Hyperprolactinaemia, Acromegaly - booklet Flashcards
What to exclude first in hyperprolactinaemia?
- Pregnancy
- Full medication history - dopamine antagonists eg anti-emetics, antipsychotics
- Profound hypothyroidism
- PCOS
What suggests prolactinoma on test results?
- Prolactin levels greater than 5,000 iU/L suggests active secretion rather than stalk effect from non-functioning adenoma
Microprolactinoma
- Most common pituitary tumour
- Seen more in women
- Typically present with menstrual disturbance, galactorrhoea, infertility
Distinguishing PCOS from microprolactinoma
- Presence of androgenic symptoms
- Less elevated prolactin (less 1000 miU/L)
- Absence of pituitary lesion on MRI
Macroprolactinoma
- More than 1cm and can be very large
- Prolactin levels typicall more than 5,000 miU/L
- When levels extremely high, immunoassay can incorrectly give lower results (Hook effect) so it may be necessary to dilute sample to achieve accuracy
Treatment prolactinomas
- D2 agonists - Cabergoline or Bromocriptine
- Cabergoline once/twice weekly, better tolerated usually than bromo
Side effects D2 agonists
- Nausea
- Postural hypotension
- Rarer psychiatric disturbance
What happens to macroprolactinomas as they shrink sometimes?
- CSF leak occurs due to rapid reduction in size
- Potential risk of meningitis
Problem with high cumulative dose of dopamine agonists
- Cardiac valve abnormalities in Parkinsons disease
- But this is not a concern in prolactinoma doses
- Cardiac symptoms should be investigated though with an echo if on D2 agonists
What causes acromegaly?
GH secreting pituitary tumour
Risk of leaving acromegaly untreated
Increase risk of premature death from CV disease
Increase risk of bowel cancer
Clinical features acromegaly
- Increase size hands and feet
- Facial features coarser
- Frontal bossing forehead
- Protruding chin
- Widely spaced teeth
Soft tissue swelling:
* Enlarged tongue and soft palete
* Sleep apnoea
* Puffiness hands +/- carpal tunnel syndrome
Whole body:
* Sweating
* Headaches
* HTN
* Diabetes mellitus
Test for acromegaly
- OGTT - failure to suppress GH
- IGF-1- elevated
Some acromegaly tumours secrete…
- Prolactin sinultaenously as they share same cell origin
- This may be elevated too
Imaging acromegaly
- MRI pituitary gland
- Microadenomas may need contrast to see
- Increasing role of functional imaging
Management for acromegaly
- Surgery
- With micro, high chanve surgical remission (complete gone)
- With macro, chance is only 60%
- Medical treatment
- Radiotherapy
Medical treatment for acromegaly
- Somatostain analogue - Monthly injections
- GH receptor blockers
Radiotherapy for acromegaly
- External beam or stereotactic radiotherapy (gamma knife)
- STRT provides targeted treatment at higher dose - BUT only suitable for lesions far away from optic chiasm
Long term side effects radiotherapy for acromegaly
- Gradual hypopituitarism
- Cerebrovascular disease
Monitoring acromegaly post surgery
- Repeat OGTT
- Long term follow up to ensure GH and IGF-1 controlled & exclude recurrence
- Periodic colonoscopy screening considered due to increase bowel cancer risk
- Assess for sleep apnoea, diabetes, CV disease and symptoms of recurrence
Non functioning pituitary adenomas often present with…
- Visual field loss
- HEadache
- Hypopituitarism
Treatment for non-functioning adenoma
- Surgery - transphenoidal if visual field defect or threat to vision
Causes of hypopituitarism
- Pituitary adenoma
- Inflammatory and ilfiltrative disorders (Diabetes insipidus related)
- Traumatic brain injury
- Radiotherapy
Hypopituitarism symptoms
- Non specific
- Lethargy
- Weight gain
- Sexual dysfunction
Medical emergency presentations of pituitary adenoma
- Hypo-adrenal crisis with
- Hyponatraemia
- Hypotension
Investigation for hypopituitarism
- Exclude adrenal insufficiency
Treatment hypopituitarism
- ACTH deficiency - Hydrocortisone
- TSH deficiency - Thyroxine
- Gonadrotrophin deficiency - Men testosterone, women oesttogen and progesterone (COCP or HRT)
- GH - GH sc injection if clinical benefit
Cushing disease characteristsics
- Central obesity
- Dorso-cervical fat pad
- Increased roundness of face
Often have:
* Red face (plethora)
* Thin skin
* Easily bruising
* Proximal myopathy
Associated diseases with Cushings
- HTN
- Premature osteoporosis
- Diabetes mellitus
What happens if Cushings is left untreated?
Significant morbidity and has 5yr mortality rate of 50%
Investigations for Cushings
- Alcoholism and severe depression can cause Cushingoid (pseudocushings) so screen for this
- 24hr urine free cortisol
- Low dose dexamethasone supression test
- Overnight dexamethasone supression test
- Late night salivary cortisol
Results for investigations Cushings
- 24hr UFC elevated
- Failure to suppress cortisol to less than 50nmol/L after LDDST or overnight suggests Cushing syndrome
- Late night salivary cortisol - elevated
3 causes of Cushings
- Pituitary
- Adrenal
- Ectopic ACTH
What suggests ectopic ACTH?
- Hypokalaemia
- History of smoking
- Weight loss
Lung cancer or another malignancy
What suggests adrenal tumour?
- Accelerated hirsutism (hair)
- ACTH low - negative feedback from high cortisol levels from adrenals
ACTH normal or high
- Suggests ectopic ACTH or pituitary
CRH response in Cushings
- If give CRH:
- Exaggerated response rise in ACTH and cortisol in pituitary lesion
- Flat response in ectopic
HDDST results Cushings
- Suppresses pituitary Cushings disease
- Does not suppress ectopic
What should we do if results suggest pituitary cause?
- MRI pituitary
- If no lesion seen do inferior petrosal sinus sampling
- Can confirm central ACTH secretion by showing clear gradient between central and peripheral ACTH levels after CRH injection
What should we do if we suspect ectopic ACTH?
- Whole body CT and PET imaging
- Carcinoma elsewhere often in thorax
uspect
- If adrenal - laparoscopic adrenalectomy
- Ectopic - treat underlying malignancy and medically control cortisol
- Cushing disease - transphenoidal removal, can use Ketoconazole and Metyrapone and radiotherapy
