Health Library

A sachet is a bag that holds perfumed powder or a mix of dried flowers, herbs, spices, and aromatic wood shavings (potpourri). Sachet poisoning occurs when someone accidentally or intentionally swallows the ingredients of a sachet. This is for information only and not for use in the treatment or ...

Safe sex means taking precautions during sex that can keep you from getting a sexually transmitted infection (STI), or from giving an STI to your partner. STIs are also referred to as sexually transmitted diseases, or STDs. These diseases include genital herpes, genital warts, HIV, chlamydia, ...

Salivary duct stones are crystallized minerals in the ducts that drain the salivary glands. Salivary duct stones are a type of .

Salivary gland biopsy is the removal of a small piece of tissue or cells from a salivary gland for examination.

Salivary gland disorders are conditions that lead to swelling or pain in the saliva-producing tissues around the mouth.

Salivary gland infections are viral or bacterial infections of the saliva-producing glands. There are three pairs of major salivary glands. The two largest are the parotid glands, one in each cheek over the jaw in front of the ears. Inflammation of one or more of these glands is called parotitis, ...

Salivary gland tumors are abnormal cells growing in the ducts that drain the salivary glands.

Salmonella enterocolitis is an infection in the lining of the small intestine caused by Salmonella bacteria.

Sanfilippo syndrome is an inherited disease of metabolism that makes the body unable to properly break down long chains of sugar molecules called glycosaminoglycans (formerly called mucopolysaccharides). The syndrome belongs to a group of diseases called mucopolysaccharidoses (MPS). Specifically, ...

Sarcoidosis is a disease in which swelling (inflammation) occurs in the lymph nodes, lungs, liver, eyes, skin, or other tissues.

Sassafras oil is an oil taken from the root-bark of the sassafras tree. Sassafras oil overdose occurs when someone accidentally or intentionally takes more than the normal or recommended amount of this substance. This is for information only and not for use in the treatment or management of an ...

Satiety is the satisfied feeling of being full after eating. Early satiety is feeling full sooner than normal or after eating less than usual.

Scabies is an easily spread skin disease caused by a very small species of mite.

Scalded skin syndrome is a skin infection in which the skin becomes damaged and sheds.

Scales are a visible peeling or flaking of outer skin layers.

Scar revision is surgery to improve or reduce the appearance of scars. It also restores function, and corrects skin changes (disfigurement) caused by an injury, wound, or previous surgery.

Scarlet fever is a disease caused by infection with the group A Streptococcus bacteria (the same bacteria that causes ).

Scheie syndrome is an inherited disease of metabolism in which the body cannot properly break down long chains of sugar molecules called glycosaminoglycans (formerly called mucopolysaccharides). The syndrome belongs to a group of diseases called mucopolysaccharidoses (MPS). Specifically, it is ...

The Schilling test is used to determine whether the body absorbs normally.

Schirmer’s test determines whether the eye produces enough tears to keep it moist.

Schistosomiasis is infection with a type of Schistosoma parasite.

Schizoaffective disorder is a mental condition that causes both a loss of contact with reality (psychosis) and mood problems.

Schizoid personality disorder is a psychiatric condition in which a person has a lifelong pattern of indifference to others and social isolation.

Schizophrenia is a mental disorder that makes it difficult to tell the difference between real and unreal experiences, to think logically, to have normal emotional responses, and to behave normally in social situations.

Disorganized schizophrenia is a type of in which behavior is disturbed and has no purpose.

Paranoid type schizophrenia is a mental illness that involves false beliefs of being persecuted or plotted against.

Schizotypal personality disorder is a mental health condition in which a person has trouble with relationships and disturbances in thought patterns, appearance, and behavior.

Proper preparation for a test or procedure may reduce your child’s anxiety, encourage cooperation, and help the child develop coping skills.

The nutritional goal of the school lunch program is to provide children a meal that contains approximately one-third of the Recommended Dietary Allowances (RDA) of nutrients. The lunches provide one-third of the RDA of nutrients when averaged over time — not at each meal.

School-age child development describes the expected physical, emotional, and mental abilities of children ages 6 – 12.

Sciatica refers to pain, weakness, numbness, or tingling in the leg. It is caused by injury to or compression of the sciatic nerve. Sciatica is a symptom of another medical problem, not a medical condition on its own.

The sclera is the white outer wall of the eye. It is a tough, fibrous tissue that extends from the cornea (the clear front section of the eye) to the optic nerve at the back of the eye. The sclera gives the eye its white color.

Scleritis is an inflammation of the sclera (the white outer wall of the eye).

Scleroderma is a widespread connective tissue disease that involves changes in the skin, blood vessels, muscles, and internal organs.

A scleroma is a hardened patch of tissue in the skin or mucous membranes (for example, the tissues lining the mouth or nose).

Sclerosing cholangitis refers to swelling (inflammation), scarring, and destruction of the ducts inside and outside of the liver.

Scoliosis is a curving of the spine. The spine curves away from the middle or sideways.

Scoliosis surgery repairs abnormal curving of the spine (). The goal is to safely straighten the spine, align your child’s shoulders and hips, and give you long-term correction for your child’s back problem.

Scorpion fish are members of the family Scorpaenidae, which includes lionfish and stonefish. The fins of these prickly fish carry poisonous venom. This article describes the effects of a sting from such fish. This is for information only and not for use in the treatment or management of an actual ...

