Hereditary spherocytic hemolytic anemia is a rare blood disorder characterized by defects within red blood cells (intracorpuscular) that result in a shortened survival time for these cells. Red blood cells (erythrocytes) normally circulate for a f...

Acquired agranulocytosis is a rare, drug-induced blood disorder that is characterized by a severe reduction in the number of white blood cells (granulocytes) in the circulating blood. The name granulocyte refers to grain-like bodies within the cel...

Primary aldosteronism (al-DOS-tuh-ro-niz-um) is a type of hormonal disorder that leads to high blood pressure. Your adrenal glands produce a number of essential hormones. One of these is aldosterone, which balances sodium and potassium in your blo...

Allergic granulomatosis also known as Eosinophilic granulomatosis with polyangiitis (EGPA, formerly Churg-Strauss Syndro...

Allergic granulomatosis and angiitis or Eosinophilic granulomatosis with polyangiitis is a condition that affects the sm...

What is alpha thalassemia? Alpha thalassemia is a blood disorder that reduces the production of normal hemoglobin. Hemoglobin is the protein in red blood cells that carries oxygen to cells throughout the body. What are the types of...

What is sickle cell anemia? Sickle cell anemia (sickle cell disease) is a disorder of the blood caused by an inherited abnormal hemoglobin (the oxygen-carrying protein within the red blood cells). The abnormal hemoglobin causes distorted (...

What is sickle cell anemia? Sickle cell anemia (sickle cell disease) is a disorder of the blood caused by an inherited abnormal hemoglobin (the oxygen-carrying protein within the red blood cells). The abnormal hemoglobin causes distorted (...

What is angina? The heart is the pump responsible for circulating blood throughout the body. Myocardium (myo=muscle + cardium=muscle) is the heart muscle that contracts to pump that blood and like any other muscle, it requires oxygen rich ...

The heart is the pump responsible for circulating blood throughout the body. Myocardium (myo=muscle + cardium=muscle) is the heart muscle that contracts to pump that blood and like any other muscle, it requires oxygen rich blood for energy. Angina...

Ankylosing spondylitis facts Ankylosing spondylitis belongs to a group of arthritis conditions that tend to cause chronic inflammation of the spine (spondyloarthropathies). Ankylosing spondylitis affects males two to three...

What is aortic stenosis? Aortic stenosis is abnormal narrowing of the aortic valve. A number of conditions cause disease resulting in narrowing of the aortic valve. When the degree of narrowing becomes significant enough to impede the flow...

Aortic stenosis is abnormal narrowing of the aortic valve. A number of conditions cause disease resulting in narrowing of the aortic valve. When the degree of narrowing becomes significant enough to impede the flow of blood from the left ventricle...

Polymyalgia rheumatica is a rare inflammatory disease characterized by muscle pain (myalgia), stiffness, and additional generalized systemic symptoms such as fatigue, low-grade fever, and/or a general feeling of ill health (malaise). Polymyalgia r...

Like many people with chronic ailments, sufferers of chronic arthritis are potentially vulnerable to proponents of heavily marketed "cure-all" treatments. These "quick fix" treatments are promoted as having great benefits, but in reality have no r...

Atrial fibrillation (A-fib) is an irregular and often very rapid heart rhythm (a...

Atrial fibrillation (A-fib) is an irregular and often very rapid heart rhythm (arrhythmia) that can lead to blood clots in the heart. A-fib increases the risk of stroke, heart failure and other he...

Bile duct cancer, also called cholangiocarcinoma, is when unusual cells grow out of control inside your bile ducts. Those are thin tubes about 4 to 5 inches long that move a fluid called bile from your liver to your gallbladder and small intestine...

Bile duct cancer, also called cholangiocarcinoma, is when unusual cells grow out of control inside your bile ducts. Those are thin tubes about 4 to 5 inches long that move a fluid called bile from your liver to your gallbladder and small intestine...

What is bone cancer? What is metastatic bone cancer? Bone cancer is a cancer of the cells that make up the bones of the body. When cancer is found in bones, it has usually started in another organ or another location in the body and has sp...

What is bone cancer? What is metastatic bone cancer? Bone cancer is a cancer of the cells that make up the bones of the body. When cancer is found in bones, it has usually started in another organ or another location in the body and has sp...

Turcot syndrome is a rare inherited disorder characterized by the association of benign growths (adenomatous polyps) in the mucous lining of the gastrointestinal tract with tumors of the central nervous system. Symptoms associated with polyp forma...

General DiscussionChagas Disease is a tropical infectious disease caused by the parasite Trypanosoma cruzi. It is transmitted by the bite of one of several species of blood-sucking insects or by blood transfusion. Acute Chagas Disease usu...

Bronchitis is an infection that causes irritation and inflammation in the lungs' major airways (bronchi). Bronchitis is divided into two types: acute and chronic. Chronic bronchitis is a long-term condition that can reoccur. Long-term stress, such...

