Find definitions for thousands of medical terms, treatments, and tests -- even health-related abbreviations, prefixes, and suffixes.
Electrical pulses in the heart are controlled by special groups of
cells called nodes. The SA (sinoatrial) node generates an electrical signal
that causes the upper heart chambers (atria) to contract. The signal then
passes through the AV (atrioventricular) node to the lower heart chambers
(ventricles), causing them to contract, or pump.
The SA node is considered the pacemaker of the heart. Its
electrical signals normally cause the atria to contract at a rate of 60 to 100
times a minute.
Disturbance anywhere along this electrical pathway can cause
irregular heartbeats (arrhythmia).
August 9, 2012
Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology & John M. Miller, MD, FACC - Cardiology, Electrophysiology
Sarcoidosis is a rare disease that causes inflammation and scar
tissue throughout the body, especially the lungs, lymph nodes, liver, skin, and
The cause of sarcoidosis is not known. It occurs most often
in young and middle-aged adults.
Symptoms may include fever, body
aches, swelling of the lymph glands, breathlessness, a reddish rash on the
face, painful joints, and numbness. But sometimes sarcoidosis does not
cause any symptoms. It may lead to lung (respiratory) failure and heart
problems in some cases.
Sarcoidosis may require long-term
treatment (lasting months to years) with corticosteroids and other medicines,
especially if it causes severe breathing problems or affects the brain and
April 28, 2011
E. Gregory Thompson, MD - Internal Medicine & Mark A. Rasmus, MD - Pulmonology, Critical Care Medicine, Sleep Medicine
Saturated fats are those that become hard at room temperature. They
are found mostly in animal-based foods (such as meat, butter, milk, and cheese)
and in coconut oil, palm oil, and cocoa butter.
Saturated fats should only be eaten in limited amounts because they
harm blood vessels, which increases a person's risk for developing hardening of
the arteries (atherosclerosis). Saturated fats also affect the levels of
cholesterol in the blood and increase the risk of developing coronary artery
Most of a person's fat calories should be from monounsaturated fats (such as from olive oil, peanut oil,
avocados, and nuts) or polyunsaturated fats (such as
from liquid vegetable oils, corn oil, or soybean oil).
January 25, 2013
Kathleen Romito, MD - Family Medicine & Rhonda O'Brien, MS, RD, CDE - Certified Diabetes Educator
Schizophrenia is a severe mental illness that can affect your ability to think clearly, manage your emotions, and interact with others. Most people who have it hear or see things that aren't there (hallucinations), believe things that aren't true (delusions), or think someone is trying to harm them (paranoia).
Schizophrenia is not the same as a "split personality" (dissociative identity disorder).
October 9, 2012
Kathleen Romito, MD - Family Medicine & Lisa S. Weinstock, MD - Psychiatry
Sclerotherapy is a nonsurgical treatment to get rid of varicose
veins. A chemical called a sclerosant is injected into the varicose vein,
causing it to close.
Sclerotherapy may be used to make spider veins and small varicose
veins go away or become less visible. It is usually done only for cosmetic
reasons because these types of varicose veins rarely cause symptoms or
problems. It might be done along with other procedures to treat varicose veins.
February 1, 2012
E. Gregory Thompson, MD - Internal Medicine & David A. Szalay, MD - Vascular Surgery
Scoliosis is a problem with the curve in your spine. In scoliosis, your spine makes a large curve from side to side in the shape of the letter "S" or the letter "C." If this curve is severe, it can cause pain and make it hard to breathe.
Most cases of scoliosis are mild and don't need treatment. If your scoliosis is severe, you may need a brace or surgery.
John Pope, MD - Pediatrics & Robert B. Keller, MD - Orthopedics
Secondhand smoke is tobacco smoke that affects a nonsmoker.
Secondhand smoke can come directly from a cigarette or other lit tobacco; it
may also be exhaled by a person smoking.
