Health Library

Rabies is a deadly viral infection that is mainly spread by infected animals.

Radial nerve dysfunction is a problem with the radial nerve. Damage to the radial nerve leads to problems with movement or sensation of the back of the arm (triceps), forearm, or hand.

Radiation is damage to the lining of the intestines (bowels) due to , a type of cancer treatment.

Radiation sickness is illness and symptoms resulting from excessive exposure to ionizing radiation. There are two basic types of radiation: ionizing and nonionizing. Nonionizing radiation comes in the form of light, radio waves, microwaves and radar. This kind of radiation usually does not cause ...

Radiation therapy uses high-powered x-rays, particles, or radioactive seeds to kill cancer cells.

Radical prostatectomy is surgery to remove all of the prostate gland and some of the tissue around it, to treat . See also:

Radioactive iodine uptake (RAIU) is a test of thyroid function. It measures how much radioactive iodine is taken up by the thyroid gland in a given time period. See also:

A radionuclide cisternogram is a nuclear scan test used to diagnose spinal fluid circulation problems.

A radionuclide cystogram is a special imaging test called a that involves placing radioactive material into the bladder. A scanner then detects radioactivity to check bladder and urinary tract functions.

Ramsay Hunt syndrome is a painful rash around the ear that occurs when the virus infects a nerve in the head.

Rape is defined as sexual intercourse forced on a person without his or her permission, either by threat of force or on someone who is unable to give consent. Sexual intercourse may be vaginal, anal, or oral, and may involve the use of a body part or an object.

Rape is defined as sexual intercourse forced on a person without his or her permission. The most useful rape prevention tool available is to be more aware about rape. Always trust your instincts if you are somewhere or with someone that does not feel safe and comfortable.

A normal breathing rate for an adult at rest is 8 to 16 breaths per minute. For an infant, a normal rate is up to 44 breaths per minute. Tachypnea is the medical term that your doctor uses to describe your breathing if it is too fast, particularly if you have rapid, shallow breathing due to an ...

A rash is a change in the color or texture of the skin. A skin rash can be flat, bumpy, scaly, red, skin-colored, or slightly lighter or darker than skin color.

Rashes involve changes in the color or texture of your skin.

Rat-bite fever is a rare disease spread by infected rodents.

Raynaud’s phenomenon is a condition in which cold temperatures or strong emotions cause blood vessel spasms that block blood flow to the fingers, toes, ears, and nose.

The RBC urine test measures the number of red blood cells in a urine sample.

An RBC count is a blood test that tells how many red blood cells (RBCs) you have. RBCs contain , which carries oxygen. How much oxygen your body tissues get depends on how many RBCs you have and how well they work.

Red blood cell (RBC) indices are part of the (CBC) test. They are used to help diagnose the cause of anemia, a condition in which there are too few red blood cells. The indices include: Average red blood cell size (MCV) amount per red blood cell (MCH) The amount of hemoglobin relative to the size ...

An RBC nuclear scan uses small amounts of radioactive material to mark (tag) red blood cells (RBCs). Your body is then scanned to determine the location of the cells and to see how they move through the body. See:

Reactive arthritis is a group of inflammatory conditions that involves the joints, urethra, and eyes. There may also be sores (lesions) on the skin and mucus membranes.

Reactive attachment disorder is a problem with social interaction that occurs when a child’s basic physical and emotional needs are neglected, particularly when the child is an infant.

A rectal biopsy is a procedure to remove a small piece of rectal tissue for examination.

Rectal culture is a laboratory test to identify organisms in the rectum that can cause gastrointestinal symptoms and disease.

Rectal prolapse occurs when the tissue that lines the rectum falls down into or sticks through the anal opening.

Rectal prolapse repair is surgery to fix a , in which the rectum (the last part of the colon) protrudes through the anus.

A reflux board is a device prescribed for use in children who have gastroesophageal . The board tilts the child upward, to prevent or reduce gastroesophageal reflux while the child is lying in bed.

Reflux nephropathy is a condition in which the kidneys are damaged by the backward flow of urine into the kidney.

The refraction test is an eye exam that measures a person’s prescription for eyeglasses or contact lenses.

A refrigerant is a chemical that makes things cold. This article discusses poisoning from sniffing or swallowing such chemicals. The most common poisoning occurs when people intentionally sniff a type of refrigerant called freon. This is for information only and not for use in the treatment or ...

Reifenstein syndrome is one of a group of diseases in which the body is unable to respond appropriately to the male sex hormones (androgens), which include testosterone.

Relapsing fever is an infection transmitted by a louse or tick. It is characterized by repeated episodes of .

The term “renal” refers to the kidney. For example, renal failure means kidney failure. Related topics:

Renal disorders refers to any disease of the kidneys. Urological disorders are diseases of the kidneys/urinary tract. This includes: Kidneys, ureters, urinary bladder, and urethra Male reproductive organs including the testes, epididymis, vas deferens, seminal vesicles, prostate, and penis

Renal arteriography is a special x-ray of the blood vessels of the kidneys. Renal arteriography is also called renal angiography. See also:

A renal biopsy is the removal of a small piece of kidney tissue for laboratory examination.

