HYPERTENSION

HYPERTENSION  

John P. Veinot MD Pathology, Ottawa Hospital, Civic Campus

Hypertension  High blood pressure 

Hypertension may be systolic or diastolic. Systolic hypertension is more common in the elderly and is probably related to increased vascular tone.

The components of blood pressure relate to the cardiac output and to total peripheral resistance. These in turn are related to stroke volume and heart rate.

In young hypertensives, cardiac output plays a large contribution towards hypertension whereas vascular resistance plays an increasing role in the elderly.

Hypertension Types: 

Primary essential salt, volume, genetic abnormality
Secondary renal, endocrine, drug, vascular, neurogenic and others

Primary hypertension, the common type, usually occurs in middle age people, is moderate, has a gradual onset, is not associated with physical findings and has a strong family history. 

Secondary hypertension may occur in young people, even children. It tends to be severe, sudden onset and associated with physical findings. Family history may be present in rare cases but is not common.

 

Primary hypertension relates to a genetic abnormality in vascular tone, or in the absorption or excretion of sodium and calcium. It should be remembered that the kidney plays an important role in hypertension with the renin angiotensin system.

Pressure receptors in the blood vessels, and the brain and nervous system regulation of vascular tone are also important.

 

 Secondary Hypertension: This is important as many causes may be treated and the hypertension may be cured. Common causes include: 

Renal disease glomerulonephritis, chronic renal failure, renal artery stenosis, and renin producing tumours

Vascular related renal atrophy

Endocrine/drug pheochromocytoma, adrenal cortical hyperplasia or tumors, thyroid disease, or birth control pill

Pheochromocytoma- an adrenal tumor

Vascular causes aortic insufficiency and aortic coarctation
Neurogenic spinal cord trauma/transection, increased intracranial pressure

 

Hypertension Complications: 

Hypertension enhances other cardiovascular disease and is risk major factor for sudden death and atherosclerosis. Complications of hypertension affect the small vessels with scarring and microaneurysms and the large vessels with vascular ectasia, aneurysms, dissection and vascular rupture.

fusiform aneurysm

 The organs involve include the:

Eyes - microaneurysms, papilledema (raised intracranial pressure)
Heart left ventricular hypertrophy, myocardial infarct, congestive heart failure
Brain raised intracranial pressure, cerebral hemorrhages
Blood vessels atherosclerosis, aneurysms
Kidney acute renal failure, chronic renal failure 

 

Malignant Hypertension 

This is severe accelerated hypertension, often associated with a sudden hypertensive crisis with diastolic blood pressure greater than 130 mm of mercury. It is rare and may relate to a coagulation disturbance. It causes renal failure, encephalopathy, myocardial failure and intravascular coagulation.

Artery with changes of maligant hypertension ; more arterial changes of malignant hypertension