Secondhand smoke is sometimes referred to as environmental tobacco
smoke (ETS), involuntary smoking, or passive smoking.
Secondhand smoke contains the same cancer-causing and lung-damaging
chemicals that affect smokers. Repeated exposure to secondhand smoke over many
years can cause damage to a nonsmoker's lungs that is similar to that of a
Secondhand smoke is the most important risk factor for cancer among
nonsmokers, far greater than other known cancer-causing substances. Secondhand
smoke is most harmful to:
September 12, 2012
E. Gregory Thompson, MD - Internal Medicine & Michael Seth Rabin, MD - Medical Oncology
Sedatives and tranquilizers are medicines that have a calming
effect. Generally, sedatives and tranquilizers depress or slow down certain
body functions or the activity of an organ, such as the heart.
Mild sedatives and tranquilizers may be used to reduce anxiety or
other nervous system problems, promote sleep, or regulate an organ system. For
example, light doses of sedatives can help reduce coughing, nausea, or
convulsions. Stronger doses of these substances may be used for severe sleep
problems, severe anxiety, symptoms related to psychotic disorders (such as
hallucinations or delusions), or as part of anesthesia. These types of
sedatives and tranquilizers should only be used as directed by a doctor because they can become habit-forming. Abuse of some stronger
substances can lead to severe health problems.
April 8, 2011
E. Gregory Thompson, MD - Internal Medicine & Jerome B. Simon, MD, FRCPC, FACP - Gastroenterology
Seizures are sudden bursts of abnormal electrical activity in the
brain that may affect a person's muscle control, movement, speech, vision, or
awareness (consciousness). The effects of seizures depend on a person's
individual response, as well as the seizure type, frequency, and
Some seizures make a person fall to the ground in convulsions, in
which the muscles stiffen or jerk out of control. Others may stare as if in a trance, have only a few muscle twitches, or sense a strange smell or
visual disturbance not experienced by anyone else.
Sometimes a seizure is a symptom of another medical problem, such
as a high fever (especially in children), a stroke, infection, low blood sugar
(hypoglycemia), very low blood pressure, or a brain tumor.
August 26, 2011
Susan C. Kim, MD - Pediatrics & Steven C. Schachter, MD - Neurology
A child who is having severe difficulty breathing:
or emergency services if these signs are present.
January 10, 2012
William H. Blahd, Jr., MD, FACEP - Emergency Medicine & David Messenger, MD
Shingles is a painful skin rash caused by the same virus that causes chickenpox. After you've had chickenpox, the virus stays in your nerve tissue and can cause shingles later in life.
Shingles usually appears in a band, a strip, or a small area on one side of the face or body. It is also called herpes zoster.
Shingles is more common in older adults and people who have weak immune systems because of stress, injury, certain medicines, or other reasons.
December 18, 2012
E. Gregory Thompson, MD - Internal Medicine & Christine Hahn, MD - Epidemiology
Shock is a life-threatening condition. Immediate medical care
can make the difference between life and death.
Signs of shock
(most of which will be present) include:
Also, a person in shock usually has an abnormal increase in
heart rate and an abnormal decrease in blood pressure.
occur in response to a sudden illness or injury. When the body loses too much
blood or fluids, the circulatory system can't get enough blood to the vital
organs, and shock results.
Shock is a life-threatening condition. Immediate medical care is required any time shock is suspected.
June 6, 2012
William H. Blahd, Jr., MD, FACEP - Emergency Medicine & H. Michael O'Connor, MD - Emergency Medicine
Sickle cell disease is a blood disorder in which the body
produces an abnormal type of the oxygen-carrying substance hemoglobin in the
red blood cells. Normal hemoglobin is called hemoglobin A, but people with
sickle cell disease have only hemoglobin S, which turns normal, round red blood
cells into abnormally curved (sickle) shapes.
cells are destroyed by the body faster than normal blood cells, which can
result in an inadequate oxygen supply to the body (anemia). Most people with
sickle cell disease have at least mild symptoms of chronic anemia,
Sickle-shaped blood cells are also more likely to get stuck
in and block small blood vessels throughout the body. Reduced blood flow caused
by blocked blood vessels can damage certain organs, muscles, and bones. This
may cause repeated episodes of pain (called sickle cell crises) that may last
from hours to days. The pain most often occurs in the bones of the
spine, arms and legs, the chest, and the abdomen.
