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. Central hypothyroidism may be due to congenital, neoplastic, inflammatory, infiltrative, traumatic, or iatrogenic aetiologies.
History and exam
Key diagnostic factors
- presence of risk factors
- cold intolerance
Other diagnostic factors
- decreased memory
- muscle cramps
- weight gain
- dry, coarse skin
- reduced body and scalp hair
- delayed relaxation of deep tendon reflexes
- hearing impairment
- impassive facial expression
- diabetes insipidus (DI)
- decreased peripheral vision
- atrophic breasts
- moon facies
- buffalo hump
- presence of pituitary mass lesions
- multiple endocrine neoplasia (MEN) type I
- head and neck irradiation
- traumatic brain injury (TBI)
- age between 5-15 years and 45-60 years (craniopharyngiomas)
- age 20-50 years (prolactinomas)
- age 40-80 years (non-functioning pituitary adenomas)
- Sheehan syndrome (postnatal pituitary necrosis)
- lymphocytic hypophysitis
- family history of central hypothyroidism
- anticonvulsant drugs
1st investigations to order
- serum free thyroxine (FT4)
- serum thyroid-stimulating hormone (TSH)
Investigations to consider
- pituitary MRI
- head CT
- serum prolactin (PRL)
- fasting morning serum cortisol
- serum testosterone
- serum gonadotrophins
- genetic analyses
- Primary hypothyroidism
- Non-thyroidal illness
- Iodine deficiency
- Hypothalamic-pituitary and growth disorders in survivors of childhood cancer
- Guidelines on the diagnosis and management of central hypothyroidism
Underactive thyroid: questions to ask your doctorMore Patient leaflets
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