Find definitions for thousands of medical terms, treatments, and tests -- even health-related abbreviations, prefixes, and suffixes.
Radiation therapy is the use of high-dose X-rays to destroy cancer
cells and shrink tumors. Radiation may come from a machine outside the body
(external radiation therapy) or from the placement of thin plastic tubes
containing radiation (radioisotopes) into the area where the cancer cells are
found (internal radiation therapy, or brachytherapy).
Radiation therapy is standard treatment for many types of cancer.
It may be used in combination with surgery, chemotherapy, or hormonal therapy.
July 27, 2011
E. Gregory Thompson, MD - Internal Medicine & Matthew I. Kim, MD - Endocrinology
Radioactive tracers are used in imaging tests that help find
problems inside the body. These tracers give off particles that can be detected
and turned into a picture to help find problems in organs or other
The tracer is usually given through an intravenous (IV) line
placed in a vein. But the tracer also may be given by mouth or by inhaling it into the lungs. The tracer then travels through the body and may collect in a
certain organ or area.
The types of tests that use radioactive tracers include positron
emission tomography (PET) and nuclear medicine scans to look at specific organs
such as the liver, lungs, kidneys, and gallbladder.
October 1, 2012
Anne C. Poinier, MD - Internal Medicine & Myo Min Han, MD - Nuclear Medicine
Radiologic technologists perform
imaging tests such as X-rays, computed tomography (CT) scans, and magnetic
resonance imaging (MRI). They are also called radiographers. They work under the direction of a radiologist, who
interprets the images to diagnose illness.
Training programs in radiography lead to
a certificate, associate degree, or bachelor's degree. State requirements for
licensing vary. And radiologic technologists may be registered through the
American Registry of Radiologic Technologists.
August 17, 2012
Anne C. Poinier, MD - Internal Medicine & E. Gregory Thompson, MD - Internal Medicine
Radiologists are medical doctors who specialize in performing and
interpreting diagnostic imaging tests. They read X-rays and scans, such as
chest X-rays, ultrasounds, or magnetic resonance imaging (MRI).
Another specialist or primary care doctor may base treatment
decisions on findings reported by the radiologist. Radiologists may also
supervise people who perform special tests, such as barium enemas or computed
tomography (CT) scans.
Diagnostic radiologists further specialize in performing tests to diagnose diseases. People might see a diagnostic radiologist to get a test such as an ultrasound.
Radiologists can be board-certified through the Board of Radiology,
which is recognized by the American Board of Medical Specialties.
Range of motion is the degree of movement a joint has when it is
extended, flexed, and rotated through all of its possible movements. A joint
becomes stressed or overextended if it is moved past its natural range.
A person may increase a joint's range of motion through regular,
gentle stretching exercises as directed by a health professional. Often these
exercises are recommended after an injury or surgery to help prevent joint
February 16, 2011
Anne C. Poinier, MD - Internal Medicine & Nancy Greenwald, MD - Physical Medicine and Rehabilitation
Recreational therapists are health and rehabilitation professionals who provide treatment
services and recreation activities to people who have disabilities or
illnesses. They are also called therapeutic recreation specialists.
Recreational therapists use arts and crafts, animals, sports,
games, dance and movement, drama, music, and community outings to help people
who have disabilities and illnesses. These activities not only help people be more independent but also reduce the depression,
stress, and anxiety caused by being disabled or ill.
After recreational therapists complete their undergraduate
work, they can be certified through the National Council for Therapeutic
Red blood cells, or erythrocytes, travel through circulating blood
carrying oxygen to body tissues and organs while removing waste. These blood
cells make up the largest part of the blood system.
As the red blood cells in blood travel through the lungs, oxygen
molecules from the lungs attach to the hemoglobin, a protein in the blood cells
that contains iron. The oxygen is then released to tissues and organs, and the
hemoglobin bonds with carbon dioxide and other waste gases. These waste
products are transported away and removed as blood continues to
Millions of red blood cells are contained in a single drop of
blood. Red blood cells are constantly being produced in the bone marrow to
replenish those that gradually wear out and die. The average life of a red
blood cell is about 120 days.
A significant decrease in the number of red blood cells causes
anemia and shortness of breath.
August 6, 2012
E. Gregory Thompson, MD - Internal Medicine & Joseph O'Donnell, MD - Hematology, Oncology
Registered dietitians (RDs) are health professionals who teach
people about nutrition or develop diets to promote health. They can also
specialize in nutritional counseling to help treat food-related psychological
problems, such as anorexia or bulimia.
