Cardiovascular Diseases 4: Aneurysms and Hypertension

What is an aneurysm?

Aneurysms are an abnormal localised dilation of an artery or vein, most commonly occurring in the aorta.

Causes: congenital weakness in blood vessel, hypertension, atherosclerosis, trauma, syphilis (STI)

  1.   Berry Aneurysm
  • Small
  • Spherical dilation of a blood vessel
  • Less than 1.5cm in diameter
  • Common in Circle of Willis
  2.   Fusiform Aneurysm
  • Involves entire circumference of the vessel
  • Gradual and progressive dilation of a vessel
  • Up to 20cm in diameter
  • Can occur in entire ascending and transverse portion of the thoracic aorta
  3.   Saccular
  • Ranges from 5 to 20cm in diameter
  • Partially or completely filled by thrombi
  4.   Dissecting
  • False aneurysm caused by a tear in the intimal layer of the vessel
  • Life-threatening
  • Common in 40-60 years
  • Ascending and descending thoracic aorta


What is hypertension?

Hypertension is defined as blood pressure that exceeds 140mmHg systolic and 90mmHg diastolic. It can be primary, which is most common and has no specific cause, or secondary, which is less common but has an underlying cause e.g. renal or endocrine disorders. Both primary and secondary hypertension can be benign or malignant. Benign hypertension is when the blood pressure is gradually elevated over many years. Malignant hypertension is when the blood pressure is accelerated to an elevated state in a very short period of time.

Hypertensive Heart Disease is when massive hypertrophy occurs in the left ventricle due to persistent strain from chronic hypertension. The hypertrophy in the ventricular wall makes it stiff and means it has higher than normal metabolic requirements. As a result, the muscle can easily become infarcted if the coronary circuit happens to become obstructed.

Consequences: congestive heart failure, myocardial infarction and cardiac arrhythmia

Characteristics: dizziness, unsteadiness, blurred vision, fibrotic lesions in the nephron, renal failure, cardiovascular accident (i.e. stroke), myocardial infarction, hypertrophy of the heart (bigger heart)

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