HYPERTENSION

 

Hypertension is a prevalent condition that is simply described as persistent chronically increased arterial blood pressure (BP. The 2017 ACC/AHA guideline revised the definition of hypertension from a BP of 140/90 mmHg to 130/80 mmHg. 

As a result, the prevalence of hypertension has skyrocketed. The prevalence of hypertension changes with age but is generally similar in men and women. Prior to the age of 65, men had a higher prevalence of high blood pressure than women, and the prevalence is similar between the ages of 65 and 74. However, more women than males have high blood pressure beyond the age of 74.

Etiology

Hypertension is caused by either essential or primary etiology, which cannot be cured, or secondary hypertension, which can be mitigated or potentially cured. Primary hypertension is caused by unknown pathophysiologic etiology, while secondary hypertension is caused by a comorbid disease or drug. When a secondary cause is identified, removing the offending agent or treating/correcting the underlying condition should be the first step in management.

Secondary causes of Hypertension are: 

Diseases - Chronic kidney disease, Cushing’s syndrome, Thyroid disease, Obstructive sleep apnea, etc.

Medications - Amphetamines, Antivascular endothelin growth factor agent, Corticosteroids, Calcineurin inhibitors, NSAIDs, Testosterone, etc.

Special situations with medications - Beta blockers or centrally acting alpha agonists, Beta blockers without alpha blocker first when treating pheochromocytoma, Use of a mono amine oxidase inhibitors.

Excessive consumption of food substances- Sodium, Ethanol, Licorice.

Classification

There are four BP classifications, according to ACC/AHA: normal, elevated, stage 1 hypertension, and stage 2 hypertension. Although elevated blood pressure is not a disease category, it is linked to higher CV risks when compared to people with normal blood pressure.

It identifies patients whose blood pressure is expected to rise to the point of hypertension in the future, in which case lifestyle changes should be made to slow down this progression.

 Patients who are experiencing hypertensive crises often have high blood pressure spikes, typically >180/120 mm Hg. They fall into one of two categories: hypertension urgency or hypertensive emergency. Extreme BP increases that are accompanied by acute or developing end-organ damage are known as hypertensive emergencies.  Extreme blood pressure rises associated with hypertension urgencies do not cause immediate or progressive end-organ damage.

 

Classification of Blood Pressure in Adults

Normal - systolic BP : <120mmHg & Diastolic BP : <80mmHg

Elevated - systolic BP : 120-129mmHg & diastolic BP: <80mmHg 

Stage 1 HTN - systolic BP: 130-139mmHg or diastolic BP: 80-89mmHg 

Stage 2 HTN - systolic BP : >140mmHg or diastolic BP : >90mmHg

Pathophysiology 

Numerous physiologic factors regulate blood pressure and anomalies in these factors may play a role in Essential Hypertension. These include aberrant neural mechanisms, defects in peripheral autoregulation, dysfunctions in sodium, calcium and natriuretic hormones as well as malfunctions in either humoral or vasodepressor mechanisms. 

Potential mechanisms of Pathogenesis

Increased cardiac output:

Increased cardiac preload- Increased fluid volume from excess sodium intake or renal sodium retention 

Venous constriction- Excess stimulation of RAAS 

Increased peripheral resistance:

Functional vascular constriction:

Excess stimulation of RAAS, Sympathetic nervous system over activity, Genetic alteration and Endothelial derived factors

Structural vascular hypertrophy- hyperinsulinemia

Clinical Presentation

Since most patients with Hypertension don’t exhibit any symptoms, it is known as the silent killer. Persistently high BP is the primary physical finding. To diagnose hypertension, the average two or more BP readings are recorded during two or more clinical encounters.

General: may appear healthy or may have additional CV risk factors: 

Age (>55years for men, >65years for women

Diabetics 

Dyslipidemia 

Albuminuria 

Family history 

Overweight 

Physical inactivity 

Tobacco use

Signs - previous BP values in the elevated or hypertension category 

Routine lab test - BUN/serum creatinine with eGFR, haemoglobin Hematocrit and ECG. 

Another test - Spot urine albumin to creatinine ratio, Uric acid 

Complications- 

Stroke, Transient Ischemic Attack, Dementia, Retinopathy, left ventricular hypertrophy, angina, CKD, Peripheral arterial disease.

Treatment

Non Pharmacological Treatment

Implementing blood pressure-lowering lifestyle changes has consequences for both hypertension prevention and therapy. Healthy lifestyle changes are indicated for those with "elevated" blood pressure and as an addition to pharmacological therapy in hypertensive people. 

Although the influence of lifestyle interventions on blood pressure is greater in people with hypertension, weight loss and dietary NaCI reduction have been proven in short-term trials to prevent the development of hypertension. 

Prevention and treatment of obesity are important for reducing blood pressure and cardiovascular disease risk. 

Lifestyle Modifications to Manage Hypertension

Weight reduction - Attain and maintain BMI <25 kg/m2

Dietary salt reduction - <6 g NaCl/d

Adapt DASH-type dietary plan - Diet rich in fruits, vegetables, and low fat dairy products with reduced content of saturated and total fat. Diet is also rich in potassium, calcium, and magnesium.

Moderation of alcohol consumption - 

For those who drink alcohol, consume <2 drinks/d in men and <1 drink/d in women

Regular aerobic activity, e.g., brisk walking for 30 min/d