Central hypothyroidism

Symptoms of central hypothyroidism are similar to those of primary hypothyroidism (including fatigability, cold intolerance, weight gain, and depression), and may or may not be accompanied by symptoms of hypopituitarism, such as those of hypogonadism (i.e., decreased libido, infertility) and secondary adrenal insufficiency (i.e., weakness, nausea, vomiting).

Signs of central hypothyroidism on physical examination would also be similar to those of primary hypothyroidism and may include dry skin, hair loss, bradycardia, and delayed deep tendon reflexes.

Specific signs suggestive of a sellar or parasellar mass include papilloedema and bitemporal hemianopia.

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

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

Complications of treatment may include thyrotoxicosis and osteoporosis.

Hypothyroidism is a condition resulting from the deficiency of thyroid hormones, which leads to a generalised slowing of metabolic processes. Central hypothyroidism arises from an anatomical or functional disorder of the pituitary gland and/or the hypothalamus. This decreases thyroid-stimulating hormone secretion, leading in turn to decreased thyroid hormone synthesis and release.[1]Beck-Peccoz P, Rodari G, Giavoli C, et al. Central hypothyroidism: a neglected thyroid disorder. Nat Rev Endocrinol. 2017 Oct;13(10):588-98. http://www.ncbi.nlm.nih.gov/pubmed/28549061?tool=bestpractice.com Central hypothyroidism may be due to congenital, neoplastic, inflammatory, infiltrative, traumatic, or iatrogenic aetiologies.