| Hypertension is a familiar disease. Approximately 95% of all hypertensive patients have "essential" or "primary" hypertension, and have no underlying disease. Secondary hypertension comprises 5%, which can be the result of a range of different pathological processes.The level of the blood pressure remains the most direct risk factor for premature cardiovascular and cerebrovascular disease. Every increment of pressure is associated with a greater overall risk for both stroke and coronary heart disease. In many study, the systolic blood pressure was more closely correlated with risk than the diastolic. Hypertension is common and if left untreated is a major risk factor for premature cardiovascular disease.In 2004,JNC-7 defined that if the blood pressure still can-not be reduced below 140/90mmHg with the treatment of 3 kinds of antihypertensive drugs, including a kind of diuretic and in isolated systolic hypertension in elderly, if the systolic blood pressure can-not be reduced below 140mmHg.Then this can be called refractory hypertension.The majority of the refractory hypertension is primary hypertension. Through lifestyle change, smoking cessation, weight reduction, reduction of excessive alcoholintake and physical exercise, the blood pressure can be controlled. But some patients still need to be treated with antihypertensive drugs.Refractory hypertension includes the following kinds:1. Unsuitable treatment of patients :There is no diuretic in 3 kinds of antihypertensive drugs; the doctor can not change the treatment in time when patients have side effects; the doctor can-not follow-up the patients in time; some patients can not comply with the treatment.2. Many other drugs can induce hypertension :A variety of drugs may be responsible for hypertension, including oral contraceptive , liquorice , steroids, cyclosporins, erythropoietin, and so on. The patients should be asked specifically at the time when clinical history is taken, and the use of drugs that can raise blood pressure, and when necessary, should be monitored carefully.3. Overweight, obesity, insulin resistance and diabetes :Obesity, impaired glucose tolerance and hypertensulinism all can reduce the antihypertensive drugs' effects, which induce the refractory hypertension. Blood pressure has positive correlation with weight and waist circumference. Approximately 50% patients of primary hypertension have insulin resistance. About 88% patients of obesity have insulin resistance. Doctor should choose systematic management, such as life style change and choose ACE inhibitors (ACEI), angiotensin II antagonist, angiotensin II receptor blocker (ARB), or diuretics.4. Sleep-related Breathing Disorders (SRBD):SRBD has a stronger correlation with hypertension. The study suggests that more than 50% of SRBD patients have systemic hypertension. It is an important risk factor isolated from age, weight, diet and gene. The management of the SRBD includes: getting rid of etiology and using ACE inhibitors (ACEI), nasal continuous positive airway pressure (nCpaP ), Bi-level positive Airway Pressure (BipaP), and even having therapy of surgery.10% of the refractory hypertension is secondary hypertension .The common causes are :1. Renal Parenchymal Disease :The diagnosis is simple, based on the presence of renal damage and hypertension. Diabetes are particularly vulnerable to renal damage when hypertensive. Effective control of hypertension has been shown to slow the progress of their renal damage. Therefore the diabetic hypertensive patients should be carefully monitored with measurement of urine protein excretion and serum creatinine, and even have minimal hypertension treated vigorously, probably to a diastolic blood pressure level of less than 80mmHg.2. Renovascular Hypertension:Many patients have renal artery lesions that are not functionally significant. It is another mechanism responsible for as much as 0-4% of hypertension. Primary diseases of the renal arteries often involve the large renal arteries, whereas secondary diseases are frequently characterized by small vessel and intrarenal vascular disease. Atherosclerotic renal-artery stenosis is the main manifestation of generalized atherosclerosis in other countries and frequently associated with hypertension and excretory dysfunction.Particular attention should be paid to any patient with accelerated malignant hypertension or refractoriness to potent therapy. For now, reparative surgery ,such as renal artery angioplasty ,is probably the best choice for those with proved renovascular hypertension. Regarding medical therapy, ACE inhibitors and ARB are effective in 86% to 92% of these patients.3. Primary Aldosteronism :Aldosterone induces hypertension and renal potassium wastage, but hypokalemia may not always be present, making its recognition more difficult. In the patients with aldosterone producing adenomas, the hypertension may be of any degree of severity. Aduenal masses are found incidentally when abdominal CTs are performed of various reasons. Patients with hyperplasia should be treated with spironolactone. Those with tumors should have surgery.4. Cushing's Syndrome:Hypertension may also be induced by the mineralorcorticoid activity of high levels of cortisol . Hypokalemia is usually less prominent than with primary aldosteronism, except in those with very high cortisol levels, as with ectopic adrenocorticotropic hormone (ACTH) producing tumors. The more common variety is the pituitary ACTH induced bilateral adrenal hyperplasa, hypertension may be prominent and if left untreated , may lead to serious cardiac damage.5. Pheochromocytoma:The hypertension may be widely episodic or fairly constant but is almost always accompanied by peculiar spells of profuse sweating, tremor, headache and various other symptoms.Once the clinical signs have been confirmed by the biochemical assays, the pathology should be elucidated by abdominal CT scanning. After adequate a -adrenergic blockade, surgery is almost always indicated, with a caution to avoid severe hypertension during induction of anesthesia and manipulation of the tumor.6. Pregnant Women with Hypertension:In caring of pregnant women with hypertension, it is important to differentiate among chronic hypertension, gestational hypertension, and preeclampsia. Maternal and neonatal outcomes are usually good among pregnant women who have either mild chronic hypertension or gestational hypertension. In addition, antihypertensive drug therapy may permit such women to continue their pregnancies to term. In contrast, preeclampsia is a unique syndrome of pregnancy that is potentially dangerous for both mother and fetus; it does not respond well to the conventional antihypertensive therapy used in nonpregnant patients. Close medical supervision and timely delivery are the keys to the treatment of preeclampsia.7. Coarctation of aorta :Coarctation of aorta is a common normal of hypertension, occurring in 5% to 15% of all cases of secondary hypertension in children. If the patients have severe hypertension, the antihypertensive drugs should be considered. ACE inhibitors, P-blockers, diuretics, and calcium antagonists are options for initial therapy, but the surgery is probably the best choice.
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