Respiratory distress syndrome (RDS) of the newborn, also known as infant RDS, is an acute lung disease present at birth, which usually affects premature babies. Layers of tissue called hyaline membranes keep the oxygen that is breathed in from passing into the blood. The lungs are said to be "airless." Without treatment, the infant will die within a few days after birth, but if oxyge…
Respiratory failure is nearly any condition that affects breathing function or the lungs themselves and can result in failure of the lungs to function properly. The main tasks of the lungs and chest are to get oxygen from the air that is inhaled into the bloodstream, and, at the same to time, to eliminate carbon dioxide (C02) from the blood through air that is breathed out. In respiratory failure,…
Respiratory syncytial virus (RSV) is a virus that can cause severe lower respiratory infections in children under the age of two, and milder upper respiratory infections in older children and adults. RSV infection is also called bronchiolitis, because it is marked in young children by inflammation of the bronchioles. Bronchioles are the narrow airways that lead from the bronchi to the tiny air sac…
Restless legs syndrome (RLS) is characterized by unpleasant sensations in the limbs, usually the legs, that occur at rest or before sleep and are relieved by activity such as walking. These sensations are felt deep within the legs and are described as creeping, crawling, aching, or fidgety. Restless legs syndrome, also known as Ekbom syndrome, Wittmaack-Ekbom syndrome, anxietas tibiarum, or anxiet…
Cardiomyopathy is an ongoing disease process that damages the muscle wall of the lower chambers of the heart. Restrictive cardiomyopathy is a form of cardiomyopathy in which the walls of the heart become rigid. Restrictive cardiomyopathy is the least common type of cardiomyopathy in the United States. The stiffened heart walls cannot stretch properly to allow enough blood to fill the ventricles be…
A reticulocyte count is a blood test performed to assess the body's production of immature red blood cells (reticulocytes). A reticulocyte count is usually performed when patients are evaluated for anemia and response to its treatment. It is sometimes called a retic count. A reticulocyte count provides information about the rate at which the bone marrow is producing red cells. A normal coun…
Retinal artery occlusion refers to the closure of the central retinal artery and usually results in complete loss of vision in one eye. Occlusion of its branches causes loss of vision in only a portion of the field of vision. Retinal artery occlusion (RAO) occurs when the central retinal artery, the main source of blood supply to the retina, or one of its branches becomes blocked. The main causes …
Retinal detachment is movement of the transparent sensory part of the retina away from the outer pigmented layer of the retina. In other words, the moving away of the retina from the outer wall of the eyeball. There are three layers of the eyeball. The outer, tough, white sclera. Lining the sclera is the choroid, a thin membrane that supplies nutrients to part of the retina. The innermost layer is…
Retinal vein occlusion refers to the closure of the central retinal vein that drains the retina or to that of one of its branches. Retinal vein occlusion (RVO) occurs when the central retinal vein, the blood vessel that drains the retina, or one of its branches becomes blocked. RVO may be categorized by the anatomy of the occluded vein and the degree of ischemia produced. The two major RVO types a…
Retinitis pigmentosa (RP) refers to a group of inherited disorders that slowly leads to blindness due to abnormalities of the photoreceptors (primarily the rods) in the retina. The retina lines the interior surface of the back of the eye. The retina is made up of several layers. One layer contains two types of photoreceptor cells referred to as the rods and cones. The cones are responsible for sha…
Retinoblastoma is a malignant tumor of the retina that occurs predominantly in young children. The eye has three layers, the sclera, the choroid, and the retina. The sclera is the outer protective white coating of the eye. The choroid is the middle layer and contains blood vessels that nourish the eye. The front portion of the choroid is colored and is called the iris. The opening in the iris is c…
Retinopathy is a noninflammatory disease of the retina. There are many causes and types of retinopathy. The retina is the thin membrane that lines the back of the eye and contains light-sensitive cells (photoreceptors). Light enters the eye and is focused onto the retina. The photoreceptors send a message to the brain via the optic A slit lamp view of a human eye with diabetic retinopathy. (Cu…