Dietitians work in hospitals, nursing homes, and schools.
Registered dietitians also work in government, restaurant management, fitness,
food companies, and private practices.
Registered dietitians complete a bachelor's degree. They also must complete a supervised
practice program and pass a national examination given by the Commission on
Dietetic Registration (CDR). Some RDs hold additional certifications in
specialized areas of practice, such as pediatric or renal nutrition, nutrition
support, or diabetes education. These certifications are awarded through the
CDR or other medical and nutrition groups.
January 25, 2013
Kathleen Romito, MD - Family Medicine & Rhonda O'Brien, MS, RD, CDE - Certified Diabetes Educator
Multiple sclerosis (MS) is a chronic neurological disease that
involves the central nervous system—specifically the brain, spinal cord, and
optic nerves. Relapsing-remitting multiple sclerosis is a form of MS in which
symptoms randomly flare up (relapse) and then improve or fade
This relapsing-remitting pattern emerges with the onset of the
disease and may last for many years. MS can cause problems with muscle control
and strength, vision, balance, sensation, and mental functions.
The disease does not advance during the remissions. But loss of
nerve function that can occur during relapses may be permanent. After repeated
relapse episodes, the loss of nerve function may cause symptoms that do
There is no cure for MS, but medicines can reduce the number,
frequency, and severity of relapses and may slow the progression of the
February 15, 2012
Adam Husney, MD - Family Medicine & Anne C. Poinier, MD - Internal Medicine & Barrie J. Hurwitz, MD - Neurology
Respiratory therapists (RTs) are health professionals who evaluate,
treat, and care for people who have breathing problems. Respiratory therapists use
oxygen, medicines, and mechanical measures such as chest percussion to help
people breathe more effectively.
Most respiratory therapists work under the direct supervision of a
doctor. Respiratory therapists treat people of all ages, from premature babies
with undeveloped lungs to older adults with respiratory disease. Most
respiratory therapists work in hospitals. But some work in nursing homes
and doctor's offices.
Respiratory therapists can be certified as RTs after they complete a college-level, accredited RT program. The National
Board for Respiratory Care (NBRC) offers voluntary certification and
registration to graduates of accredited programs. Two credentials are awarded
to respiratory therapists who satisfy the requirements: registered respiratory
therapist (RRT) and certified respiratory therapist (CRT). Either the CRT or
RRT examination is the standard in the states that require licensure.
Restrictive cardiomyopathy is a problem in which the heart
muscle becomes stiff and cannot fully expand to let enough blood enter its
chambers. Blood that would normally enter the heart backs up in the circulatory
system instead of getting pumped out to the body.
In most cases,
restrictive cardiomyopathy leads to heart failure. Heart failure means that
your heart can't pump enough blood to meet your body's needs.
cause of restrictive cardiomyopathy is often not known. But a number of
diseases can lead to restrictive cardiomyopathy. Symptoms of restrictive
cardiomyopathy happen if a person gets heart failure. Heart failure symptoms
include shortness of breath, feeling weak and tired, and swollen legs and
The treatment of restrictive cardiomyopathy includes
medicine and lifestyle changes. Treatment focuses on relieving the symptoms of
heart failure and slowing its progression.
July 24, 2012
Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology & Robert A. Kloner, MD, PhD - Cardiology
The retina is a thin nerve membrane that detects light entering the
eye. Nerve cells in the retina send signals of what the eye sees along the
optic nerve to the brain.
The retina lines the back two-thirds of the eye and is made up of
two layers: the sensory retina and the retinal pigment epithelium (RPE).
The macula, near the center of the retina at the back of the
eyeball, provides the sharp, detailed, central vision a person uses for
focusing on what is directly in the line of sight. The rest of the retina
provides side (peripheral) vision, which lets a person see shapes but not fine
August 7, 2011
Adam Husney, MD, MD - Family Medicine & Carol L. Karp, MD - Ophthalmology
Reye syndrome is a very rare but serious disease that is most
likely to occur in children younger than 15 years of age. The exact cause is not known, but
it is linked with children who have recently had chickenpox (varicella), a cold, or
flu (influenza) and taken aspirin.
