Sat27November0556PM 18

A 58-year-old man with known alcoholism is admitted to the Emergency Department following a large upper GI haemorrhage. As far as you are, aware he has no other significant past medical history and is non-compliant with medications for his liver disease, including propranolol which was started after his last admission to the Gastroenterology ward.

On admission to the Emergency Department, he is drunk and aggressive

Which of the following is the likely initial reaction to blood loss in this patient?

(Please select 1 option)

Aldosterone release

Angiotensin 2 production

Hypotension

Increased aquaporin 2 expression

Tachycardia Correct

Explanation

The answer is Tachycardia. Increased output of noradrenaline, coupled with decreased vagal tone post acute blood loss is responsible for the initial tachycardia seen. These changes also drive increased myocardial contractility and vasoconstriction, preserving blood pressure at least in the initial period after blood loss. Blood pressure generally only falls if the amount of blood loss exceeds these compensatory mechanisms (increased cardiac output, tachycardia, and increased arterial tone).

Aldosterone release and angiotensin 2 production are incorrect. The renin system is activated by blood loss, but the resultant angiotensin 2 production with subsequent aldosterone release is less rapid. Aquaporin 2 expression is increased in response to more chronic hypovolaemia, improving the action of ADH and promoting greater reabsorption of water in the kidney.

Answer Statistics

1

7%

2

7%

3

10%

4

4%

5

75%

Times answered: 286