Spinal instrumentation is a method of straightening and stabilizing the spine after spinal fusion, by surgically attaching hooks, rods, and wire to the spine in a way that redistributes the stresses on the bones and keeps them in proper alignment. Spinal instrumentation is used to treat instability and deformity of the spine. Instability occurs when the spine no longer maintains its normal shape d…
Spinal stenosis is any narrowing of the spinal canal that causes compression of the spinal nerve cord. Spinal stenosis causes pain and may cause loss of some body functions. Spinal stenosis is a progressive narrowing of the opening in the spinal canal. The spine is a long series of bones called vertebrae. Between each pair of vertebra is a fibrous intervertebral disk. Collectively, the vertebrae a…
Splenectomy is the surgical removal of the spleen, which is an organ that is part of the lymphatic system. The spleen is a dark-purple, bean-shaped organ located in the upper left side of the abdomen, just behind the bottom of the rib cage. In adults, the spleen is about 4.8 2.8 1.6 in (12 7 4 cm) in size, and weighs about 4–5 oz (113–142 g). Its functions include a role in the immun…
Splenic trauma is physical injury to the spleen, the lymphatic organ located in the upper left side of the abdomen. The spleen is an organ that produces white blood cells, filters the blood, stores blood cells and destroys those that are aging. It is located near the stomach on the left side of the abdomen. A direct blow to the abdomen may bruise, tear or shatter the spleen. Trauma to the spleen c…
Sporotrichosis is a chronic infection caused by the microscopic fungus Sporothrix schenckii. The disease causes ulcers on the skin that are painless but do not heal, as well as nodules or knots in the lymph channels near the surface of the body. Infrequently, sporotrichosis affects the lungs, joints, or central nervous system and can cause serious illness. The fungus that causes sporotrichosis is …
Sports injuries result from acute trauma or repetitive stress associated with athletic activities. Sports injuries can affect bones or soft tissue (ligaments, muscles, tendons). Adults are less likely to suffer sports injuries than do children, whose vulnerability is heightened by: Each year, about 3.2 million children between the ages of five and 14 are injured while participating in athletic act…
Sprain refers to damage or tearing of ligaments or a joint capsule. Strain refers to damage or tearing of a muscle. When excessive force is applied to a joint, the ligaments that hold the bones together may be torn or damaged. This results in a sprain, and its seriousness depends on how badly the ligaments are torn. Any joint can be sprained, but the most frequently injured joints are the ankle, k…
Sputum is material coughed up from the lungs and expectorated (spit out) through the mouth. A sputum culture is done to find and identify the microorganism causing an infection of the lower respiratory tract such as pneumonia (an infection of the lung). If a microorganism is found, more testing is done to determine which antibiotics will be effective in treating the infection. A person with a feve…
Hypericum perforatum is the most medicinally important species of the Hypericum genus, commonly known as St. John's wort. There are as many as 400 species in the genus, which is part of the Guttiferae family. Native to Europe, St. John's wort is found throughout the world. It thrives in sunny fields, open woods, and gravelly roadsides. Early colonists brought this valuable medicinal …
The Stanford-Binet intelligence scale is a standardized test that assesses intelligence and cognitive abilities in children and adults aged two to 23. The Stanford-Binet intelligence scale is used as a tool in school placement, in determining the presence of a learning disability or a developmental delay, and in tracking intellectual development. In addition, it is sometimes included in neuropsych…
Stapedectomy is a surgical procedure in which the innermost bone (stapes) of the three bones (the stapes, the incus, and the malleus) of the middle ear is removed, and replaced with a small plastic tube of stainless-steel wire (a prosthesis) to improve the movement of sound to the inner ear. A stapedectomy is used to treat progressive hearing loss caused by otosclerosis, a condition in which spong…
Staphylococcal (staph) infections are communicable conditions caused by certain bacteria and generally characterized by the formation of abscesses. They are the leading cause of primary infections originating in hospitals (nosocomial infections) in the United States. Classified since the early twentieth century as among the deadliest of all disease-causing organisms, staph exists on the skin or in…