This article describes the effects of a scorpion sting. 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 Poison Control Center at ...

A scrape is an area where the skin is rubbed off. It usually occurs after you fall down or hit something. A scrape is usually not serious, but it can be painful and may bleed slightly.

Scrofula is a infection of the lymph nodes in the neck.

A scrotal mass is a lump or bulge that can be felt in the scrotum, the sac that contains the testicles. See also:

Scrotal swelling is abnormal enlargement of the scrotum, the sac surrounding the testicles.

The scrotum is a part of a male’s body located behind the . The scrotum is the sac (pouch) that contains the , blood vessels, and part of the spermatic cord.

Scurvy is a disease that occurs when you have a severe lack of vitamin C (ascorbic acid) in your diet. It causes general weakness, , gum disease, and . Scurvy is rare in the United States. It is most frequently seen in older, malnourished adults.

Seasonal affective disorder (SAD) refers to episodes of depression that occur every year during fall or winter. Symptoms improve in spring and summer.

A sebaceous adenoma is a noncancerous tumor of an oil-producing gland.

A sebaceous cyst is a closed sac under the skin filled with a cheese-like or oily material. See also:

Seborrheic dermatitis is a common, inflammatory skin condition that causes flaky, white to yellowish to form on oily areas such as the scalp or inside the ear. It can occur with or without reddened skin. Cradle cap is the term used when seborrheic dermatitis affects the scalp of infants.

Seborrheic keratosis is noncancerous () wart-like growths on the surface of the skin.

Secobarbital is a drug used to treat insomnia. It may also be given before surgery to relieve anxiety. Secobarbital occurs when someone takes too much of this medicine. This is for information only and not for use in the treatment or management of an actual poison exposure. If you have an ...

Secondary amenorrhea occurs when a woman who has been having normal menstrual cycles stops getting her periods for 6 or more months. Amenorrhea is when a woman does not get her monthly menstrual cycle, or period. See also:

Secondary aplastic anemia is a failure of the bone marrow to make enough blood cells. All blood cell types are affected.

Secondary hyperparathyroidism is when the parathyroid glands in your neck produce too much parathyroid hormone (PTH) because your calcium levels are too low. See also:

A secondary infection is an infection that occurs during or after treatment of another, already existing infection. It may result from the treatment itself or from alterations in the immune system. For example, a vaginal yeast infection that occurs after antibiotic treatment of a bacterial ...

Secondary parkinsonism is similar to , but it is caused by certain medicines, a different nervous system disorder, or another illness.

Secondary systemic amyloidosis is a disorder in which abnormal proteins build up in tissues and organs. Clumps of the abnormal proteins are called amyloid deposits. Secondary means it occurs because of another disease or situation. For example, this condition usually occurs as a result of ...

The secretin stimulation test measures the ability of the pancreas to respond to a hormone called secretin. Secretin is produced by the small intestine when partially digested food has moved into the area from the stomach.

A seizure is the physical findings or changes in behavior that occur after an episode of abnormal electrical activity in the brain. See also: (seizures in children with high fever)

Selective deficiency of IgA is the most common . Persons with this disorder have low or absent levels of a blood protein called immunoglobulin A.

Selective mutism is a condition in which a child who can speak well stops speaking, usually in school or social settings.

Selenium is an essential trace mineral. This means your body must get this mineral in the food you eat. Small amounts of selenium are good for your health.

Semen analysis is a test to measure the amount and quality of a man’s semen and sperm. Semen is the thick, white, sperm-containing fluid released during ejaculation. The test is sometimes called a sperm count.

Sensitivity analysis determines the effectiveness of antibiotics against microorganisms such as bacteria that have been isolated from cultures. Sensitivity analysis may be performed along with: urine culture or urine culture Wound and other cultures

Sensorimotor polyneuropathy causes a decreased ability to move or feel (sensation) due to nerve damage.

Sensorineural deafness is hearing loss that occurs from damage to the inner ear, the nerve that runs from the ear to the brain (auditory nerve), or the brain.

Separation anxiety is a developmental stage during which the child experiences when separated from the primary caregiver (usually the mother).

Sepsis is a severe illness in which the bloodstream is overwhelmed by bacteria.

A septal hematoma is a bruise or bleeding within the nasal septum. The septum of the nose separates the two nostrils.

Septic arthritis is due to a bacterial infection other than gonorrhea (joint infection due to gonorrhea has different symptoms).

Septic shock is a serious condition that occurs when an overwhelming infection leads to life-threatening low blood pressure. See also:

Septicemia is the presence of bacteria in the blood () and is often associated with severe infections.

Septoplasty is surgery to correct any problems in the nasal septum, the wall inside the nose that separates the nostrils. See also:

Serologic test for B. anthracis is a blood test to look for against the bacteria that cause .

Serology is a blood test to detect the presence of against a microorganism. Certain microorganisms stimulate the body to produce antibodies during an active infection.

Serology for brucellosis is a blood test to look for against Brucella, the bacteria that causes the disease .

This blood test looks for against Francisella tularensis, the bacteria that cause the disease .

Serosanguineous means containing or relating to both blood and the liquid part of blood (serum). It usually refers to fluids collected from or leaving the body. For example, fluid exiting a wound is serosanguineous, and usually is yellowish with small amounts of blood.

Serotonin syndrome is a potentially life threatening drug reaction that causes the body to have too much serotonin, a chemical produced by nerve cells.