Bronchitis is an infection that affects the lungs' major airways (bronchi), causing irritation and inflammation. Bronchitis can be classified into two types: acute and long-term. Chronic bronchitis is a long-term problem that can come back. It is usu...

  Cellulitis is a spreading bacterial infection of the skin and tissues beneath the skin. Staphylococcus and Streptococcus are the types of bacteria that are usually responsible for cellulitis, although many types of ...

Hajdu-Cheney syndrome (HCS) is a rare, heritable disorder of connective tissue; only about 50 cases have been reported in the medical literature. The breakdown of bone (osteolysis), especially the outermost bones of the fingers and toes (acroosteo...

Chickenpox, also known as varicella, is a highly contagious viral infection caused by the varicella-zoster virus. It is characterized by a red, itchy rash that usually starts on the face, chest, and back and then spreads to the rest of the body. O...

Childhood acute lymphoblastic leukemia (ALL) is a type of cancer in which the bone marrow makes too many immature lymphocytes (a type of white blood cell). Childhood acute lymphoblastic leukemia (also called acute lymphocytic leukemia or A...

An epidemic is defined as occurring when "new cases of a certain disease, in a given human population during a given time period, substantially exceed what is expected based upon recent experience." Pediatric obesity has reached epidemic proportio...

Cold antibody hemolytic anemia (CAHA) is a rare autoimmune disorder characterized by the premature destruction of red blood cells (rbcs) by the body's natural defenses against invading organisms (antibodies). Normally, the red blood cells have a l...

What are congenital heart defects? Congenital (kon-JEN-ih-tal) heart defects are problems with the heart's structure that are present at birth. These defects can involve: The interior walls of the heart The valves ...

What is congestive heart failure (CHF)? Heart failure describes the inability or failure of the heart to adequately meet the needs of organs and tissues for oxygen and nutrients. This decrease in cardiac output, the amount of blood that th...

Mixed connective tissue disease facts Connective tissues are the framework of the cells of the body. Mixed connective tissue disease is an "overlap" combination of connective tissue diseases. Diagnosis of mixed c...

COPD is a chronic lung disease that results in obstructed airflow from the lungs. Asthmatics have difficulty breathing, cough, cough up mucus (sputum), and wheeze. It is most commonly caused by long-term exposure to irritating particles or gases, ...

COPD is a long-term lung disease that causes blocked airflow from the lungs. People who have asthma have trouble breathing, cough, cough up mucus (sputum), and wheeze. It is most often caused by exposure to irritating particles or gases over a long p...

COVID-19 is a highly contagious respiratory illness caused by the novel coronavirus SARS-CoV-2. It was first identified in Wuhan, China in late 2019 and has since spread globally, leading to a pandemic. Symptoms of COVID-19 can range from mild to ...

Cytomegalovirus (CMV) is a common virus that belongs to the herpesvirus family. It can infect people of all ages and is usually harmless to those with a healthy immune system. However, it can cause serious complications in individuals with weakene...

General DiscussionThe word "neurasthenia" is a term that has fallen into disuse among psychiatrists in the United States and Australia. It remains in use in the United Kingdom. Where it is used, it covers a wide spectrum of symptoms inclu...

Clinical depression in the elderly is common. Although, that doesn't mean it's normal. Late-life depression affects about 6 million Americans age 65 and older. But only 10% receive treatment for depression. The likely reason is that the elderly of...

Urine tests for diabetes facts Urine tests may be done in people with diabetes to evaluate severe hyperglycemia (severe high blood sugar) by looking for ketones in the urine. Ketones are a metabolic product produced when fat...

Urine tests for diabetes facts Urine tests may be done in people with diabetes to evaluate severe hyperglycemia (severe high blood sugar) by looking for ketones in the urine. Ketones are a metabolic product produced when fat...

Type 2 diabetes is an impairment in the way the body regulates and uses sugar (g...

Diabetic ketoacidosis is a serious complication of diabetes that occurs when you...

Diabetic ketoacidosis is a serious complication of diabetes that occurs when you...

Blackfan-Diamond anemia (BDA) is a rare blood disorder that is caused by a failure of the bone marrow to generate enough red blood cells. It is characterized by deficiency of red blood cells at birth (congenital hypoplastic anemia) as well as slow...

The diencephalic syndrome is a very rare neurological disorder characterized by failure to thrive, abnormal thinness (emaciation), amnesia, intense sleepiness, unusual eye position and sometimes blindness. It is normally seen in infancy or early c...

The diencephalic syndrome is a very rare neurological disorder characterized by failure to thrive, abnormal thinness (emaciation), amnesia, intense sleepiness, unusual eye position and sometimes blindness. It is normally seen in infancy or early c...

Ehlers-Danlos syndrome (EDS) is a group of hereditary connective tissue disorders characterized by defects of the major structural protein in the body (collagen). Collagen, a tough, fibrous protein, plays an essential role in holding together, str...