The disease primarily targets
the brain and liver and can cause drowsiness, confusion, seizures, coma, and in
severe cases, death. The symptoms usually develop 3 to 7 days after the viral
illness starts. Reye syndrome is not contagious.
with Reye syndrome are treated in a hospital intensive care unit, and most
recover in a few weeks. But some children develop lasting brain damage. Early
treatment increases the chance for full recovery.
aspirin products should not be given to anyone younger than 20, unless they are
specifically prescribed by a doctor. Aspirin is also called acetyl salicylate,
acetylsalicylic acid, salicylic acid, salicylate, or subsalicylate. Aspirin
products are found in over-the-counter medicines such as Pepto-Bismol,
Kaopectate, and Alka Seltzer.
May 16, 2012
John Pope, MD - Pediatrics & Chuck Norlin, MD - Pediatrics
Rh sensitization happens when a pregnant woman with Rh-negative blood is exposed to blood from her Rh-positive baby, usually during delivery. This isn't a problem in her first pregnancy, but if she gets pregnant again with an Rh-positive baby, antibodies in her blood can attack the baby's blood cells and cause serious problems.
A blood test is the only way to know you have Rh sensitization or are at risk for it.
October 9, 2012
Sarah Marshall, MD - Family Medicine & William Gilbert, MD - Maternal and Fetal Medicine
Rhabdomyolysis is a process in which dying muscle cells cause the
toxic buildup of certain substances in the blood. Some of these substances are creatine, myoglobin,
aldolase, potassium, and lactate dehydrogenase. Left untreated, rhabdomyolysis
can cause life-threatening damage to body organs, including kidney
Rhabdomyolysis can be caused by a variety of problems,
Early symptoms are often subtle. Muscle weakness, pain, tenderness,
and stiffness may develop along with fever, nausea, confusion, and a general
ill feeling (malaise). Urine may also be noticeably dark.
Treatment for rhabdomyolysis includes removing the cause of the
muscle cell destruction whenever possible, such as by stopping certain
medicines. Measures to help the kidneys remove the buildup of toxins and
other chemicals, such as providing plenty of fluids, is also important. Other
treatment (such as dialysis) may be needed if rhabdomyolysis is severe.
June 29, 2012
Kathleen Romito, MD - Family Medicine & Robert A. Kloner, MD, PhD - Cardiology & Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology
Rheumatic fever results from an infection caused by certain strains
of streptococcal bacteria and may be triggered by a strep infection (most often
strep throat) that has not been treated. Proper treatment of strep infection
can prevent rheumatic fever.
Rheumatic fever affects the joints and heart, causing symptoms
similar to arthritis as well as heart problems (rheumatic heart disease).
Rheumatic fever may also affect the skin, brain, and other organs and tissues.
Most of the damage caused by rheumatic fever is temporary. But if any
heart damage occurs, it is usually permanent.
August 2, 2012
Kathleen Romito, MD - Family Medicine & Donald R. Mintz, MD - Otolaryngology
Rheumatic heart disease is inflammation and damage to the heart
muscle and heart valves that develop as a result of rheumatic fever. A strep
throat infection that is not properly treated can trigger rheumatic
Not all people who have rheumatic fever develop rheumatic
heart disease. But any heart damage that occurs is usually
Rheumatoid arthritis is a type of arthritis in which your body's immune system attacks healthy tissue in your joints. This makes the joints swollen, stiff, and painful. Over time, it may destroy the joint tissues and make it hard for you to walk and use your hands.
Medicine may help control rheumatoid arthritis or keep it from getting worse.
Anne C. Poinier, MD - Internal Medicine & Nancy Ann Shadick, MD, MPH - Internal Medicine, Rheumatology
Rubella, also called German measles, is a contagious infection
caused by a virus. It usually causes a mild illness with a fine, red rash over
most of the body, swollen glands, and low fever.
Rubella is not common in the United States because most children
are vaccinated (immunized) against it. Most people who get rubella are young
adults who have not been vaccinated. A person can develop immunity to rubella
by having the disease or being vaccinated.
Rubella is a mild illness in adults. But if a woman gets
rubella during pregnancy, her baby is at risk for birth defects, such as heart defects, deafness, and
cataracts. The illness can also result in miscarriage or stillbirth. The
earlier the infection occurs in a woman's pregnancy, the greater the risk that her baby will have severe defects. Women who are not immune to rubella should be vaccinated before
August 31, 2012
John Pope, MD - Pediatrics & W. David Colby IV, MSc, MD, FRCPC - Infectious Disease