Hypertension known more commonly as high blood pressure is an elevation of the arterial blood pressure above the upper limits of the normal range. It is defined as a blood pressure of 140/90 mm Hg or more. It is a global problem associated with various risk factors including obesity, cigarette smoking, alcohol misuse, family history and is more commonly seen in certain ethnic groups. Hypertension is one of the leading cause of cardiovascular disease and accounts for a number of other acute and chronic disorders. Understanding the causes, identifying risk factors and undertaking dietary and lifestyle changes even if not at risk is key to preventing hypertension.
Primary and Secondary Hypertension
Most cases of hypertension (+90%) is essential hypertension, which is also known as primary hypertension or idiopathic hypertension. The causes of essential hypertension is not clearly understood. Secondary hypertension is high blood pressure that occurs as a consequence of various diseases.
Both primary and secondary hypertension fall under the category of benign hypertension. Despite the use of the word benign, it can still cause extensive damage to various organs and systems and lead to complications that can eventually result in death. This usually happens over several years or even decades.
The early stages of benign hypertension, particularly primary hypertension, are often asymptomatic leading to the use of the word ‘silent killer’. With increased awareness, regular screening and an understanding of the risk factors, hypertension is often detected in the early stages where proper management can prevent or at least delay the onset of complications.
Causes of Essential Hypertension
The exact cause of primary hypertension is unknown. It has been observed to occur more frequently in people with a family history of primary hypertension and certain groups, particularly African Americans.
Causes of Secondary Hypertension
- Chronic renal diseases
- Polycystic kidney disease
- Renal vascular disease – arterial stenosis, vasculitis
- Tumors, particularly renin-producing tumors
- Cushing syndrome
- Primary hyperaldosteronism (Conn’s syndrome)
- Congenital adrenal hypeplasia
- Thyroid disorders – hypothyrodism and hyperthyroidism
- Primary hyperparathyroidism
- Pregnancy-induced, pre-eclampsia
- Coarctation of aorta
- Polyarteritis nodosa
- Fluid retention
- Raised intracranial pressure
- Sleep apnea
- Acute trauma
- Glucocorticoids – corticosteroids, anabolic steroids
- Oral contraceptives
- Monoamine oxidase inhibitors
- Diet and Lifestyle
- Alcohol intake
- Cigarette smoking
- Narcotic stimulants like cocaine
Malignant hypertension is sudden and severe high blood pressure with systolic pressure above 200 mm Hg and diastolic pressure above 120 mm Hg. Also known as accelerated phase hypertension, it often causes a host of signs and symptoms usually from the outset and is therefore detected at an earlier stage. Left untreated, however, malignant hypertension may lead to death in just 1 to 2 years or sometimes within months.
Causes of Malignant Hypertension
- Toxemia of pregnancy
- Many of the same kidney disorders mentioned under secondary hypertension
- Collagen vascular disorders