Renal cell carcinoma is a type of kidney cancer in which the cancerous cells are found in the lining of very small tubes (tubules) in the kidney.

Renal papillary necrosis is a disorder of the kidneys in which all or part renal papillae die. The renal papillae is the area where the openings of the collecting ducts enter the kidney.

A renal perfusion scintiscan is a nuclear medicine test that uses a small amount of a radioactive substance to create an image of the kidneys.

A renal scan is a exam in which a small amount of radioactive material (radioisotope) is used to measure the function of the kidneys.

Renal vein thrombosis is a that develops in the vein that drains blood from the kidney.

A renal venogram is a test to look at the veins in the kidney. It uses and a special dye (called contrast). X-rays are a form of electromagnetic radiation like light, but of higher energy, so they can move through the body to form an image on film. Structures that are dense (such as bone) will ...

Renin is a protein (enzyme) released by special kidney cells when you have decreased salt (sodium levels) or low blood volume. Renin also plays a role in the release of aldosterone, a hormone that helps control the body’s salt and water balance. A test can be done to measure the amount of ...

Renovascular hypertension is high blood pressure due to narrowing of the arteries that carry blood to the kidneys. See also:

Repair of is surgery to fix webbing of the toes, fingers, or both. The middle and ring fingers or the second and third toes are most often affected.

Repeated are bad dreams that recur frequently and involve the same theme. Nightmares usually begin before the age of 10 and are considered a normal part of childhood, unless they significantly interfere with sleep, physical development, or psychosocial development. They tend to be more common in ...

Replantation of digits is surgery to reattach completely amputated fingers or toes.

Reportable diseases are diseases considered to be of great public health importance. Local, state, and national agencies (for example, county and state health departments or the U.S. Centers for Disease Control and Prevention) require that such diseases be reported when they are diagnosed by doctors ...

The words “respiratory” and “respiration” refer to the lungs and breathing. Related topics:

Respiratory acidosis is a condition that occurs when the lungs cannot remove all of the carbon dioxide the body produces. This disrupts the body’s acid-base balance causing body fluids, especially the blood, to become too acidic.

Respiratory alkalosis is a condition marked by low levels of carbon dioxide in the blood due to breathing excessively. See also:

Respiratory syncytial virus (RSV) is a very common virus that leads to mild, cold-like symptoms in adults and older healthy children. It can be more serious in young babies, especially to those in certain high-risk groups.

Restless leg syndrome is a disorder in which there is an urge or need to move the legs to stop unpleasant sensations.

Restrictive cardiomyopathy refers to a group of disorders in which the heart chambers are unable to properly fill with blood because of stiffness in the heart.

A reticulocyte count measures the percentage of reticulocytes (slightly immature red blood cells) in the blood.

The retina is the light-sensitive layer of tissue at the back of the inner eye. It acts like the film in a camera — images come through the eye’s lens and are focused on the retina. The retina then converts these images to electric signals and sends them via the optic nerve to the ...

Retinal artery occlusion is a blockage in one of the small arteries that carry blood to the . The retina is a layer of tissue in the back of the eye that is able to sense light.

Retinal detachment is a separation of the light-sensitive membrane in the back of the eye (the retina) from its supporting layers.

Retinal detachment repair is eye surgery to place a detached back into its normal position. A means the light-sensitive tissue in the back of the eye has separated from its supporting layers. This article describes the repair of rhegmatogenous retinal detachments — retinal detachments ...

Retinal vein occlusion is a blockage of the small veins that carry blood away from the retina. The retina is the layer of tissue at the back of the inner eye that converts light images to nerve signals and sends them to the brain.

Retinitis pigmentosa is an eye disease in which there is damage to the . The retina is the layer of tissue at the back of the inner eye that converts light images to nerve signals and sends them to the brain.

Retinoblastoma is a rare, cancerous tumor of a part of the eye called the retina.

Retinopathy of prematurity (ROP) is abnormal blood vessel development in the retina of the eye in a .

Retrocalcaneal bursitis is swelling (inflammation) of the fluid-filled sac (bursa) at the back of the heel bone (calcaneus) under the Achilles tendon.

Retrograde cystography is a detailed examination of the bladder in which contrast dye is placed into the bladder through the urethra. The urethra is the tube that carries urine from the bladder to the outside of the body.

Retrograde ejaculation refers to the entry of semen into the bladder instead of going out through the urethra during ejaculation.

Retroperitoneal fibrosis is a rare disorder in which the tubes (ureters) that carry urine from the kidneys to the bladder are blocked by a mass in the area behind the stomach and intestines.

Retroperitoneal inflammation is swelling that occurs in the retroperitoneal space. The retroperitoneal space is in front of the lower back and behind the abdominal lining (peritoneum). Organs in this space include the pancreas, spleen, and kidneys.

Retropharyngeal abscess is a collection of pus in the tissues in the back of the throat. It is a potentially life-threatening medical condition. See also:

The thyroid gland is normally located at the front of the neck. A retrosternal thyroid refers to the abnormal placement of all or part of the thyroid gland below the breastbone (sternum).

