Different Types and Causes of Hypertension (HTN)

Hypertension Disease: Types, Causes and Grading

Definition of Hypertension:

Hypertension (HTN) is a worldwide health problem that affects about 25-40% of individuals. It is a major cardiovascular risk factor and it is associated with many cardiovascular complications (e-g., stroke, heart failure). The prevalence of raised blood pressure is highest in Africa, where it is 46% for both sexes combined. HTN can affect people at any age; women at child-bearing age are no exception.

Hypertension (HTN) is the most common medical disorder during pregnancy, with a prevalence of 5-10%% of all pregnancies worldwide. HTN and antihypertensive drugs have adverse effects on both the mother and the foetus.

Causes of hypertension (HTN)
Fig: Causes of hypertension (HTN)

Management of HTN during pregnancy needs expertise in the field of high-risk pregnancy and cardiovascular diseases, which is why a combined team of obstetricians and cardiologists is an important prerequisite.

It is the level of blood pressure at which the institution of therapy reduce BP related morbidity & mortality. When arterial pressure (diastolic) rises above its normal level (90 mm of Hg) in the resting supine subject, then this condition is called hypertension.

Hypertension = Systolic BP>120 mm of Hg and diastolic BP>80 mm of Hg.

Grading Of Hypertension:


Systolic blood pressure (mmHg)

Diastolic blood pressure (mmHg)

Blood pressure


< 120





High normal




Grade 1 (mild)



Grade 2 (moderate)



Grade 3 (severe)



Isolated systolic hypertension

Grade 1



Grade 2



Classification or Types of Hypertension:

1. Primary Hypertension (also known as Essential Hypertension):

For almost 90% of the patients, the cause of this Hypertension is unknown. Your doctor will diagnose this Hypertension type after analyzing your blood pressure after three or four visits. People who suffer from this Hypertension type show no significant symptoms. However, a few patients do show the below signs:

  • Frequent headaches,
  • Fatigue,
  • Dizziness,
  • Nosebleeds.

2. Secondary Hypertension:

This Hypertension type occurs when there is an abnormality in the arteries that supply blood to the kidneys. Some common causes of this Hypertension include:

  • Abnormalities or tumours of the adrenal glands,
  • Thyroid,
  • Hormonal imbalances,
  • Excessive salt or alcohol intake.

3. Malignant Hypertension:

Here the blood pressure rises rather quickly and causes a medical emergency where the patient needs to be rushed to the hospital. It is typically observed in small emergency fractions of society such as young African-American men and Women with pregnancy toxaemia, to name a few. Some common symptoms include:

  • Numbness in arms and legs,
  • A headache,
  • Chest pain,
  • Blurry vision.

4. Resistant Hypertension:

This type of hypertension is usually observed in people who are aged, obese or are suffering from diabetes or kidney ailments.

Main Causes of Hypertension:

1. Primary or essential hypertension:

a) Genetic factors. (40-60%)

b) Environmental factors:

  • Obesity,
  • Alcohol intake,
  • Salt intake.

c) Humoral factors:

  • Catecholamines,
  • Renin angiotensin system,
  • Atrial natriuretic peptide.

2. Secondary hypertension:

a) Alcohol,

b) Obesity,

c) Pregnancy (Pre-eclampsia),

d) Renal causes:

  • Renal vascular disease – Renal artery stenosis.
  • Parenchymal renal disease: – Glomerulonephritis.
  • Polycystic kidney disease.

e) Endocrine causes:

  • Phaeochromocytoma,
  • Cushing’s syndrome,
  • Primary hyper-aldosteronism (Conn’s syndrome),
  • Adrenal hyperplasia,
  • Acromegaly,
  • Hyper-parathyroidism,
  • Primary hypothyroidism,
  • Thyrotoxicosis,
  • Liddle’s syndrome,
  • Congenital adrenal hyperplasia due to 11 -beta hydroxylase or 17 hydroxylase deficiency.
  • 11 -beta hydroxysteriod dehydrogenase deficiency.

f) Drugs:

  • Oral contraceptive pill containing oestrogens,
  • Anabolic steroids,
  • NSAIDs,
  • Carbenoxolone,
  • Corticosteriod,
  • Sympathomimetic agents.

g) Coarctation of the aorta.

h) Obstructive sleep apnea.

More questions related to this article:

  • Define hypertension.
  • What is hypertension?
  • Write down the types of hypertension?
  • What are the classifications of hypertension?
  • What are the causes of hypertension?
  • Write down the grading of hypertension.

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