Sinus histiocytosis: Another name for Rosai-Dorfman disease (or close medical condition association). Rosai-Dorfman disease: A rare condition characterized by excessive production and accumulation of a particular white blood cell (histiocyte). Accumulation primarily occurs in the lymph nodes, especially in the neck, but may also occur in the skin, central nervous system, digestive tract and kidneys.
Sinus node disease and myopia: A very rare disorder characterized by nearsightedness.
Sirenomelia is a lethal birth defect of the lower body characterized by apparent fusion of the legs into a single lower limb. Other birth defects are always associated with sirenomelia, most commonly abnormalities of the kidneys, large intestines, and genitalia. This pattern of birth defects is associated with abnormal umbilical cord blood vessels. The normal fetus develops two umbilical arteries, which pump blood from the fetus to the placenta, and one umbilical vein, which returns blood from the placenta to the fetus. The umbilical arteries branch off the iliac arteries in the pelvis. The iliac arteries supply the legs and pelvic organs such as the genitalia. Most babies with sirenomelia have only one umbilical artery and one vein. Rarely a baby with sirenomelia can have the typical two arteries and one vein with occlusion (blockage) of one artery. In sirenomelia, the one functional artery is larger than normal and branches from the aorta high in the abdomen. Below this umbilical artery, the aorta becomes abnormally narrow. This type of single umbilical artery is known as a vitelline artery because it is thought to arise from the primitive vitelline arteries early in the life of the embryo. The vitelline arteries normally fuse a few weeks after conception to form the arteries that supply the gastrointestinal system and genitourinary system (superior mesenteric, inferior mesenteric, and celiac arteries). If the normal umbilical arteries do not form correctly as branches from the iliac arteries, then a vitelline artery might persist. The vitelline umbilical artery steals blood and nutrition from the lower body and diverts it to the placenta. This results in a small aorta and variable absence of the arteries that supply the kidneys, large intestine, and genitalia (renal, inferior mesenteric, and celiac arteries). Because of the loss of nutrition and blood flow, the lower limbs fail to form as separate limbs, the kidneys do not form or are malformed, the large intestine ends blindly in the abdominal cavity, the anus is imperforate, and the internal and external genitalia are absent or malformed. The typical malformation of the lower limbs seen in babies with sirenomelia consists of apparent fusion of the legs. There is a spectrum of severity with severe cases having one lower limb that tapers to a point with the absence of foot structures. In these severe cases there are only two bones present in the entire limb (a femur and presumably a tibia). On the mild end of the spectrum are babies with fusion of the skin of the lower limbs only. In these infants the feet may be fully formed with fusion at the ankles. All bones are fully formed and separate. Normally there are three bones in each leg—the femur in the upper leg (thigh) and the tibia and fibula in the lower leg (calf). Other birth abnormalities of the upper body involving the heart, lungs, spine, brain, and arms can also be seen in this syndrome, however, not in every affected individual. It is unknown at this time why a single umbilical artery could cause these changes. Single umbilical artery occurs in about 1% of all live-born infants. In most of these infants the one umbilical artery is normally formed and not of vitelline origin. In these cases, the risk of other birth defects is low (about 8%). All infants born with a vitelline umbilical artery will have other malformations, the most common being sirenomelia.
Sitosterolemia (also known as phytosterolemia) is a rare autosomal recessively inherited lipid metabolic disorder. It is characterized by hyperabsorption and decreased biliary excretion of dietary sterols leading to hypercholesterolemia, tendon and tuberous xanthomas, premature development of atherosclerosis, and abnormal hematologic and liver function test results.
Situs inversus totalis with cystic dysplasia of kidneys and pancreas: A rare syndrome where the position of the internal organs of the chest and abdomen is transposed. In addition there are kidney and pancreatic abnormalities.
Situs inversus (also called situs transversus) is a congenital condition in which the major visceral organs are reversed or mirrored from their normal positions. The normal arrangement is known as situs solitus. In other rare cases, in a condition known as situs ambiguus or heterotaxy, situs cannot be determined. The term situs inversus is a short form of the Latin phrase "situs inversus viscerum," meaning "inverted position of the internal organs." Dextrocardia (the heart being located on the right side of the thorax) was first recognised by Marco Severino in 1643. However, situs inversus was first described more than a century later by Matthew Baillie.
Situs inversus, X-linked: A X-linked (occurs only in males but females can be carriers) disorder where the position of the internal organs of the chest and abdomen is transposed. For example, the heart is on the right side of the chest instead of the left. Generally this condition poses no problems but may become relevant during surgery or medical examinations as organs will be on the wrong side of the body.