Ehlers-Danlos syndrome (EDS) is a group of hereditary connective tissue disorders characterized by defects of the major structural protein in the body (collagen). Collagen, a tough, fibrous protein, plays an essential role in holding together, str...

General DiscussionEisenmenger syndrome is a rare progressive heart condition that develops in some individuals with structural malformations of the heart that are present from birth (congenital heart defects). The disorder is characterize...

Williams syndrome, also known as Williams-Beuren syndrome, is a rare genetic disorder characterized by growth delays before and after birth (prenatal and postnatal growth retardation), short stature, a varying degree of mental deficiency, and dist...

Atrioventricular septal defect (ASVD) is a general term for a group of rare heart defects that are present at birth (congenital). Infants with ASVDs have improperly developed atrial and ventricular septa and adjoining valves. The norma...

Endocardial fibroelastosis (EFE) is a rare heart disorder that affects infants and children. It is characterized by a thickening within the muscular lining of the heart chambers due to an increase in the amount of supporting connective tissue (ine...

Erythema multiforme (EM) is the name applied to a group of hypersensitivity disorders, affecting mostly children and young adults, and characterized by symmetric red, patchy lesions, primarily on the arms and legs. The cause is unknown, but EM fre...

Until recently the relationship of Stevens-Johnson syndrome to other severe blistering disorders was a matter of some debate. Now a consensus seems to be evolving that describes SJS as a rare disorder involving lesions of the mucous membranes alon...

Erythema nodosum is a type of skin inflammation that is located in a certain portion of the fatty layer of skin. Erythema nodosum (also called EN) results in reddish, painful, tender lumps most commonly located in the front of the legs below the k...

Polycythemia vera is a rare, chronic disorder involving the overproduction of blood cells in the bone marrow (myeloproliferation). The overproduction of red blood cells is most dramatic, but the production of white blood cells and platelets are al...

General DiscussionCongenital rubella is a syndrome that occurs when a fetus has been infected with the rubella virus while in the uterus. It is primarily characterized by abnormalities of the heart and nervous system, the eyes and the ear...

Extrinsic Allergic Pneumonia, also known as Allergic Interstitial Pneumonitis and Hypersensitivity Pneumonitis, is an inflammatory syndrome that affects the lungs. Extrinsic: the origin is an external matter - an antigen. Allergic: The cau...

Fabry disease is caused by the lack of or faulty enzyme needed to metabolize lipids, fat-like substances that include oils, waxes, and fatty acids. The enzyme is known as ceramide trihexosidase, also called alpha-galactosidase-A. A mutation in the...

Pediatric cardiomyopathy is a rare heart condition that affects infants and children. Specifically, cardiomyopathy means disease of the heart muscle (myocardium). Several different types of cardiomyopathy exist and the specific symptoms vary from ...

A fibroma is a benign tumor that is composed of fibrous or connective tissue. It can develop in various parts of the body, including the skin, organs, and soft tissues. Fibromas are typically slow-growing and non-cancerous, but they can cause symp...

Fibromyalgia facts Fibromyalgia is a pain syndrome characterized by chronic pain, fatigue, and tenderness to touch. Fibromyalgia is the most common cause of chronic, widespread pain in the United States. Fibromya...

Megaloblastic anemia is a condition in which the bone marrow produces unusually large, structurally abnormal, immature red blood cells (megaloblasts). Bone marrow, the soft spongy material found inside certain bones, produces the main blood cells ...

The word "neurasthenia" is a term that has fallen into disuse among psychiatrists in the United States and Australia. It remains in use in the United Kingdom. Where it is used, it covers a wide spectrum of symptoms including the sensation of pain ...

Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency (G6PDD) is an inherited, sex-linked, metabolic disorder characterized by an enzyme defect that leads to the breakdown of red blood cells (hemolysis) upon exposure to stresses associated with some...

Schindler disease is a rare inherited metabolic disorder characterized by the deficient activity of the lysosomal enzyme alpha-N-acetylgalactosaminidase (alpha-NAGA or alpha-galactosidase B). The enzyme defect leads to the abnormal accumulation of...

Pseudo-Hurler polydystrophy (mucolipidosis type III) is a rare genetic metabolic disorder characterized by a defective enzyme known as UPD-N-acetylglucosamine-1-phosphotransferase. This defective enzyme ultimately results in the accumulation of ce...

Giant cell myocarditis is a rare cardiovascular disorder that occurs for unknown reasons (idiopathic). It is characterized by inflammation of the heart muscle (myocardium), a condition referred to as myocarditis. Inflammation is caused by widespre...

Giardiasis is a common intestinal infection caused by a microscopic parasite called Giardia lamblia. It is typically contracted by ingesting contaminated food or water, and can cause symptoms such as diarrhea, abdominal cramps, bloating, and weigh...

Gaucher disease is a rare, inherited metabolic disorder in which deficiency of the enzyme glucocerebrosidase results in the accumulation of harmful quantities of certain fats (lipids), specifically the glycolipid glucocerebroside, throughout the b...

