Hypertension

Definition

World Health organization (WHO) defines hypertension as sustained elevation of blood pressure ≥140/90mmHg. Centers for Disease Control and Prevention (CDC) defines Hypertension as blood pressure ≥130/80 mmHg. Pharmacological treatment for hypertension is recommended by both WHO and CDC when blood pressure is equal or above 140/90mmHg. Hypertension can have serious complications in multiple organs if left untreated.

Normal systolic blood pressure in adults is 99-120 mmHg while normal diastolic BP should be less than 80mmHg. When systolic BP is between 120-130 millimeters of mercury (mmHg), it is called “high normal”.

Hypertension prevalence is high with 1.28 billion adults between ages 30 to 79 years of age according to WHO. Two thirds of people living with hypertension are in low and middle income countries. An estimated 46% of adults with hypertension are unaware of the condition because it is usually asymptomatic.

Hypertension is responsible for 7.5 million deaths worldwide each year, which accounts for about 12.8% of all deaths. It is sometimes referred to as silent killer.

Classification

There are three main types of hypertension:

1. Essential Hypertension (primary hypertension): This is the most common type, accounting for about 90-95% of all hypertension cases. It develops gradually over many years and has no identifiable cause.
2. Secondary Hypertension: This type accounts for 5-10% of hypertension cases and is caused by an underlying condition.
3. Gestational Hypertension: This type occurs during pregnancy, typically after 20 weeks of gestation. It is characterized by high blood pressure without the presence of protein in the urine or other signs of preeclampsia. While it usually resolves after childbirth, it needs careful monitoring to avoid complications for both the mother and baby.

Causes of Hypertension

As mention above primary hypertension, which is the most common type has no identifiable causes but there are some risk factors associated with it. Secondary hypertension on the other hand has a cause that if treated reverses the condition.

Risk factors of hypertension

• Cigarette Smoking
• Obesity
• Genetics: Family history of hypertension
• Old age: especially after 65 years
• Diet: Diets high in salt, saturated fats, and sugar can lead to hypertension.
• Sedentary lifestyle: Lack of physical activity contributes to higher blood pressure.
• Stress: Long-term stress may affect blood pressure levels
• Race/Ethnicity: Blacks, Hispanics and Asians have higher rate of hypertension.
• Gender: Males are more affected by hypertension than females.

Causes of secondary hypertension

• Diabetes Mellitus
• Kidney Disease: Renal failure, Polycystic kidney disease, and Glomerular disease
• Thyroid Disorders: both hyperthyroidism and hypothyroidism can cause high blood pressure.
• Cushing’s syndrome
• Coarctation of the aorta
• Pheochromocytoma
• Hyperaldosteronism

Symptoms and Signs

Essential hypertension is usually asymptomatic. Symptoms of high blood pressure appear when vital organs have been damaged and they depend on the organ affected. Organs that are damaged by high blood pressure are called target organs.

Target organ damage from hypertension occurs in four main organs; heart, kidneys, brain and eyes.

Non-specific symptoms of high blood pressure are:

• Headache
• Dizziness
• Sweating
• Blurry vision
• Lower limb swelling
• Nose bleeding
• Tinnitus
• Anxiety

When blood pressure is severely elevated the following symptoms might be present:

• Severe Headache
• Confusion (from hypertensive encephalopathy)
• Shortness of breath
• Chest pain
• Limb weakness
• Stroke and TIA signs

Diagnosis

Hypertension diagnosis is made with multiple episodes of elevated blood pressure. A single reading of high blood pressure does not mean you have hypertension.

Diagnostic Criteria:

• Elevated blood pressure ≥ 140/90 mmHg on two separate occasions with minimum of two days apart OR
• Severely elevated BP ≥ 180/110 mmHg on two readings on the same day with at least one hour apart.

Blood pressure reading can be affected by many factors leading to falsely high BP or Low BP. It is important to ensure all factors that increase blood pressure are avoided before a measurement is taken.

Things that increase blood pressure temporarily are:

• Coffee
• Caffeinated drinks
• Full bladder
• Sever pain
• Restlessness
• Smoking
• Exercise
• Stress

How to Measure Blood Pressure correctly

Correct BP measurement technique is essential to avoid false elevated blood pressure. The following tips are important to get correct values:

1. Sit staring on a chair with both feet on the ground and back supported for at least 5 minutes
2. The arm to be measured should be at the level of the heart and supported (by table or clinician).
3. Expose the skin
4. Choose the correct cuff size: cuff should cover two thirds of the biceps. Obese patients require larger cuffs.
5. BP is measured in both arms because a blood pressure difference of more than 15 mmHg between the two arms requires evaluation of the upper vasculature.

Treatment of Hypertension

Hypertension treatment requires two main approaches

• Non-pharmacological treatment or lifestyle modification
• Pharmacological treatment.

Non-pharmacological Treatment

Hypertension is a lifestyle disease. This means that a simple change in lifestyle can significantly reduce high blood pressure and prevent long term complications of hypertension.

Diet changes: Low salt diet is key to reducing blood pressure. More fruits, vegetables and protein should replace processed food, canned food and unsaturated fatty foods.

Smoking: Smoking cessation reduce blood pressure and other medical conditions associated with it such as cancer and peptic ulcer.

Weight Control: Obesity is one of the important risk factors of high blood pressure. Weight reduction helps lower BP.

Exercise: Regular exercise of at least 180 minutes per week according to World Health Organization (WHO) plays a vital role and can even reverse hypertension in some individuals.

Pharmacological Treatment

Pharmacological treatment of hypertension depends on the severity of blood pressure.

Thiazide diuretic is preferred in patients with mild hypertension. If a single agent does not help, second agent is added after a month and dose is titrated based on blood pressure reading each month.

Most people require two antihypertensive agents for adequate control, others may need more. The following table has a list of commonly used antihypertensives and their classes.

Complications of Hypertension

Hypertension causes damage to multiple organs of the body which is called Target Organ Damage (TOD). Complications of hypertension can be divided into acute complications and chronic complications.

Acute complications of hypertension

• Pulmonary Oedema
• Myocardial infarction (MI)
•  Hypertensive Encephalopathy
• Seizures
• Papilloedema
• Aortic Dissection

Chronic Complications of Hypertension

• Left ventricular hypertrophy (LVH)
• Congestive cardiac failure
• Cardiomyopathy
• Chronic Kidney Disease and Renal failure
• Cataract
• Retinopathy
• Cerebrovascular accident (CVA)