The Neuroscience on the Web Series:
CMSD 636 Neuropathologies of Language and Cognition

CSU, Chico, Patrick McCaffrey, Ph.D.


Chapter 3.  Medical Aspects: The Stroke Prone Profile


The Stroke Prone Profile

Genetic Predisposition

A familial history of cerebral vascular accidents is one of the strongest predictors of whether or not an individual will suffer a stroke.

 Age

Older people have a much higher risk of stroke. Eighty three percent of strokes occur in individuals over 59 years of age. Most first strokes occur in people in their 60's and 70's.

 Gender

Men are more likely to have strokes, and at an earlier age than women. Women are catching up rapidly and in fact more women than men die from heart attacks.

 Primary Hypertension

Primary hypertension refers to elevated blood pressure. Diastolic pressure is measured while the heart is relaxing. Systolic blood pressure is measured while the heart is contracting. Normal blood pressure is 120 systolic over 80 diastolic, while high blood pressure is a pressure greater than 140/90. During strenuous exercise, a normal person's blood pressure will creep up into the abnormal range temporarily. In cases of hypertension, blood pressure remains high, regardless of activity level. Some people will have a high blood pressure reading when their pressure is taken in a doctor's office. It's referred to as the white coat syndrome.

Untreated hypertension increases the risk of ischemic stroke by pushing plaque up against the arterial walls. It also increases the risk of hemorrhagic stroke by causing pressure against the arterial walls which could weaken them over time.

Smoking and obesity further increase the risk of vascular problems in those who have hypertension. Losing weight and exercising regularly will be a big help with blood pressure management.

Smoking

Smoking greatly increases an individual's risk of vascular disease independently of primary hypertension. Smokers are twice as likely as non-smokers to have heart attacks and strokes

Eating Red Meat

A study in the journal, Nature Medicine (2013), points out that carnitine is a compound in red meat that is also in some energy drinks. Certain bacteria in the digestive tract convert carnitine into TMAO which promotes athersclerosis, or a thickening of the artieries. Researchers led by Stanley Hazen, chief of cellular and molecular medicine at the Cleveland Clinic, tested the carnitine and TMAO levels of omnivores, vegans and vegetarians. Robert A. Koeth et a.l 2013 examined records of 2,595 patients undergoing cardiac evaluations. Patients with high levels of TMAO, the more carnitine in the blood, were more likely to develop cardiovascular disease, heart attacks, stroke and death. A number of other studies have linked consumption of red and processed meat with cardiovascular disease and some cancers.

Diabetes

Diabetes promotes arteriosclerosis, thus increasing vulnerability to vascular problems. Diabetes and hypertension are a particularly dangerous combination.

High Cholesterol

High density lipoprotein (HDL) is the "good" cholesterol. Low-density lipoprotein (LDL) is the "bad" cholesterol. It is alright to have high levels of HDL, but a high concentration of LDL is a health risk as is high levels of triglycerides. Levels of LDL should be under 100 mg/dl. Levels of HDL should be between 40 and 60 but ideally be a little over 60. Overall cholesterol levels should be under 200. Triglyceride levesl should be under 150 mg/dl. Betwen 150-199 is borderline. Above 200 is high.

Cholesterol damages the lining of blood vessels, exposing the underlying smooth muscle tissue. This muscle tissue bulks up when exposed directly to blood. Plaque is primarily composed of cholesterol build up and smooth muscle cells.

Some feel that the relationship between cholesterol levels and stroke is not clear-cut. A minority of physicians feel that high cholesterol is not a significant factor in 80-90% of strokes. Most disagree.

Many medical professionals today (2011) feel that inflammation of the arteries as measured by C reactive protein may be a better prognostic indicator than level of cholesterol.

Niacin in relatively high doses (1. 5 grams) effectively raised my "good" cholesterol from 34 to 60. Before you try it you must see your doctor.

Hematological Disorders

Polycythemia, hemophilia and hyperuricemia can all increase an individual's risk of stroke. Polycythemia is a thickening of the blood due to an increase in the number of cells. Hemophilia is a thinning of the blood which prevents it from coagulating. Hyperuricemia involves an elevation of the level of uric acid in the blood. (This is the cause of gout.)

Congestive Heart Failure

Congestive heart failure occurs when the heart can no longer beat with sufficient strength and the lungs fill with fluid. This increases the number of red blood cells, thickening the blood and thus increases the risk of stroke. One sign of congestive heart failure is swollen ankles. Many years ago this condition was called dropsy.

Arrythmias

Some arrythmias can cause the formation of embolisms, leading to an ischemic stroke.


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Other courses in the neuroscience on the Web series:
CMSD 620 Neuroanatomy | CMSD 642 (Neuropathologies of Swallowing and Speech

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