Fabry disease is a rare genetic disorder of fat (lipid) metabolism characterized by a deficiency of the enzyme alpha-galactosidase A (previously known as ceramide trihexosidase). The disorder belongs to a group of diseases known as lysosomal stora...

Acquired agranulocytosis is a rare, drug-induced blood disorder that is characterized by a severe reduction in the number of white blood cells (granulocytes) in the circulating blood. The name granulocyte refers to grain-like bodies within the cel...

Group B Strejsonococcus (GBS) is a type of bacteria that is commonly found in the gastrointestinal tract, vagina, and rectum of healthy individuals. While GBS is usually harmless in healthy adults, it can cause serious infections in newborn babies...

What Is Restrictive Cardiomyopathy? Restrictive cardiomyopathy, the rarest form of cardiomyopathy, is a condition in which the walls of the lower chambers of the heart (the ventricles) are abnormally rigid and lack the flexibility to expan...

Restrictive cardiomyopathy, the rarest form of cardiomyopathy, is a condition in which the walls of the lower chambers of the heart (the ventricles) are abnormally rigid and lack the flexibility to expand as the ventricles fill with blood. ...

Heart disease is the leading cause of death among women. An estimated 90% of women have at least one risk factor for heart disease. Heart attack symptoms can be different for women than for men. Younger women wit...

Heart disease is the leading cause of death among women. An estimated 90% of women have at least one risk factor for heart disease. Heart attack symptoms can be different for women than for men. Younger women wit...

According to the American Heart Association, about 5 million Americans are diagnosed with valvular heart disease each year. What Is Valvular Heart Disease? Heart valve disease occurs when your heart's valves do not work the way the...

What Is a Biventricular Pacemaker? Leads are implanted through a vein into the right ventricle and into the coronary sinus vein to pace or regulate the left ventricle. Usually (but not always), a lead is also implanted into the right atriu...

What Is a Biventricular Pacemaker? Leads are implanted through a vein into the right ventricle and into the coronary sinus vein to pace or regulate the left ventricle. Usually (but not always), a lead is also implanted into the right atriu...

Helicobacter pylori (H. pylori) facts Helicobacter pylori (H. pylori) is a bacterium that causes chronic inflammation in the stomach and is a common cause of ulcers worldwide H. pylori causes chronic inflammation (gastriti...

Hemolytic uremic syndrome (HUS) is a condition caused by the abnormal destruction of red blood cells. The damaged red blood cells clog the filtering system in the kidneys, which can lead to life-threatening kidney failure. HUS usually deve...

Hepatitis A is a highly contagious liver infection caused by the hepatitis A virus. It is typically spread through contaminated food or water, or through close contact with an infected person. Symptoms of hepatitis A can include fever, fatigue, lo...

Hepatitis B is a viral infection that attacks the liver and can cause both acute and chronic disease. The virus is transmitted through contact with the blood or other body fluids of an infected person. Hepatitis B can be a mild illness lasting a f...

Hepatitis C is a viral infection that causes liver inflammation, sometimes leading to serious liver damage. The hepatitis C virus (HCV) is spread through contact with infected blood, most commonly through sharing needles or other equipment used to...

Hepatitis D, also known as delta hepatitis, is a liver infection caused by the hepatitis D virus (HDV). HDV is a small, defective RNA virus that can only replicate in the presence of the hepatitis B virus (HBV). This means that a person can only g...

Hepatitis E is a liver infection caused by the hepatitis E virus (HEV). It is typically a self-limiting illness that resolves on its own within a few weeks. However, in some cases, it can cause acute liver failure, especially in pregnant women and...

Hepatorenal syndrome (HRS) is a form of impaired kidney function that occurs in individuals with advanced liver disease. Individuals with hepatorenal syndrome do not have any identifiable cause of kidney dysfunction and the kidneys themselves are ...

Hereditary spherocytic hemolytic anemia is a rare blood disorder characterized by defects within red blood cells (intracorpuscular) that result in a shortened survival time for these cells. Red blood cells (erythrocytes) normally circulate for a f...

Kikuchi's disease, also known as histiocytic necrotizing lymphadenopathy, is a rare, benign, (noncancerous, nonmalignant) disorder of the lymph nodes of young adults, predominantly in young women. This disorder is often mistaken for malignant lymp...

Cowpox is a viral disease that normally affects the udders and teats of cows. On rare occasions, it may be transmitted to humans and produce a characteristic red skin rash and abnormally enlarged lymph nodes (lymphadenopathy). Cowpox is caused by ...

Human Immunodeficiency Virus (HIV) is a virus that attacks the immune system, specifically targeting CD4 cells (T cells), which help the body fight off infections. If left untreated, HIV can lead to the disease known as Acquired Immunodeficiency S...

Williams syndrome, also known as Williams-Beuren syndrome, is a rare genetic disorder characterized by growth delays before and after birth (prenatal and postnatal growth retardation), short stature, a varying degree of mental deficiency, and dist...