Staphylococcal scalded skin syndrome (SSSS) is a disease, caused by a type of bacteria, in which large sheets of skin may peel away. SSSS primarily strikes children under the age of five, particularly infants. Clusters of SSSS cases (epidemics) can occur in newborn nurseries, when staff in those nurseries accidentally pass the causative bacteria between patients. It can also strike other age group…
Starvation is the result of a serious, or total, lack of nutrients needed for the maintenance of life. Adequate nutrition has two components—necessary nutrients and energy in the form of calories. It is possible to ingest enough energy without a well-balanced selection of individual nutrients and produce diseases that are noticeably different from those resulting from an overall insufficien…
A stillbirth is defined as the death of a fetus at any time after the 20th week of pregnancy. Stillbirth is also referred to as intrauterine fetal death (IUFD). It is important to distinguish between a stillbirth and other words that describe the unintentional end of a pregnancy. A pregnancy that ends before the twentieth week is called a miscarriage rather than a stillbirth, even though the death…
Stomach cancer (also known as gastric cancer) is a disease in which the cells forming the inner lining of the stomach become abnormal and start to divide uncontrollably, forming a mass called a tumor. The stomach is a J-shaped organ that lies in the left and central portion of the abdomen. The stomach produces many digestive juices and acids that mix with food and aid in the process of digestion. …
Stomach flushing is the repeated introduction of fluids into the stomach through a nasogastric tube, and their subsequent withdrawal by nasogastric suction. Stomach flushing is performed to aid in controlling gastrointestinal bleeding or to cleanse the stomach of poisons. Bleeding from the esophagus due to ruptured veins or bleeding from the stomach due to ulcers is a medical emergency. In an atte…
Inflammation of the mucous lining of any of the structures in the mouth, which may involve the cheeks, gums, tongue, lips, and roof or floor of the mouth. The word "stomatitis" literally means inflammation of the mouth. The inflammation can be caused by conditions in the mouth itself, such as poor oral hygiene, poorly fitted dentures, or from mouth burns from hot food or drinks, or b…
Stool culture is a test to identify bacteria in patients with a suspected infection of the digestive tract. A sample of the patient's feces is placed in a special medium where bacteria is then grown. The bacteria that grow in the culture are identified using a microscope and biochemical tests. Stool culture is performed to identify bacteria or other organisms in persons with symptoms of gas…
Stool fats, also known as fecal fats, or fecal lipids, are fats that are excreted in the feces. When secretions from the pancreas and liver are adequate, emulsified dietary fats are almost completely absorbed in the small intestine. When a malabsorption disorder or other cause disrupts this process, excretion of fat in the stool increases. This test evaluates digestion of fats by determining exces…
The stool O & P test is the stool ova and parasites test. In this test, a stool sample is examined for the presence of intestinal parasites and their eggs, which are called ova. The ova and parasites test is performed to look for and identify intestinal parasites and their eggs in persons with symptoms of gastrointestinal infection. Patients may have no symptoms, or experience diarrhea, blo…
Strabismus is a condition in which the eyes do not point in the same direction. It can also be referred to as a tropia or squint. Strabismus occurs in 2–5% of all children. About half are born with the condition, which causes one or both eyes to turn: Strabismus is equally common in boys and girls. It sometimes runs in families. Esotropia is the most common type of strabismus in infants. Ac…
Streptococcal sore throat, or strep throat as it is more commonly called, is an infection of the mucous membranes lining the pharynx. Sometimes the tonsils are also infected (tonsillitis). The disease is caused by group A Streptococcus bacteria. Untreated strep throat may develop into rheumatic fever or other serious conditions. Strep throat accounts for between 5–10% of all sore throats. A…
Streptococcal infections are caused by a microorganism called Streptococcus. Three streptococcal anti-body tests are available: the antistreptolysin O titer (ASO), the antideoxyribonuclease-B titer (anti-Dnase-B, or ADB), and the streptozyme test. The antistreptolysin O titer, or ASO, is ordered primarily to determine whether a previous group A Streptococcus infection has caused a poststreptococca…
