BOF: 1
A 30-year-old female presents with fatigue, weight loss,
red, painful tender nodules over her shins and breathlessness. The chest X-ray
shows bilateral hilar lymphadenopathy. Investigations show that she has
hypercalcaemia.
The cause of the hypercalcaemia is:
a)
Increased parathyroid hormone production in the lungs
b)
A high serum ACE causing increased hydroxylation of 25
hydroxycholecalciferol to 1,25 dihydroxycholecalciferol in the kidney
c)
Alpha hydroxylation of 25 hydroxycholecalciferol to 1, 25
dihydroxycholecalciferol by macrophages in the lung
d)
Lytic lesions in the bones
e)
Hyperventilation
Answer:
c)
The patient has sarcoidosis. In this condition alpha
hydroxylation of 25 hydroxycholecalciferol to 1,25 dihydroxycholecalciferol
takes place in sarcoid macrophages in the lungs. This increases levels of
calcitriol in the blood and results in hypercalcaemia.
Revision Tips
Revise sarcoidosis KEYS to SUCCESS in Medicine pages
214-216
For an example of the format of the notes which are
designed to aid studying and revision by facilitating understanding and
memorising see link below:
Revision notes on
Sarcoidosis
