Blood pressure, potassium and a pounding headache

Correct answer: D. Inhibition of angiotensin converting enzyme

• A. That describes the sartans such as losartan and valsartan. They block the receptor rather than the enzyme, which is why they do not cause the bradykinin cough.
• B. Beta-1 blockade describes metoprolol and atenolol, which lower heart rate and cardiac output.
• C. Calcium channel blockade describes amlodipine and nifedipine. Nifedipine is the one to remember for drug-influenced gingival enlargement.
• D. Correct. Lisinopril blocks the enzyme that converts angiotensin I to angiotensin II, lowering vasoconstriction and aldosterone release. The same enzyme degrades bradykinin, so bradykinin accumulates, which explains the dry cough and the risk of angioedema.

Correct answer: A. Hypokalaemia

• A. Correct. Hydrochlorothiazide increases sodium delivery to the collecting duct, which drives potassium loss and causes hypokalaemia. Triamterene blocks the epithelial sodium channel there and spares potassium, so the fixed combination gives the diuretic benefit without the potassium fall.
• B. Thiazides cause hyponatraemia, not hypernatraemia, and this is one of their more common clinically significant adverse effects in older patients.
• C. Thiazides increase distal calcium reabsorption, so they tend to raise serum calcium slightly rather than lower it. This is why thiazides are sometimes chosen in patients who form calcium stones.
• D. Hyperkalaemia is the risk of triamterene used alone, particularly with renal impairment or alongside an ACE inhibitor. The combination is designed to balance potassium, not to raise it.

Note: Note that this patient is on both a potassium-sparing diuretic and an ACE inhibitor, a combination that genuinely can push potassium too high. It needs monitoring.

Correct answer: A. Rupture of a cerebral aneurysm

• A. Correct. Severe uncontrolled hypertension is the principal risk factor for rupture of an intracranial aneurysm, producing subarachnoid haemorrhage. His severe sudden headache, visual disturbance and family history make this the pressing concern. Defer all elective treatment and arrange urgent medical assessment.
• B. Orthostatic hypotension is a fall in pressure on standing. It is a real concern in medicated hypertensive patients when they rise from the dental chair, but it is not a complication of a hypertensive crisis.
• C. Hypovolaemic shock results from blood or fluid loss and presents with a low pressure and a compensatory tachycardia.
• D. Vasovagal syncope is a transient reflex event triggered by pain, anxiety or standing, in which vagal tone drops both heart rate and blood pressure. It is the opposite haemodynamic situation.