People who have
sickle cell disease need special medical care throughout their lives to treat
the variety of problems that can be caused by the illness.
October 1, 2012
E. Gregory Thompson, MD - Internal Medicine & Martin Steinberg, MD - Hematology
Sleep apnea is breathing that stops during sleep. The problem can be mild or severe, based on how often your lungs don't get enough air. This may happen from 5 to more than 50 times an hour.
The two main types of sleep apnea are obstructive sleep apnea, caused by blocked airways, and central sleep apnea, caused by a problem with how the brain signals the breathing muscles.
Sleep apnea can cause you to snore loudly. People with sleep apnea often have sleep problems and are tired during the day. And they are more likely to have high blood pressure and some heart problems.
Anne C. Poinier, MD - Internal Medicine & Mark A. Rasmus, MD - Pulmonology, Critical Care Medicine, Sleep Medicine
Social anxiety disorder means that you are so fearful about what you will say or do in front of other people that you avoid social settings like work or school. It's more than just being shy or nervous before public speaking. Counseling and sometimes medicines can help.
E. Gregory Thompson, MD - Internal Medicine & Lisa S. Weinstock, MD - Psychiatry
Social workers are health professionals who use counseling to help
people function in their environment, improve their relationships with others,
and solve personal and family problems. They also help people locate and access
appropriate resources for their particular needs.
A social worker may work in a hospital, community organization, or
private counseling. Most social workers concentrate on a specific area of
practice. For example, clinical social workers provide psychotherapy or
counseling and a range of diagnostic services in public agencies, clinics, and
private practice. Child or adult protective services social workers investigate
reports of abuse and neglect and intervene if needed. And medical social
workers provide counseling in hospitals, nursing homes, and rehabilitation
facilities to people who are receiving therapy for physical problems or
Most social worker positions require a
master's degree (MSW). But many social worker positions, such as a child protective
services social worker, require a bachelor's degree (BSW) only. All 50 states require licensing, certification, and
registration of social workers. Requirements vary from state to state.
August 17, 2012
Anne C. Poinier, MD - Internal Medicine & E. Gregory Thompson, MD - Internal Medicine
Sodium is a naturally occurring mineral that the body needs to
But too much sodium can cause problems, such as high blood
pressure (hypertension) or heart failure, or make problems worse.
Salt is the most familiar source of sodium. Sodium is often hidden in
foods that don't taste salty, such as cheddar cheese and processed foods.
Sodium is also a major ingredient of monosodium glutamate (MSG), disodium
phosphate, and baking soda.
July 12, 2012
Speech-language pathologists assess, diagnose, treat, and help
prevent speech, language, and communication disorders.
Speech-language pathologists work with people who cannot make
speech sounds or cannot make them clearly; have speech rhythm and fluency
problems, such as stuttering; have voice quality problems, such as an
inappropriate pitch or harsh voice; have problems understanding and producing
language; have cognitive communication problems, such as attention, memory, and
problem-solving disorders; or have oral motor problems that cause eating and
swallowing difficulties. Speech pathologists work in hospitals, nursing homes,
clinics, rehabilitation facilities, schools, and private practices.
A speech-language pathologist has a master's degree in speech and
language and has completed postgraduate clinical work under the supervision of
a licensed speech-language pathologist.
Speech-language pathologists can
acquire the certificate of clinical competence in speech-language pathology
(CCC-SLP) offered by the American Speech-Language-Hearing Association.
Spider veins are small varicose veins that have a bluish, weblike
appearance. Varicose veins are twisted and enlarged veins near the surface of
the skin that most often occur in the legs and ankles.