Sixth nerve palsy, or abducens nerve palsy, is a disorder associated with dysfunction of cranial nerve VI (the abducens nerve) which is responsible for contracting the lateral rectus muscle to abduct (i.e. turn out) the eye. The inability of an eye to turn outward results in a convergent strabismus or esotropia of which the primary symptom is double vision or diplopia in which the two images appear side-by-side. The condition is commonly unilateral, but can also occur bilaterally.
Sjogren-Larsson syndrome is an inborn error of lipid metabolism, characterized by congenital ichthyosis (dry, scaly skin), intellectual disability, and spasticity (stiffness and involuntary muscle spasms). These symptoms are apparent by early childhood and usually do not worsen with age. SLS is an autosomal recessive form of ichthyosis apparent at birth. Sjögren–Larsson syndrome is a rare autosomal, recessive, neurocutaneous disease. This disease can be identified by a triad of medical disorders. The first is ichthyosis, which is a buildup of skin to form a scale-like covering that causes dry skin and other problems. The second identifier is spastic paraplegia which is characterized by leg spasms. The final identifier is intellectual delay. The gene of SLS is found on chromosome 17. In order for a child to receive SLS both parents must be carriers of the SLS gene. If they are carriers their child has a ¼ chance of getting the disease. In 1957 Sjogren and Larsson proposed that the Swedes with the disease all descended from a common ancestor 600 years ago. Today only 30-40 persons in Sweden have this disease.
Affected infants tend to be born prematurely. At birth the skin is red (erythema), but later in infancy the skin becomes dry, rough, and scaly with a brownish or yellowish tone. Mild to severe itchiness (pruritus) is also common. These skin abnormalities are generally dispersed over the whole body, most severely affecting the nape of the neck, the torso, and the extremities. The skin of the face is usually not affected.
People with this condition may also have neurological signs and symptoms. Most affected individuals have leukoencephalopathy, which is a change in a type of brain tissue called white matter. White matter consists of nerve fibers covered by a substance (myelin) that insulates and protects the nerves. The leukoencephalopathy is thought to contribute to many of the neurological signs and symptoms in people with Sjögren-Larsson syndrome. Most affected individuals have intellectual disability that varies from mild to profound and is usually apparent by early childhood. People with Sjögren-Larsson syndrome have speech difficulties (dysarthria) and delayed speech. Usually they are able to produce only short sentences with poorly formed words. Rarely, people with this condition have normal intelligence. In addition, approximately 40 percent of people with Sjögren-Larsson syndrome have seizures.
Children with this condition often experience delayed development of motor skills (such as crawling and walking) due to abnormal muscle stiffness (spasticity) that is typically in their legs and, less commonly, also in their arms. About one-half of people with Sjögren-Larsson syndrome require wheelchair assistance and many others need some form of support to walk.
Affected individuals have tiny crystals in the light-sensitive tissue at the back of the eye (retina) that can be seen during an eye exam. Based on their appearance, these retinal crystals are often called glistening white dots. These white dots are usually apparent by early childhood, and it is unclear if they affect normal vision. People with Sjögren-Larsson syndrome may also have nearsightedness (myopia) or an increased sensitivity to light (photophobia).
Sjogren-Larsson-like syndrome: A very rare syndrome characterized by a thickened scaly skin similar to that observed in sufferers of Sjogren-Larsson syndrome.
Sjögren syndrome is an autoimmune disorder in which immune cells attack and destroy the glands that produce tears and saliva. Sjögren syndrome is also associated with rheumatic disorders such as rheumatoid arthritis or systemic lupus erythematosus. The hallmark symptoms of the disorder are dry mouth and dry eyes. In addition, Sjogren syndrome may cause skin, nose, and vaginal dryness, and may affect other organs of the body including the kidneys, blood vessels, lungs, liver, pancreas, and brain. Treatment is symptomatic and supportive and may include moisture replacement therapies, nonsteroidal anti-inflammatory drugs and, in severe cases, corticosteroids or immunosuppressive drugs.
Skeletal dysplasia - orofacial anomalies: A very rare disorder characterized mainly by face, mouth and skeletal abnormalities.
Skeletal dysplasia, San Diego type: A very rare disorder characterized mainly by short limbs and flattened spinal vertebrae. Infants are stillborn or die soon after birth.