Streptococcal (strep) infections are communicable diseases that develop when bacteria normally found on the skin or in the intestines, mouth, nose, reproductive tract, or urinary tract invade other parts of the body and contaminate blood or tissue. Some strep infections don't produce symptoms. Some are fatal. Most people have some form of strep bacteria in their body at some time. A person …
Stress is defined as an organism's total response to environmental demands or pressures. When stress was first studied in the 1950s, the term was used to denote both the causes and the experienced effects of these pressures. More recently, however, the word stressor has been used for the stimulus that provokes a stress response. One recurrent disagreement among researchers concerns the defi…
Stress is the body's normal response to anything that disturbs its natural physical, emotional, or mental balance. Stress reduction refers to various strategies that counteract this response and produce a sense of relaxation and tranquility Although stress is a natural phenomenon of living, stress that is not controlled and that continues for a long period of time can seriously compromise h…
Used to evaluate heart function, a stress test requires that a patient exercises on a treadmill or exercise bicycle while his or her heart rate, breathing, blood pressure, electrocardiogram (ECG), and feeling of well being are monitored. When the body is active, it requires more oxygen than when it is at rest, and, therefore, the heart has to pump more blood. Because of the increased stress on the…
Stridor is a term used to describe noisy breathing in general, and to refer specifically to a high-pitched crowing sound associated with croup, respiratory infection, and airway obstruction. Stridor occurs when erratic air currents attempt to force their way through breathing passages narrowed by: Stridor can usually be heard from a distance but is sometimes audible only during deep breathing. Som…
A stroke is the sudden death of brain cells in a localized area due to inadequate blood flow. A stroke occurs when blood flow is interrupted to part of the brain. Without blood to supply oxygen and nutrients and to remove waste products, brain cells quickly begin to die. Depending on the region of the brain affected, a stroke may cause paralysis, speech impairment, loss of memory and reasoning abi…
Stuttering is a speech problem characterized by repetitions, pauses, or drawn out syllables, words, and phrases. Stutterers are different than people experiencing normal fluency problems because a stutterer's disfluency is more severe and consistent than that of people who do not stutter. Normal language development in a child can include a period of disfluency. Children might repeat syllab…
Subacute sclerosing panencephalitis is a rare, progressive brain disorder caused by an abnormal immune response to the measles virus. This fatal condition is a complication of measles, and affects children and young adults before the age of 20. It usually occurs in boys more often than in girls, but is extremely rare, appearing in only one out of a million cases of measles. Experts believe this co…
A subarachnoid hemorrhage is an abnormal and very dangerous condition in which blood collects beneath the arachnoid mater, a membrane that covers the brain. This area, called the subarachnoid space, normally contains cerebrospinal fluid. The accumulation of blood in the subarachnoid space can lead to stroke, seizures, and other complications. Additionally, subarachnoid hemorrhages may cause perman…
A subdural hematoma is a collection of blood in the space between the outer layer (dura) and middle layers of the covering of the brain (the meninges). It is most often caused by torn, bleeding veins on the inside of the dura as a result of a blow to the head. Subdural hematomas most often affect people who are prone to falling. Only a slight hit on the head or even Subdural hematoma present o…
Substance abuse and dependence refer to any continued pathological use of a medication, non-medically indicated drug (called drugs of abuse), or toxin. Although there are on-going debates on the exact distinctions between substance abuse and substance dependence, the current practice standard—distinguishes between the two by defining substance dependence in terms of physiological and behavi…
Sudden cardiac death (SCD) is an unexpected death due to heart problems, which occurs within one hour from the start of any cardiac-related symptoms. SCD is sometimes called cardiac arrest. When the heart suddenly stops beating effectively and breathing ceases, a person is said to have experienced sudden cardiac death. SCD is not the same as actual death. In actual death, the brain also dies. The …
