Endocrine Flashcards
C. DHEAS, plasma fractionated metanephrines, PAC and PRA
D. Adrenalectomy
Answer = C
Biochemical testing is the first step in assessing patients with adrenal incidentalomas. Overnight DST should not be performed if the patient is thought to have a pheochromocytoma based upon the initial imaging study (unenhanced CT attenuation >10 HU).
Denosumab is used for the prevention of fractures in conditions such as osteoporosis and
malignancies. Its mechanism of action is by:
a. Preventing the maturation of osteoclasts
b. Enhancing osteoblast proliferation
c. Inhibition of the Wnt signalling pathway
d. Enhancing the apoptosis of osteoclasts
e. Preferential activation of osteoblasts rather than osteoclasts
Answer: A
Denosumab is a monoclonal antibody that inhibits RANK Ligand. RANK Ligand promotes osteoclast
differentiation and activation. Therefore, inhibition of RANK Ligand with Denosumab prevents the
maturation of osteoclasts.
The Wnt signalling pathway is required for osteoblast proliferation. This pathway is inhibited by
Sclerostin and DKK1. Hence, anti-sclerostin agents such as Romosuzumab can increase bone
formation by enhancing osteoblast proliferation.
DKK1 is activated by corticosteroids, which inhibits
the Wnt signally pathway, leading to osteoblast apoptosis. This is one of the mechanisms in which
supraphysiological doses of corticosteroids can lead to osteoporosis.
Option D = bisphosphanates
Option E describes Teriparatide: Continuous PTH activity results in bone resorption. However,
intermittent exposure to PTH results in the preferential activation of osteoblasts rather than
osteoclasts.
Which of the following complications of Hereditary Haemochromatosis is MOST LIKELY to be
reversible?
a. Cirrhosis
b. Arthropathy
c. Hypogonadism
d. Left ventricular dysfunction
e. Diabetes mellitus
Answer: D
Treatment of Haemochromatosis has been associated with reversal of left ventricular dysfunction (although irreversible myocardial dysfunction can also occur in subjects with advanced disease). Other reversible manifestations of Haemochromatosis include the bronzing of the skin and hepatomegaly. The other manifestations/complications listed above are very
rarely improved with iron depletion therapy.
Which of the following steroid medications has the LEAST mineralocorticoid activity?
a. Prednisone
b. Dexamethasone
c. Methylprednisolone
d. Triamcinolone
e. Hydrocortisone
Answer: B
Dexamethasone and Betamethasone have very high glucocorticoid action in conjunction with
insignificant mineralocorticoid activity. This makes them suitable for short term high-dose
therapy in conditions where fluid retention would be a disadvantage. This property also makes
Dexamethasone and betamethasone inappropriate for the treatment of Addison’s disease
unless fludrocortisone or other mineralocorticoids are prescribed concurrently.
Which of the following results are NOT in keeping with Sick Euthyroid Syndrome?
TSH fT3 fT4
A Decreased Increased Normal
B Normal Decreased Decreased
C Increased Normal Decreased
D Decreased Normal Increased
E Normal Decreased Increased
Answer: A
In sick euthyroid syndrome, fT3 concentrations either stay the same or decrease due to increased conversion of fT4 to reverse T3 (rT3) by Type 3 deiodinase, rather than fT3 by Type 1 or 2 deiodinase. fT3 concentrations never go up in sick euthyroid syndrome, and any rise in fT3 is likely to reflect genuine thyroid pathology. In sick euthyroid syndrome, all other thyroid function tests can either increase, decrease or stay the same.