A retrograde cystogram provides x-ray visualization of the bladder with injection of sterile dye. A retrograde cystogram is performed to evaluate the structure of the bladder and identify bladder disorders, such as tumors, or recurrent urinary tract infections. The presence of urine reflux (backward flow) into the ureters may also be visualized with this x-ray study. The doctor should be made awar…
A retrograde ureteropyelogram provides x-ray visualization of the bladder, ureters, and the kidney (renal) pelvis by injection of sterile dye into the renal collecting system. A retrograde ureteropyelogram is performed to determine the exact location of a ureteral obstruction when it cannot be visualized on an intravenous pyelogram (a dye is injected and an x ray taken of the kidneys and the tubes…
Retrograde urethrography involves the use of x-ray pictures to provide visualization of structural problems or injuries to the urethra. Retrograde urethrography is used, in combination with a doctor's observation and other tests, to establish a diagnosis for individuals, almost exclusively men, who may have structural problems of the urethra. The doctor should be made aware of any previous …
Reye's syndrome is a disorder principally affecting the liver and brain, marked by rapid development of life-threatening neurological symptoms. Reye's syndrome is an emergency illness chiefly affecting children and teenagers. It almost always follows a viral illness such as a cold, the flu, or chicken pox. Reye's syndrome may affect all the organs of the body, but most serious…
Rheumatic fever (RF) is an illness which arises as a complication of untreated or inadequately treated strep throat infection. Rheumatic fever can seriously damage the valves of the heart. Throat infection with a member of the Group A streptococcus (strep) bacteria is a common problem among school-aged children. It is easily treated with a ten-day course of antibiotics by mouth. However, when such…
Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes inflammation and deformity of the joints. Other problems throughout the body (systemic problems) may also develop, including inflammation of blood vessels (vasculitis), the development of bumps (called rheumatoid nodules) in various parts of the body, lung disease, blood disorders, and weakening of the bones (osteoporosis). The …
Rhinitis is inflammation of the mucous lining of the nose. Rhinitis is a nonspecific term that covers infections, allergies, and other disorders whose common feature is the location of their symptoms. In rhinitis, the mucous membranes become infected or irritated, producing a discharge, congestion, and swelling of the tissues. The most widespread form of infectious rhinitis, is the common cold. Th…
The term rhinoplasty means "nose molding" or "nose forming." It refers to a procedure in plastic surgery in which the structure of the nose is changed. The change can be made by adding or removing bone or cartilage, grafting tissue from another part of the body, or implanting synthetic material to alter the shape of the nose. Rhinoplasty is most often performed for cosm…
Riboflavin deficiency occurs when the chronic failure to eat sufficient amounts of foods that contain riboflavin produces lesions of the skin, lesions of smooth surfaces in the digestive tract, or nervous disorders. Riboflavin, also called vitamin B2, is a water-soluble vitamin. The recommended daily allowance (RDA) for riboflavin is 1.7 mg/day for an adult man and 1.3 mg/day for an adult woman. T…
Rickettsialpox is a relatively mild disease caused by a member of the bacterial family called Rickettsia. Rick-ettsialpox causes rash, fever, chills, heavy sweating, headache, eye pain (especially when exposed to light), weakness, and achy muscles. Like other members of the family of Rickettsia, the bacteria causing rickettsialpox live in mice. Tiny mites feed on these infected mice, thus acquirin…
Ringworm is a common fungal infection of the skin. The name is a misnomer since the disease is not caused by a worm. More common in males than in females, ringworm is characterized by patches of rough, reddened skin. Raised eruptions usually form the circular pattern that gives the condition its name. Ringworm may also be referred to as dermatophyte infection. As lesions grow, the centers start to…
Rocky Mountain spotted fever (RMSF) is a tick-borne illness caused by a bacteria, resulting in a high fever and a characteristic rash. The bacteria causing RMSF is passed to humans through the bite of an infected tick. The illness begins within about two weeks of such a bite. RMSF is the most widespread tick-borne illness in the United States, occurring in every state except Alaska and Hawaii. The…
