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...

Amenorrhea facts Amenorrhea refers to the absence of menstrual periods; it may be either primary (meaning a woman never developed menstrual periods) or secondary (absence of menstrual periods in a woman who was previously menstruati...

Arachnoid cysts are fluid-filled sacs that occur on the arachnoid membrane that covers the brain (intracranial) and the spinal cord (spinal). There are three membranes covering these parts of the central nervous system: the dura mater, arachnoid, ...

Astigmatism is a common eye condition that causes blurred vision due to an irregularly shaped cornea. It occurs when the cornea is curved more in one direction than the other, which causes light to be focused unevenly on the retina. This can cause...

Balo Disease is a rare and progressive variant of multiple sclerosis. It usually first appears in adulthood, but childhood cases have also been reported. While multiple sclerosis typically is a disease that waxes and wanes, Balo Disease is differe...

Bell's palsy (Bell palsy) is paralysis of the facial nerve of unknown cause. The diagnosis is made when no other cause can be identified. Although Bell's palsy is thought to be caused by a viral infection of the facial nerve, this hasn't been prov...

Brain aneurysm  An aneurysm is a ballooning at a weak spot in an artery wall. An aneurysm's walls can be thin enough to rupture. The illustration shows an individual with an unruptured aneurysm. The inset shows what happens when the a...

What is brain cancer? Brain cancer is a disease of the brain in which cancer cells (malignant cells) arise in the brain tissue. Cancer cells grow to form a mass of cancer tissue (tumor) that interferes with brain functions such as muscle c...

A brain tumor is a mass or growth of abnormal cells in your brain. Many different types of brain tumors exist. Some brain tumors are noncancerous (benign), and some brain tumors are cancerous (malignant). Brain tumors can begin in your bra...

A brain tumor is a mass or growth of abnormal cells in your brain. Many different types of brain tumors exist. Some brain tumors are noncancerous (benign), and some brain tumors are cancerous (malignant). Brain tumors can begin in your bra...

A brain tumor is a mass or growth of abnormal cells in your brain. Many different types of brain tumors exist. Some brain tumors are noncancerous (benign), and some brain tumors are cancerous (malignant). Brain tumors can begin in your bra...

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...

Dengue Fever is an acute viral infection characterized by fever. It is caused by a bite from mosquitoes carrying dengue virus. The primary form of Dengue Fever is characterized by a skin rash and a high fever with severe pain in the head and muscl...

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...

Familial articular chondrocalcinosis is a rare inherited metabolic disorder characterized by deposits of calcium pyrophosphate dihydrate crystals (CPPD) in one or more joint cartilages resulting in eventual damage to the joints. Symptoms may devel...

The carotid arteries provide blood supply to the head. There are two common carotid arteries, located on each side of the neck, that divide into the internal and external carotid arteries. The external carotid artery provides blood supply to the s...

The carotid arteries provide blood supply to the head. There are two common carotid arteries, located on each side of the neck, that divide into the internal and external carotid arteries. The external carotid artery provides blood supply to the s...

Chiari-Frommel Syndrome is a rare endocrine disorder that affects women who have recently given birth (postpartum) and is characterized by the over-production of breast milk (galactorrhea), lack of ovulation (anovulation), and the absence of regul...

Chickenpox (varicella) is a viral infection that causes an itchy rash with small, fluid-filled blisters. Chickenpox is highly contagious to people who haven't had the disease or been vaccinated against it. Before routine chickenpox vaccination, vi...

Chikungunya is a viral disease transmitted to humans by infected mosquitoes, specifically the Aedes aegypti and Aedes albopictus species. The most common symptoms of Chikungunya include fever, joint pain, headache, muscle pain, rash, and joint swe...

Cluster headache is pain that occurs along one side of the head. It's frequently described as pain that occurs around, behind, or above the eye and along the temple in cyclic patterns or clusters. The pain of a cluster headache is very severe. Man...

Collagenous colitis is a rare digestive disorder that primarily affects females and typically becomes apparent during middle age. The disorder is characterized by inflammatory changes of the mucous membranes (mucosa) of the colon (colitis) and abn...

Cryptococcus is a fungus that is found in soil all over the world, usually in association with bird droppings. Cryptococcus neoformans is the most common Cryptococcus species that causes illness in humans. Cryptococcus gattii, a less common specie...

Cyclic vomiting syndrome is characterized by episodes of severe vomiting that ha...

Cysticercosis (pork tapeworm infection) facts Cysticercosis is a parasitic disease caused by ingesting the eggs of the pork tapeworm, Taenia solium. Humans are infected by ingesting raw or undercooked pork, and cysticercos...