Sertoli-Leydig cell tumor is a rare cancer of the ovaries. The cancer cells produce and release a male sex hormone. This article focuses on Sertoli-Leydig cell tumors in women. For information on Sertoli-Leydig cell tumors in men, see the article on .

Serum cholinesterase is a test that looks at blood levels of certain (acetylcholinesterase and pseudocholinesterase) that help the nervous system work properly. Acetylcholinesterase (also known as RBC cholinesterase) and pseudocholinesterase (also known as butyrylcholinesterase or plasma ...

Serum chromium is a test for abnormal levels of chromium in the blood.

Serum globulin electrophoresis is a laboratory test that looks at proteins called globulins in the blood. See also:

Serum hemoglobin is a test that measures the level of free in the liquid part of the blood (the serum). Free hemoglobin is the hemoglobin outside of the red blood cells. Most of the hemoglobin is found inside the red blood cells, not in the serum.

Serum herpes simplex antibodies is a blood test that looks for to the virus. See also:

Serum iron is a test that measures how much iron is in your blood.

Ketones are substances produced when fat cells break down in the blood. A serum ketone test is a measurement of how many ketones are in the blood.

A serum magnesium test is a measurement of how much magnesium there is in the blood.

Serum phenylalanine screening is a blood test to look for signs of the disease (PKU). The test detects abnormally high levels of an amino acid called phenylalanine.

The serum phosphorus test measures the amount of phosphate in the blood.

Serum progesterone is a test to measure the amount of progesterone in the blood. Progesterone is a hormone produced mainly in the ovaries. In women, progesterone plays a vital role in pregnancy. After an egg is released by the ovaries (ovulation), progesterone helps make the uterus ready for ...

Serotonin is a chemical produced by nerve cells. The serum serotonin level is a blood test to measure the amount of serotonin in your body.

Serum sickness is a reaction similar to an allergy. Specifically, it is an immune system reaction to certain medications, injected proteins used to treat immune conditions, or antiserum, the liquid part of blood that contains that help protect against infectious or poisonous substances. See also:

Serum TBG level is a blood test to measure the level of a protein that moves thyroid hormone throughout your body. The protein is called thyroxine binding globulin (TBG).

Severe acute respiratory syndrome (SARS) is a serious form of pneumonia, caused by a virus isolated in 2003. Infection with the SARS virus results in respiratory distress (severe breathing diffculty) and sometimes death. It is a dramatic example of how quickly world travel can spread a disease. It ...

Sex-linked dominant is a rare way that a trait or disorder can be passed down through families. A single abnormal gene on the X chromosome can cause a sex-linked dominant disease. Related terms and topics: Genetic counseling and prenatal diagnosis

Sex-linked diseases are inherited through one of the “sex chromosomes” — the X or Y chromosomes. Autosomally inherited diseases are inherited through the non-sex chromosomes (autosomes), pairs 1 through 22. Dominant inheritance occurs when an abnormal gene from one parent is able ...

For both men and women, pain can occur in the pelvic area during or soon after sexual intercourse. It can happen at any time during sex — for example, at the time of penetration, erection, or ejaculation — or after sexual activity. Eventually, ongoing pain may cause a person to lose ...

Sexual problems are defined as difficulty during any stage (desire, arousal, orgasm, and resolution) of the sexual act, which prevents the individual or couple from enjoying sexual activity.

Shaken baby syndrome is a severe form of child abuse caused by violently shaking an infant or child.

Shampoo is a liquid used to clean the scalp and hair. This article describes the effects of swallowing a liquid shampoo. 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 ...

Shaving cream is a cream applied to the face before shaving the skin. Shaving cream poisoning occurs when someone accidentally or intentionally eats shaving cream. 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 ...

Sheehan syndrome is a condition that may occur in a woman who bleeds severely during childbirth. See also:

This is poisoning from swallowing shellac. 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 Poison Control Center at 1-800-222-1222.

Shigellosis is an bacterial infection of the lining of the intestines.

Shin splints refers to pain in the front of the lower legs. The pain is located along the inside edge of the tibia, the large bone in the lower part of the leg. Pain most often occurs during or right after a change in activity level, such as running more often or increasing the number of miles. ...

Shingles (herpes zoster) is a painful, blistering skin rash due to the varicella-zoster virus, the virus that causes chickenpox. See also:

Shock is a life-threatening condition that occurs when the body is not getting enough blood flow. This can damage multiple organs. Shock requires immediate medical treatment and can get worse very rapidly.

Short bones in the human body are cubelike — the length, width, and height measurements are all about the same. Short bones include the carpal bones (hands, wrist) and tarsal bones (feet, ankles).

Short bowel syndrome is a condition in which nutrients are not properly absorbed () due to severe intestinal disease or the surgical removal of a large portion of the small intestine.

A short philtrum is a shorter than normal distance between the upper lip and the nose.

Short stature refers to any person who is significantly below the average height for a person of the same age and sex. The term often refers to children or adolescents who are significantly below the average height of their peers.

Shoulder arthroscopy is surgery that uses a tiny camera called an arthroscope to examine or repair the tissues inside or around your shoulder joint. The arthroscope is inserted through a small incision (cut) in your skin.

A computed tomography (CT) scan of the shoulder is an imaging method that uses x-rays to create cross-sectional pictures of the shoulder.