Rolfing, also called Rolf therapy or structural integration, is a holistic system of bodywork that uses deep manipulation of the body's soft tissue to realign and balance the body's myofascial structure. Rolfing improves posture, relieves chronic pain, and reduces stress. Rolfing helps to improve posture and bring the body's natural structure into proper balance and alignment.…
Root canal treatment, also known as endodontic treatment, is a dental procedure in which the diseased or damaged pulp (core) of a tooth is removed and the inside areas (the pulp chamber and root canals) are filled and sealed. Inflamed or infected pulp (pulpitis) most often causes a toothache. To relieve the pain and prevent further complications, the tooth may be extracted (surgically removed) or …
Rosacea is a skin disease typically appearing in people during their 30s and 40s. It is marked by redness (erythema) of the face, flushing of the skin, and the presence of hard pimples (papules) or pus-filled pimples (pustules), and small visible spider-like veins called telangiectasias. In later stages of the disease, the face may swell and the nose may take on a bulb-like appearance called rhino…
Roseola is a common disease of babies or young children, in which several days of very high fever are followed by a rash. Roseola rash on infant's back and shoulders. (Custom Medical Stock Photo. Reproduced by permission.) Roseola is an extraordinarily common infection, caused by a virus. About 90% of all children have been exposed to the virus, with about 33% actually demonstrating …
A rotator cuff injury is a tear or inflammation of the rotator cuff tendons in the shoulder. Rotator cuff injury is known by several names, including pitcher's shoulder, swimmer's shoulder, and tennis shoulder. As these names imply, the injury occurs most frequently in athletes practicing sports that require the arm to be moved over the head repeatedly, such as pitching, swimming, te…
Rotavirus is the major cause of diarrhea and vomiting in young children worldwide. The infection is highly contagious and may lead to severe dehydration (loss of body fluids) and even death. In the United States, more than 50,000 children are hospitalized and up to 125 die each year as a result of rotavirus infection. Gastroenteritis, or inflammation of the stomach and the intestine, is the second…
Roundworm infections are diseases of the digestive tract and other organ systems caused by nematodes. Nematodes are parasitic worms with long, cylindrical bodies. Roundworm infections are widespread throughout the world, with some regional differences. Ascariasis and trichuriasis are more common in warm, moist climates where people use human or animal feces for fertilizer. Anisakiasis is most comm…
Rubella is a highly contagious viral disease, spread through contact with discharges from the nose and throat of an infected person. Although rubella causes only mild symptoms of low fever, swollen glands, joint pain, and a fine red rash in most children and adults, it can have severe complications for women in their first trimester of pregnancy. These complications include severe birth defects or…
The rubella test is a routine blood test performed as part of prenatal care of pregnant women. It is sometimes also used to screen women of childbearing age before the first pregnancy. The test is given to evaluate whether a woman is immune to rubella (German measles) as a result of childhood exposure or immunization, or whether she may be presently infected with the disease. The question of a cur…
Sacroiliac disease is high-impact trauma to the sacroiliac joint that can cause death or bone and nerve damage. The sacroiliac joint is a strong, weight bearing synovial joint between the ilium and sacrum bones of the pelvis. The bones are held in place and allowed limited movements by a system of sacroiliac ligaments. Relaxation of this and other joints and ligaments is important during pregnancy…
A salivary gland scan is a nuclear medicine test that examines the uptake and secretion in the salivary glands of a radioactively labeled marker substance. The pattern of uptake and secretion shows if these glands are functioning normally. A salivary gland scan is done to help diagnose the cause of dry mouth. It is a test that is done when Sjogren's syndrome, salivary duct obstruction, asym…
A salivary gland tumor is an uncontrolled growth of cells that originates in one of the many saliva-producing glands in the mouth. The tongue, cheeks, and palate (the hard and soft areas at the roof of the mouth) contain many glands that produce saliva. In saliva there are enzymes, or catalysts, that begin the breakdown (digestion) of food while it is still in the mouth. The glands are called sali…
