| System | Test |
|---|---|
| Renal | Microscopic urinalysis, albumin excretion, serum BUN and/or creatinine |
| Endocrine | Serum sodium, potassium, calcium, ?TSH |
| Metabolic | Fasting blood glucose, total cholesterol, HDL and LDL (often computed) cholesterol, triglycerides |
| Other | Hematocrit, electrocardiogram |
Note: BUN, blood urea nitrogen; TSH, thyroid-stimulating hormone; HDL, LDL, high-/low-density lipoprotein
Damage of organs fed by the circulatory system due to uncontrolled hypertension is called end-organ damage. As already mentioned, chronic high blood pressure can lead to an enlarged heart, kidney failure, brain or neurological damage, and changes in the retina at the back of the eyes. Examination of the eyes in patients with severe hypertension may reveal damage; narrowing of the small arteries, small hemorrhages (leaking of blood) in the retina, and swelling of the eye nerve. From the amount of damage, the doctor can gauge the severity of the hypertension.
People with high blood pressure have an increased stiffness, or resistance, in the peripheral arteries throughout the tissues of the body. This increased resistance causes the heart muscle to work harder to pump the blood through these blood vessels. The increased workload can put a strain on the heart, which can lead to heart abnormalities that are usually first seen as enlarged heart muscle. Enlargement of the heart can be evaluated by chest x-ray, electrocardiogram, and most accurately by echocardiography (an ultrasound examination of the heart). Echocardiography is especially useful in determining the thickness (enlargement) of the left side (the main pumping side) of the heart. Heart enlargement may be a forerunner of heart failure, coronary (heart) artery disease, and abnormal heart rate or rhythms (cardiac arrhythmias). Proper treatment of the high blood pressure and its complications can reverse some of these heart abnormalities.
Blood and urine tests may be helpful in detecting kidney abnormalities in people with high blood pressure. (Remember that kidney damage can be the cause or the result of hypertension.) Measuring the serum creatinine in a blood test can assess how well the kidneys are functioning. An elevated level of serum creatinine indicates damage to the kidney. In addition, the presence of protein in the urine (proteinuria) may reflect chronic kidney damage from hypertension, even if the kidney function (as represented by the blood creatinine level) is normal. Protein in the urine alone signals the risk of deterioration in kidney function if the blood pressure is not controlled. Even small amounts of protein (microalbuminuria) may be a signal of impending kidney failure and other vascular complications from uncontrolled hypertension.
Uncontrolled hypertension can cause strokes, which can lead to brain or neurological damage. The strokes are usually due to a hemorrhage (leaking blood) or a blood clot (thrombosis) of the blood vessels that supply blood to the brain. The patient's symptoms and signs (findings on physical examination) are evaluated to assess the neurological damage. A stroke can cause weakness, tingling, or paralysis of the arms or legs and difficulties with speech or vision. Multiple small strokes can lead to dementia (impaired intellectual capacity). The best prevention for this complication of hypertension or, for that matter, for any of the complications, is control of the blood pressure. Recent studies have also suggested the angiotensin receptor blocking drugs may offer an additional protective effect against strokes above and beyond control of blood pressure.
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