EMQs in Clinical Medicine.pdf - Peshawar Medical College

Endocrine problems – answers 203
ANSWERS
78 Endocrine problems
Answers: E D F K I
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A 40-year-old woman presents with skin hyperpigmentation after
bilateral adrenalectomy.
The removal of the adrenal glands has removed the physiological feedback
inhibition of ACTH production. Excessive ACTH secretion gives rise
to the increased pigmentation.
A 21-year-old woman presents with amenorrhoea, vaginal dryness
and galactorrhoea. On examination she has a bitemporal hemianopia.
Symptoms of vaginal dryness, amenorrhoea and galactorrhoea are associated
with hyperprolactinaemia. The presence of a bitemporal hemianopia
suggests that the cause is oversecretion of prolactin by a
prolactinoma. The treatment of choice is a resection via a transsphenoidal
approach.
Drugs that have an anti-dopaminergic effect, e.g. metoclopramide and
phenothiazines, can also cause hyperprolactinaemia.
A 26-year-old woman complains of weight gain, menstrual irregularity
and hirsuitism. Examination reveals proximal muscle weakness and BP
of 150/100 mmHg.
Cushing’s syndrome is the term used to describe a state of glucocorticoid
excess. This is usually caused by increased ACTH secretion from a pituitary
tumour (Cushing’s disease).
Other causes include ectopic secretion of ACTH by a tumour, e.g. small
cell carcinoma, an iatrogenic excess of glucocorticosteroids and adrenal
adenoma/carcinoma.
Some patients have a distinctive ‘moon-shaped’ face (although a cushingoid
appearance can also be caused by excessive alcohol consumption)
with a buffalo lump visible at the neck and centripetal obesity. The skin
is usually thin and bruises easily with purple striae. There is a higher
incidence of osteoporosis and pathological fractures.
Investigation aims to identify the cause. If plasma ACTH is very
low/undetectable, the lesion is likely to be an adrenal tumour. The highdose
dexamethasone test can differentiate between ectopic ACTH/pituitary
oversecretion if plasma ACTH proves to be detectable. An ectopic
source of ACTH is associated with poor cortisol suppression, but a pituitary
source (Cushing’s disease) is associated with complete or at least
partial suppression.