Arachnoid cysts are fluid-filled sacs that occur on the arachnoid membrane that covers the brain (intracranial) and the spinal cord (spinal). There are three membranes covering these parts of the central nervous system: the dura mater, arachnoid, ...

Degos disease is a very rare disease in which small and medium-sized arteries become blocked, preventing proper blood flow to the affected areas. You may also develop skin lesions, which can last from weeks to years depending on the extent of the ...

Wolfram syndrome is the inherited association of childhood-onset diabetes mellitus and progressive-onset optic atrophy. All people affected by Wolfram syndrome have juvenile-onset diabetes mellitus and degeneration of the optic nerve (optic atroph...

Harlequin ichthyosis is a rare genetic skin disorder. The newborn infant is covered with plates of thick skin that crack and split apart. The thick plates can pull at and distort facial features and can restrict breathing and eating. Harlequin inf...

Meningiomas are benign, slow-growing tumors, classified as brain tumors, but actually growing in the three protective membranes that surround the brain (meninges). Sometimes they cause thickening or thinning of adjoining skull bones. Meningiomas d...

Empty sella syndrome is a rare disorder characterized by enlargement or malformation of a structure in the head known as the sella turcica. The sella turcica is a saddle-shaped depression located in the bone at the base of skull (sphenoid bone), i...

Encephalitis is an inflammation of the brain. Meningitis is an inflammation of the membranes (called meninges) that surround the brain and spinal cord. Both infections can be caused by bacteria or viruses and rarely a fungus. ...

Herpes simplex encephalitis (HSE) is a rare neurological disorder characterized by inflammation of the brain (encephalitis). Common symptoms include headaches, fevers, drowsiness, hyperactivity, and/or general weakness. The disorder may have some ...

Japanese Encephalitis is a severe inflammation of the brain caused by the Japanese B Encephalitis Virus that is transmitted by the bite of infected mosquitoes in certain areas of the world, particularly Asia. This disorder most commonly affects ch...

The largest part of the brain, the cerebrum, is divided into four paired sections -- the frontal, parietal, occipital, and temporal lobes. Each lobe controls a specific group of activities. The temporal lobe, located on either side of the brain ju...

The largest part of the brain, the cerebrum, is divided into four paired sections -- the frontal, parietal, occipital, and temporal lobes. Each lobe controls a specific group of activities. The temporal lobe, located on either side of the brain ju...

Cryptococcosis is caused by a fungus known as Cryptococcosis neoformans. The infection may be spread to humans through contact with pigeon droppings or unwashed raw fruit. Contact with an infected individual may also spread the infection. Individu...

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...

Eye allergies, also known as allergic conjunctivitis, are a type of allergic reaction that affects the eyes. Symptoms of eye allergies include redness, itching, burning, tearing, and swelling of the eyes. Eye allergies are usually caused by airbor...

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...

Familial idiopathic basal ganglia calcification (FIBGC) is a rare neurological disorder characterized by the presence of abnormal calcium deposits (calcifications) of unknown cause. Associated symptoms include progressive deterioration of cognitiv...

Familial idiopathic basal ganglia calcification (FIBGC) is a rare neurological disorder characterized by the presence of abnormal calcium deposits (calcifications) of unknown cause. Associated symptoms include progressive deterioration of cognitiv...

Farsightedness, also known as hyperopia, is a vision condition in which distant objects appear clearly, but close objects appear blurry. It occurs when the eyeball is too short or the cornea has too little curvature, so light entering the eye is n...

Fitz-Hugh-Curtis syndrome is a rare disorder that occurs almost exclusively in women. It is characterized by inflammation of the membrane lining the stomach (peritoneum) and the tissues surrounding the liver (perihepatitis). The muscle that separa...

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 ...

Formaldehyde Poisoning is a disorder brought about by breathing the fumes of formaldehyde. This can occur while working directly with formaldehyde, or using equipment cleaned with formaldehyde. Major symptoms may include eye, nose, and throat irri...

Formaldehyde Poisoning is a disorder brought about by breathing the fumes of formaldehyde. This can occur while working directly with formaldehyde, or using equipment cleaned with formaldehyde. Major symptoms may include eye, nose, and throat irri...

Formaldehyde is a transitional molecule that participates in a wide range of biological activities. It can be found in a variety of everyday items, including meals. It's also used in medicine to treat a variety of ailments. Formalin is a 40 percen...

