HYPERTENSION

BY ,DR SURYA PRASAD R

History of Hypertension

• Historical records as far back as 2600 B.C. hold mention of “hard pulse disease”

•First treatments: Leeching/phlebotomy, acupuncture

•Hippocrates recommended phlebotomy

Lithograph showing the leeching of a patient, date unknown.National Library of Medicine, Bethesda, Maryland

• 1733 –Reverend Stephen Hales measured the intra-arterial BP of a horse.

• 1905 –N.C. Korotkoff reported on the method of auscultation of brachial artery, the method which is widely used today.

• Blood pressure is defined as pressure exerted by blood against the walls of the blood vessels,especially the arteries.

• Blood pressure =cardiac output * systemic vascular resistance.

Factors influencing BP

• Heart rate

• Nervous system(SNS/PNS)

• Vasoconstriction/vasodilation

• Fluid volume

–Renin-angiotensin

–Aldosterone

–ADH

Hypertension Definition

Hypertension is sustained elevation of BP

-Systolic blood pressure >/=140 mm Hg

-Diastolic blood pressure >/=90 mm Hg

-Any level of BP in patients taking antihypertensive medication.

Classification of hypertension for adults aged >18yrs according JNC

Category Systolic (mm Hg) Diastolic (mm Hg)

Normal 90-119 60-79

Prehypertension 120-139 80-89

stage 1 Hypertension 140-159 90-99

Stage 2 Hypertension >160 >100

Isolated systolic Hypertension

>/=140 <90

Classification of Hypertension

• Primary HypertensionElevated BP with unknown cause-90% to 95% of all cases.

• Secondary HypertensionElevated BP with a specific cause Coarctation of aorta Renal disease-diabetes, interstital tubular disease, glomerular

disease, polycystic kidney disease, analgesic nephropaty, renal artery stenosis.

Endocrine disorders- Phaeochromacytoma, primary aldosteronism, cushings disease, pituitary disorder, thyroid disorders.

Others –sleep apnoea, oral contraceptives, cerebral hemorrhage.

Risk factors for hypertension

• Role of genetics: 20% to 60% of essential hypertension is inherited.

• Age and Sex : BP raises with age in both men and women. In adult women, BP is lower than in men of comparable age, but the rise is more steep thereafter and around middle age BP is about the same, in later life it is higher in women.

• Weight gain : approximately 1mm Hg rise of SBP for every 1.25kg of weight gain. 70%of hypertensive in men and 60% in women could be attributed to abdominal obesity.

• Salt intake: intake of sodium chloride <3g or less per day have low average BP.

• Physical activity: sedentary individual have a 20% to 50% increased risk of developing hypertension.

• Alcohol intake: excess alcohol consumption accounts for 5% to 30% of all hypertension.

• Smoking: tobacco smoking reported to cause acute rise of BP.

• Stress

Pathogenesis of hypertension

• Hypertension caused by increased cardiac output and or increased peripheral resistance.

• Factors involved in increased cardiac output-

1. Increased circulating fluid volume-

excess sodium intake causes HTN by increasing fluid volume and preload thus increasing cardiac output and contractility.

2.Renin angiotensin system-Renin angiotensin 1

ACE angiotensin 2

Aldosterone synthesis sodium retension vasoconstriction

increase in blood pressure

3. Renal sodium retention.

4. Sympathetic nervous system over activity-

augments release of renin, vascular constriction, increases the heart rate.

5. Resetting of pressure natriuresis

Symptoms

• Frequently asymptomatic until severe and target organ disease has occurred

–Fatigue, reduced activity tolerance

–Dizziness

–Palpitations, angina

–Dyspnea

Investigation

• Urine examination- protein, glucose, microscopic(red blood cells, other sediments)

• Hemoglobin • RFT and serum potassium• Fasting blood glucose• Electrocardiogram• Lipid profile• Uric acid • Chest radiography• Other tests to rule out secondary hypertension.

Management

• The primary goal of therapy of hypertension is effective control of BP to prevent, reverse or delay the progression of complication and thus reduce the overall risk of an individual without affecting the quality of life.

• BP < 140/90

• In patients with diabetes or renal disease, goal is < 130/80

Guidelines for selecting the most appropriate antihypertensive drugs

Class of drugs Indication Contraindication

Diuretics Heart failureElderly patientsSystolic hypertension

Gout

Beta blockers Angina Post MITachyarrhythmiaHeart failure

AsthmaCOPDHeart blocks

Calcium channel blockers Angina Diabetes CVA

Heart blocks

ACE inhibitors Heart failure Left ventricular dysfunctionSignificant proteinuria

PregnancyLactationBilateral renal artery stenosisHyperkalaemia

Class of drugs Indication Contraindication

Angiotensin 2 receptor blockers

ACE inhibitors induced coughIntolerant to ACE inhibitors

PregnancyLactationBilateral renal artery stenosisHyperkalaemia

Alpha blockers Prostatic hypertrophy Orthostatic hypertensionCCF

Hypertensive emergencies

• Severe elevation in BP often higher than 220/140 mmHg, complicated by clinical evidence of progressive target organ dysfunction.

• Hypertensive encephalopathy, intracranial hemorrhage, acute myocardial infraction, acute left ventricular failure with pulmonary edema, dissecting aneurysm of aorta, acute renal failure, eclampsia of pregnancy.

Emergency Drug of choice

Aortic dissection Nitroprusside *esmolol

Ischaemia NitroglycerinNitroprusside, nicardia

Pulmonary edema NitroglycerinNitroprusside, labetalol

Renal emergencies FenoldopamNitroprusside

Cathecholamine excess PhentolamineLabetalol

Hypertensive encephalopathy Nitroprusside

Subarachnoid hemorrhage Nitroprussidenicardipine

Hypertensive urgencies

• Marked elevation of BP higher than 180/110mmHg

• Evidence of end organ damage may be present, but non progressive

• Symptoms-headache, shortness of breath, pedal edema and epitasis.

• Drug of choice- amlodipine, labetalol, clonidine, captopril.

Hypertension complication

• Complications are primarily related to development of atherosclerosis (“hardening of arteries”), or fatty deposits that harden with age.

Left ventricular hypertrophy

Thank you