GOITER

Goiter is an enlargement of thyroid gland with normal or abnormal functions, i.e. euthyroid (most common), hypothyroid or hyperthyroid state.

While in euthyroid/hypothyroid states, goiter repre­sents a compensatory mechanism to restore normal thyroid hormone activity, hyperthyroid goiters are often caused by primary tumors of gland.

Etiology of Goiter is enumerated in Table 22.7, though some important causes are as follows:

• Endemic goiter due to iodine deficiency is the commonest cause of goiter in Indian children (Ch 22.3.3), though the incidence has declined in recent years due to universal iodination of common salt.

• Puberty Goiter is common in adolescent girls of endemic regions for Iodine deficiency due to increased physiological demand unmasking sub-clinical iodine deficiency. It is essentially euthyroid and disappears spontaneously after a few years.

• Congenital goiter is mainly caused by endemic iodine deficiency in mother or rarely due to hormonal- biosynthesis defects or exposure of fetal thyroid to goitrogens, e.g. anti-thyroid drugs in mother. Clinically, congenital goiters are usually small and asymptomatic, but large goiters may present with pressure symptoms, e.g. respiratory distress. While most cases are euthyroid, a short course (1-2 weeks) of Eltroxin therapy is indicated to suppress feedback mechanisms and reduce the gland size.

• Sporadic goiter: Hashimoto's thyroiditis is the commonest cause of sporadic goiter in older children, which is typically nodular and must be differentiated from non-nodular puberty goiter.

IDD: Iodine deficiency disorders

e.g. Cough syrups, antithyroid drugs, amiodarone, lithium, etc.

• Solitary thyroid nodules may be benign or malignant and need fine needle aspiration cytology to exclude malignancy, specially if they are firm, less-mobile and have associated lymphadenopathy.

22.3.3