Hypoglycemia is the clinical syndrome that results from low blood sugar. The symptoms of hypoglycemia can vary from person to person, as can the severity. Classically, hypoglycemia is diagnosed by a low blood sugar with symptoms that resolve when ...

General DiscussionPediatric cardiomyopathy is a rare heart condition that affects infants and children. Specifically, cardiomyopathy means disease of the heart muscle (myocardium). Several different types of cardiomyopathy exist and the s...

General DiscussionGiant cell myocarditis is a rare cardiovascular disorder that occurs for unknown reasons (idiopathic). It is characterized by inflammation of the heart muscle (myocardium), a condition referred to as myocarditis. Inflamm...

Influenza, commonly known as the flu, is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness and can sometimes lead to hospitalization or even death. Symptoms of the flu include fever, cough, sore thro...

Insulin is a hormone that is produced by the beta cells of the pancreas. These cells are scattered throughout the pancreas in small clusters known as the islets of Langerhans. The insulin produced is released into the blood stream and travels thro...

Jarcho-Levin syndrome is a rare genetic disorder characterized by distinctive malformations of bones of the spinal column (vertebrae) and the ribs, respiratory insufficiency, and/or other abnormalities. Infants born with Jarcho-Levin syndrome have...

Dercum's disease is an extremely rare disorder characterized by multiple, painful growths consisting of fatty tissue (lipomas). These growths mainly occur on the trunk, the upper arms and upper legs and are found just below the skin (subcutaneousl...

Bartter's syndrome (BS) is a group of conditions involving enlargement of certain kidney cells, blood that is more alkaline than normal, high levels of potassium and chloride in the urine, loss of potassium from the kidneys (renal potassium wastin...

Kikuchi's disease, also known as histiocytic necrotizing lymphadenopathy, is a rare, benign, (noncancerous, nonmalignant) disorder of the lymph nodes of young adults, predominantly in young women. This disorder is often mistaken for malignant lymp...

Kohler disease is a rare bone disorder of the foot in children that may be the result of stress-related compression at a critical time during the period of growth. It is characterized by limping caused by pain and swelling in the foot. It most oft...

Madelung's disease is a disorder of fat metabolism (lipid storage) that results in an unusual accumulation of fat deposits around the neck and shoulder areas. Adult alcoholic males are most often affected, although women and those who do not drink...

Childhood acute lymphoblastic leukemia (ALL) is a type of cancer in which the bone marrow makes too many immature lymphocytes (a type of white blood cell). Childhood acute lymphoblastic leukemia (also called acute lymphocytic leukemia or A...

Leukoedema is a benign condition that affects the mucous membranes inside the mouth, causing them to appear white or grayish in color. It is often mistaken for oral thrush or leukoplakia, but it is actually a harmless and temporary condition that ...

Von Hippel-Lindau syndrome (VHL) is an autosomal dominant genetic disorder characterized by the abnormal growth of blood vessels in certain parts of the body (angiomatosis). Very small blood vessels (capillaries) "knot" together to form benign gro...

Drug-induced liver diseases are diseases of the liver that are caused by physician-prescribed medications, over-the-counter medications, vitamins, hormones, herbs, illicit ("recreational") drugs, and environmental toxins. What is the liver...

Congenital lobar emphysema is a rare respiratory disorder in which air can enter the lungs but cannot escape, causing overinflation (hyperinflation) of the lobes of the lung. It is most often detected in newborns or young infants, but some cases d...

If you have hypokalemia, that means you have low levels of potassium in your blood. Potassium is a mineral your body needs to work normally. It helps muscles to move, cells to get the nutrients they need, and nerves to send their signals. It&rsquo...

Systemic lupus erythematosus (SLE) is an autoimmune disease. SLE is characterized by the production of unusual antibodies in the blood. SLE is eight times more common in women than men. The cause(s) of SLE is (ar...

Dextrocardia with Situs Inversus is a rare heart condition characterized by abnormal positioning of the heart. In this condition, the tip of the heart (apex) is positioned on the right side of the chest. Additionally, the position of the heart cha...

What is mitral valve prolapse? Mitral valve prolapse (also known as "click murmur syndrome" and "Barlow's syndrome") is the most common heart valve abnormality. The condition is slightly more prevalent in women than in men. The mitral valv...

Mononucleosis, commonly known as mono, is a viral infection caused by the Epstein-Barr virus (EBV). It is most commonly seen in teenagers and young adults, but can affect people of any age. Mono is typically spread through saliva, which is why it ...

Multiple epiphyseal dysplasia (MED) is a rare inherited spectrum of disorders characterized by malformation (dysplasia) of the "growing portion" or head of the long bones (epiphyses). Affected individuals may have an abnormally short thighbone (fe...

Multiple sclerosis (MS) is a disease that causes demyelination (disruption of the myelin that insulates and protects nerve cells) of spinal nerve and brain cells. Although the exact case is unknown, multiple sclerosis is considered ...

