Paediatrics: Hypopituitarism

Hypopituitarism

Hypopituitarism refers to either partial or complete deficiency of the an-terior and/or posterior pituitary function. Hypopituitarism may be congen-ital or acquired, secondary to pituitary disease or to hypothalamic pathol-ogy that interferes with pituitary function. Clinical features depend on the type of hormone deficiency, its severity, and rate of development.

Congenital hypopituitarism

Mutations in pituitary transcription factor genes (e.g. HESX-1, PIT-1, LHX-4) can result in isolated or multiple anterior pituitary hormone deficiencies.

A number of specific inherited genetic defects have been characterized. Abnormalities in the hypothalamic–pituitary structures and other midline brain structures (e.g. septo-optic dysplasia; optic nerve hypoplasia; absent corpus callosum) are often detected on imaging.

Acquired hypopituitarism

Potential causes of pituitary hormone deficiency include the following:

·Intracranial (parapituitary) tumours.

·Cranial irradiation/radiotherapy: GH axis is the most sensitive to radiation damage, followed by gonadotrophin, and adrenal axes, and finally by thyroid axis.

·Traumatic brain injury.

·Inflammatory/infiltrative disease: Langerhan’s cell histiocytosis; sarcoidosis.

·Pituitary infarction (apoplexy).

·Intracranial infection.

Investigations

·Basal hormone levels: e.g. LH/FSH; TSH, fT4; prolactin; cortisol (9 a.m.); IGF-I.

·Dynamic endocrine testing: specific tests to assess secretory capacity of the anterior pituitary gland.

·MRI scan: brain.

Treatment 

Treatment involves adequate and appropriate hormone replacement therapy and, where applicable, management of underlying cause.