A magnetic resonance imaging (MRI) scan of the shoulder is a method to create detailed pictures of the shoulder area and surrounding joint, muscles, and tissues. Unlike and computed tomographic () scans, which use radiation, MRI uses powerful magnets and radio waves. The MRI scanner contains the ...

Shoulder pain involves any pain in or around the shoulder joint.

Shoulder replacement is surgery to replace the bones of the shoulder joint with artificial joint parts.

A sialogram is an of the salivary ducts and glands. The salivary glands are located on each side of the face and send saliva into the mouth.

Sick sinus syndrome is a collection of heart rhythm disorders that include: Sinus bradycardia — slow heart rates from the natural pacemaker of the heart Tachycardias — fast heart rates Bradycardia-tachycardia — alternating slow and fast heart rhythms

Sickle cell anemia is a disease passed down through families in which red blood cells form an abnormal crescent shape. (Red blood cells are normally shaped like a disc.)

A sickle cell test looks for the presence or absence of abnormal in the blood that causes

Sigmoidoscopy is a procedure used to see inside the sigmoid colon and rectum.

Silent thyroiditis is swelling (inflammation) of the thyroid gland, in which the person alternates between and .

Silicosis is a disease caused by breathing in (inhaling) silica dust.

A simian crease is a single line that runs across the palm of the hand. People usually have three creases in their palms. The term “simian crease” is not used much anymore since it tends to have a negative meaning (it refers to monkey or ape). The crease is usually just referred to as ...

Simple prostate removal is a surgery to remove all or part of the prostate gland through a surgical cut in your lower belly, to treat an . See also:

Simple pulmonary eosinophilia is inflammation of the lungs associated with an increase in eosinophils, a type of white blood cell.

A computed tomography (CT) scan of the sinus is an imaging test that uses x-rays to create detailed pictures of the air-filled spaces inside the face (sinuses).

A magnetic resonance imaging (MRI) scan of the sinuses is a method to create detailed pictures of the the air-filled spaces inside the skull. These spaces are called the sinuses. Unlike and computed tomographic () scans, which use radiation, MRI uses powerful magnets and radio waves. Signals ...

A sinus is a picture of the air-filled cavities in the front of the skull.

Sinusitis refers to inflammation of the sinuses that occurs with a viral, bacterial, or fungal infection. See also:

A sitz bath is a warm water bath used for healing or cleansing purposes. You sit in the bath. The water covers only the hips and buttocks. The water may contain medication. Sitz baths are often used to relieve pain, itching, or muscle spasms. The baths are often recommended to relieve pain and ...

Sjogren syndrome is an in which the glands that produce tears and saliva are destroyed. The condition may affect many different parts of the body, including the kidneys and lungs.

Skeletal limb abnormalities refer to a variety of bone structure problems in the arms or legs (limbs).

Skin that has turned darker or lighter than normal is usually not a sign of a serious medical condition. See also:

Clammy skin is cool, moist, and usually .

A skin abscess is a collection of pus and infected material in or on the skin.

Skin blushing or flushing is a sudden reddening of the face, neck, or upper chest.

Skin cancer is the uncontrolled growth of abnormal skin cells. If left unchecked, these cancer cells can spread from the skin into other tissues and organs. There are different types of skin cancer. Basal cell carcinoma is the most common. Melanoma is less common, but more dangerous.

The appearance and texture of a newborn infant’s skin goes through many changes. See also:

Patchy skin color refers to areas of irregular skin coloring. Mottling or mottled skin refers specifically to blood vessel changes in the skin which cause a patchy appearance.

A skin culture is a laboratory test to look for and identify disease-causing substances in a sample of skin. It is called a mucosal culture if the sample involves the .

Cyanosis is a bluish color to the skin or mucus membranes due to a lack of oxygen in the blood.

A skin graft is a patch of skin that is removed by surgery from one area of the body and transplanted, or attached, to another area.

Skin lesion aspiration is the withdrawal of fluid from a (sore).

A skin lesion biopsy is the removal of a piece of skin to diagnose or rule out an illness.

The skin lesion KOH exam is a test to diagnose a .

A skin lesion of blastomycosis is a symptom of an infection with the fungus Blastomyces dermatitidis. The skin becomes infected as the fungus spreads throughout the body.

Skin lesions of coccidioidomycosis are a symptom of infection with the Coccidioides immitis fungus. This article discusses skin lesions due to coccidioidomycosis. For more general information about this disease, see:

Skin lesions of histoplasmosis are a symptom of widespread infection with the fungus Histoplasma capsulatum. This article talks about skin lesions due to histoplasmosis only. For more general information on the disease, see:

Skin lumps are any abnormal lump or swelling on the skin.

Skin self-exam means checking your own skin regularly for any abnormal growths or unusual changes. A skin self-exam helps find any suspicious skin problems early. The earlier skin cancer is diagnosed, the better chance you will have for a cure.

Skin turgor is the skin’s ability to change shape and return to normal (elasticity).

A skull is a fracture or break in the cranial (skull) bones. See also:

A skull is a picture of the bones surrounding the brain, including the facial bones, the nose, and the sinuses. See also:

Sleep disorders involve any difficulties related to sleeping, including difficulty falling or staying asleep, falling asleep at inappropriate times, excessive total sleep time, or abnormal behaviors associated with sleep.

Sleep disorders in the elderly involve any disrupted sleep pattern, such as problems falling or staying asleep, too much sleep, or abnormal behaviors with sleep.

