Hypopituitarism

Question 1

Define hypopituitarism?

Answer 1

Deficiency in one or more of the hormones secreted by the anterior pituitary.

Panhypopituitarism is deficiency of ALL pituitary hormones.

Question 2

what are the causes of hypopituitarism?

Answer 2

Pituitary Masses

• Most commonly adenomas
• Others include craniopharyngioma, meningioma, glioma, metastases
• Cysts

Pituitary Trauma - radiation, surgery, base of skull fractures, empty sella turcica

Hypothalamic Dysfunction - due to anorexia, starvation, over-exercise

Infiltrative Diseases - sarcoidosis, haemochromatosis, Langerhans’ cell histiocytosis, tuberculosis

Vascular - pituitary apoplexy, Sheehan’s syndrome

• Pituitary apoplexy is the sudden spontaneous development of a haemorrhage into or infarction of a pre-existing adenoma.
• Sheehan syndrome is infarction of the pituitary after substantial blood loss with hypotension during childbirth.

Infection - meningitis, encephalitis

Genetic Mutations - Pit-1 and Prop-1 genes

Question 3

what is pituitary apoplexy?

Answer 3

sudden spontaneous development of haemorrhage into or inarction of pre-existing adenoma

Question 4

what is sheehan’s syndrome?

Answer 4

is infarction of the pituitary after substantial blood loss with hypotension during childbirth.

Question 5

summarise the epidemiology of hypopituitarism?

Answer 5

Pituitary adenoma annual incidence: 1/100,000

Question 6

what are the symptoms of pituitary apoplexy?

Answer 6

headache

visual loss

cranial nerve palsies

Question 7

what are the signs and signs of hypopituitarism?

Answer 7

GH

• CHILDREN: short stature, failure to thrive
• ADULTS: low mood, fatigue, reduced exercise capacity and muscle strength, increased abdominal fat mass

LH or FSH

• Delayed puberty
• FEMALES: loss of secondary sexual hair, breast atrophy, menstrual irregularities, dyspareunia, decreased libido, infertility
• MALES: loss of secondary sexual hair, gynaecomastia, small and soft testes, decreased libido, impotence

ACTH- signs/symptoms of adrenal insufficiency e.g. hypoglycaemia, hypotension, N+V, fatigue, weakness, dizziness

TSH - signs/symptoms of hypothyroidism e.g. cold intolerance, weight gain, constipation, dry skin

Prolactin - absence of lactation (not usually noticed clinically)

Question 8

what are the appropriate investigation for hypopituitarism?

Answer 8

Bloods

• Sodium – low in ACTH and TSH def vs high in DI
• Serum and urine osmorality- low urine omsolarity and high serum osmolarity

Basal Tests

• 9 am cortisol and ACTH- low
• LH and FSH levels- low
• Testosterone levels- low
• Oestrogen levels- low
• IGF-1 levels- low in GH deficiency
• Prolactin levels
• Free T4 and TSH levels- low T4 and T3 and low/ normal TSH

Dynamic Tests (rarely performed)

• Insulin-induced hypoglycaemic (should cause a rise in GH and cortisol)
• Short synacthen test (for adrenal insufficiency)
• Water deprivation and desmopressin response test (for DI)

MRI- lesion in sellar or parasellar regions

CT of brain- calcification if craniopharyngioma present

Visual field testing

Question 9

Outline a management plan for hypopituitarism?

Answer 9

Hydrocortisone – IV given first line with pit apoplexy then norm oral dose

Levothyroxine

Sex hormones

• Testosterone in males
• Oestrogen with/without progesterone in females
• Women and men with secondary hypogonadism who desire fertility are given gonadotrophins

Growth hormone – somatropin

Desmopressin (if central diabetes insipidus as a result of panhypopituitarism)

Question 10

what are the possible complications of hypopituitarism?

Answer 10

Addisonian crisis

Hypoglycaemia

Myxoedema coma

Infertility

Osteroporosis

Dwarfism (children)

Complications of pituitary mass:

• Optic chiasm compression (leading to bitemporal hemianopia)
• Hydrocephalus
• Temporal lobe epilepsy

Question 11

state 3 complications of a pituitary mass?

Answer 11

Optic chiasm compression (leading to bitemporal hemianopia)

Hydrocephalus

Temporal lobe epilepsy

Question 12

summarise the prognosis of hypopituitarism?

Answer 12

GOOD prognosis with lifelong treatment