Chiari-Frommel Syndrome is a rare endocrine disorder that affects women who have recently given birth (postpartum) and is characterized by the over-production of breast milk (galactorrhea), lack of ovulation (anovulation), and the absence of regul...

Giant Cell Arteritis (GCA) is a type of vasculitis, or inflammation of the blood vessels. It is a chronic inflammatory disorder that affects the large and medium-sized arteries, most commonly the temporal arteries. Symptoms of GCA include headache...

Glaucoma is a disease that is often associated with elevated intraocular pressure, in which damage to the eye (optic) nerve can lead to loss of vision and even blindness. Glaucoma is the leading cause of irreversible blindness in th...

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...

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...

Vogt-Koyanagi-Harada disease is a rare disorder of unknown origin that affects many body systems, including as the eyes, ears, skin, and the covering of the brain and spinal cord (the meninges). The most noticeable symptom is a rapid loss of visio...

Paroxysmal cold hemoglobinuria (PCH) is a rare type of anemia characterized by the premature destruction of healthy red blood cells by autoantibodies. The disorder is classified as an autoimmune hemolytic anemia (AIHA), an uncommon group of disord...

Migraine is a type of headache that is often localized in a certain area of the head and is sometimes accompanied by a pronounced sensitivity to light and sound. Other common migraine symptoms include nausea and vomiting. Migraines are usually gra...

A hematoma is a collection of blood outside of a blood vessel. Symptoms of hematomas depend upon their location and whether adjacent structures are affected by the inflammation and swelling associated with the bleeding. Tr...

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...

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...

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...

Histoplasmosis is an infection caused by the fungus Histoplasma. The fungus can be found in the environment, particularly in soil with a high concentration of bird or bat droppings. Histoplasma is mostly found in the central and eastern United Sta...

A number of factors, including unrealistic expectations, financial pressures, and too many commitments can cause stress and anxiety at holiday time. Certain people may feel anxious or depressed around the winter holidays due to seas...

Hydrocephalus is a condition characterized by excessive accumulation of fluid in the brain. Hydrocephalus may be congenital or acquired. Communicating hydrocephalus occurs when cerebrospinal fluid (CSF) can still flow amon...

High blood sugar (hyperglycemia) affects people who have diabetes. Several facto...

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 ...

Idiopathic intracranial hypertension (IIH) is a neurological disorder characterized by increased pressure in the fluid surrounding the brain (cerebrospinal fluid). It is also known as pseudotumor cerebri. Symptoms of IIH include headaches, vision ...

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...

Japanese enenchephalitis is a viral infection that is transmitted through the bite of infected mosquitoes. It is a type of encephalitis, which is inflammation of the brain. Symptoms of Japanese encephalitis can include fever, headache, vomiting, c...

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...

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...

Listeriosis is an infection caused by a gram-positive motile bacterium named Listeria monocytogenes. The infection produces fever, muscle aches, and, in many people, diarrhea. Severe infections can cause headaches, meningitis, convulsions, and dea...

Sneddon syndrome is a rare progressive disorder affecting the blood vessels characterized by the association of a skin condition and neurological abnormalities. Characteristics include multiple episodes of reduced blood flow to the brain (cerebral...

Degos disease is an extremely rare disorder in which small and medium sized arteries become blocked (occlusive arteriopathy), restricting the flow of blood to affected areas. Degos disease usually causes characteristic skin lesions that may last f...

Encephalitis is an inflammation of the brain. Meningitis is an inflammation of the membranes (called meninges) that surround the brain and spinal cord. Both infections can be caused by bacteria or viruses and rarely a fung...

Meningococcal disease is a serious bacterial infection caused by the bacterium Neisseria meningitidis. It can lead to meningitis (inflammation of the membranes surrounding the brain and spinal cord) and septicemia (blood poisoning). Meningococcal ...

Menstrual cramps that occur in the absence of a known abnormality or cause are medically referred to as primary dysmenorrhea. Non-drug treatments for menstrual cramps include adequate rest and sleep, regular exercise (especially wal...

Migraine is a type of headache that is usually characterized by a throbbing or pulsing pain on one side of the head, accompanied by nausea, vomiting, and sensitivity to light and sound. It is a neurological disorder that affects about 12% of the p...

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 ...

Hyperostosis Frontalis Interna is characterized by the thickening of the frontal bone of the skull. It is not clear that this disorder is actually rare. Some clinicians believe that it may be a common abnormality found in as many as 12 percent of ...

Syringomyelia is a neurological disorder characterized by the formation of a fluid-filled cyst (syrinx) within the spinal cord. This cyst may, for unknown reasons, expand during adolescence or the young adult years, destroying the center of the sp...