Spider veins do not usually cause symptoms, although some people
may feel mild itching or burning.
Spider veins are common and generally are not a serious health
problem. Most people can manage varicose veins with home treatment, such as
exercising, wearing compression stockings, and elevating the legs.
Other treatments include sclerotherapy, in which a chemical
injection into a vein makes it close; or laser therapy, which scars and closes
a vein. A closed vein loses its source of blood and dies. This makes it likely
to fade or disappear.
Spinal discs are located between each of the 33 vertebrae,
which are the interlocking bones of the spine that are stacked on top of one
another. These discs act as shock absorbers for the spine and allow it to flex,
bend, and twist.
The outer portion of a spinal disc, called the
capsule (annulus fibrosus), is made of tough, elastic cartilage. The capsule
surrounds a mass of jellylike material called the nucleus (nucleus
Aging, injury, and illness can cause the spinal discs
to crack or rupture. The jellylike nucleus can leak out, putting pressure on
the spinal nerves. Pain, numbness, and weakness may result, and
sometimes surgery is needed.
Spinal discs are also called
March 12, 2012
William H. Blahd, Jr., MD, FACEP - Emergency Medicine & Robert B. Keller, MD - Orthopedics
Spinal stenosis is the narrowing of the spinal canal. It can be caused by several problems, including overgrowth of bone or other tissue or by a herniated disc. When the spinal canal gets too narrow, it can squeeze and irritate your spinal cord or nearby nerve roots.
Spinal stenosis can cause pain, numbness, or weakness in your legs, buttocks, arms, or neck, depending on what area of your spine is affected.
Spinal tumors are growths that develop on the bones and ligaments
of the spine, on the spinal cord, or on nerve roots. These tumors can be
noncancerous (benign) or cancerous (malignant).
Malignant tumors rarely start in the spine. They are usually tumors
that have spread from other parts of the body, particularly the breast,
prostate gland, thyroid gland, or kidney.
May 16, 2011
Kathleen Romito, MD - Family Medicine & Howard Schaff, MD - Diagnostic Radiology
Angina happens when there is not enough
blood flow to the heart muscle. This is often a result of narrowing of the
blood vessels that supply blood to the heart. Angina symptoms include chest pain or pressure. But you might feel other symptoms like pain, pressure, or a strange feeling in the back, neck, jaw, or upper belly, or one or both shoulders or arms.
Stable angina occurs at fairly predictable times, usually with
activity or exertion. It is relieved by rest and may continue without much
change for years. Stable angina develops after a predictable amount of exertion
or emotion and usually lasts 1 to 5 minutes.
A change in the usual pattern of stable angina means that the blood
flow has become more impaired (called unstable angina). It is a warning sign
that a heart attack may soon occur.
April 4, 2011
E. Gregory Thompson, MD - Internal Medicine & John M. Miller, MD, FACC - Cardiology, Electrophysiology
Stasis pigmentation is a brownish discoloration of the skin, often
with swelling, that usually appears around the ankles. It results from blood
cells breaking down and leaking out of tiny blood vessels.
Typically, stasis pigmentation occurs in people who have had
varicose veins or other vein problems for many years.
Statins are a type of medicine used to treat high cholesterol.
These medicines block an enzyme the body needs to produce cholesterol, thereby
lowering the total amount of it in the blood.
Statins, also known
as HMG-CoA reductase inhibitors, help reduce the risk of heart attack and
stroke. Along with reducing cholesterol levels in the blood, statins reduce
inflammation around the cholesterol buildup (called a plaque). By stabilizing
the plaque, there is less risk that it will rupture and cause a blood clot that
can lead to a heart attack or stroke.
June 29, 2012
Kathleen Romito, MD - Family Medicine & Robert A. Kloner, MD, PhD - Cardiology & Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology
A stent is a small, expandable tube that can be inserted into
a blood vessel and expanded using a small balloon during a procedure called
angioplasty. A stent is used to open a narrowed or clotted blood vessel.