Salmonella food poisoning is a bacterial food poisoning caused by the Salmonella bacterium. It results in the swelling of the lining of the stomach and intestines (gastroenteritis). While domestic and wild animals, including poultry, pigs, cattle, and pets such as turtles, iguanas, chicks, dogs, and cats can transmit this illness, most people become infected by ingesting foods contaminated with si…
Salpingectomy is the removal of one or both of a woman's fallopian tubes, the tubes through which an egg travels from the ovary to the uterus. A salpingectomy may be performed for several different reasons. Removal of one tube (unilateral salpingectomy) is usually performed if the tube has become infected (a condition known as salpingitis). Salpingectomy is also used to treat an ectopic pre…
The surgical removal of a fallopian tube and an ovary. This surgery is performed to treat ovarian or other gynecological cancers, or infections as a result of pelvic inflammatory disease. Occasionally, removal of one or both ovaries may be done to treat endometriosis. If only one tube and ovary are removed, the woman may still be able to conceive and carry a pregnancy to term. If the procedure is …
Sarcoidosis is a disease which can affect many organs within the body. It causes the development of granulomas. Granulomas are masses resembling little tumors. They are made up of clumps of cells from the immune system. Sarcoidosis is a very puzzling disorder. In addition to having no clear-cut understanding of the cause of sarcoidosis, researchers are also puzzled by its distribution in the world…
A sarcoma is a bone tumor that contains cancer (malignant) cells. A benign bone tumor is an abnormal growth of noncancerous cells. A primary bone tumor originates in or near a bone. Most primary bone tumors are benign, and the cells that compose them do not spread (metastasize) to nearby tissue or to other parts of the body. Malignant primary bone tumors account for fewer than 1% of all cancers di…
Saw palmetto is an extract derived from the deep purple berries of the saw palmetto fan palm (Serenoa repens), a plant indigenous to the coastal regions of the southern United States and southern California. There is an estimated one million acres of wild saw palmetto palms in Florida, where the bulk of commercial saw palmetto is grown. Saw palmetto is used by natural health practitioners to treat…
Scabies is a relatively contagious infection caused by a tiny mite. Scabies is caused by a tiny, 0.3 mm long insect called a mite. When a human comes in contact with the female mite, the mite burrows under the skin, laying eggs along the line of its burrow. These eggs hatch, and the resulting offspring rise to the surface of the skin, mate, Scabies is a contagious skin infection common among p…
Scarlet fever is an infection that is caused by a bacteria called streptococcus. The disease is characterized by a sore throat, fever, and a sandpaper-like rash on reddened skin. It is primarily a childhood disease. If scarlet fever is untreated, serious complications such as rheumatic fever (a heart disease) or kidney inflammation (glomerulonephritis) can develop. Scarlet fever, also known as sca…
Schistosomiasis, also known as bilharziasis or snail fever, is a primarily tropical parasitic disease caused by the larvae of one or more of five types of flatworms or blood flukes known as schistosomes. The name bilharziasis comes from Theodor Bilharz, a German pathologist, who identified the worms in 1851. Infections associated with worms present some of the most universal health problems in the…
Schizoaffective disorder is a mental illness that shares the psychotic symptoms of schizophrenia and the mood disturbances of depression or bipolar disorder. The term schizoaffective disorder was first used in the 1930s to describe patients with acute psychotic symptoms such as hallucinations and delusions along with disturbed mood. These patients tended to function well before becoming psychotic;…
Schizophrenia is a psychotic disorder (or a group of disorders) marked by severely impaired thinking, emotions, and behaviors. Schizophrenic patients are typically unable to filter sensory stimuli and may have enhanced perceptions of sounds, colors, and other features of their environment. Most schizophrenics, if untreated, gradually withdraw from interactions with other people, and lose their abi…
Sciatica refers to pain or discomfort associated with the sciatic nerve. This nerve runs from the lower part of the spinal cord, down the back of the leg, to the foot. Injury to or pressure on the sciatic nerve can cause the characteristic pain of sciatica: a sharp or burning pain that radiates from the lower back or hip, possibly following the path of the sciatic nerve to the foot. The sciatic ne…
