Hypertension: Causes and Effects

What are  the causes of Hypertension?

There are no clear reasons why most people develop Hypertension.

Essential hypertension: 95% percent of cases; no underlying cause.

Secondary Hypertension: Very rare but there is an underlying cause.
 

Predisposing factors for essential Hypertension:

• Genetics: - if parents have it (one or both) you have a good chance of developing the disease.  2x more likely
• Age: the longer you live the more likely you are to develop the disorder
• High intake of alcohol: no clear definition of what HIGH really is….the average consensus is no more than 1-2 drinks a day.
• Excessive salt intake: now salt intake is not a direct causative agent but it is a clear contributor.  Experiments in newborns on a low salt diet for a year experienced lower BP levels that lasted years after they were taken off of the diet.
• Obesity
• Race: African Americans are extremely vulnerable to developing Hypertension at young ages.
   

What diseases can be attributed to Hypertension?

• Myocardial infarctions
• Left ventricular hypertrophy
• Heart failure
• Gangrene of the lower extremities
• Aortic aneurisms
• Blindness
• Chronic Kidney Failure
• Stroke
• And some others that were not mentioned.
   

Causes of Resistant Hypertension

• Non-compliance with meds due to side effects
• Improper BP measurement (make sure been resting for awhile)
• Excess sodium intake
• Medication
• Inadequate doses
• Kind of expensive
• Drug actions and possible interactions. (Illicit drug use-cocaine)
• Over the counter drugs and herbal supplements (chronic use of NSAID’s and decongestants)
• Excess alcohol intake
• Identifiable causes of Hypertension

End Organ Damage

• We mentioned before that Hypertension was a silent killer…so how/when does it manifest??
• Well it damages our organs and causes symptoms. 
• Patients come in reporting chest pains (CAD and heart failure), inability to urinate (renal disease), cramping in legs (Peripheral artery disease), and blurry vision (retinopathy).
•  A quick way of finding Hypertension is by looking at the fundus (remember the eyes are not just the window to your soul they also provide a good view of your blood vessels). 
• You can pretty much assume that the appearance of the blood vessels in the eyes is very similar to the appearance of the vessels in other important areas.

• The picture below on the left is of a normal fundus (note sharp edges) and the picture on the right shows papilledema and swelling of the fundus with hemorrhages in the vessels (see how they aren’t as continuous as the normal vessels) and exudates.
   

Aortic Dissection:

Another example of end-organ damage of Hypertension.

• Theorized to be caused by the constant assault of the blood flowing at such a high pressure (we will learn later that the actual pathology is not known)
• The tear in the inner layer of the aorta creates another channel for the blood to flow through.
  •  The larger channel is usually the one that has been created.
• Can be due to uncontrolled Hypertension 80% of time but is also caused by Artherosclerosis and Marfan’s Syndrome (genetic weakness of the Aorta that leads to dissection even with a normal BP).
• Types of Dissection:
  • Type A: involves the arch (either first part or extends all the way).  Is very serious and requires surgery
  • Type B: does not involve the arch
• Patients present with severe chest pain and a tearing pain that radiates to the back, severe hypertension, Asymmetric pulses (possible compromise to extremities). 
  • The patient is usually elderly (>60-70y/o) (Once again it takes time to wear out the organ)
• Diagnose with chest x-ray (widened mediastinum), echo/ trans-esophageal echo, and CT scan.
• Treatment: IV meds (sodium nitroprusside and B-blockers)

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