Sudden infant death syndrome (SIDS) is the unexplained death without warning of an apparently healthy infant, usually during sleep. Also known as crib death, SIDS has baffled physicians and parents for years. In the 1990s, advances have been made in preventing the occurrence of SIDS, which killed more than 4, 800 babies in 1992 and 3, 279 infants in 1995. Education programs aimed at encouraging pa…
Sulfonamides are medicines that prevent the growth of bacteria in the body. Sulfonamides are used to treat many kinds of infections caused by bacteria and certain other microorganisms. Physicians may prescribe these drugs to treat urinary tract infections, ear infections, frequent or long-lasting bronchitis, bacterial meningitis, certain eye infections, Pneumocystis carinii pneumonia, traveler�…
Inflammation of the skin caused by overexposure to the sun. Sunburn is caused by exposure to the ultraviolet (UV) rays of the sun. There are two types of ultraviolet rays, UVA and UVB. UVA rays penetrate the skin more deeply and can cause melanoma in susceptible people. UVB rays, which don't penetrate as deeply, cause sunburn and wrinkling. Most UVB rays are absorbed by sunscreens, but only…
Sunscreens are products applied to the skin to protect against the harmful effects of the sun's ultraviolet (UV) rays. Everyone needs a little sunshine. About 15 minutes of exposure a day helps the body make Vitamin D, which is important for healthy bones and teeth. But longer exposure may cause many problems, from wrinkles to skin cancer. One particularly deadly form of skin cancer, malign…
The superior vena cava is the major vein in the chest that carries blood from the upper part of the body into the heart. A restriction of the blood flow (occlusion) through this vein can cause superior vena cava syndrome (SVCS). Superior vena cava syndrome is a partial occlusion of the superior vena cava. This leads to a lower than normal blood flow through this major vein. SVCS is also called sup…
Also called St. Vitus' dance, Sydenham's chorea is a disorder effecting children and characterized by jerky, uncontrollable movements, either of the face or of the arms and legs. Sydenham's chorea is a disorder that occurs in children and is associated with rheumatic fever. Rheumatic fever is an acute infectious disease caused by certain types of streptococci bacteria. It usua…
Sympathectomy is a surgical procedure that destroys nerves in the sympathetic nervous system. The procedure is done to increase blood flow and decrease long-term pain in certain diseases that cause narrowed blood vessels. It can also be used to decrease excessive sweating. This surgical procedure cuts or destroys the sympathetic ganglia, collections of nerve cell bodies in clusters along the thora…
Syphilis is an infectious systemic disease that may be either congenital or acquired through sexual contact or contaminated needles. Syphilis has both acute and chronic forms that produce a wide variety of symptoms affecting most of the body's organ systems. The range of symptoms makes it easy to confuse syphilis with less serious diseases and ignore its early signs. Acquired syphilis has f…
Systemic lupus erythematosus (also called lupus or SLE) is a disease where a person's immune system attacks and injures the body's own organs and tissues. Almost every system of the body can be affected by SLE. The body's immune system is a network of cells and tissues responsible for clearing the body of invading foreign organisms, like bacteria, viruses, and fungi. Antibodie…
T'ai chi is a Chinese exercise system that uses slow, smooth body movements to achieve a state of relaxation of both body and mind. As a system of physical exercise used to improve and maintain health, t'ai chi can be helpful in achieving a state of physical and mental relaxation while also strengthening the cardiovascular system. As a very slow and gentle form of moving, t'ai…
Tapeworms are a group of parasitic worms that live in the intestinal tracts of some animals. Several different species of tapeworms can infect humans. Tapeworm disease or cestodiasis occurs most commonly after eating raw or undercooked meat or fish that contains the immature form of the tapeworm. Tapeworm infections pose a serious public health problem in many less developed countries due to poor …
Tardive dyskinesia is a mostly irreversible neurological disorder of involuntary movements caused by longterm use of antipsychotic or neuroleptic drugs. Antipsychotic or neuroleptic drugs are powerful tranquilizers generally prescribed for serious psychiatric disorders, as well as neurological and gastrointestinal disorders. Some common antipsychotics are: chlorpromazine HCl (Thorazine), thioridaz…