Colorado Tick Fever is a rare viral disease transmitted by ticks that commonly inhabit the western United States. Major symptoms may include fever, headaches, muscle aches, and/or generalized discomfort (myalgia). The symptoms usually last for abo...

Moyamoya syndrome is a progressive disorder that affects the blood vessels in the brain (cerebrovascular). It is characterized by the narrowing (stenosis) and/or closing (occlusion) of the carotid artery inside the skull, the major artery that del...

Moyamoya syndrome is a progressive disorder that affects the blood vessels in the brain (cerebrovascular). It is characterized by the narrowing (stenosis) and/or closing (occlusion) of the carotid artery inside the skull, the major artery that del...

Mucha-Habermann disease, also known as pityriasis lichenoides et varioliformis acuta or PLEVA, is a rare skin disorder. The lesions most often appear on the trunk and the arms and legs. Lesions tend to develop in small groups. Mucha-Habermann dise...

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...

Nasopharyngeal cancer is a disease in which malignant (cancer) cells form in the tissues of the nasopharynx. The nasopharynx is the upper part of the pharynx (throat) behind the nose. The pharynx is a hollow tube about 5 inches long that s...

Nasopharyngeal cancer is a disease in which malignant (cancer) cells form in the tissues of the nasopharynx. The nasopharynx is the upper part of the pharynx (throat) behind the nose. The pharynx is a hollow tube about 5 inches long that s...

Pain located in the neck is a common medical condition. Neck pain can come from a number of disorders and diseases and can involve any of the tissues in the neck. Examples of common conditions causing neck pain are degenerative disc disease, neck ...

Henoch-Schonlein purpura is a rare inflammatory disease of the small blood vessels (capillaries) and is usually a self-limited disease. It is the most common form of childhood vascular inflammation (vasculitis) and results in inflammatory changes ...

Norovirus is a highly contagious virus that causes gastroenteritis, which is inflammation of the stomach and intestines. It is commonly referred to as the "stomach flu" or "winter vomiting bug" because it often causes symptoms such as vomiting, di...

Tolosa-Hunt syndrome is a rare disorder characterized by severe periorbital headaches, along with decreased and painful eye movements (ophthalmoplegia). Symptoms usually affect only one eye (unilateral). In most cases, affected individuals experie...

Tolosa-Hunt syndrome is a rare disorder characterized by severe periorbital headaches, along with decreased and painful eye movements (ophthalmoplegia). Symptoms usually affect only one eye (unilateral). In most cases, affected individuals experie...

Optic neuritis is an inflammation of the optic nerve, which is the nerve that carries visual information from the eye to the brain. Symptoms of optic neuritis include sudden vision loss, pain in the eye, and color vision changes. Optic neuritis is...

Narcolepsy is a neurological sleep disorder characterized by chronic, excessive attacks of drowsiness during the day, sometimes called excessive daytime sleepiness (EDS). Attacks of drowsiness may persist for only a few seconds or several minutes....

Pheochromocytomas are a type of tumor of the adrenal glands that can release high levels of epinephrine and norepinephrine. As the name implies, the adrenalglands are located near the "renal" (kidney) area.  One adrenal gland sits on top of e...

Photokeratitis is a painful eye condition caused by exposure to ultraviolet (UV) radiation. It is sometimes referred to as "snow blindness" or "welder's flash." Symptoms of photokeratitis include redness, tearing, pain, and temporary vision loss. ...

Pineal cysts are benign (non-cancerous) fluid-filled sacs located in the region of the brain that contains the pineal gland. Small pineal cysts (.5 cm or smaller) are common occurrences, often found incidentally on routine neurological exams. Smal...

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...

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...

Preeclampsia is a pregnancy complication characterized by high blood pressure and signs of damage to another organ system, most often the liver and kidneys. Preeclampsia usually begins after 20 weeks of pregnancy in women whose blood pressure had ...

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...

A pituitary tumor is a tumor that forms in the pituitary gland near the brain that can cause changes in hormone levels in the body. This illustration shows a smaller tumor (microadenoma). Pituitary tumors are abnormal growths that develop ...

Pseudotumor cerebri literally means "false brain tumor." It is likely due to high pressure within the skull caused by the buildup or poor absorption of cerebrospinal fluid (CSF). The disorder is most common in women between the ages of 20 and 50....

Pulmonary edema is a disease that is caused due to congestion of liquid substances in the lungs. It is also known as pulmonary congestion. It is related to our respiratory system. When you get this disease, there may be a high risk of respiratory ...

