John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.
Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.
During relaxation of the heart (diastole) the left ventricle of the heart fills with blood returning from the lungs. The left ventricle then contracts and pumps blood into the arteries (systole). The blood pressure
in the arteries during contraction of the ventricle (systolic pressure) is
higher because blood is being actively ejected into the arteries. It is lower during relaxation of the ventricle (diastolic pressure)
when no blood is being ejected into the arteries. The pulse that we can feel when we place our fingers over an artery is caused by the contraction of the left ventricle
and the ejection of blood.
Blood pressure is determined by two factors: 1) The amount of blood pumped by the left ventricle of the heart into the arteries, and 2) the resistance to the flow of blood caused by the walls of the arterioles (smaller arteries).
Generally, blood pressure tends to be higher if more blood is pumped into the arteries or if the arterioles are narrow and/or stiff. (Narrow and/or stiff arterioles, by resisting the flow of blood, increase blood pressure.) Arterioles may become narrower when the muscles surrounding them contract. Arterioles may become stiff and narrow when older patients develop atherosclerosis.
Blood pressure tends to be lower if less blood is being pumped into the
arteries or if the arterioles are larger and more flexible and, therefore, have
less resistance to the flow of blood.
How does the body maintain normal blood pressure?
The body has mechanisms to alter or maintain blood pressure and blood flow. There are sensors that sense blood pressure in the walls of the arteries and send signals to the heart, the arterioles, the veins, and the kidneys that cause them to make changes that lower or increase blood pressure.
There are several ways in which blood pressure can be adjusted - by adjusting the amount of blood pumped by the heart into the arteries (cardiac output), the amount of blood contained in the veins, the arteriolar resistance, and the volume of blood.
The heart can speed up and contract more frequently and it can eject more blood with each contraction. Both of these responses increase the flow of blood into the arteries and increase blood pressure.
The veins can expand and narrow. When veins expand, more blood can be stored in the veins and less blood returns to the heart for pumping into the arteries. As a result, the heart pumps less blood, and blood pressure is lower. On the other hand, when veins narrow, less blood is stored in the veins, more blood returns to the heart for pumping into the arteries, and blood pressure is higher.
The arterioles can expand and narrow. Expanded arterioles create less resistance to the flow of blood and decrease blood pressure, while narrowed arterioles create more resistance and raise blood pressure.
The kidney can respond to
changes in blood pressure by increasing or decreasing the amount of urine that is produced. Urine is primarily water that is removed from the blood. When the kidney makes more urine, the amount (volume) of blood that fills the arteries and veins decreases, and this lowers blood pressure. If the kidneys make less urine, the amount of blood that fills the arteries and veins increases and this increases blood pressure. Compared with the other mechanisms for adjusting blood pressure, changes in the production of urine affect blood pressure slowly over hours and days. (The other mechanisms are effective in seconds.)
For example, low blood volume due to bleeding (such as a bleeding ulcer in
the stomach or from a severe laceration from an injury) can cause low blood pressure. The body quickly responds to the low blood volume and pressure by the following adjustments which all increase blood pressure:
The heart rate increases
and the forcefulness of the heart's contractions increase thus
pumping more blood through the heart.
Veins narrow to return more blood to the heart for
pumping.
Blood flow to the kidneys decreases to reduce the formation of urine and thereby increases the volume of blood in the arteries and veins.
Arterioles narrow to increase resistance to blood flow
These adaptive responses will keep the blood pressure in the normal range unless blood loss becomes so severe that the responses are overwhelmed.
Kidney failure can occur from an acute event or a chronic condition or disease. Prerenal kidney failure is caused by blood loss, dehydration, medication. Some of the renal causes of kidney failure are from sepsis, medications, rhabdomyolysis, multiple myeloma, and acute glomerulonephritis. Post renal causes of kidney failure include bladder obstruction, prostate problems, tumors, or kidney stones. Treatment options included diet, medications, or dialysis.
Diverticulitis is a condition in which diverticuli in the colon rupture. The rupture results in infection in the tissues that surround the colon. Diverticulitis symptoms include: abdominal pain, abdominal cramps, diarrhea, constipation, and bloating. Treatment methods include prescription medications, and in some cases, diverticulitis surgery.
Dehydration is the excessive loss of body water. There are a number of causes of dehydration including heat exposure, prolonged vigorous exercise, and some diseases of the gastrointestinal tract. The best way to treat dehydration is to prevent it from occurring.