Sleeping difficulty can involve difficulty falling asleep when you first go to bed at night, waking up too early in the morning, or waking up often during the night. It can also involve combinations of these patterns. See also:

Sleeping sickness is infection with germs carried by certain flies. It results in swelling of the brain.

Sleepwalking is a disorder that occurs when a person walks or does another activity while they are still asleep.

A slipped capital femoral epiphysis is a separation of the ball of the hip joint from the thigh bone (femur) at the upper growing end (growth plate) of the bone.

The slit-lamp examination looks at structures that are at the front of the eye.

Small bowel bacterial overgrowth is a condition in which abnormally large numbers of bacteria grow in the small intestine.

Small bowel resection is surgery to remove part or all of your small bowel. It is done when part of your small bowel is blocked or diseased. The small bowel is also called the small intestine. Most digestion (breaking down and absorbing nutrients) of the food you eat takes place in the small ...

Small bowel tissue smear is a laboratory test that checks for disease in a sample of tissue from the small intestine.

Small for gestational age (SGA) means a fetus or infant is smaller in size than normal for the baby’s gender and .

Small intestine aspirate and culture is a laboratory test to check for infection in the small intestine.

Smallpox is a serious and contagious disease that causes a rash on the skin.

Smashed fingers is an injury involving direct trauma to one or more fingers.

Smear of duodenal fluid aspirate is an examination of fluid taken from the , for a possible infection. Usually the health care practitioner is looking for either or , which are parasites.

Impaired smell is the partial or total loss of the sense of smell.

Snake bites occur when a snake bites the skin, and are medical emergencies if the snake is poisonous.

A sneeze is a sudden, forceful, involuntary burst of air through the nose and mouth. See also:

Snoring is a loud, hoarse, or harsh breathing sound that occurs during sleep.

Social phobia is a persistent and irrational fear of situations that may involve scrutiny or judgment by others, such as parties and other social events.

This test measures the concentration of sodium in the blood.

The sodium urine test measures the amount of salt (sodium) in a urine sample. Sodium can also be measured in a blood sample. See also:

Sodium bisulfate is a dry acid that may be harmful if swallowed in large amounts. This article discusses poisoning from swallowing sodium bisulfate. 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 ...

Sodium carbonate (also known as washing soda or soda ash) is a chemical found in many household and industrial products. This article focuses on poisoning due to sodium carbonate. This is for information only and not for use in the treatment or management of an actual poison exposure. If you have ...

Sodium hydroxide is a very strong chemical that is also known as lye and caustic soda. This article discusses poisoning from touching, breathing in (inhaling), or swallowing sodium hydroxide. This is for information only and not for use in the treatment or management of an actual poison exposure. ...

Sodium hypochlorite is a chemical commonly found in bleach, water purifiers, and cleaning products. Swallowing sodium hypochlorite can lead to poisoning. Breathing sodium hypochlorite fumes may also cause poisoning, especially if the product is mixed with ammonia. This is for information only ...

Sodium is an element that the body needs to function properly.

Solder is used to connect electric wires or other metal parts together. Solder poisoning occurs when someone swallows solder in large amounts. It can also cause burns to the skin. This is for information only and not for use in the treatment or management of an actual poison exposure. If you have ...

A solitary pulmonary nodule is a round or oval spot (lesion) in the lungs that is seen with a or .

Somatization disorder is a long-term (chronic) condition in which a person has physical symptoms that involve more than one part of the body, but no physical cause can be found. The pain and other symptoms people with this disorder feel are real, and are not created or faked on purpose ...

Somatoform pain disorder is pain that is severe enough to disrupt a person’s everyday life. The pain is like that of a physical disorder, but no physical cause is found. The pain is thought to be due to psychological problems. The pain that people with this disorder feel is real. It is not ...

A sore throat is discomfort, pain, or scratchiness in the throat. A sore throat often makes it painful to swallow.

The soybean has been a part of the human diet for almost 5,000 years. Unlike most plant foods, the soybean is high in protein and is considered equivalent to animal foods in terms of the quality of the protein it contains.

Spasmodic dysphonia is difficulty speaking due to spasms (dystonia) of the muscles that control the vocal cords.

Spasmus nutans is a disorder affecting infants and young children. It involves rapid, uncontrolled eye movements, head bobbing, and occasionally, abnormal positioning of the neck. See also:

Spasticity is stiff or rigid muscles with exaggerated, deep tendon reflexes (for example, a knee-jerk reflex). The condition can interfere with walking, movement, or speech. See also:

Speech disorders refer to several conditions in which a person has problems creating or forming the speech sounds needed to communicate with others. Three common speech disorders are: Articulation disorders Disfluency Voice disorders See also:

Spider angioma is an abnormal collection of blood vessels near the surface of the skin.

Spinal and epidural anesthesia are medicines that numb parts of your body to block pain. They are given through shots in or around the spine. You will stay awake during both of these types of anesthesia.

Spinal cord abscess is swelling and irritation (inflammation) and the collection of infected material (pus) around the spinal cord.

Spinal cord trauma is damage to the spinal cord. It may result from direct injury to the cord itself or indirectly from damage to surrounding bones, tissues, or blood vessels.

Spinal fusion is surgery to join together two bones (vertebrae) in the spine. Fusing permanently joins two bones together so there is no longer movement between them. Spinal fusion is usually done along with other surgical procedures of the spine.

