Hypopituitarism

Question 1

What is hypopituitarism?

Answer 1

Deficiency of one or more of the hormones secreted by the anterior pituitary - Panhypopituitarism is deficiency of all pituitary hormones

Question 2

What is the aetiology of hypopituitarism?

Answer 2

• Pituitary masses: Most commonly adenomas. Other parapituitary tumours (e.g. craniopharyngioma, meningioma, glioma, metastases), cysts (arachnoid cyst, Rathke’s cleft cyst) - Pituitary trauma: Radiation, surgery or skull case fracture - Hypothalamus (functional): Anorexia, starvation, over-exercise - Infiltration: Tuberculosis, sarcoidosis, haemochromatosis, histicytosis X - Vascular: Pituitary apoplexy, Sheehan’s syndrome - Infection: Meningitis, encephalitis, syphilis, fungal abscess - Genetic mutations: Pit-1 and Prop-1 genes

Question 3

What is the aetiology of hypopituitarism?

Answer 3

Annual incidence and prevalence of pituitary adenoma: 1 in 100,000 and 9 in 100,000, respectively

Question 4

What are signs and symptoms of hypopituitarism with GH deficient?

Answer 4

• Children: Short stature (less than 3rd centile/not in keeping with parental height) - Adults: Low mood, fatigue, reduced exercise capacity, muscle strength, increased abdominal fat mass

Question 5

What are the signs and symptoms of hypopituitarism with LH/FSH deficient?

Answer 5

Delayed puberty - Females: Loss of secondary sexual hair, breast atrophy, menstrual irregularities, dyspareunia, decreased libido, infertility - Males: Loss of secondary sexual hair, gynaecomastia, small or soft testes, reduced libido, impotence

Question 6

What are the signs and symptoms of hypopituitarism with prolactin deficient?

Answer 6

Absence of lactation - in Sheehan’s syndrome

Question 7

What are the signs and symptoms of pituitary apoplexy?

Answer 7

Life-threatening hypopituitarism with headache, visual loss and cranial nerve palsies

Question 8

What are the investigations for hypopituitarism?

Answer 8

Pituitary function tests - Basal tests: 9am cortisol, LH, FSH, testosterone, oestradiol, IGF-1, prolactin, free T4 and TSH - Dynamic tests: insulin-induced hypoglycaemia (contraindicated in pts with epilepsy, IHD, hypoadrenalism) Give 0.15 U/kg IV insulin. In hypopituitarism, peak GH and cortisol response to insulin-induced hypoglycaemia are less than20 U/L and less than 550 nmol/L respectively - Short Synacthen test - MRI or CT of brain - Visual field testing

Question 9

How is hypopituitarism managed?

Answer 9

Hormone replacement: - Hydrocortisone: Should be provided with Medicalert bracelet and steroid card - L-thyroxine: Take after hydrocortisone to avoid Addisonian crisis - Sex hormones: Testosterone in males. Oestrogen with/or progesterone in females - Growth hormones: children require specialist supervision - Posterior pituitary deficiency: Desmopressin

Question 10

What are the complications of hypopituitarism?

Answer 10

• Adrenal cris, hypoglycaemia, myxoedema coma, infertility/ - Osteoporosis, dwarfism (children) - Complications of pituitary mass: optic chiasm compression, hydrocephalus (third ventricular compression), temporal lobe epilepsy

Question 11

What is the prognosis of hypopituitarism?

Answer 11

Good with lifelong hormone replacement