When the balloon inside the stent is inflated, the stent expands
and presses against the walls of the artery. This traps any fat and calcium
buildup against the walls of the artery, allows blood to flow through the
artery. The stent helps prevent the artery from closing again (restenosis). It can
also help prevent small pieces of plaque from breaking off and causing a heart
attack or stroke.
To insert the stent, a flexible, thin tube (catheter) is passed
through an artery in the groin or arm into the narrowed artery. Then the
balloon inside the stent is inflated.
Some stents, called drug-eluting stents, are coated with a medicine to more effectively prevent
E. Gregory Thompson, MD - Internal Medicine & John M. Miller, MD - Electrophysiology
Strep throat is an infection in the throat and the tonsils caused by strep bacteria. It causes a severe sore throat and may cause a fever.
It's treated with antibiotics.
Kathleen Romito, MD - Family Medicine & Donald R. Mintz, MD - Otolaryngology
Stress is what you feel when you have to handle more than you are used to. When you are stressed, your body responds as though you are in danger. It makes hormones that speed up your heart, make you breathe faster, and give you a burst of energy.
Some stress is normal and even useful. Stress can help if you need to work hard or react quickly.
But if stress happens too often or lasts too long, it can cause health problems.
A stroke happens when a blood vessel in the brain is blocked or bursts. Without blood and the oxygen it carries, part of the brain starts to die. Then the part of the body controlled by that area of the brain can't work properly.
Brain damage can start within minutes of a stroke. But quick treatment can help limit brain damage and increase the chance of a full recovery.
January 3, 2013
E. Gregory Thompson, MD - Internal Medicine & Karin M. Lindholm, DO - Neurology
Stroke rehabilitation is training and therapy that helps a person
regain function and relearn skills that were lost as a result of a stroke. The
focus of rehabilitation depends on which part of the brain was damaged from the
stroke and how much damage was done.
Rehabilitation begins in the hospital, as soon as the person is
stable after having a stroke. A rehabilitation team that includes doctors and
nurses and physical, occupational, speech, and recreational therapists helps
the person to resume activities of daily living, such as eating, bathing, and
dressing. Some people may need help learning how to walk again, communicate,
and overcome disabilities from the stroke.
June 28, 2011
E. Gregory Thompson, MD - Internal Medicine & Richard D. Zorowitz, MD - Physical Medicine and Rehabilitation
Sudden heart failure causes rapid fluid buildup, or congestion, in
the lungs and other parts of the body. It occurs when the heart does not pump
as much blood as the body needs.
Symptoms develop suddenly and include:
Sudden heart failure is an emergency medical situation and requires
April 26, 2012
Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology & Stephen Fort, MD, MRCP, FRCPC - Interventional Cardiology
Sudden infant death syndrome (SIDS) is the death of a baby who is
younger than 1 year old without a known cause. Typically, a parent or other
caregiver puts the baby—who seems healthy—down to sleep and returns later to
find the baby has died.
No one is at fault when a baby dies of SIDS: it can be neither
predicted nor completely prevented. A baby's death is not considered a case of
SIDS when a specific cause is discovered, such as carbon monoxide poisoning. By
definition, SIDS is considered the cause of a baby's death only when the death
remains unexplained, even after a thorough investigation.
SIDS is also known as sudden infant
death, unexplained (SIDU).
Placing babies on their backs when putting them down to sleep
reduces the risk of SIDS.
May 16, 2012
John Pope, MD - Pediatrics & Chuck Norlin, MD - Pediatrics
A superficial venous thrombosis is a blood clot in a vein that
is close to the surface of the skin. A superficial thrombosis usually forms a
firm lump, sometimes like a rope, under the skin. Often the skin is red and
tender. The skin may look infected, but an actual infection is not common.
If the area around the clot has inflammation, it is called
superficial thrombophlebitis, or simply phlebitis.