Mumps is a contagious viral infection that primarily affects the salivary glands, causing swelling and pain in the cheeks and jaw. It is spread through respiratory droplets, such as coughing or sneezing, and can also be transmitted through close p...

Myofascial pain syndrome facts Muscle pain, tenderness, and spasm are characteristics of myofascial pain syndrome. Myofascial pain syndrome typically affects muscle in asymmetric areas of the body. The precise ca...

Diabetic Retinopathy is a complication of diabetes and a disorder of the light sensitive tissue of the eye (the retina). This condition is characterized by destructive changes in the blood vessels of the retina, which, if left unchecked, may lead ...

General DiscussionPediatric cardiomyopathy is a rare heart condition that affects infants and children. Specifically, cardiomyopathy means disease of the heart muscle (myocardium). Several different types of cardiomyopathy exist and the s...

Renal glycosuria, also known as renal glucosuria, is a rare condition in which the simple sugar glucose is eliminated (excreted) in the urine despite normal or low blood glucose levels. With normal kidney (renal) function, glucose is excreted in t...

A norovirus is a small virus that contains RNA and is surrounded by a protein coating. By sequencing the RNA, scientists have discovered that there are many different types of norovirus. Originally, strains were named based on the city in which th...

Hypertrophic cardiomyopathy (HCM) is a disease in which the heart muscle becomes...

Ovarian cancer is a type of cancer that begins in the ovaries. The female reproductive system contains two ovaries, one on each side of the uterus. The ovaries — each about the size of an almond — produce eggs (ova) as well as the horm...

The term "ovarian cancer" includes several different types of cancer that all arise from cells of the ovary. Most commonly, tumors arise from the epithelium, or lining cells, of the ovary. These include epithelial ovarian (from the cells on the su...

What is the pancreas, and what is the function of the pancreas? The pancreas is an organ in the abdomen that sits in front of the spine above the level of the belly button. It performs two main functions. First, it makes insulin, a hormone...

What is the pancreas, and what is the function of the pancreas? The pancreas is an organ in the abdomen that sits in front of the spine above the level of the belly button. It performs two main functions. First, it makes insulin, a hormone...

Acquired aplastic anemia is a rare disorder caused by profound, almost complete bone marrow failure. Bone marrow is the spongy substance found in the center of the bones of the body, in adults mainly the spine, pelvis, and large bones of the legs....

Idiopathic nodular panniculitis is a rare spectrum of skin disorders characterized by single or multiple, tender or painful bumps below the surface of the skin (subcutaneous nodules) that usually lead to inflammation of the subcutaneous layer of f...

Idiopathic nodular panniculitis is a rare spectrum of skin disorders characterized by single or multiple, tender or painful bumps below the surface of the skin (subcutaneous nodules) that usually lead to inflammation of the subcutaneous layer of f...

What is pericarditis? The heart muscle has a tight covering that surrounds it, a lining sac called the pericardium (peri=around +cardium=heart). This sac actually has two layers. The visceral pericardium is only one cell layer thick and fi...

Pertussis, also known as whooping cough, is a highly contagious respiratory infection caused by the bacterium Bordetella pertussis. It is characterized by severe coughing fits that can be followed by a "whooping" sound when the person tries to tak...

Pneumonia is a lung infection that can be caused by bacteria, viruses, or fungi. It causes inflammation in the air sacs in the lungs, leading to symptoms such as cough, fever, difficulty breathing, and chest pain. Pneumonia can range from mild to ...

Polio, short for poliomyelitis, is a highly contagious viral infection that can lead to paralysis, muscle weakness, and in severe cases, death. It primarily affects children under the age of 5. The virus is spread through contaminated food and wat...

Polymyalgia rheumatica and giant cell arteritis facts Polymyalgia rheumatica causes pain and stiffness in muscles and joints. Polymyalgia rheumatica is diagnosed by characteristic symptoms associated with abnormal blood te...

Respiratory depression (hypoventilation) is a breathing disorder characterized by slow and ineffective breathing. During a normal breathing cycle, you inhale oxygen into your lungs. Your blood carries the oxygen around your body, deliverin...

Premenstrual dysphoric disorder (PMDD) can be considered to be a severe form of premenstrual syndrome (PMS), with symptoms that interfere with daily activities and functioning. PMDD occurs in 3% to 8% of menstruating women. ...

Pernicious anemia is a rare blood disorder characterized by the inability of the body to properly utilize vitamin B12, which is essential for the development of red blood cells. Most cases result from the lack of the gastric protein known as intri...

Problem sleepiness occurs when sleepiness during the day interferes with work or social functioning. Symptoms of problem sleepiness may include difficulty concentrating, falling asleep while driving, or problems with emotional contr...

Pulmonary angiitis is a term used to describe a collection of disorders with both a vascular (angiitis) and granulomatous components. It means inflammation of blood vessels in the lungs.  There are five unique clinical syndromes that ...

Damage and scarring in lung tissue lead to pulmonary fibrosis. The scars thicken the tissue around and between the air sacs in your lungs, making it difficult for oxygen to pass into the bloodstream.  The reason for scarring ca...