Tarsorrhaphy is a rare procedure where the eyelids are partially sewn together to narrow the opening. The eye needs a lid to protect it. It also needs tears and periodic blinking to cleanse it and keep it moist. There are many conditions that impair these functions and threaten the eye, specifically the cornea, with drying. Until they can be corrected, sewing the eyelids partially together helps p…
Tay-Sachs disease is a genetic disorder caused by a missing enzyme that results in the accumulation of a fatty substance in the nervous system. This results in disability and death. Gangliosides are fatty substances necessary for the proper development of the brain and nerve cells (nervous system). Under normal conditions, gangliosides are continuously broken down, so that an appropriate balance i…
The technetium heart scan is a noninvasive nuclear scan that uses a radioactive isotope called technetium to evaluate blood flow after a heart attack. The technetium heart scan is used to evaluate the heart after a heart attack. It can confirm that a patient had a heart attack when the symptoms and pain usually associated with a heart attack were not present; identify the size and location of the …
The term temporal arteritis literally means "inflammation of the temporal arteries."As implied by the name, these blood vessels run along the temples after they branch off from the carotid artery in the neck. They provide the blood supply to portions of the scalp, jaw muscles, and salivary glands. Inflammation of these arteries, probably resulting from an abnormal immune reaction, di…
Temporomandibular joint disorder (TMJ) is the name given to a group of symptoms that cause pain in the head, face, and jaw. The symptoms include headaches, soreness in the chewing muscles, and clicking or stiffness of the joints. They often have psychological as well as physical causes. TMJ disorder, which is also sometimes called TMJ syndrome, results from pressure on the facial nerves due to mus…
Tendinitis is the inflammation of a tendon, a tough rope-like tissue that connects muscle to bone. Tendinitis usually occurs in individuals in middle or old age because it is often the result of overuse over a long period of time. Tendinitis does occur in younger patients as a result of acute overuse. Tendons that commonly become inflamed include: Sudden stretching or repeated overuse injures the …
Tennis elbow is an inflammation of several structures of the elbow. These include muscles, tendons, bursa, periosteum, and epicondyle (bony projections on the outside and inside of the elbow, where muscles of the forearm attach to the bone of the upper arm). The classic tennis elbow is caused by repeated forceful contractions of wrist muscles located on the outer forearm. The stress created at…
Tensilon is the trade name for edrophonium chloride. The Tensilon test is an injection of edrophonium chloride used to diagnosis myasthenia gravis (MG). Tensilon blocks the action of an enzyme, acetylcholinesterase, an important part of the system regulating neuromuscular transmission. To stimulate a muscle, a nerve cell (neuron) releases the chemical acetylcholine. To prevent prolonged muscle res…
This most common type of headache is caused by severe muscle contractions triggered by stress or exertion. It affects as many as 90% of adult Americans. While most American adults get a tension headache from time to time, women and people with more education are slightly more likely to suffer with them. People who are so anxious that they grind their teeth or hunch their shoulders may find that th…
Testicular cancer is a disease in which cancer cells are discovered in one or both testicles. The testicles, also known as testes or gonads, are located in a pouch beneath the penis called the scrotum. The testicles make up one portion of the male reproductive system. Normally, they are each somewhat smaller than a golf ball in size and are contained within the scrotum. The testicles are a man�…
A testicular self-examination (TSE) is the procedure by which a man checks the appearance and consistency of his testes. Most testicular cancers are first noticed by the man himself. Men should do a TSE every month to find out if the testes contain any suspicious lumps or other irregularities, which could be signs of cancer or infection. None. A TSE should take place during a warm shower or bath, …
Testicular surgery is any surgical operation on the testicles. Testicular surgery is used primarily to correct developmental defects, treat infection, and treat cancer of the testes. Testicular surgery, a group of surgical operations performed on the testicles, is considered major surgery. In all cases, except when the testes are being removed, care must be taken not to damage any of the nerves an…
