Hyperpituitarism

Hyperpituitarism is the primary hypersecretion of pituitary hormones. It typically results from a pituitary adenoma. Most pituitary adenomas are functional and secrete a hormone that produces clear symptoms characteristic of their condition.^[1] In children with hyperpituitarism, disruption of growth regulation and/or sexual maturation is common, either because of hormone hypersecretion or because of manifestations caused by local compression of the adenoma. Pituitary adenomas are rare in children, accounting for only 3-6% of all adenomas, whereas they comprise 30% of adenomas in adults.

There are three hormones that are oversecreted resulting in the pituitary adenoma: prolactin, adrenocorticotropic hormone (ACTH), and growth hormone (GH).^[2]

Excess prolactin may result in a prolactinoma. The symptoms may vary, depending on the age and sex of the child. Prepubertal children typically experience a combination of headaches, visual disturbance, and growth failure. Pubertal females frequently have symptoms of pubertal arrest or hypogonadism due to suppression of gonadotropin secretion or local compression of the pituitary. Pubertal males may have symptoms of headaches, visual impairment, and pubertal arrest or growth failure.^[3]

Excess ACTH commonly results in weight gain. Hirsutism and premature adrenarche may occur in prepubertal children. Pubertal arrest, acne, fatigue, and depression are also common.^[1]

Excess GH results in gigantism. The severity of gigantism depends on whether the epiphyseal plate is open. Before epiphyseal fusion, accelerated growth velocity is prominent. As epiphyseal fusion approaches, the spectrum of symptoms resembles that in adults (eg, coarsening of facial features, change in ring and shoe size).^[4]

The four most common types of hyperpituitarism are prolactinoma, corticotropinoma (Cushing's disease), somatotropinoma (gigantism), and thyrotropinoma (a rare pituitary cancer).^[2]

Clinical manifestations

Depending on the cell type(s) affected, clinical manifestations of hormone excess may include:

• Hyperprolactinaemia
• Cushing's disease
• Precocious puberty
• Gigantism or Acromegaly
• Hyperthyroidism (rare)

Associated conditions

When there is an enlargement of the pituitary tissue, hyperpituitarism is often associated with:

• Visual field defects, classically bitemporal hemianopia
• Radiographic abnormalities of the sella turcica, such as sellar expansion, bony erosion and disuption of the diaphragma sellae
• Increased intracranial pressure

Symptoms

Symptoms caused by hormone excess and associated mass effects include:

• Headache
• Visual field loss or Double vision
• Excessive sweating
• Hoarseness
• Milk secretion from breast
• Sleep apnea
• Carpal tunnel syndrome
• Joint pain and limitation of motion
• Muscle weakness
• Numbness or tingling of skin
• Elevated PTH level

See also

• Hypopituitarism

References