The spinal cord contains the nerves that carry messages between your brain and body. The cord passes through your neck and back. A is very serious because it can cause loss of movement (paralysis) below the site of the injury.

Spinal muscular atrophy is a group of inherited diseases that cause progressive muscle degeneration and weakness, eventually leading to death.

Spinal stenosis is narrowing of the spinal column that causes pressure on the spinal cord, or narrowing of the openings (called neural foramina) where spinal nerves leave the spinal column.

A spinal tumor is a growth of cells (mass) in or surrounding the spinal cord.

Spitting up is the gentle sloshing of stomach contents up and out of the mouth in babies, sometimes accompanied by a burp. It is different than vomiting.

Spleen removal (splenectomy) is surgery to remove a diseased or damaged spleen. This organ is in the upper part of your belly, on the left side underneath the rib cage. The spleen helps your body fight germs and infections. It also helps filter your blood.

Splenic infarction is death of tissue ( ) in the spleen due to a blockage in blood flow.

Splenomegaly is an enlargement of the spleen beyond its normal size.

Splinter hemorrhages are small areas of bleeding (hemorrhage) under the fingernails or toenails.

A splinter is a thin piece of material (like wood, glass, or metal) that gets embedded just below the top layer of your skin.

Spondylolisthesis is a condition in which a bone (vertebra) in the lower part of the spine slips out of the proper position onto the bone below it.

A spore is a reproductive cell produced by certain fungi, plants (moss, ferns), and some bacteria. Often, the spore fully develops after a state of dormancy or hibernation. Certain bacteria produce spores as a defensive mechanism. Bacterial spores have thick walls and are very resistant to high ...

Sporotrichosis is a long-term () skin infection due to a certain fungus.

Sports creams are cream- or ointment-based medicines used to treat aches and pains. Sports cream occurs when someone accidentally or intentionally uses more than the normal or recommended amount of this product. This is for information only and not for use in the treatment or management of an ...

A sprain is an injury to the ligaments around a joint. Ligaments are strong, flexible fibers that hold bones together. When a ligament is stretched too far or tears, the joint will become painful and swell.

Sputum direct fluorescent antibody (DFA) is a test that looks for microorganisms in lung secretions.

A sputum fungal smear is a laboratory test that looks for fungus in a sputum sample. Sputum is the material that comes up from air passages when you cough very deeply.

A sputum Gram stain is a laboratory test that uses a series of stains to check for bacteria in a sputum sample. Sputum is the mucous material that comes up from your air passages when you cough very deeply. The Gram stain method is one of the most commonly used techniques for the rapid diagnosis ...

Sputum stain for mycobacteria is a test to check for a type of bacteria that cause tuberculosis and other kinds of infection.

Squamous cell skin cancer is a type of that affects the skin.

Stable angina is or discomfort that typically occurs with activity or stress. Angina is a type of chest discomfort caused by poor blood flow through the blood vessels (coronary vessels) of the heart muscle (myocardium). See also:

A standard ophthalmic exam is a series of tests done to check your vision and the health of your eyes.

Starch is a substance, one form of which is used for cooking, and another of which is used to add firmness and shape to clothing. Starch poisoning occurs when someone accidentally or intentionally swallows starch. This is for information only and not for use in the treatment or management of an ...

Stasis dermatitis is a skin condition due to the buildup of fluid (swelling) under the skin.

Steam iron cleaner is a substance used to clean steam irons. Poisoning occurs when someone swallows steam iron cleaner. 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 ...

A stem cell is a generic cell that can make exact copies of itself indefinitely. A stem cell has the ability to produce specialized cells for various tissues in the body, such as heart muscle, brain tissue, and liver tissue. Stem cells can be saved and used as a later date to produce specialized ...

A stent is a tiny tube placed into an artery, blood vessel, or other duct (such as one that carries urine) to hold the structure open.

Stereotactic radiosurgery is a form of radiation therapy that focuses high-powered x-rays on a small area of the body. With regular radiation therapy treatment, the healthy tissue nearby also receives radiation. Stereotactic radiosurgery better focuses the radiation on the abnormal area. ...

Stereotypic movement disorder is a condition in which a person makes repetitive, purposeless movements (such as hand waving, body rocking, or head banging) for at least four weeks. The movements interfere with normal activity or have the potential to cause bodily harm.

A stillbirth is when a fetus that was expected to survive dies during birth or during the last half of pregnancy. See also:

Stimulants are medications that increase heart rate, breathing rate, and brain function. Some stimulants affect only a specific organ, such as the heart, lungs, brain, or nervous system. Some medications are given for their stimulant effect. For example, epinephrine is given during cardiac arrest ...

A stimulus is anything that can trigger a physical or behavioral change. The plural of stimulus is stimuli. Stimuli can be external (a patient responds to a medication) or internal (a patient’s vital signs change due to a change in a bodily system). Examples of stimuli include irritants, sights, ...

A stingray is a sea animal with a whip-like tail. The tail contains sharp spines that contain venom. This article describes the effects of a stingray sting. 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 ...

Stoddard solvent is a flammable, liquid chemical that smells like kerosene. Stoddard solvent poisoning occurs when someone swallows or touches this chemical. 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 ...

The stomach acid test is used to measure the quantity and acidity of stomach contents.

This article describes the health effects that occur due to the venom of a sting from a stonefish. It does not discuss allergic reactions. 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 ...

