Acromegaly and Prolactinoma Flashcards
Define acromegaly
abnormal growth of hands, feet and face due to overproduction of GH
Name the co-morbidities of acromegaly
- Hypertension and heart disease
- Cerebrovascular events and headache
- Arthritis
- Sleep apnea
- Insulin – resistant diabetes
What is the diagnosis of acromegaly dependent on?
- Clinical Features
- GH
- IGF-I
What are the presenting features of acromegaly?
- Acral (hands + feet) enlargement
- Arthralgias (joint stiffness)
- Maxillofacial changes
- Excessive sweating
- Headache
- Hypogonadal symptoms
In the criteria for diagnosing acromegaly, what result shows no acromegaly?
random GH <0.4 ng/ml and normal IGF-I
When would you do a glucose tolerance test (GTT) in diagnosing acromegaly?
If either GH>0.4 ng/ml or high IGF-I
How much glucose is given in a GTT?
75g
What result would exclude acromegaly after a GTT?
IGF-I normal and GTT nadir GH <1 ng/ml
What are the objectives of therapy in acromegaly?
- restoration of basal GH and IGF-I to normal levels
- relief of symptoms
- reversal of visual and soft tissue changes
- prevention of further skeletal deformity
- normalization of pituitary function
What are some options for acromegaly treatment?
- Pituitary surgery
- Medical therapy
- Radiotherapy
What is the primary treatment for all types of pituitary adenoma (except prolactinoma)?
Transsphenoidal pituitary surgery
What makes transsphenoidal pituitary surgery harder?
- Large size
- Invasiveness
What are 2 important determinants of success of surgery?
- size of tumour
- the surgeon
What are some examples of medical therapy?
- Dopamine agonists e.g. cabergoline
- Somatostatin analogues
- Growth Hormomne receptor antagonist
What are problems with radiotherapy?
- Loss of pituitary function in the long-term
- Potential damage to local structures – e.g. eye nerves
- Control of tumour growth / excess hormone secretion not always achieved
- Life-long monitoring needed for all patients
What are disadvantages of conventional radiotherapy?
- delayed response
- hypopituitarism
- rare secondary tumors
- rare visual defects
Define prolactinoma
lactotroph cell tumour of the pituitary
Do prolactinomas affect men or women more?
Women
How does hyperprolactinemia occur?
- Dopamine inhibits prolactin
- If you lose inhibition then it occurs
How does amenorrhea occur?
- Hyperprolactinemia occurs
- Inhibits LH and FSH, no oestrogen → secondary amenorrhea
What are clinical features of prolactinomas?
- Local effect of tumour – macroadenoma
- Headache
- Visual field defect (bi-temporal hemianopia)
- CSF leak (rare)
What are the effects of prolactin?
- Menstrual irregularity/ amenorrhoea
- Infertility
- Galactorrhoea
- Low libido
- Low testosterone in men
Define a microadenoma
tumour <1cm
Define a macroadenoma
tumour >1cm
What does a microprolactinoma do?
virtually always stays small
What does a macroprolactinoma do?
can be massive
What does a non functional pituitary tumour do?
compresses pituitary stalk – prolactin <4000 mIU/L
What group of drugs needs a drug history for hyperprolactinaemia?
Antidopaminergic drugs
What are other causes of hyperprolactinaemia?
stress, hypothyroidism, PCOS, drugs, renal failure, chest wall injury
Describe the management of prolactinoma
- Unlike other pituitary tumours management is medical rather than surgery
- Dopamine agonists – cabergoline, bromocriptine, quinagolide
- Remarkable shrinkage usual with macroadenoma – sight saving
- Microadenoma - usually respond to small doses of cabergoline just once or twice per week
What can prolactinomas lead to?
infertility and hypogonadism
