264. Disorders of the Pituitary Gland Flashcards
Hypopituitarism is decreased secretion of anterior pituitary hormones. What are its causes?
Hypothalamus: Kallman’s syndrome, tumour, inflammation/infection
Pituitary stalk: trauma, surgery, mass legion, meningioma, carotid artery aneurysm.
Pituitary: tumours, irradiation, inflammation, autoimmunity
What are the features of hypopituitarism?
Very non-specific, tends to effect GH first therefore:
Central obesity, dry wrinkly skin, decreased strength and balance, decreased exercise ability
Will also have the effects of other hormone deficincies e.g. erectile dysfunction, low bp, low glucose, hypothyroid symptoms
What are the tests for hypopituitarism?
All levels of circulating hormones will be low, dynmaic tests include short synatchen to investigate adrenal axis or insulin tolerance test
MRI scan can be useful to look for a lesion
How is hypopituitarism treated?
hormone replacement, hydrocortisone first for adrenal failure
What are the three types of pituitary tumours?
Chromophole (70%)
Acidophil
Basophil
Nearly all tumours are benign adenomas
What are the features of a pituitary tumours?
Headache, visual field defect
Palsy of cranial nerves III,IV and VI
How are pituitary tumours treated?
Once assessed by MRI scan they are typically surgically removed typically trans-sphenoidal
Radiotherapy- used for residual or recurrent adenomas
What is pituitary apoplexy?
Rapid pituitary enlargement caused by bleed into a tumour. Presents with headaches, blurred vision and reduced GCS.
Urgent steroids and a careful fluid balance is needed to prevent cardiovascular collapse
How does hyperprolactinaemia present?
woman- menstrual disturbances, galactorrhoea
men- erectile dysfunction, decreased facial hair galactorrhoea
What are the causes of hyperprolactinaemia?
Phsyiological- pregancy, breastfeeding, stress
Drugs- metoclopramide, haloperidol, methyldopa, eccies, anti-psychotics.
Diseases- prolactinoma, stalk damage, hypothalmic disease
What tests are done to investigate hyperprolactinaemia?
Basal PRL
pregnancy test
How is hyperprolactinaemia managed?
Microprolactinomas <10mm- bromocriptine titrate up. Consider surgery if intolerant
Macroprolactinomas >10mm- treat initially with bromocriptine but consider surgery if pressure symptoms
What is acromegaly?
Increased growth hormone typically from a pituitary tumour and very rarely from a carcinoid tumour
What are the symptoms of acromegaly?
pins and needles in the hands and feet (acroparasthesia)
Reduced libido, increased snorining, headache
“my rings wont fit”, curly hair, was muscle, now fat.
What are the signs of acromegaly?
Growth of hands, jaw and feet
Wide nose, big tongue, widely spaced teeth,
Skin darkening, sleep apnoea, goitre, carpal tunnel signs
What complications can those with acromegaly run into?
Impaired glucose tolerance
Vascular problems
Neoplasia (colon)
Gigantasisim if occurs before epiphyseal plates fuse
What tests are carried out to investigate acromegaly?
Glucose, calcium and phosphate increased
Sample growth hormone every 30 mins for 3 hours and then if above 1 then acromegaly confirmed
What is the treatment for acromegaly?
Excise lesion
somatostatin analogues
If still intolerant GH antagonist
Radiotherapy can be used as adjuvant to surgery
What is diabetes insipidus?
What are the two types?
Passage of large volumes of urine (>3L) per day due to impaired water reabsorption by the kidneys due to impaired and secretion or impaired kidney responses to ADH
Cranial- lack of ADH
Nephrogenic- imapired response to ADH
What are the symptoms?
Polyuria, polydyspia, dehydration
symptoms of hypernatraemia (fatigue, muscle twitches)
What are the causes of cranial DI?
Idiopathic, congenitalm tumour, trauma
Autoimmune, infection
What are the causes of nephrgenic DI?
Inherited,
Metbolic
Iatrogenic- lithium
Chronic renal disease
What tests are done for initial investigation for diabetes insipidus?
U&E, calcium, glucose
Serum and urine osmlalilties
What is the 8 hour water deprivation test?
- Fluid deprive for 8 hours
- Give desmopressin- drink water
- Compare measured samples between the two times
How are both types of DI treated?
Cranial DI- MRI head, desmopressin
Nephrogenic- Treat the cause, then if not resolved- bendroflumethiazide
How can diabetes insipidus become an emergency?
Severe hypernatraemia
Needs to lower sodium slowly
Desmopressin as therapeutic trial
What is SIADH?
syndrome of inappropriate ADH secretion. ADH secreted despite low plasma osmolality
Causes strong urine, low plasma osmolality and hyponatraemia
