Hypopituitarism

Question 1

Define

Answer 1

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

They are affected in this order:

1. Growth hormone
2. Gonadotropins: FSH and LH
3. Prolactin
4. Thyroid-stimulating hormone (TSH)
5. Adreno-corticotropic hormone (ACTH)

Question 2

Causes

Answer 2

Hypothalamus: anorexia, starvation, over-exercise

• Pituitary masses: most commonly adenomas
• Pituitary trauma: radiation, surgery, skull base fracture
• Infiltration: TB, sarcoidosis, haemochomatosis
• Vascular: pituitary apoplexy, Sheehan’s syndrome
• Infection: meningitis, encephalitis
• Genetic mutations

Pituitary apoplexy: haemorrhage/ infarction of a pituitary tumour Life threatening – headache, visual loss, CN palsies

Sheehan’s syndrome: pituitary infarction, haemorrhage and necrosis following post-partum haemorrhage

Question 3

Epidemiology

Answer 3

pituitary adenomas 9/100 000

Question 4

Causes

Answer 4

Depends on CAUSE

Symptoms and signs are dependent on the hormone that is deficient:

GH

• CHILDREN: short stature
• 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

TSH - signs/symptoms of hypothyroidism

Prolactin - absence of lactation (not usually noticed clinically)

Pituitary Apoplexy has some other symptoms:

• Headache
• Visual loss
• Cranial nerve palsies

Question 5

Investigation

Answer 5

Pituitary Function Tests

Basal Tests

• 9 am cortisol
• LH and FSH levels
• Testosterone levels
• Oestrogen levels
• IGF-1 levels
• Prolactin levels
• Free T4 and TSH levels

Dynamic Tests (rarely performed)

• Insulin-induced hypoglycaemic (should cause a rise in GH and cortisol)

Short synacthen test (for adrenal insufficiency)

MRI/CT of brain

Visual field testing

Question 6

Management

Answer 6

Hormone Replacement

Hydrocortisone

Levothyroxine

Sex hormones

• Testosterone in males
• Oestrogen with/without progesterone in females
• Growth hormone
• Desmopressin (if central diabetes insipidus as a result of panhypopituitarism)

Question 7

Complications

Answer 7

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 8

Prognosis

Answer 8

GOOD prognosis with lifelong treatment