Even in first world countries like Australia and USA, a General Practitioner (GP) may face 1 patient of thyroid disorder in every 2500 patients a year. In a country like ours where Congenital Hypothyroidism is seen in 1.5 newborns in every 1000 (Source: Study on The Incidence on Congenital Hypothyroidism, Khulna Medical College Hospital) and 60% of salt samples collected from Rangpur District are non iodized (Study of Thyroid Volume In Urban and Rural School Going Children of Rangpur District Rangpur Medical College Hospital), the high incidence of hypothyroidism cannot be ignored and requires prompt diagnosis and intervention on part of every GP.

Investigations:

T4 -- Subnormal           

 TSH-elevated (>10 is clear gland failure) If T¬4 is low and TSH is low or normal, one may consider pituitary dysfunction (secondary hypothyroidism) or sick euthyroid syndrome.

Other tests

Serum cholesterol level elevated.

Anaemia: usually normocytic; may be macrocytic.

ECG: sinus bradycardia, low voltage, A at T waves.

Management:

Thyroid medication

 Thyroxine 100-150 meg daily (once daily)

Aim to achieve TSH levels of 0.5-2 mUJL.

We should monitor TSH levels monthly at first. As euthyroidism is achieved, monitoring may be less frequent.

Special treatment considerations

Ischaemic heart disease. Rapid thyroxine replacement can precipitate myocardial infarction, especially in the elderly.

Pregnancy and postpartum. Continue thyroxine during pregnancy; watch for hypothyroidism (an increased dose of T4  is often required).

Elective surgery. If euthyroid, thyroxine maybe stopped for one week. If subthyroid, defer surgery until euthyroid.

Myxoedema coma. Urgent hospitalization under specialist care is required. Intensive treatment is required, which may involve parenteral T4 or T3.  (Reprint)