Blood clots in
superficial veins usually are not serious. Home treatment is typically all that
is needed unless the clots are very painful or uncomfortable.
December 28, 2011
E. Gregory Thompson, MD - Internal Medicine & Jeffrey S. Ginsberg, MD - Hematology
Supraventricular tachycardia (SVT) is a very fast heartbeat that happens from time to time because of a problem with your heart's electrical system. It may make you feel like your heart is racing, pounding, or out of rhythm. It usually isn't life-threatening, but you may need treatment.
Kathleen Romito, MD - Family Medicine
Surgeons are medical doctors who specialize in evaluating people
who have potential surgical problems and performing surgical operations and
Common surgeries include hernia repairs, gallbladder removal, and
removal of the appendix. There are many subspecialties in surgery, including
chest (thoracic) surgery, blood vessel (vascular) surgery, and plastic surgery. Surgeons may further specialize by limiting their
practice to specific age groups, such as pediatric surgeons, who only treat
Surgeons can be board-certified through the Board of Surgery, which
is recognized by the American Board of Medical Specialties.
Symptoms of a heart attack may include:
The more of these symptoms you have, the more likely it is
that you're having a heart attack. Chest pain or pressure is the most common
symptom, but some people, especially women, may not notice it as much as other
symptoms. You may not have chest pain at all but instead have shortness of breath, nausea, numbness,
tingling, or a strange feeling in your chest or other areas.
you have symptoms of a heart attack, call 911 or other emergency services immediately. After you call 911, the operator may tell you to chew 1 adult-strength or 2 to 4 low-dose aspirin. Wait for an ambulance. Do not try to drive yourself.
September 13, 2012
Symptoms of a stroke or transient ischemic attack (TIA) happen quickly. A stroke or TIA may cause:
A stroke is an emergency and requires immediate medical
Syncope is a loss of consciousness (fainting) that occurs when
blood pressure drops very low and not enough blood reaches the brain. A person
may have shortness of breath, palpitations, or chest discomfort before
The reduction in blood flow usually happens quickly, which causes
symptoms to appear suddenly.
Syncope can be caused by several conditions, but it most often
occurs when changes in heart rate or heart rhythm reduce the amount of blood
flow to the body. Fainting caused by a problem in the heart is called cardiac
syncope. Other types of syncope that are not linked with heart problems
include neurally mediated syncope, also called vasovagal, neurocardiogenic, and
Syncope requires medical attention.
January 2, 2013
Syphilis is a sexually transmitted infection (STI) caused by the bacterium
Treponema pallidum. The most common initial symptom is a
painless sore called a chancre (say "shanker") that develops on the
Syphilis can be easily cured with antibiotics. If syphilis is not
treated, it can eventually lead to serious health problems, such as blindness
or heart problems.
September 29, 2011
Sarah Marshall, MD - Family Medicine & Devika Singh, MD, MPH - Infectious Disease
Systolic blood pressure refers to the pressure of blood in the
artery when the heart contracts. It is the top (and higher) number in a blood
Diastolic blood pressure refers to the pressure of blood in the
artery when the heart relaxes between beats. It is the bottom (and lower)
number in a blood pressure reading.
For example, if a person's systolic pressure is 120 millimeters of
mercury (mm Hg) and the diastolic pressure is 80 mm Hg, blood pressure is
recorded as 120/80 and read as "120 over 80."
E. Gregory Thompson, MD - Internal Medicine & Robert A. Kloner, MD, PhD - Cardiology
Systolic pressure is the pressure of blood against the artery walls
when the heart has just finished contracting or pumping out blood. (Diastolic
pressure is the pressure of blood against the artery walls between heartbeats,
when the heart is relaxed and filling with blood.)
Systolic blood pressure is the upper number of a blood pressure
reading. For example, if a person's systolic pressure is 120 millimeters of
mercury (mm Hg) and the diastolic pressure is 80 mm Hg, blood pressure is
recorded as 120/80 and read as "120 over 80."
April 5, 2011