Examination of a patient suffering from high blood pressure should be started from anamnesis and physical examination. But previously it is recommended to patients to check the blood pressure themselves for 3 days at least 3 times daily. Then some special lab tests are taken – blood tests, and «Holter» that checks the pressure during 24-48 h is put.
The cause of elevation in blood pressure is rarely found (only in 5% of cases), but it is really important to find one. First of all, this cause can be eliminated and the disease can be managed. Secondly, symptomatic hypertension study provides new matters of its etiology. In the vast majority of cases, the cause that can be diagnosed is connected whether with endocrine or kidney pathologies.
The baseline data can show the presence of symptomatic hypertension. In sudden emergence of severe hypertension or onset of the disease before 25 or after 50 years, it is necessary to remove or confirm the diagnosis of renovascular hypertension or adrenal tumor – pheochromocitoma. Pheochromocitoma can be diagnosed in cases of complaints about racking headache and heartbeat attacks, panic attacks, sweating, hyperglycemia and fat loss. Creatinine level growth in serum and ACE against the background of proteinuria and hematuria makes it necessary to exclude the possibility of renal insufficiency onset. If the treatment is not effective, secondary analyses are recommended. The list depends on the possibility of hypertension onset.
The easiest and the most reliable method of tumor diagnostics is catecholamine and metabolite definition in daily urine. It is also recommended to collect the urine at the time when pressure is risen. Catecholamine level measurement in plasma should be taken infrequently. Furthermore, in 50% of cases pressure in pheochromocitoma has an attack-like growth, so, it is important to exclude the possibility of tumor in any stable hypertension.
At suspicion on this disease, cortisol level in daily urine or dexamethasone analysis result should be taken into consideration.
Recently this pathology determination was made throughout descending urography with the shots made at short intervals. Over the last years most of the top-ranked clinics have replaced descending urography by other examination methods.
- 1. Subtraction angiography – more accurate method that demands intra-arterial contrast medium injection what prevents from using it as a first-line treatment method.
- 2. Renal scintigraphy after the captopril admission: this method is based on the renal vascular tone dependence on angiotensin II level. In renal artery stenosis angiotensin transforming enzyme inhibitor (captopril) decreases the angiotensin II level, the blood flow in kidney drops, accumulation and remove of isotope slows down. Many clinics use this method as a primary one.
- 3. Renal artery duplex ultrasound examination gives artery images and measures the blood flow. Theoretically, this is the best method from the non-invasive ones but its accuracy completely depends on specialists’ qualification.
At suspicion on renal artery stenosis it is necessary to prove that it is curable and the result can bring pressure normalization. This can be reached by selective angiography and measured renin activity in renal vein. Angiography makes the cause of the stenosis clear (atherosclerosis or fibromuscular dysplasia). Functional signification of stenosis is estimated with the help of renal veins’ catheterization in renin activity measurement. In case of one-kidney ischemia, the renin flows out from it. If the renin activity in one kidney is higher in 1,5 times than in the other one, it is considered to be diagnostically significant. The renin activity in vein blood from healthy kidney is equal to vena cava.
The stenosis treatment is effective in 80% of cases, only when renal vein catheterization was undertaken after the right preparation: 10 days before the catheterization cancel all the drugs that decrease the renin activity (β-adrenoblockers), 4-days of low-salt diet, 24 h of ACE blockers intake. If the angiography has detected stenosis in renal artery branch, the test blood should be taken from the main renal artery branches to prove that the hypotension was caused by stenosis itself.
It is always accompanied with hypokalemia. In these cases, it is important to find out the relation between renin plasma activity and the aldosterone level to make an accurate diagnosis. In the true hyperaldosteronism the level and daily excretion of aldosterone are excessive, the renin activity decreased and sodium level in plasma does not effect these criteria. Furthermore, it is necessary to know, whether one or two adrenal bodies are injured, as far as only the first case makes it possible to decrease pressure within the surgery.