The stool C. difficile toxin test detects harmful substances produced by the bacterium Clostridium difficile (C. difficile) in a stool sample. This infection is a common cause of diarrhea after antibiotic use.

A stool Gram stain is a laboratory test that uses different stains to detect and identify bacteria in a stool sample. The Gram stain method is sometimes used to rapidly diagnose bacterial infections.

The stool guaiac test finds hidden (occult) blood in the stool (bowel movement), even when you cannot see the blood yourself. It is the most common form of fecal occult blood test (FOBT) in use today.

Stool ova and parasites exam is a laboratory test to determine if a stool sample contains parasites or eggs (ova) that are associated with intestinal infections.

Stools that float are usually due to poor absorption () of nutrients or excessive (flatus).

Foul-smelling stools are stools with a very bad odor. They usually have to do with what you eat, but may be a sign of a medical condition.

Stools that are pale, or clay- or putty-colored may result from problems in the biliary system (the drainage system of the gallbladder, liver, and pancreas).

Many people store their medications in the bathroom. But this popular spot is actually one of the worst places to keep medicine. Bathroom cabinets tend to be warm and humid, an environment that speeds up a drug’s break down process. This is especially true for tablets and capsules. ...

A stork bite is a common type of birthmark seen in a newborn. It is most often temporary. The medical term for a stork bite is nevus simplex. A stork bite is also called a salmon patch.

Strabismus is a disorder in which the two eyes do not line up in the same direction, and therefore do not look at the same object at the same time. The condition is more commonly known as “crossed eyes.”

A strain is when a muscle becomes overstretched and tears. This painful injury, also called a “pulled muscle,” can be caused by an accident, improper use of a muscle, or overuse of a muscle.

Strep throat is caused by Group A Streptococcus bacteria. It is the most common bacterial infection of the throat.

A streptococcal screen is a test to detect group A streptococcus, the most common cause of .

Stress can come from any situation or thought that makes you feel frustrated, angry, or anxious. What is stressful to one person is not necessarily stressful to another. Anxiety is a feeling of apprehension, nervousness, or fear. The source of this uneasiness is not always known or recognized, ...

Stress echocardiography is a test that uses ultrasound imaging to determine how the heart muscles respond to stress. It is mainly used to diagnose and evaluate .

Stress gastritis is swelling (inflammation) and weakening of the stomach lining that occurs during a serious illness.

Childhood can be caused by any situation that requires a person to adapt or change. The situation often produces . Stress may be caused by positive changes, such as starting a new activity, but it is most commonly linked with negative changes such as illness or death in the family.

Stress incontinence is an involuntary loss of urine that occurs during physical activity, such as coughing, sneezing, laughing, or exercise.

is a feeling of emotional or physical tension. See also:

Striae are irregular areas of skin that look like bands, stripes, or lines. Striae are seen when a person grows or gains weight rapidly or has certain diseases or conditions. Striae are commonly called stretch marks.

Stridor is an abnormal, high-pitched, musical breathing sound caused by a blockage in the throat or voice box (larynx). It is usually heard when taking in a breath. See also:

A string test involves swallowing a string to obtain a sample from the upper part of the small intestine. The sample is then tested to detect the presence of intestinal parasites. The string test is rarely used in the United States.

A stroke is an interruption of the blood supply to any part of the brain. A stroke is sometimes called a “brain attack.” See also: (AVM)

A stroke is an interruption of the blood supply to any part of the brain. Stroke is the leading cause of disability among adults in the United States. It is the country’s third leading cause of death. This article discusses recovery from stroke. How well a person does after a stroke depends ...

A stroke is an interruption of the blood supply to any part of the brain. A stroke is sometimes called a “brain attack.” There are two major types of stroke: ischemic stroke and hemorrhagic stroke. When a blood vessel that supplies blood to the brain is blocked by a blood clot, this ...

Strongyloidiasis is infection with the roundworm Strongyloides stercoralis (S. stercoralis).

Sturge-Weber syndrome is a rare disorder that is present at birth. A child with this condition will have a birthmark (usually on the face) and neurologic problems.

Stuttering is a in which sounds, syllables, or words are repeated or last longer than normal. These problems cause a break in the flow of speech (called disfluency).

Subacute combined degeneration of the spinal cord is a disorder that involves , , mental problems, and .

Subacute sclerosing panencephalitis (SSPE) is a progressive, debilitating, and deadly brain disorder related to (rubeola) infection.

Subacute thyroiditis involves swelling (inflammation) of the thyroid gland that usually follows an upper respiratory infection.

Subarachnoid hemorrhage is bleeding in the area between the brain and the thin tissues that cover the brain. This area is called the subarachnoid space.

A subareolar is an abscess or growth on the areolar gland, which is located in the breast under or below the areola (colored area around nipple).

Subconjunctival hemorrhage is a bright red patch appearing in the white of the eye. This condition is also called red eye.

The term “cutaneous” refers to the skin. Subcutaneous means beneath or under all the layers of the skin. For example, a subcutaneous is under the skin.

Subcutaneous emphysema occurs when air gets into tissues under the skin. This usually occurs in the skin covering the chest wall or neck, but can also occur in other parts of the body.

A subdural effusion is a collection of fluid beneath the outer lining of the brain. If this fluid becomes infected, the condition is called a subdural empyema.

A subdural hematoma is a collection of blood on the surface of the brain.

