A 55-year old man is referred to the nephrologist by his family doctor because of his persisting hypertension, which has been going on for several years. Despite treatment with a combination of an ACE-inhibitor, a beta-blocker and a calcium channel blocker his blood pressure remains high at 170/105 mm Hg. The patient has smoked for many years and he seems to be suffering from dysbasia. Physical examination reveals a blood pressure of 180/110 mm Hg and a pulse of 68/min. The patient has a body mass index of 31, there’s a soft murmur in the carotid arteries, right > left, and some of the pulsations in the lower extremities are absent. There’s slight pretibial edema. Blood tests reveal: - creatinine: 121 micromol/l - glucose: 7,8 mmol/l - LDL cholesterol: 3,9 mmol/l - ACE-levels: 2 units (very low) Also, the 24h urine sample contains 1,5 g protein and the ECG shows signs of left ventricular hypertrophy. Ultrasound shows a left kidney of 10,2 cm and a the right one is 9,7 cm. The patient is prescribed a diuretic and is asked to return in 6 weeks. Only 4 weeks later, the patient is back again because he’s not feeling well. Then, his blood pressure is 120/70 mm Hg and he has a pulse of 70/min. However, he clearly has orthostatic hypotension and his creatinine has gone up to 567 micromol/l. Furthermore, his bicarbonate is 15 mmol/l and his potassium level is 6,1 mmol/l. The patient is then admitted. Questions. 1. What’s the most likely diagnosis, at the time the patient presented with hypertension? 2. Could the complication of orthostatic hypotension have been foreseen, and ”“ in that view ”“ was it a right decision to prescribe a diuretic?
Answers. 1. In this case, there are clues for the existence of a kind of generalized vascular disease. This, combined with the persisting hypertension which remained high even when using three antihypertensive drugs, the smoking and the elevated creatinine points to renovascular hypertension due to atherosclerosis. It is also clear that most likely both kidneys had extensive vascular pathology, because if only one kidney had been affected, ACE-inhibiting (which has taken place, based on the low ACE levels) should have been enough to lower the blood pressure. Since the blood pressure was still quite high there had to be another hypertensive cause, which most likely was an increased extra cellular volume. 2. Yes, the orthostatic hypotension could have been foreseen, but it was still a good choice to prescribe a diuretic. It had both a therapeutic and a diagnostic purpose, because as mentioned, it was very likely the patient had an increased extra cellular volume and a diuretic is designed to lower this excess volume. If the patient had been given alpha-blockers or another type of vasodilator the hypertension could also have been controlled, but then the doctor wouldn’t have learned anything about the pathophysiology of the hypertension. Of course, the dosage of the diuretic mustn’t be too high at the start, unless the patient will return very soon. Literature: ’Klinische nefrologie’ (De Jong et al.) (4th edition); a Dutch medical book on nephrology.
Answers 1. The most likely diagnose is essential hypertension 2. Yes, it could. the complication of orthostatic hypotension could be foreseen, and I think it's still a good decision to prescribe a diuretic in order for lowering the extra celullar fluid volume
