Pituitary Disease Flashcards
What are some types of pituitary disease?
Tumours:
Adenoma,
Prolactinoma
Acromegaly
Cushing’s disease
Deficiencies:
Hypopituitarism
Growth hormone deficiency
Gonadotrophin deficiency
SIADH
Describe features of a pituitary adenoma
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
What is the most common secretory tumour of the pituitary?
How is it classified
Prolactinoma.
Microadenoma if <10mm.
Macroadenoma if >10mm
Explain the presentation of a prolactinoma
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.
What are the investigations for a prolactinoma?
MRI brain and serum prolactin
What is the management of a prolactinoma
Pharmacological - Dopamine agonists (Carbergoline/bromocriptine) which decreases serum prolactin
Hormone replacement with oestrogen if galactorrhoea and fertility are not an issue
Surgical - Trans-sphenoidal resection
Radiotherapy
What is the cause of Acromegaly?
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.
What are the effects of growth hormone?
Increased release of glucose into blood
Muscle growth
Thickened bone
Insulin resistance
What is the presentation of Acromegaly in adults?
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
What does excess growth hormone in children cause?
Increased growth velocity = gigantism
What are the investigations for acromegaly?
Serum Insulin growth factor 1 (first line)
Oral glucose tolerance test (failure to suppress GH in response to glucose
MRI brain
What is the treatment for acromegaly?
surgery/radiation if pituitary adenoma
Medications such as somatostatin analogues which limit GH production
What are the causes of SIADH?
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
What are the symptoms of SIADH?
These are caused by hyponatraemia:
Headaches
Nausea
Vomiting
Muscle cramps
Tremors
Cerebral oedema - Confusion, mood swings, hallucinations
Why do you get hyponatraemia in SIADH?
ADH increases the water reabsorption (dilutes sodium) and this increases BP which reduces aldosterone which causes sodium excretion.
What are the investigations for SIADH?
Hyponatraemia
Low plasma osmolality
High urine osmolality
High urine sodium
What is the treatment for SIADH?
Find underlying cause
Managed by reducing fluid intake and starting a high salt/protein diet.
Can use drugs such as Tolvaptan
What is central pontine myelinolysis (osmotic demyelination syndrome)?
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
What are causes of hypopituitarism
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
Infiltration - Haemachromatosis/ sarcoidosis
In hypopituitarism what is the first hormone lost?
Growth hormone followed by LH and FSH
What are the symptoms for hypopituitarism?
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.
How can you make the diagnosis of hypopituitarism and treat it?
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
what is the cause of diabetes insipidus?
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
What are the symptoms of diabetes insipidus?
Polyuria
Polydipsia
Hypernatraemia (lethargy, thirst, weakness, confusion, coma)