Skeletal dysplasias are a group of congenital abnormalities of the bone and cartilage that are characterized by short stature. Skeletal dysplasia, sometimes called dwarfism, is a disorder of short stature defined as height that is three or more standard deviations below the mean height for age, race, and gender. Although all skeletal dysplasias involve disproportionately short stature, there are many other associated conditions. Skeletal dysplasia may also have additional skeletal abnormalities, including: * short arms and truck, bowlegs, and a waddling gait * skull malformations, such as a large head, cloverleaf skull, craniosynostosis (premature fusion of the bones in the skull), and wormian bones (abnormal thread-like connections between the skull bone) * anomalies of the hands and feet, including polydactyly (extra fingers), "hitchhiker" thumbs, and abnormal finger and toe nails * chest anomalies, such as pear-shaped chest and narrow thorax Other anomalies that may be present in individuals with skeletal dysplasia include: * anomalies of the eyes, mouth, and ears, such as congenital cataract, myopia (nearsightedness), cleft palate, and deafness * brain malformations, such as hydrocephaly, porencephaly, hydranencephaly, and agenesis of the corpus callosum * heart defects, such as atrial septal defect (ASD), patent ductus arteriosus (PDA), and transposition of the great vessels (TGV) * developmental delays and mental retardation
Nonmelanoma skin cancer in children is similar to the disease in adults except that it often progresses more quickly among the young. The increased cases of skin cancer around the world have been labeled an epidemic by some experts.
Slavotinek-Pike-Mills-Hurst syndrome: A very rare inherited syndrome characterized mainly by cataracts, short stature, learning difficulties, skeletal abnormalities and a motor system disorder.
Mucopolysaccharidosis type VII (Sly syndrome) is a progressive condition that affects most tissues and organs. The severity of MPS VII varies widely among affected individuals.
The most severe cases of MPS VII are characterized by hydrops fetalis, a condition in which excess fluid builds up in the body before birth. Most babies with hydrops fetalis are stillborn or die soon after birth. Other people with MPS VII typically begin to show signs and symptoms of the condition during early childhood. The features of MPS VII include a large head (macrocephaly), a buildup of fluid in the brain (hydrocephalus), distinctive-looking facial features that are described as "coarse," and a large tongue (macroglossia). Affected individuals also frequently develop an enlarged liver and spleen (hepatosplenomegaly), heart valve abnormalities, and a soft out-pouching around the belly-button (umbilical hernia) or lower abdomen (inguinal hernia). The airway may become narrow in some people with MPS VII, leading to frequent upper respiratory infections and short pauses in breathing during sleep (sleep apnea). The clear covering of the eye (cornea) becomes cloudy, which can cause significant vision loss. People with MPS VII may also have recurrent ear infections and hearing loss. Affected individuals may have developmental delay and progressive intellectual disability, although intelligence is unaffected in some people with this condition.
MPS VII causes various skeletal abnormalities that become more pronounced with age, including short stature and joint deformities (contractures) that affect mobility. Individuals with this condition may also have dysostosis multiplex, which refers to multiple skeletal abnormalities seen on x-ray. Carpal tunnel syndrome develops in many children with MPS VII and is characterized by numbness, tingling, and weakness in the hands and fingers. People with MPS VII may develop a narrowing of the spinal canal (spinal stenosis) in the neck, which can compress and damage the spinal cord.
The life expectancy of individuals with MPS VII depends on the severity of symptoms. Some affected individuals do not survive infancy, while others may live into adolescence or adulthood. Heart disease and airway obstruction are major causes of death in people with MPS VII.
Small bowel adenocarcinoma (SBA) is a rare malignancy of the gastrointestinal tract. However, these tumors are among those with worst prognosis. Vague clinical signs and symptoms and radiological diagnostic challenges often delay treatment, which negatively impacts the prognosis of the patients. However, recent advances in imaging technology, like multidetector computed tomography, magnetic resonance imaging, and capsule endoscopy, have made earlier and accurate diagnosis possible. Surgery is the treatment of choice followed by adjuvant therapy. However, there are no strict treatment guidelines available for the management of SBA. Most of the available evidence from colorectal and gastric carcinoma has been extrapolated to adequately manage SBA. Prognosis for SBA is better than gastric carcinoma but worse than colorectal carcinoma. Currently, there is not enough information on the molecular characteristics and tumor pathogenesis. Because the incidence of SBA is very low, there is a need for further studies to evaluate the possible application of newer investigative agents and strategies to obtain a better outcome within the framework of international collaborations.
Small cell lung cancer is a disease in which malignant (cancer) cells form in the tissues of the lung.
There are two types of small cell lung cancer.
These two types include many different types of cells. The cancer cells of each type grow and spread in different ways. The types of small cell lung cancer are named for the kinds of cells found in the cancer and how the cells look when viewed under a microscope:
• Small cell carcinoma (oat cell cancer).
• Combined small cell carcinoma.