Scleroderma is a progressive disease that affects the skin and connective tissue (including cartilage, bone, fat, and the tissue that supports the nerves and blood vessels throughout the body). There are two major forms of the disorder. The type known as localized scleroderma mainly affects the skin. Systemic scleroderma, which is also called systemic sclerosis, affects the smaller blood vessels a…
Sclerotherapy for esophageal varices (also called endoscopic sclerotherapy) is a treatment for esophageal bleeding that involves the use of an endoscope and the injection of a sclerosing solution into veins. In most hospitals, sclerotherapy for esophageal varices is the treatment of choice to stop esophageal bleeding during acute episodes, and to prevent further incidences of bleeding. Emergency s…
Scoliosis is a side-to-side curvature of the spine. When viewed from the rear, the spine usually appears perfectly straight. Scoliosis is a lateral (side-to-side) curve in the spine, usually combined with a rotation of the vertebrae. (The lateral curvature of scoliosis should not be confused with the normal set of front-to-back spinal curves visible from the side.) While a small degree of lateral …
Scrotal nuclear medicine scan is a study of the blood circulation in the scrotum using radioactive contrast agent to highlight obstruction. This test is used almost exclusively to differentiate infection in the testis (testicle) from twisting and infarction. Infection is called epididymitis because it mostly involves a collection of tubules on top of the testicle called the epididymis. Twisting of…
Scrotal ultrasound is an imaging technique used for the diagnosis of suspected abnormalities of the scrotum. It uses harmless, high-frequency sound waves to form an image. The sound waves are reflected by scrotal tissue to form a picture of internal structures. It is not invasive and involves no radiation. Ultrasound of the scrotum is the primary imaging method used to evaluate disorders of the te…
Scrub typhus is an infectious disease that is transmitted to humans from field mice and rats through the bite of mites that live on the animals. The main symptoms of the disease are fever, a wound at the site of the bite, a spotted rash on the trunk, and swelling of the lymph glands. Scrub typhus is caused by Rickettsia tsutsugamushi, a tiny parasite about the size of bacteria that belongs to the …
Scurvy is a condition caused by a lack of vitamin C (ascorbic acid) in the diet. Signs of scurvy include tiredness, muscle weakness, joint and muscle aches, a rash on the legs, and bleeding gums. In the past, scurvy was common among sailors and other people deprived of fresh fruits and vegetables for long periods of time. Scurvy is very rare in countries where fresh fruits and vegetables are readi…
Seasonal affective disorder (SAD) is a form of depression most often associated with the lack of daylight in extreme northern and southern latitudes from the late fall to the early spring. Although researchers are not certain what causes seasonal affective disorder, they suspect that it has something to do with the hormone melatonin. Melatonin is thought to play an active role in regulating the &#…
Seborrheic dermatitis is a common inflammatory disease of the skin characterized by scaly lesions usually on the scalp, hairline, and face. Seborrheic dermatitis appears as red, inflamed skin covered by greasy or dry scales that may be white, yellowish, or gray. It can effect the scalp, eyebrows, forehead, face, folds around the nose and ears, the chest, armpits (axilla), and groin. Dandruff and c…
Secondary polycythemia is an acquired form of a rare disorder characterized by an abnormal increase in the number of mature red cells in the blood. Secondary polycythemia is also called secondary erythrocytosis. Polycythemia means too many red blood cells. The resulting excess of red cells thickens the blood and impedes its passage through small blood vessels. Secondary polycythemia usually affect…
Sedation is the act of calming by administration of a sedative. A sedative is a medication that commonly induces the nervous system to calm. The process of sedation has two primary intentions. First, sedation is recommended to allow patients the ability to tolerate unpleasant diagnostic or surgical procedures and to relieve anxiety and discomfort. Second, sedation for uncooperative patients may ex…
A seizure is a sudden disruption of the brain's normal electrical activity accompanied by altered consciousness and/or other neurological and behavioral manifestations. Epilepsy is a condition characterized by recurrent seizures that may include repetitive muscle jerking called convulsions. There are more than 20 different seizure disorders. One in ten Americans will have a seizure at some …