Pleuropulmonary blastoma (PPB) is a rare childhood cancer occurring in the chest, specifically in the lungs or in the coverings of the lungs called "pleura". PPB occurs almost exclusively in children under the age of approximately 7-8 years and ra...

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...

Rabies is a viral disease that affects the central nervous system of mammals, including humans. It is usually transmitted through the bite of an infected animal, such as a dog, bat, raccoon, or fox. Rabies is a serious and often fatal disease if n...

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, ...

Respiratory syncytial virus (RSV) infection is a common respiratory virus that causes cold-like symptoms. It commonly affects infants by the time they reach the age of two.  Respiratory syncytial virus (RSV) infection symptoms ...

Japanese Encephalitis is a severe inflammation of the brain caused by the Japanese B Encephalitis Virus that is transmitted by the bite of infected mosquitoes in certain areas of the world, particularly Asia. This disorder most commonly affects ch...

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...

Sleep apnea is defined as a reduction or cessation of breathing during sleep. The three types of sleep apnea are central apnea, obstructive apnea, and a mixture of central and obstructive apnea. Central sleep apnea is caus...

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...

General DiscussionSneddon syndrome is a rare progressive disorder affecting the blood vessels characterized by the association of a skin condition and neurological abnormalities. Characteristics include multiple episodes of reduced blood ...

Sneddon syndrome is a rare progressive disorder affecting the blood vessels characterized by the association of a skin condition and neurological abnormalities. Characteristics include multiple episodes of reduced blood flow to the brain (cerebral...

Spinal headaches are a fairly common complication in those who undergo a spinal tap (lumbar puncture) or spinal anesthesia. Both procedures require a puncture of the membrane that surrounds the spinal cord and, in the lower spine, the lumbar and s...

Introduction The superior vena cava is a large vein located in the upper chest, which collects blood from the head and arms and delivers it back to the right atrium of the heart. If this vein is compressed by outside structures, or if a th...

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...

Cryptococcosis is caused by a fungus known as Cryptococcosis neoformans. The infection may be spread to humans through contact with pigeon droppings or unwashed raw fruit. Contact with an infected individual may also spread the infection. Individu...

Torulosis is an airborne disease. It is more famously referred to as cryptococcosis. When you inhale infected dust, torulosis slowly spreads throughout your lungs, presenting as pneumonia. It could potentially be fatal. Sometimes, i...

Toxoplasmosis is an infection caused by the parasite Toxoplasma gondii. It is most commonly spread through contact with infected cat feces, but can also be spread through contaminated food or water, or from mother to baby during pregnancy. Symptom...

Toxoplasmosis is a disease caused by the Toxoplasma gondii parasite. It is commonly found in cat feces and can also be present in contaminated soil, water, and raw or undercooked meat. In healthy individuals, toxoplasmosis may cause mild flu-like ...

Typhoid fever is a bacterial infection caused by Salmonella typhi bacteria. It is a serious illness that can be life-threatening if not treated promptly. Symptoms of typhoid fever include high fever, weakness, stomach pain, headache, and loss of a...

Urticaria pigmentosa is a rare skin disorder that is a localized (cutaneous) form of mastocytosis. Some clinicians suggest that urticaria pigmentosa is the childhood form of mastocytosis. Mast cells are specialized cells of connective tissue that ...

General DiscussionVACTERL association is a nonrandom association of birth defects that affects multiple median and para-median structures. The term VACTERL is an acronym with each letter representing the first letter of one of the more co...

General DiscussionVACTERL association is a nonrandom association of birth defects that affects multiple median and para-median structures. The term VACTERL is an acronym with each letter representing the first letter of one of the more co...

Nephrogenic diabetes insipidus (NDI) is a rare kidney disorder that may be inherited or acquired. NDI is not related to the more common diabetes mellitus (sugar diabetes), in which the body does not produce or properly use insulin. NDI is a distin...

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...

Weil syndrome, a rare infectious disorder, is a severe form of the bacterial infection caused by Leptospira bacteria known as leptospirosis. Weil syndrome is characterized by dysfunction of the kidneys and liver, abnormal enlargement of the liver ...

Whiplash is a relatively common injury that is often ignored or mistreated due to lack of understanding of the condition. Whiplash is usually the result of a rear impact while in a stationary position. Early range of motio...

Yellow fever is a viral infection that is transmitted through the bite of infected mosquitoes. The virus is primarily found in tropical and subtropical areas of Africa and South America. Symptoms of yellow fever can include fever, headache, muscle...

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. ...