Heat Rash Causes of low blood pressure - Heart disease Weakened heart muscle can cause the heart to fail and reduce the amount of blood it pumps. One common cause of weakened heart muscle is the death of a large portion of the heart's muscle due to a single, large heart attack or repeated smaller heart attacks. Other examples of conditions that can weaken the ability of the heart to pump blood include medications that are toxic to the heart, infections of the muscle of the heart by viruses myocarditis , and diseases of the heart's valves such as aortic stenosis that reduce the flow of blood from the heart and into the arteries.
Pericarditis is an inflammation of the pericardium the sac surrounding the heart. Pericarditis can cause fluid to accumulate within the pericardium and compress the heart, restricting the ability of the heart to expand, fill, and pump blood. Pulmonary embolism is a condition in which a blood clot in a vein deep vein thrombosis breaks off and travels to the heart and eventually the lung.
A large blood clot can block the flow of blood into the left ventricle from the lungs and severely diminish the blood returning to the heart for pumping.
Pulmonary embolism is a life-threatening emergency. A slow heart rate bradycardia can decrease the amount of blood pumped by the heart. In fact, some highly trained athletes can have resting heart rates in the 40s and 50s beats per minute without any symptoms.
The slow heart rates are offset by more forceful contractions of the heart that pump more blood than in non-athletes. But in many patients bradycardia can lead to low blood pressure, lightheadedness, dizziness, and even fainting.
Several common reasons for bradycardia include: Many of these conditions occur in the elderly. Sick sinus syndrome occurs when the diseased electrical system of the heart cannot generate electrical signals fast enough to maintain a normal heart rate.
Heart block occurs when the specialized tissues that transmit electrical current in the heart are damaged by heart attacks , degeneration from atherosclerosis, and medications. Heart block prevents some or all of the electrical signals from reaching parts of the heart, and this prevents the heart from contracting as well as it otherwise would.
Drugs such as digoxin Lanoxin or beta blockers for high blood pressure can slow the transmission of electricity in the heart chemically and can cause bradycardia and hypotension see section "Medications that cause low blood pressure". An abnormally fast heart rate tachycardia also can cause low blood pressure. The most common example of tachycardia causing low blood pressure is atrial fibrillation. Atrial fibrillation is a disorder of the heart characterized by rapid and irregular electrical discharges from the muscle of the heart causing the ventricles to contract irregularly and usually rapidly.
The rapidly contracting ventricles do not have enough time to fill maximally with blood before each contraction, and the amount of blood that is pumped decreases in spite of the faster heart rate. Other abnormally rapid heart rhythms such as ventricular tachycardia also can produce low blood pressure, sometimes even life-threatening shock.
Causes of low blood pressure - Medications Medications that cause low blood pressure Medications such as calcium channel blockers , beta blockers, and digoxin Lanoxin can slow the rate at which the heart contracts. Some elderly people are extremely sensitive to these medications since they are more likely to have diseased hearts and electrical conduction tissues.
In some individuals, the heart rate can become dangerously slow even with small doses of these medications. Medications used in treating high blood pressure such as angiotensin converting enzyme or ACE inhibitors , angiotensin receptor blockers, beta blockers, calcium channel blockers, and alpha blockers can excessively lower blood pressure and result in symptomatic low blood pressure especially among the elderly.
Medications used for treating depression , such as amitriptyline Elavil ; Parkinson's disease, such as levodopa-carbidopa Sinemet ; and erectile dysfunction impotence , such as sildenafil Viagra , vardenafil Levitra , and tadalafil Cialis when used in combination with nitroglycerin , can cause low blood pressure.
Alcohol and narcotics also can cause low blood pressure. I also agree to receive emails from MedicineNet and I understand that I may opt out of MedicineNet subscriptions at any time. Other caues of low blood pressure Other conditions that cause low blood pressure Vasovagal reaction is a common condition in which a healthy person temporarily develops low blood pressure, slow heart rate, and sometimes fainting.
A vasovagal reaction typically is brought on by emotions of fear or pain such as having blood drawn, starting an intravenous infusion, or by gastrointestinal upset. Vasovagal reactions are caused by activity of the involuntary autonomic nervous system, especially the vagus nerve, which releases hormones that slow the heart and widen the blood vessels.
The vagus nerve also controls digestive tract function and senses activity in the digestive system. Thus, some people can have a vasovagal reaction from straining at a bowel movement or vomiting. Postural orthostatic hypotension is a sudden drop in blood pressure when an individual stands up from a sitting, squatting, or supine lying position.
When a person stands up, gravity causes blood to settle in the veins in the legs so that less blood returns to the heart for pumping, and, as a result, the blood pressure drops. The body normally responds automatically to the drop in blood pressure by increasing the rate and narrowing the veins to return more blood to the heart.
In patients with postural hypotension , this compensating reflex fails to occur, resulting low blood pressure and its symptoms. Other causes of postural hypotension include dehydration, adrenal insufficiency discussed later , prolonged bed rest, diabetes , and certain rare neurological syndromes for example, Shy-Drager syndrome that damage the autonomic nerves.
Another form of postural hypotension occurs typically in young healthy individuals. After prolonged standing, the individual's heart rate and blood pressure drop, causing dizziness, nausea , and often fainting. In these individuals, the autonomic nervous system wrongly responds to prolonged standing by directing the heart to slow down and the veins to dilate thereby removing blood from circulating in the arteries.
Micturition syncope is a temporary drop in blood pressure and loss of consciousness brought about by urinating. This condition typically occurs in elderly patients and may be due to the release of hormones that lower blood pressure. Adrenal insufficiency, for example, due to Addison's disease, can cause low blood pressure.
Addison's disease is a disorder in which the adrenal glands small glands next to the kidneys are destroyed. The destroyed adrenal glands can no longer produce sufficient adrenal hormones specifically cortisol necessary to maintain normal bodily functions. Cortisol has many functions, one of which is to maintain blood pressure and the function of the heart.
Addison's disease is characterized by weight loss , muscle weakness , fatigue , low blood pressure, and, sometimes, darkening of the skin. Septicemia is a severe infection in which bacteria or other infectious organisms such as fungi enter the blood. The infection typically originates in the lungs as pneumonia , bladder, or in the abdomen due to diverticulitis or gallstones.
The bacteria then enter the blood where they release toxins and cause life-threatening and profound low blood pressure septic shock , often with damage to several organs. Anaphylaxis anaphylactic shock is a potentially fatal allergic reaction to medications such as penicillin , intravenous iodine used in some X-ray studies, foods such as peanuts, or bee stings insect stings.
In addition to a severe drop in blood pressure, individuals may also experience hives and wheezing due to constriction of the airways, and a swollen throat which cause difficulty breathing. The shock is caused by enlargement of blood-containing blood vessels and escape of water from the blood into the tissues.