Source: National Cancer Institute (US)
The small intestine, or small bowel, lies between the stomach and the colon. The small intestine is about 6 m (20 ft) long. Its primary function is to digest and absorb nutrients. The small intestine makes up more than 70% of the length and 90% of the surface area of the gastrointestinal (GI) tract. The most common cancerous (malignant) tumors of the small bowel include adenocarcinoma, lymphoma, sarcoma, and carcinoids. * In industrialized countries, adenocarcinomas occur most often. * In developing countries, lymphomas are much more common. * All these tumors have the potential to invade the bowel wall, spread into adjoining lymph nodes, and move to distant organs (metastasize).
Small lymphocytic lymphoma (SLL) is a B-cell lymphoma. Chronic Lymphocytic Leukemia (CLL) and Small Lymphocytic Lymphoma (SLL) are essentially the same disease, the only difference being where the cancer primarily occurs: When most of the cancer cells are located in the bloodstream and the bone marrow, the disease is referred to as CLL, although the lymph nodes and spleen are often involved.
When the cancer cells are located in the lymph nodes, the disease is called SLL.
Chronic lymphocytic leukemia (CLL) is a cancer of the lymphocytes (a type of white blood cell) that begins in the stem cells of the bone marrow and then invades the blood. Overtime, CLL may also spread to the lymph nodes and other organs including the liver, spleen and lungs. It occurs when the stem cells that make lymphocytes become out of control and produce increasing amounts of abnormal lymphocytes (also called leukemic cells). Eventually, these abnormal cells replace normal lymphocytes and can crowd out other types of normal blood cells, leading to the features of the condition. The exact underlying cause of CLL/SLL is unknown; however, approximately 5% of affected people have other family members with the condition, which suggests there may be a genetic component in rare cases. The best treatment depends on many factors including the stage of the condition, the age of the affected person, the blood cell counts, whether the CLL has recurred, and the signs and symptoms present in each person.
Alternative Names: Burkitt lymphoma, B-cell lymphoma; High-grade B-cell lymphoma; Small non-cleaved cell lymphoma Burkitt lymphoma is a very fast growing form of non-Hodgkin's lymphoma.
Smallpox was an infectious disease caused by either of two virus variants, Variola major and Variola minor. The disease is also known by the Latin names Variola or Variola vera, derived from varius ("spotted") or varus ("pimple"). The disease was originally known in English as the "pox" or "red plague"; the term "smallpox" was first used in Britain in the 15th century to distinguish variola from the "great pox" (syphilis). The last naturally occurring case of smallpox (Variola minor) was diagnosed on 26 October 1977.
Infection with smallpox is focused in small blood vessels of the skin and in the mouth and throat before disseminating. In the skin it results in a characteristic maculopapular rash and, later, raised fluid-filled blisters. V. major produced a more serious disease and had an overall mortality rate of 30–35 percent. V. minorcaused a milder form of disease (also known as alastrim, cottonpox, milkpox, whitepox, and Cuban itch) which killed about 1 percent of its victims. Long-term complications of V. major infection included characteristic scars, commonly on the face, which occur in 65–85 percent of survivors. Blindness resulting from corneal ulceration and scarring, and limb deformities due to arthritis and osteomyelitis were less common complications, seen in about 2–5 percent of cases.
Smallpox is believed to have emerged in human populations about 10,000 BC. The earliest physical evidence of it is probably the pustular rash on the mummified body of Pharaoh Ramses V of Egypt. The disease killed an estimated 400,000 Europeans annually during the closing years of the 18th century (including five reigning monarchs), and was responsible for a third of all blindness. Of all those infected, 20–60 percent—and over 80 percent of infected children—died from the disease. Smallpox was responsible for an estimated 300–500 million deaths during the 20th century. As recently as 1967, the World Health Organization (WHO) estimated that 15 million people contracted the disease and that two million died in that year.
After vaccination campaigns throughout the 19th and 20th centuries, the WHO certified the global eradication of smallpox in 1979. Smallpox is one of two infectious diseases to have been eradicated, the other being rinderpest, which was declared eradicated in 2011.
Main name of condition: Smith-Lemli-Opitz Syndrome Other names or spellings for Smith-Lemli-Opitz Syndrome: Smith-Lemli-Opitz syndrome, type 1, SLO syndrome type 1, 7-Dehydrocholesterol reductase deficiency, RSH syndrome. hereditary developmental disorder; characterized by nostrils that tilt forward (anteverted nares), drooping eyelids, webbing between the second and third toes, male genital abnormalities, mental retardation, and small stature; biochemical defect is a lack of 7-dehydrocholesterol-delta-7-reductase, resulting in abnormally high levels of 7-dehydrocholesterol and low levels of cholesterol.