Pulmonary hypertension is a life-threatening illness if not taken care of properly. If diagnosed, treatments can alleviate the symptoms and help you live with the disease more comfortably. High blood pressure in the arteries that run from your hea...

General DiscussionSecondary pulmonary hypertension is a disorder of the blood vessels in the lungs. It usually is the result of other lung diseases or related diseases in other organs. Affected individuals have high blood pressure (hypert...

Pump lung, (also known as Shock Lung), is inflammatory lung damage.  Pump lung is caused by fluid buildup in the lungs' small air sacs (called alveoli), which makes breathing very difficult. It also results in severely low bloo...

Acquired Pure Red Cell Aplasia is a rare bone marrow disorder characterized by an isolated decline of red blood cells (erythrocytes) produced by the bone marrow. Affected individuals may experience fatigue, lethargy, and/or abnormal paleness of th...

Thrombotic thrombocytopenia purpura (TTP) is a rare, serious blood disease. Major symptoms may include a severe decrease in the number of blood platelets (thrombocytopenia), abnormal destruction of red blood cells (hemolytic anemia), and disturban...

Radiation sickness describes the harmful effects--acute, delayed, or chronic--produced by exposure to ionizing radiation. An observable effect due to radiation exposure becomes quite certain after a single dose of several hundred rads. As a rule, ...

Radiation sickness describes the harmful effects--acute, delayed, or chronic--produced by exposure to ionizing radiation. An observable effect due to radiation exposure becomes quite certain after a single dose of several hundred rads. As a rule, ...

Radiation sickness is damage to your body caused by a large dose of radiation often received over a short period of time (acute). The amount of radiation absorbed by the body — the absorbed dose — determines how sick you'll be. ...

Radiation sickness describes the harmful effects--acute, delayed, or chronic--produced by exposure to ionizing radiation. An observable effect due to radiation exposure becomes quite certain after a single dose of several hundred rads. As a rule, ...

Rheumatoid arthritis is a chronic inflammatory disorder that can affect more than just your joints. In some people, the condition can damage a wide variety of body systems, including the skin, eyes, lungs, heart and blood vessels. An autoi...

Rheumatoid arthritis is a chronic inflammatory disorder that can affect more than just your joints. In some people, the condition can damage a wide variety of body systems, including the skin, eyes, lungs, heart and blood vessels. An autoi...

Toxic epidermal necrolysis (TEN) is a rare, sometimes life-threatening unless properly treated, immunological disorder of the skin. It is characterized by blisters that meld into one another to cover a substantial portion of the body (30% and more...

Rothmund-Thomson syndrome (RTS) is a rare genetic disorder that can affect many parts of the body. The disorder is characterized by distinctive abnormalities of the skin, sparse hair, eyelashes and/or eyebrows, small stature, skeletal and dental a...

The diencephalic syndrome is a very rare neurological disorder characterized by failure to thrive, abnormal thinness (emaciation), amnesia, intense sleepiness, unusual eye position and sometimes blindness. It is normally seen in infancy or early c...

The diencephalic syndrome is a very rare neurological disorder characterized by failure to thrive, abnormal thinness (emaciation), amnesia, intense sleepiness, unusual eye position and sometimes blindness. It is normally seen in infancy or early c...

The sarcoid of boeck (sarcoidosis) is a chronic inflammatory disease that can affect any organ in the body, but most often involves the skin and lungs.  Sarcoid of boeck is characterized by the formation of small, round bumps (...

Toxic epidermal necrolysis (TEN) is a rare, sometimes life-threatening unless properly treated, immunological disorder of the skin. It is characterized by blisters that meld into one another to cover a substantial portion of the body (30% and more...

Short bowel syndrome is a rare condition in which the small intestine is significantly shorter than normal, leading to malabsorption of nutrients and fluids. This can result from surgical removal of a portion of the small intestine, congenital def...

Sick building syndrome is believed by some to be an illness caused by unknown agents in buildings. Sick building syndrome is a controversial subject because many experts do not think it is a true syndrome. Sick building sy...

Sjogren's Syndrome is a chronic autoimmune disorder in which the body's immune system mistakenly attacks its own moisture-producing glands, leading to symptoms such as dry eyes, dry mouth, and dry skin. It can also affect other parts of the body, ...

Mucopolysaccharidoses, which are also known as mucopolysaccharide storage (MPS) diseases, are a group of rare genetic disorders caused by the deficiency of one of ten specific lysosomal enzymes. The lysosomes are particles bound in membranes withi...

Smallpox facts Smallpox is a contagious disease caused by the variola virus. Smallpox was the first disease to be eliminated from the world through public-health efforts and vaccination. Smallpox still poses a th...

Kugelberg Welander syndrome is a milder type of spinal muscular atrophy. It is a rare inherited neuromuscular disorder characterized by wasting and weakness in the muscles of the arms and legs, leading to walking difficulties in, and eventual loss...