Sudden infant death syndrome (SIDS) is the unexpected, sudden death of a child under age 1 in which an autopsy does not show an explainable cause of death.

The sugar-water hemolysis test is a blood test to detect fragile red blood cells by testing their ability to withstand swelling in a low-salt solution.

Suicide is the act of deliberately taking one’s own life. Suicidal behavior is any deliberate action with potentially life-threatening consequences, such as taking a drug overdose or deliberately crashing a car.

Sulfuric acid is a very strong chemical that is corrosive. Corrosive means it can cause severe burns and tissue damage when it comes into contact with the skin or mucous membranes. This article discusses poisoning from sulfuric acid. This is for information only and not for use in the treatment or ...

Sulindac is a nonsteroidal anti-inflammatory drug (NSAID). It is used to relief pain and swelling associated with certain types of arthritis. Sulindac occurs when someone takes too much of this medicine. This is for information only and not for use in the treatment or management of an actual ...

A sunburn is reddening of the skin that occurs after you are exposed to the sun or other ultraviolet light.

Superficial thrombophlebitis is inflammation of a vein due to a in a vein located just below the skin’s surface.

Supernumerary nipples is the presence of extra nipples.

Supranuclear ophthalmoplegia is a condition that affects the movement of the eyes.

Surgical excision is the removal of tissue using a scalpel (sharp knife) or other cutting instrument.

Ridged sutures refer to an overlap of the bony plates of the skull in an infant, with or without early closure. See also:

Separated sutures are abnormally wide spaces in the bony joints of the skull in an infant. See also:

SVC obstruction is a narrowing or blockage of the superior vena cava — the second largest vein in the human body. The superior vena cava moves blood from the upper half of the body to the heart.

Difficulty with swallowing is the sensation that food is stuck in the throat, or from the neck down to just above the abdomen behind the breastbone (sternum).

This article discusses the health effects that may occur from accidentally or intentionally eating or swallowing soap. 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 ...

Sunscreen is a cream or lotion used to protect the skin from the sun’s rays. Sunscreen poisoning occurs when someone accidentally or intentionally swallows sunscreen. This is for information only and not for use in the treatment or management of an actual poison exposure. If you have an ...

Swan-Ganz catheterization is the passing of a thin tube (catheter) into the right side of the heart and the arteries leading to the lungs to monitor the heart’s function and blood flow, usually in persons who are very ill.

Sweat electrolytes is a test that measures the level of chloride in sweat. Although genetic tests have become important methods for determining whether a child has cystic fibrosis, the sweat chloride test remains important.

Sweating is the release of a salty liquid from the body’s sweat glands. This process is also called perspiration. Sweating is an essential function that helps your body stay cool. Sweat is commonly found under the arms, on the feet, and on the palms of the hands.

An abnormal lack of sweat in response to heat may be harmful, because sweating allows heat to be released from the body. The medical term for absent sweating is anhidrosis.

There are two types of sweeteners: Caloric (nutritive) Noncaloric (non-nutritive) The caloric sweeteners provide 4 calories per gram. The noncaloric varieties provide zero calories

Swelling is the enlargement of organs, skin, or other body parts. It is caused by a buildup of fluid in the tissues. The extra fluid can lead to a rapid increase in weight over a short period of time (days to weeks). Swelling can occur all over the body (generalized) or only in one part of the ...

Swimmer’s ear is inflammation, irritation, or infection of the outer ear and ear canal. The medical term for swimmer’s ear is otitis externa. Swimmer’s ear may be or chronic.

Swimming pool cleaner poisoning occurs when someone swallows these substances, touches the chemicals and acids in them, or breathes in their fumes. Chlorine, a chemical in swimming pool cleaners, is more likely than the acids to cause serious poisoning. This is for information only and not for use ...

A swimming pool granuloma is a long-term (chronic) skin infection caused by the bacteria Mycobacterium marinum.

Lymph nodes are found throughout your body. They are an important part of your immune system. Lymph nodes help your body recognize and fight germs, infections, and other foreign substances. The term “swollen glands” refers to enlargement of one or more lymph nodes. In a child, a node ...

Sydenham chorea is a movement disorder that occurs with .

Symptomatic can mean showing symptoms, or it may concern a specific symptom. Symptoms are signs of disease or injury. They are noticed by the patient. Many conditions and diseases have symptoms. A cough can be a symptom of an . When someone has the common symptoms associated with a disease or ...

A synovial biopsy is the removal of a piece of tissue lining a joint. The tissue is called the synovial membrane.

Synovial fluid analysis is a group of tests that examine joint (synovial) fluid. The tests help diagnose and treat joint-related problems.

Syphilis is infection with the bacteria Treponema pallidum.

is a frequently diagnosed sexually transmitted disease.

Syphilitic aseptic meningitis is a complication of untreated that involves inflammation of the tissues covering the brain and spinal cord. People with this condition have and problems with nerve function.

Syphilitic myelopathy is a complication of untreated that involves and .

Syringomyelia is damage to the spinal cord due to the formation of a fluid-filled area within the cord.

Systemic means “affecting the entire body,” rather than a single organ or body part. For example, systemic disorders such as or systemic diseases such as affect the entire body. An infection that is in the bloodstream is called a systemic infection. An infection that affects only ...

Systemic lupus erythematosus (SLE) is a chronic . SLE may affect the skin, joints, kidneys, and other organs.