Acromegaly, Hypopituitarism & Cushing's Flashcards
Cause of acromegaly.
Almost exclusively GH-secreting pituitary tumour.
Risks of untreated acromegaly.
Disfiguring features
Premature death from CVS disease.
Increased risk of bowel cancer
Clinical features of acromegaly.
Increased size of hands and feet.
Coarse facial features with frontal bossing of forehead and protrusion of chin and widely spaced teeth.
Enlargement of tongue and soft-palate which leads to snoring and sleep apnoea.
Puffiness of hands with carpal tunnel syndrome.
Amenorrhoea
Decreased libido
Headaches
Sweating
Snoring
“My rings don’t fit, nor my old shoes, and now I’ve got a wonky bite and curly hair. I put on lots of weight, all muscle and looked good for a while. Now I look so haggard”.
Specific features of acromegaly due to GH secretion.
Sweating
Headache
Hypertension
Diabetes Mellitus
Investigations done for acromegaly.
Oral glucose tolerance test (OGTT)
IGF-1 assay.
Glucose, Ca2+ and PO43- all increased.
Don’t rely on random GH since is is pulsatile and can increase with other factors as well.
MRI scan of pituitary fossa
Visual fields and acuity
ECG and ECHO.
Ask patient to show old photos.
Explain OGTT and IGF-1 testing in acromegaly.
Failure to suppress GH after OGTT as well as elevated IGF-1 levels are found in active acromegaly.
Some acromegaly tumours also secrete another hormone along GH.
Which?
Prolactin
This is because they share the same cell origin.
What imaging can be done in acromegaly tumour?
MRI will usually show.
Micro-adenomas may only be visible with contrast enhanced scans.
Types of treatment of acromegaly.
Surgery
Medical treatment
External beam radiotherapy
Stereotactic radiotherapy (gamma knife)
What is the treatment of choice for most patients?
Surgery
Surgical remission in acromegaly adenomas.
High likelihood of surgical remission in microadenomas
Remission only achieved in approx. 60% of patients with macro-adenomas.
What is given as medical treatment for acromegaly?
Somatostatin analogues
How is somatostain analogues administered?
Monthly subcut injection
What otherm medications can be given to treat acromegaly?
GH receptor blockers may control IGF-1 levels in refractory acromegaly.
Dopamine agonists may control GH in certain patients as well.
When is stereotactic radiotherapy suitable?
When the lesion is well away from the optic chiasm.
Issues with radiotherapy in acromegaly.
May take many years to lower GH.
There are also long-term side effects such as gradual onset hypopituitarism and possible cerebrovascular disease.
After initial surgery of acromegaly tumour what is done?
A repeat OGTT to indicate whether there is persisent disease even after surgery.
What other long-term follow ups after surgery of acromegaly is done?
Ensure adequate control of GH and IGF-1 levels and exclude recurrence.
Periodic screening of colonoscopy due to the risk of neoplasia.
Sleep apnoea, diabetes and CVS risk assessment.
Usual presentation of non-functioning pituitary adenomas (NFPAs).
Visual field loss
Headache
Hypopituitarism
How is this diagnosis increasingly made?
As a pituitary incidentaloma meaning that it is discovered for unrelated reasons.
When is surgery made for NFPAs?
If there is a visual field defect or threat to vision.
Usual route for NFPA surgery.
Trans-sphenoidal
Sometimes trans-cranial if need be.
Histological markers that may present in NFPAs
Positive immunostaining for biologically inactive FSH and LH.
They do not secrete bio-active hormones however.
Most common cause of acquired hypopituitarism.
Pituitary tumour
Less common causes of acquried hypopituitarism.
Inflammatory and infiltrative disorders which are usually associated with Diabetes Insipidus as well.
Traumatic brain injury
Radiotherapy
1 - Hypothalmus => Kallman’s syndrome, tumour, inflammation, infection, ischaemia.
2 - Pituitary stalk => Trauma, surgery, mass lesion (Craniopharyngioma), meningioma, carotid artery aneurysm.
3 - Pituitary => Tumour, irradiation, inflammation, autoimmunity, infiltration, ischaemia.
In what order are hormones affected in hypopituitarism?
GH
Gonadotropins
TSH
ACTH
PRL
Clinical features of hypopituitarism.
Often non-specific symptoms such as lethargy, weight gain and sexual dysfunction.
Medical emergency of hypopituitarism.
Hypo-adrenal crisis with hyponatraemia and hypotension.
What might be a specific feature for hypopituitarism in children?
Short stature