Felty syndrome is usually described as associated with or a complication of rheumatoid arthritis. This disorder is generally defined by the presence of three conditions: rheumatoid arthritis (RA), an enlarged spleen (spenomelgaly) and a low white ...

General DiscussionEndocardial fibroelastosis (EFE) is a rare heart disorder that affects infants and children. It is characterized by a thickening within the muscular lining of the heart chambers due to an increase in the amount of suppor...

Syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum. It can be transmitted through sexual contact, including vaginal, anal, and oral sex. Syphilis can also be passed from mother to baby during pregnancy or...

Large arteries Open pop-up dialog box Close Large arteries Large arteries Takayasu's arteritis is a form of vasculitis — inflammation of the blood vessels — that damages the large arteries, especially the aorta. Chamber...

Acquired aplastic anemia is a rare disorder caused by profound, almost complete bone marrow failure. Bone marrow is the spongy substance found in the center of the bones of the body, in adults mainly the spine, pelvis, and large bones of the legs....

Trichinosis (trik-ih-NO-sis), sometimes called trichinellosis (trik-ih-nuh-LOW-sis), is a type of roundworm infection. These roundworm parasites (trichinella) use a host body to live and reproduce. These parasites infect animals such as bears, cou...

Tuberculosis (TB) is a contagious bacterial infection that primarily affects the lungs, but can also affect other parts of the body such as the kidneys, spine, and brain. It is caused by the bacterium Mycobacterium tuberculosis and is spread throu...

Turcot syndrome is a rare inherited disorder characterized by the association of benign growths (adenomatous polyps) in the mucous lining of the gastrointestinal tract with tumors of the central nervous system. Symptoms associated with polyp forma...

Type 1 diabetes, once known as juvenile diabetes or insulin-dependent diabetes, is a chronic condition in which the pancreas produces little or no insulin. Insulin is a hormone needed to allow sugar (glucose) to enter cells to produce energy. ...

Type 2 diabetes is an impairment in the way the body regulates and uses sugar (glucose) as a fuel. This long-term (chronic) condition results in too much sugar circulating in the bloodstream. Eventually, high blood sugar levels can lead to disorde...

Type 2 diabetes is an impairment in the way the body regulates and uses sugar (glucose) as a fuel. This long-term (chronic) condition results in too much sugar circulating in the bloodstream. Eventually, high blood sugar levels can lead to disorde...

Gilbert syndrome is a mild genetic liver disorder in which the body cannot properly process bilirubin, a yellowish waste product that is formed when old or worn out red blood cells are broken down (hemolysis). Individuals with Gilbert syndrome hav...

Usual Interstitial Pneumonia (UIP) is a radiologic and histopathologic pattern of interstitial lung disease.  The prognosis of usual interstitial pneumonia (UIP) is poor as the current therapies related to it are of unproven va...

Varicella, commonly known as chickenpox, is a highly contagious viral infection caused by the varicella-zoster virus. It is characterized by an itchy rash with red spots and fluid-filled blisters that typically appear on the face, chest, back, and...

Cutaneous necrotizing vasculitis (CNV) is characterized by inflammation and tissue damage (necrosis) of blood vessel walls (lumen) and associated skin (cutaneous) lesions. CNV may be a primary disease process or occur as a result of, or in associa...

What is a ventricular septal defect (VSD)? A ventricular septal defect (VSD) is a heart malformation present at birth. Any condition that is present at birth can also be termed a "congenital" condition. A VSD, therefore, is a type of conge...

What is a ventricular septal defect (VSD)? A ventricular septal defect (VSD) is a heart malformation present at birth. Any condition that is present at birth can also be termed a "congenital" condition. A VSD, therefore, is a type of conge...

What is vitamin D? The "sunshine" vitamin is a hot topic. You may have recently found out that you are deficient or know someone who is. It's shocking for most people when they have never had a problem before and believe nothing has change...

Glycogen storage diseases are a group of disorders in which stored glycogen cannot be metabolized into glucose to supply energy for the body. Type I glycogen storage disease is inherited as an autosomal recessive genetic disorder. Glycogen storage...

Whipple disease is a rare disease resulting from bacterial infection that leads to inadequate absorption of nutrients (malabsorption) from the intestine. It is believed to result from infection with bacteria known as Tropheryma whippelii. The infe...

Wilson's disease is a rare inherited disorder that causes copper to accumulate in your liver, brain and other vital organs. Most people with Wilson's disease are diagnosed between the ages of 5 and 35, but it can affect younger and older people, a...

Familial hypophosphatemia is a rare inherited disorder characterized by impaired transport of phosphate and often altered vitamin-D metabolism in the kidneys. In addition, phosphate may not be well-absorbed in the intestines. The hypophosphatemia ...

Takayasu arteritis is a rare disorder characterized by the progressive inflammation of one or more of the larger arteries leading from the heart. The main artery of the heart (aorta) and the pulmonary (lung) artery, among others, may be affected. ...