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LOW BLOOD OR HYPOTENSION
Blood pressure is the force exerted by circulating blood on the walls of blood vessels, and constitutes one of the principal vital signs. Blood pressure is generated by the heart pumping blood into the arteries and is regulated by the response by the arteries to the flow of blood.
By convention, an individual's blood pressure is expressed as systolic/diastolic blood pressure, for example, 120/80.The systolic blood pressure (the top number) represents the pressure in the arteries as the muscle of the heart contracts and pumps blood into them. The diastolic blood pressure (the bottom number) represents the pressure in the arteries as the muscle of the heart relaxes after it contracts. Blood pressure always is higher when the heart is pumping than when it is relaxing.
Systolic blood pressure for most healthy adults falls between 90 and 120 millimeters of mercury (mm Hg). Normal diastolic blood pressure falls between 60 and 80 mm Hg. Current guidelines define normal blood pressure as lower than 120/80. Blood pressures over 130/80 are considered high. High blood pressure increases the risk of developing heart disease, kidney disease, hardening of the arteries (atherosclerosis or arteriosclerosis), eye damage, and stroke.
Low blood pressure (hypotension) is pressure that is so low that it causes symptoms or signs due to the low flow of blood through the arteries and veins. When the flow of blood is too low to deliver enough oxygen and nutrients to vital organs such as the brain, heart, and kidney, the organs do not function normally and may be permanently damaged.
Unlike high blood pressure, low blood pressure is defined primarily by signs and symptoms of low blood flow not by a specific blood pressure number. Some individuals may have a blood pressure of 90/50 with no symptoms of low blood pressure and therefore do not have low blood pressure. However, others who normally have high blood pressure may develop symptoms of low blood pressure if their blood pressure drops to 100/60.
Signs and symptoms
Some people with low blood pressure are in peak physical condition with strong cardiovascular systems and a reduced risk of heart attack and stroke. But low blood pressure can also signal an underlying problem, especially when it drops suddenly or is accompanied by signs and symptoms such as:
- Dizziness or lightheadedness
- Fainting (syncope)
- Lack of concentration
- Blurred vision
- Nausea
- Cold, clammy, pale skin
- Rapid, shallow breathing
- Fatigue
- Depression
- Thirst
LOW BLOOD CAUSES
Common causes of low blood sugar include the following:
- Overmedication with insulin or antidiabetic pills
- Use of medications like beta-blockers, pentamidine, and Bactrim
- Use of alcohol
- Missed meals
- Reactive hypoglycemia is the result of the delayed insulin release after a meal has been absorbed and occurs 4-6 hours after eating.
- Severe infection
- Cancer causing poor oral intake or involving the liver
- Adrenal insufficiency
- Kidney failure
- Liver failure
- Insulinoma or insulin-producing tumor
- Other tumors like hepatoma, mesothelioma, and fibrosarcoma
- What follows are expansions on the points noted above and should be incorporated within those points (such as cancer, diabetes drugs, organ failures).
- Most cases of hypoglycemia in adults happen in people with diabetes mellitus. Diabetes has 2 forms, type 1 (lack of insulin) and type 2 (ineffective insulin action or resistance to the actions of insulin). If people with type 1, who take insulin to control their glucose level, skip meals or have a decreased appetite without changing their insulin dose, they may develop hypoglycemia.
- If a person with diabetes type 1 accidentally takes too much insulin or a person with type II diabetes accidentally takes too much of their oral medications, they also may develop hypoglycemia. Alternatively, if they take their medications correctly but do not eat properly or do too much exercise, hypoglycemia may result.
- Often a person who has more than one medical problem may become confused about how much of a certain medication they should take, or the medications may interact to cause hypoglycemia.
- Hypoglycemia also may occur in people with cancer, which often causes loss of appetite. Many such people skip meals because they are not hungry or because chemotherapy causes foods to taste differently. To prevent this, people on chemotherapy should be encouraged by their doctors and loved ones to try to stay on special diets and take medications to keep them from feeling sick. If this does not work, special medications to help with appetite are available.
- Adrenal insufficiency is a disease that affects the adrenal glands, which are located above the kidneys. These small structures make certain hormones and substances, such as cortisol and epinephrine, which also help elevate glucose. If these substances are not made, low blood pressure or hypoglycemia or both can result.
- The pituitary gland makes growth hormone, which helps in maintaining the balance of glucose. Deficiency of growth hormone causes hypoglycemia, especially in young infants and children.
- Kidney failure causes hypoglycemia in 3 separate ways. The kidneys help in generating new glucose from amino acids, and this is impaired in kidney failure. Also, insulin circulates for a longer period of time and is cleared slowly when kidney function is poor. The third important reason is that kidney failure causes one's appetite to be poor.
- The liver stores glucose in a form called glycogen. In the presence of liver failure, the ability to generate new glucose is affected.
- Insulin-producing tumors of the pancreas called insulinomas cause hypoglycemia by producing inappropriately high amounts of insulin. Certain tumors of the liver called hepatoma or other tumors called fibrosarcomas and mesotheliomas also cause hypoglycemia by producing an insulinlike substance.