MRCP 2 Flashcards
(356 cards)
What is abetalipoproteinaemia?
rare autosomal recessive disorder caused by a mutation in the microsomal triglyceride transfer protein.
This results in deficiencies in the apolipoproteins B-48 and B-100.
What are the features of abetalipoproteinaemia?
failure to thrive + developmental delay
steatorrhoea
retinitis pigmentosa
cerebellar signs
deep tendon reflexes are absent
acanthocytosis
hypocholesterolaemia
What is the most common reason for acromegaly?
Pituitary adenoma
Excess GH
A minority of cases are caused by ectopic GHRH or GH production by tumours e.g. pancreatic.
What are the features of acromegaly?
coarse facial appearance, spade-like hands, increase in shoe size
large tongue,
prognathism - profusion of upper jaw
interdental spaces
excessive sweating and oily skin: caused by sweat gland hypertrophy
features of pituitary tumour: hypopituitarism, headaches, bitemporal hemianopia
raised prolactin in 1/3 of cases → galactorrhoea
6% of patients have MEN-1
What conditions are associated with MEN1 ?
MEN-1
What are complications of acromegaly?
hypertension
diabetes (>10%)
cardiomyopathy
colorectal cancer
What is the test of acromegaly?
serum insulin growth factor 1
Previously oral glucose tolerance test with serial growth hormone measurements
If insulin growth factor 1 is equivocal, what test should be done?
Oral glucose tolerance
What is the normal response to growth hormone in oral glucose tolerance?
in normal patients GH is suppressed to < 2 mu/L with hyperglycaemia
in acromegaly there is no suppression of GH
may also demonstrate impaired glucose tolerance which is associated with acromegaly
First line treatment of acromegaly?
Transpehnoidal surgery
When should surgery be used in acromegaly?
If surgery cannot be pursued or is unsuccessful
What medication should be used in acromegaly ?
- somatostatin analogue
- Pegvisomant
- Dopamine antagonists
Mechanism of somatostatin analogue?
Directly inhibits the release of growth hormone
Mechanism of pegvisomant in acromegaly?
GH receptor antagonist - prevents dimerization of the GH receptor
- Does not reduce tumour volume, therefore needs surgery still
Mechanism of dopamine antagonist?
e.g. Bromocriptine
first effective medical treatment for acromegaly, however now superseded by somatostatin analogues
Features of Addisons disease?
lethargy, weakness, anorexia, nausea & vomiting, weight loss, ‘salt-craving’
hyperpigmentation (especially palmar creases)*, vitiligo, loss of pubic hair in women, hypotension, hypoglycaemia
hyponatraemia and hyperkalaemia may be seen
crisis: collapse, shock, pyrexia
Features of Addison’s crisis?
crisis: collapse, shock, pyrexia
Causes of hypoadrenalism?
Primary causes
- tuberculosis
- metastases (e.g. bronchial carcinoma)
- meningococcal septicaemia (Waterhouse-Friderichsen syndrome)
- HIV
- antiphospholipid syndrome
Secondary causes
- pituitary disorders (e.g. tumours, irradiation, infiltration)
Primary and secondary hypoadrenalism - which one has hypopigmentation?
Primary hypoadrenalism only
Secondary hypoadrenalism is not associated with hypopigmentation
What is the management for Addison’s disease?
combination of:
hydrocortisone: usually given in 2 or 3 divided doses. Patients typically require 20-30 mg per day, with the majority given in the first half of the day
fludrocortisone
What should be given to patients to prevent adrenal crisis?
hydrocortisone injections
Illness in Addisons, what should be done to the steroids?
glucocorticoid dose should be doubled, with the fludrocortisone dose staying the same
Management of addisonian crisis?
hydrocortisone 100 mg im or iv
1 litre normal saline infused over 30-60 mins or with dextrose if hypoglycaemic
continue hydrocortisone 6 hourly until the patient is stable.
fludrocortisone should begin after 24 hours and be reduced to maintenance over 3-4 day
Causes of raised ALP?
liver: cholestasis, hepatitis, fatty liver, neoplasia
Paget’s
osteomalacia
bone metastases
hyperparathyroidism
renal failure
physiological: pregnancy, growing children, healing fractures