There are two types of hypertension:

1. Primary (Essential) Hypertension - there is no known cause. Only lifestyle modificaiton and medicines can control the blood pressure.

2. Secondary Hypertension - These cases are due to specific conditions. Treatment of these conditions may bring down the blood pressure. (Less than 10% of hypertension cases are secondary hypertension)

Conditions that can cause high blood pressure are:

- Kidney failure
- Aortic Stenosis - A disease of the large blood vessel
- Renal Artery Stenosis - narrowing of the blood vessel to the kidney
- Cushing's Syndrome - excessive steroid hormones from adrenal tumour or excessive intake of steroids
- Conn's Syndrome - excessive aldosterone hormone
- Phaeochromocytoma - high blood pressure during pregnancy
- Certain medicines - steroids, contraceptive pills

Symptoms of hypertension:

Most patients suffering from hypertension do not have any symptoms eventhough their blood pressure is high. The diagnosis is only made by physical examination (e.g. during medical examination for job application or prior to going Mecca for Haj or when we see a doctor for some other complaint like fever or cough). Many patients however finds out that they have hypertension only when develop complications like heart attacks or stroke. Nevertherless patients with hypertension my have the following symptoms:

- Headaches or giddiness
- Blurred vision
- Chest pain

What are the effects of hypertension on the organs?

The main effect of hypertension is on arteries. High blood pressure causes the artery wall to become thickened (hypertrophy) and the lumen becoms narrowed. Damage to the internal surface of the artery wall results in the formation of atheromatous plaque which diminishes blood flow. A blood clot can form on the plaque. Pieces of clot may break off and travel with the blood downstream and cause obstruction of the smaller blood vessles.

All parts of our body have blood vessels. Hence, high blood pressure can damage all organs in our body. The most serious damage occurs in the following organs:

1. Heart
2. Brain
3. Kidneys
4. Eyes