Pituitary Disease

Question 1

What are some types of pituitary disease?

Answer 1

Tumours:
Adenoma,
Prolactinoma
Acromegaly
Cushing’s disease
Deficiencies:
Hypopituitarism
Growth hormone deficiency
Gonadotrophin deficiency
SIADH

Question 2

Describe features of a pituitary adenoma

Answer 2

Most common pituitary tumour. It is benign and non secretory so just presents with a headache and visual field defects (bitemporal hemianopia)
Diagnosis - MRI brain
Treatment - Neurosurgery which is usually trans-sphenoidal. Or radiotherapy

Question 3

What is the most common secretory tumour of the pituitary?
How is it classified

Answer 3

Prolactinoma.
Microadenoma if <10mm.
Macroadenoma if >10mm

Question 4

Explain the presentation of a prolactinoma

Answer 4

High levels of prolactin which can cause oligomenorrhoea/amenorrhoea, galactorrhoea, infertility and vaginal dryness in women. In men it can cause erectile dysfunction and reduced facial hair.
In both sexes you get headaches and visual field defects.

Question 5

What are the investigations for a prolactinoma?

Answer 5

MRI brain and serum prolactin

Question 6

What is the management of a prolactinoma

Answer 6

Pharmacological - Dopamine agonists (Carbergoline) which decreases serum prolactin
Hormone replacement with oestrogen if galactorrhoea and fertility are not an issue
Surgical - Trans-sphenoidal resection
Radiotherapy

Question 7

What is the cause of Acromegaly?

Answer 7

Caused by excessive GH production from anterior pituitary.
The hypothalamus secretes GH releasing hormone every few hours and can increase with low blood glucose levels, lack of food, increased exercise and increased sleep.
Negative feedback to hypothalamus by GH and somatostatin.

Question 8

What are the effects of growth hormone?

Answer 8

Increased release of glucose into blood
Muscle growth
Thickened bone
Insulin resistance

Question 9

What is the presentation of Acromegaly in adults?

Answer 9

Insidious onset
Hyperhydriasis
Headaches
Lethargy
Joint pains
Facial changes: coarsening of features, frontal bossing, enlarged nose, prognathism (protrusion/extension of mandible), macroglossia
Deepening of voice,
Enlarged hands and feet
Obstructive sleep apnoea
Diabetes mellitus
CHF (heart failure)
GI cancer
Carpal tunnel syndrome

Question 10

What does excess growth hormone in children cause?

Answer 10

Increased growth velocity = gigantism

Question 11

What are the investigations for acromegaly?

Answer 11

Serum Insulin growth factor 1 (first line)
Oral glucose tolerance test (failure to suppress GH in response to glucose
MRI brain

Question 12

What is the treatment for acromegaly?

Answer 12

surgery/radiation if pituitary adenoma
Medications such as somatostatin analogues which limit GH production

Question 13

What are the causes of SIADH?

Answer 13

Strokes
Haemorrhages
Trauma
Drugs (mood stabilisers or anti epileptics)
Surgery
Pulmonary diseases (Infections, pneumothorax, asthma, cystic fibrosis)
Ectopic ADH release from tumours (small cell carcinoma)
Infections
Family history

Question 14

What are the symptoms of SIADH?

Answer 14

These are caused by hyponatraemia:
Headaches
Nausea
Vomiting
Muscle cramps
Tremors
Cerebral oedema - Confusion, mood swings, hallucinations

Question 15

Why do you get hyponatraemia in SIADH?

Answer 15

ADH increases the water reabsorption (dilutes sodium) and this increases BP which reduces aldosterone which causes sodium excretion.

Question 16

What are the investigations for SIADH?

Answer 16

Hyponatraemia
Low plasma osmolality
High urine osmolality
High urine sodium

Question 17

What is the treatment for SIADH?

Answer 17

Find underlying cause
Managed by reducing fluid intake and starting a high salt/protein diet.
Can use drugs such as Tolvaptan

Question 18

What is central pontine myelinolysis (osmotic demyelination syndrome)?

Answer 18

Complication of long term severe hyponatremia being treated too quickly.
First phase is encephalopathy and confusion.
Second phase occurs due to demyelination of the neurons particularly in pons which can present with spastic quadriparesis, psudobulbar palsy etc

Question 19

What are causes of hypopituitarism

Answer 19

Compression - Pituitary adenoma, CSF excess (empty sella syndrome) When pituitary is squished, it just stops functioning
Tissue ischaemia -Haemorrhage (usually caused by adenoma), Infarction (Sheehan’s syndrome - pregnancy)
Iatrogenic- Radiation or neurosurgery

Question 20

In hypopituitarism what is the first hormone lost?

Answer 20

Growth hormone followed by LH and FSH

Question 21

What are the symptoms for hypopituitarism?

Answer 21

LH and FSH deficiency
Women: Oligomenorrhoea, Amenorrhoea Infertility, Breast atrophy
Men: Loss of pubic hair Loss of muscle mass
ACTH
Adrenal insufficiency
Weight loss, delayed puberty, low sodium and low glucose
GH
Failure to grow, delayed puberty,
TSH
Weight gain, hair loss, low BP, constipation
Increased ICP headaches, visual field defects.

Question 22

How can you make the diagnosis of hypopituitarism and treat it?

Answer 22

Assess baseline hormones in the morning
Giving patient insulin causes drop in blood glucose which stimulates GH and ACTH
MRI scan
Treatment is correcting underlying cause

Question 23

what is the cause of diabetes insipidus?

Answer 23

Deficiency in ADH either when there isn’t production from the pituitary gland or when the kidney fails to respond. So there is a high urine output

Question 24

What are the symptoms of diabetes insipidus?

Answer 24

Polyuria
Polydipsia
Hypernatraemia (lethargy, thirst, weakness, confusion, coma)

Question 25

What are the investigations for diabetes insipidus

Answer 25

Blood tests - Hypernatraemia and high plasma osmolality
24 hour urine collection - Sodium will be low and urine osmolality will be low
Fluid deprevation test - Deprive patient of fluids for 8 hours and then give synthetic ADH (desmopressin). If it is a pituitary cause then urine will become concentrated again

Question 26

What is the management for diabetes insipidus?

Answer 26

If pituitary then give desmopressin (synthetic ADH)