Central hypothyroidism

Symptoms of central hypothyroidism include those of primary hypothyroidism (fatigability, cold intolerance, weight gain), with or without other symptoms of hypopituitarism, including hypogonadism and secondary adrenal insufficiency.

Signs on physical examination may indicate hypothyroidism, including skin changes, hair loss, and bradycardia.

Signs indicating a sellar or parasellar mass include papilloedema and visual field deficits (a bitemporal hemianopia).

Diagnostic evaluation of central hypothyroidism includes serum thyroid-stimulating hormone (TSH) and free thyroxine (T4). In central hypothyroidism, free T4 is low and TSH may be low, normal, or minimally elevated. Magnetic resonance imaging may reveal sellar or parasellar pathology.

Treatment of central hypothyroidism is by thyroid hormone replacement (levothyroxine).

Complications of treatment may include thyrotoxicosis and osteoporosis.

Hypothyroidism is a clinical syndrome resulting from a deficiency of thyroid hormones, which results in a generalised slowing of metabolic processes. Central hypothyroidism is the result of anterior pituitary or hypothalamic hypofunction. It may be the result of congenital, neoplastic, inflammatory, infiltrative, traumatic, or iatrogenic aetiologies. It is characterised by decreased thyroid-stimulating hormone secretion in turn causing decreased thyroid hormone synthesis and release.