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.
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
- skin depigmentation
- atrophic breasts
- multiple endocrine neoplasia (MEN) type I
- age - between 5-14 years and older than 65 (craniopharyngiomas)
- age - second to fifth decades (prolactinomas)
- age - fourth to eighth decades (non-functioning pituitary adenomas)
- head and neck irradiation
- traumatic brain injury (TBI)
- family history of central hypothyroidism
1st investigations to order
- serum free thyroxine (T4)
- serum thyroid-stimulating hormone (TSH)
Investigations to consider
- MRI of brain
- CT head
- prolactin (PRL)
- 9 a.m. serum cortisol
- serum testosterone
- serum gonadotrophins
- genetic analyses
Jacqueline Gilbert, PhD, MRCP
King's College Hospital NHS Foundation Trust
JG declares that she has no competing interests.
Dr Jacqueline Gilbert would like to gratefully acknowledge Dr Rasa Zarnegar, a previous contributor to this topic.
RZ declares that he has no competing interests.
James Lee, MD
Department of Endocrine Surgery
JL declares that he has no competing interests.
James V. Hennessey, MD
Director of Clinical Endocrinology
Beth Israel Deaconess Medical Center
JVH declares that he has no competing interests.
Anthony Weetman, MD, DSc, FRCP, FMedSci
Sir Arthur Hall Professor of Medicine/Pro Vice Chancellor
University of Sheffield
AW declares that he has no competing interests.
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