Retroversion of the uterus occurs when a woman’s uterus (womb) tilts backward rather than forward. It is commonly called a “tipped uterus.”

Rett syndrome is a disorder of the nervous system that leads to developmental reversals, especially in the areas of expressive language and hand use.

Reye syndrome is sudden (acute) brain damage (encephalopathy) and liver function problems of unknown cause. The syndrome has occurred with the use of aspirin to treat chickenpox or the flu in children. However, it has become very uncommon since aspirin is no longer recommended for routine use in ...

Rh incompatibility is a condition that develops when a pregnant woman has Rh-negative blood and the baby in her womb has Rh-positive blood.

Rhabdomyolysis is the breakdown of muscle fibers resulting in the release of muscle fiber contents (myoglobin) into the bloodstream. Some of these are harmful to the kidney and frequently result in kidney damage.

Rhabdomyosarcoma is a cancerous (malignant) tumor of the muscles that are attached to the bones. It can occur in many places in the body. The most common sites are the structures of the head and neck, the urogenital tract, and the arms or legs. Rhabdomyosarcoma is the most common soft tissue ...

Rheumatic fever is an inflammatory disease that may develop after an infection with Streptococcus bacteria (such as or ). The disease can affect the heart, joints, skin, and brain.

Rheumatoid arthritis (RA) is a long-term disease that leads to inflammation of the joints and surrounding tissues. It can also affect other organs.

Rheumatoid factor (RF) is a blood test that measures the amount of the RF in the blood.

Rheumatoid lung disease is a group of lung problems related to . The condition can include fluid in the chest (), scarring (), lumps (nodules), and high blood pressure in the lungs (pulmonary hypertension).

Rhinophyma is a large, bulb-shaped, red-colored (ruddy) nose.

Rhinoplasty is surgery to repair or reshape the nose. See also:

Rhubarb leaves poisoning occurs when someone eats pieces of leaves from the rhubarb plant. This is for information only and not for use in the treatment or management of an actual poison exposure. If you have an exposure, you should call your local emergency number (such as 911) or the National ...

Rib cage pain includes any pain or discomfort in the area of the ribs. See:

Riboflavin is a type of B vitamin. It is water soluble, which means it is not stored in the body. You must replenish the vitamin every day.

Rickets is a disorder caused by a lack of vitamin D, calcium, or phosphate. It leads to softening and weakening of the bones.

Rickettsial pox is a disease spread by a mite. It causes a chickenpox-like on the body.

Right heart ventriculography is a study that images the right chambers (atrium and ventricle) of the heart.

Riley-Day syndrome is an inherited disorder that affects the development and function of nerves throughout the body.

Ringworm is a skin infection caused by a fungus. Ringworm can affect skin on your body (), scalp (), groin area (, also called jock itch), or feet (, also called athlete’s foot). Often, there are several patches of ringworm on your skin at once.

Robotic surgery is a technique in which a surgeon performs surgery using a computer that remotely controls very small instruments attached to a robot.

Rocky Mountain spotted fever is an infectious disease brought on by a specific type of bacteria carried by ticks.

A root canal is a dental procedure to remove dead or dying nerve tissue and bacteria from inside a tooth.

Rosacea is a chronic skin condition involving inflammation of the cheeks, nose, chin, forehead, or eyelids. It may appear as redness, prominent spider-like blood vessels, swelling, or skin eruptions similar to .

Roseola is an acute disease of infants and young children in which a high fever and skin rash occur.

Rotator cuff repair is a type of surgery to fix a torn tendon in the shoulder. The procedure can be done with a large (“open”) incision or with , which uses small button-hole sized incisions.

Rotator cuff tendinitis is an inflammation (irritation and swelling) of the tendons of the shoulder.

The rotavirus antigen test detects rotavirus in the feces. Rotavirus is the most common cause of in children.

Routine sputum culture is a test of secretions from the lungs and bronchi (tubes that carry air to the lung) to look for bacteria that cause infection.

RPR (rapid plasma reagin) is a screening test for . It looks for that are present in the blood of people who have the disease. The test is similar to the venereal disease research laboratory () test.

RSV antibody test is a blood test that measures the levels of antibodies (immunoglobulins) against the viral infection .

Rubber cement is a common household glue. Breathing in large amounts of rubber cement fumes or swallowing any amount can be extremely dangerous, especially for a small child. This is for information only and not for use in the treatment or management of an actual poison exposure. If you have an ...

Rubella, also known as the German measles, is an infection in which there is a rash on the skin. See also: — when a pregnant woman is infected with rubella and passes it to her baby while still in the womb.

Rubinstein-Taybi syndrome is a genetic disease characterized by broad thumbs and toes, short stature, distinctive facial features, and varying degrees of mental retardation.

Rumination disorder is a condition in which a person keeps bringing up food from the stomach into the mouth (regurgitation) and rechewing the food.

A ruptured or perforated eardrum is an opening in the tympanic membrane (eardrum).

Russell-Silver syndrome is a disorder present at birth that involves poor growth, low birth weight, short height, and differences in the size of the two sides of the body.