Dizziness is a symptom that is often applies to a variety of sensations including lightheadedness and vertigo. Causes of dizziness include low blood pressure, heart problems, anemia, dehydration, and more. Treatment of dizziness depends on the cause.
A pulmonary embolism occurs when a piece of a blood clot from deep vein thrombosis (DVT) breaks off and travels to an artery in the lung where it blocks the artery and damages the lung. The most common symptoms of a pulmonary embolism are shortness of breath, chest pain, and a rapid heart rate.
Deep vein thrombosis (DVT) is a blood clot in a vein located deep in the muscles of the legs, thighs, pelvis (lower torso), or arms. The most common symptoms of a deep vein thrombosis are swelling and pain in the leg that has the blood clot. A DVT is difficult to diagnose without specific tests in which the deep vein system can be examined.
Angina is chest pain that is due to an inadequate supply of oxygen to the heart muscle.
Angina can be caused by coronary artery disease or spasm of the coronary
arteries. EKG, exercise treadmill, stress echocardiography, stress thallium, and cardiac
catheterization are important tests used in the diagnosis of angina.
Dengue fever is contracted from the bite of a striped Aedes aegypti mosquito. Symptoms of dengue include headache, fever, exhaustion, severe joint and muscle pain, rash, and swollen glands. Since dengue is caused by a virus, there is no specific medicine to treat it. Treatment instead focuses on relieving the symptoms.
Pancreatitis is a rare disease in which the pancreas becomes inflamed, occurring when digestive enzymes are activated and begin attacking the pancreas causing damage to the gland. There are two types of pancreatitis, acute and chronic. Most commonly caused by alcohol or gallstones, it can lead to bleeding in the gland, serious tissue damage, infection, and cysts. Enzymes and toxins may then enter the bloodstream and seriously injure organs, such as the heart, lungs, and kidney.
Fainting, also referred to as blacking out, syncope, or temporary loss of consciousness has many causes. Often a person will have signs or symptoms prior to the fainting episode. Diagnosis and treatment depends upon the cause of the fainting or syncope episode.
Heart attack happens when a blood clot completely obstructs a coronary
artery supplying blood to the heart muscle. A heart attack can cause chest pain, heart failure, and electrical
instability of the heart.
Anorexia is an eating disorder characterized by markedly reduced appetite or total aversion to food. Anorexia is a serious psychological disorder and is a condition that goes well beyond out-of-control dieting. With anorexia, the drive to become thinner is actually secondary to concerns about control and/or fears relating to one's body. There are psychological and behavioral symptoms as well as physical symptoms of anorexia including: depression, social withdrawal, fatigue, food obsession, heart and gastrointestinal complications, kidney function, flaky skin, brittle nails, and tooth loss (this list is not exhaustive).
Chest pain is a common complaint by a patient in the ER. Causes of chest pain include broken or bruised ribs, pleurisy, pneumothorax, shingles, pneumonia, pulmonary embolism, angina, heart attack, costochondritis, pericarditis, aorta or aortic dissection, and reflux esophagitis. Diagnosis and treatment of chest pain depends upon the cause and clinical presentation of the patient's chest pain.
Internal bleeding occurs when an artery or vein is damaged and blood to escapes the circulatory system and collects inside the body. Internal bleeding can be caused by a variety of situations such as blunt trauma, deceleration trauma, medications, fractures, and spontaneous bleeding. Treatment of internal bleeding depends on the cause of the bleeding.
Sepsis (blood poisoning) is a potentially deadly infection with signs and symptoms that include elevated heart rate, low or high temperature, rapid breathing and/or a white blood cell count that is too high or too low and has more than 10% band cells. Most cases of sepsis are caused by bacterial infections, and some cases are caused by fungal infections. Treatment requires hospitalization, IV antibiotics, and therapy to treat any organ dysfunction.
Premature ventricular contractions (PVCs) are premature heartbeats originating from the ventricles of the heart. PVCs are premature because they occur before the regular heartbeat. There are many causes of premature ventricular contractions to include: heart attack, high blood pressure, congestive heart failure, mitral valve prolapse, hypokalemia, hypoxia, medications, excess caffeine, drug abuse, and myocarditis.
Heat stroke (heatstroke or sun stroke) is a form of hyperthermia. Heat stroke is a true medical emergency that can be fatal if not promptly and properly treated. Symptoms of heat stroke include: high body temperature, absence of sweating, with hot red or flushed dry skin, rapid pulse, difficulty breathing, strange behavior, hallucinations, confusion, agitation, disorientation, seizure, and coma. A victim of heat stroke must receive immediate treatment to avoid permanent organ damage.
