Hypertension
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Contents |
Introduction
Hypertension is a condition characterized by an increase in the blood pressure. Though it is usually a disease of the old age, it can affect even children and adolescents also. Hypertension over a period of time can affect various organs in the body. It can cause arteriosclerosis, left ventricular hypertrophy, heart failure, stroke, renal damage, retinal damage and cognitive decline. It is basically classified in to Primary and Secondary Hypertension. Primary hypertension is usually diagnosed in persons of old age as their arteries become less elastic and thus increasing the blood pressure. On the other hand secondary hypertension can affect even children and is due to various causes. Also there are other types of hypertension like pregnancy induced hypertension which are diagnosed in pregnant women. Irrespective of the type of hypertension, the treatment includes salt and fluid restriction and taking appropriate drugs.
Definition
Hypertension, or high blood pressure, is the chronic state of elevated pressure in the arteries. Systolic pressure is measured while the heart contracts and pumps blood into the arteries. Diastolic pressure is measured while the heart fills with blood. A person with systolic and/or diastolic blood pressures consistently above the normal range (130/90 mm Hg) is said to have hypertension, or high blood pressure. The term pre hypertension is used when blood pressure ranges between 120 and139 for systolic and 80-89 for diastolic pressure. Malignant hypertension is a condition in which the diastolic blood pressure exceeds 140 mm Hg.
Types
Hypertension is divided in to two types based on the etiology. They are –
- Primary hypertension
- Secondary hypertension.
About 95% of the cases of hypertension are due to primary hypertension. Primary hypertension is usually diagnosed during old age and there is no identifiable cause. Approximately 30 % of cases of essential hypertension are attributed to genetic factors. These individuals have increased resistance at the arteriolar levels.
About 5% of the cases of hypertension are due to secondary hypertension. Secondary hypertension can occur in any age including childhood. The causes of secondary hypertension include-
- Renal diseases – [[Renal Artery Stenosis] Acute Glomerulonephritis, Nephroblastoma
- Endocrine hypertension – Primary Hyperaldosteronism, Severe cases of Cushing’s Syndrome, C-11 or C-17 Hydroxylase Deficiency, Pheochromocytoma, Acromegaly, Hyperparathyroidism
- Coarctation of Aorta
- Hypertension during pregnancy - Pre-eclampsia / Eclampsia of Pregnancy, Gestational Hypertension
Signs & Symptoms
Most of the patients with uncomplicated hypertension remain asymptomatic. Hypertension is detected incidentally in them. Patients with severe hypertension like malignant hypertension may have symptoms like severe headache, nausea, visual symptoms, dizziness, and sometimes renal failure. Hypertension can affect almost all the vital organs of the body. Patients with complicated hypertension may have symptoms related to the organ affected. Some of the symptoms include palpitations, fatigability, impotence, epistaxis, hematuria, blurring of vision, weakness, dizziness, angina pectoris and dyspnea.
Diagnosis
The diagnosis of hypertension and its complications is done by history, clinical examination and investigations –
- Measurement of blood pressure with sphygmomanometer
- Renal function tests
- Urine examination
- Serum electrolytes
- Blood Glucose
- Electrocardiogram
- Chest X-Ray
- Lipid profile
The investigations that are to be done when secondary hypertension is suspected include –
- For Renal vascular disease: ACE inhibitor radionuclide renal scan, Renal Doppler flow studies, MRI angiography
- For pheochromocytoma: 24 hours urine assay for creatinine, metanephrine and catecholamines
- Cushing syndrome: Dexamethasone suppression test, 24 hours urine cortisol and creatinine
- Primary aldosteronism: Plasma aldosterone: renin activity ratio
Complications
Hypertension can affect all the vital organs of the body. The complications include-
- Arteriosclerosis
- Left ventricular hypertrophy
- Heart failure
- Stroke
- Hypertensive nephropathy
- Hypertensive retinopathy
- Hypertensive encephalopathy
Treatment
The goal of treatment for most patients is to lower the systolic blood pressure below 140 mm Hg and the diastolic blood pressure below 90 mm Hg. In pre hypertensive patients life style changes may be adequate, as it is not well established that treatment with medication of patients with pre-hypertension is beneficial.
The main modes of treatment are
- Pharmacological
- Non-Pharmacological
Non-pharmacological treatment
This includes-
- Salt restriction
- Exercise
- Restriction of alcohol intake
- Avoiding smoking
- Weight reduction
Pharmacological treatment
The various groups of drugs that are used in the treatment of hypertension are-
- Diuretics - Furosemide, Hydrochlorothiazide, Acetazolamide, Indapamide, Metolazone, Spironolactone, Torsemide and Triamterene.
- Beta-blockers - Atenolol, Bisoprolol, Carvedilol, Metoprolol , Timolol, Propranolol and Labetolol
- Calcium channel blockers – Nifedipine, Verapamil, Diltiazem, Amlodipine, Felodipine, Idradipine, Nicardipine, and Nisoldipine
- ACE inhibitors - Benazepril, Captopril, Enalapril, Fosinopril, Lisinopril, Quinapril, Ramipril, Trandolapril
- Angiotensin-receptor blockers (ARBs) - Candesartan, Irbesartin, Losartan, Telmisartin and Valsartan
- Direct-acting vasodilators - Hydralazine
- Centrally acting agents - Clonidine and Methyldopa
Reference
- Harrison’s Principles of Internal Medicine – 16th Edition
- www.emedicine.com
- www.mayoclinic.com
