar flush, Vitiligo, Erythema ab igne Periorbital edema, loss of eye brows Investigations- Non-specific Lab abnormalities seen: Serum Enzymes- Raised CK, AST, LDH. Hypercholesterolemia Anaemis- Normochromic normocytis or macrocytic Hyponatremia Thyroid Function Test- Serum free T3, T4 and TSH can determine the type of Hypothyroidism. ( Clinical , Subclinical) Measurement of Thyroid Peroxidase antibodies is helpful Management- Unless its transient Hypothyroidism, patient will require life-long replacement. Start with 50 Microgram of Thyroxine per day for 3 weeks Increase to 100 microgram per day in next 3 weeks Then to Maintainance dose of 100-150 microgram per day TFT can be repeateda after 6 weeks. Adjustment dose is increased by 25 microgram. Patient feels better in 2-3 weeks. Repeat TFT every 1-2 year. In special conditions : Ischemic heart disease: low dose of 25 Microgram per day Pregnancy:- additional 50 microgram is needed. Source