Heart rhythm disorders vary from minor palpitations, premature atrial contractions (PACs), premature ventricular contractions (PVCs), sinus tachycardia, and sinus brachycardia, to abnormal heart rhythms such as tachycardia, ventricular fibrillation, ventricular flutter, atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia (PSVT), Wolf-White-Parkinson syndrome, brachycardia, or heart blocks. Treatment is dependant upon the type of heart rhythm disorder.
Aortic valve stenosis is an abnormal narrowing of the aortic valve of the heart. The causes of aortic stenosis are wear and tear of the valve in the elderly, congenital, or scarring or scarring of the aortic valve from rheumatic fever. Symptoms include angina, fainting, and shortness of breath. Treatment is dependant upon the severity of the condition.
Heart disease (coronary artery disease) is caused by a buildup of cholesterol deposits in the coronary arteries. Risk factors for heart disease include smoking, high blood pressure, heredity, diabetes, peripheral artery disease, and obesity. Symptoms include chest pain and shortness of breath. There are a variety of tests used to diagnose coronary artery disease. Treatment includes life-style changes, medications, procedures, or surgery.
Encephalopathy means brain disease, damage, or malfunction. Causes of encephalopathy are varied and numerous. The main symptom of encephalopathy is an altered mental state. Other symptoms include lethargy, dementia, seizures, tremors, and coma. Treatment of encephalopathy depends on the type of encephalopathy (anoxia, diabetic, Hashimoto's, hepatic, hyper - hypotensive, infectious, metabolic, infections, uremic, or Wernicke's) are examples of types of encephalopathy.
Pericarditis is the inflammation of the pericardial sac that surrounds the heart. The causes of pericarditis include injury from heart attack, heart surgery, trauma; viral or fungal infection, HIV, tumors, mixed connective tissue disease, metabolic disease, medication reactions, or idiopathic. Treatment for pericarditis is generally medication, however, sometimes surgery is necessary.
Heat exhaustion is a milder form of heat-related illness that can develop after several days of exposure to high temperatures and inadequate or unbalanced replacement fluids. Warning signs of heat exhaustion include heavy sweating, paleness, muscle cramps, tiredness, weakness, dizziness, headache, nausea or vomiting, and fainting.
Myocarditis is an inflammation of the heart muscle and can be caused by a variety of infections, conditions, and viruses. Symptoms of myocarditis include chest pain, shortness of breath, fatigue, and fluid accumulation in the lungs. Treatment mainly involves preventing heart failure with medication and diet, as well as monitoring for heart rhythm abnormalities.
Plague is an infectious disease caused by the Yersinia pestis bacteria, which is primarily found in rodents the fleas that feed off of them. The bacteria are passed to humans through flea or rodent bites. There are three forms of plague: bubonic, septicemic, and pneumonic. The symptoms and method of transmission vary with each form of plague. Plague can be treated with antibiotics.
Orthostatic hypotension symptoms include lightheadedness, weakness, blurred vision, and syncope or passing out. Causes of orthostatic hypotension include dehydration, anemia, medication, blood loss, low blood pressure, heat related illnesses and more. Treatment of orthostatic hypotension depends on the underlying cause.
Renal artery stenosis is a narrowing of the diameter of the renal arteries. When the renal arteries narrow, the result is restricted blood flow to the kidneys, which may lead to impaired kidney function and high blood pressure (referred to as renovascular hypertension (RVHT). Renal artery stenosis can occur in one or both kidneys. The primary cause of renal artery stenosis is atherosclerosis. Risk factors for renal artery stenosis include high blood pressure, high cholesterol levels, age, cigarette smoking, and diabetes. Symptoms of renal artery stenosis include high blood pressure that does not respond to treatment, severe high blood pressure in individuals younger than 30 or greater than 50 years of age. Renal artery stenosis is diagnosed with imaging and functional tests. Treatment for renal artery stenosis include medication or surgery.
Toxic shock syndrome (TSS) is a condition caused by toxins formed by Staphylococcus aureus or group A Streptococcus bacteria. Signs and symptoms include fever, low blood pressure, rash, diarrhea, nausea, and vomiting. Left untreated, the patient will experience confusion, dizziness, headaches, seizures, and multiorgan failure. Treatment involves intravenous fluids and antibiotics, oxygen administration, surgery to drain the source of infection, and removal of tampons, nasal packings, or other sources of infection.
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