DAILY MRCP CHALLENGE – CVS & Nutrition- 1
Sample Question CVS- 1
A 36-year-old patient with recent onset fatigue and prior hypertension presents to the endocrinology clinic as his potassium remains low despite oral supplements. He has no medical history of note.
A full endocrine profile is requested and pending, though the most recent available blood tests demonstrate ongoing hypokalaemia:
Full blood count normal
Serum sodium 138 mmol/l (132 – 144)
Serum potassium 2.6 mmol/l (3.5 – 5.0)
Urea 6.4 mmol/l (2.5 – 7.5)
Creatinine 70 μmol/l (50 – 120)
What imaging would you advise now?
(Please choose the best answer)
- Abdominal x ray
- Barium swallow
- Chest x ray
- CT abdomen Correct
- CT brain
Low potassium with hypertension points toward the diagnosis of primary hyperaldosteronism, or Conn’s syndrome. A more complete biochemical profile would demonstrate alkalosis. The hypokalaemia is often refractory to supplements.
Liddle’s syndrome, a rare genetic abnormality of Na+channels, has a similar clinical presentation of fatigue, hypertension and hypokalaemia, but the sodium is usually higher.
Aldosterone levels are high in Conn’s syndrome and low-normal in Liddle’s syndrome.
CT or MRI of the abdomen identifies a secretory adrenal adenoma, which is usually not evident on abdominal x ray, subsequently managed by adrenalectomy.
CT brain may be indicated in hypokalaemia, with and without hyponatraemia (which may have been corrected too rapidly), to look for central pontine myelinolysis in the very different setting of alcoholic Korsakoff’s syndrome with vitamin and electrolyte deficiencies.