In-depth

Acute coronary syndrome

Acute coronary syndrome occurs when there isn't enough blood flowing through your heart. It can be felt as chest pain (angina) or a heart attack.

Acute kidney failure

Acute kidney failure is the sudden loss of your kidneys' ability to filter waste from your bloodstream. Correcting the underlying cause increases the likelihood of recovery.

Addison's disease

Addison's disease occurs when your adrenal glands produce insufficient amounts of certain important hormones. Treatment may include taking corticosteroids.

Agoraphobia

Do you feel trapped in your own home? Do you worry about having a panic attack? Find out how agoraphobia can be treated.

Airplane ear

Airplane ear, a problem with air pressure in the middle ear, can cause pain and muffled hearing. It can usually be treated with self-care techniques.

Alcohol intolerance

Think you have alcohol intolerance? Here's what might be causing your reaction to wine, beer or other beverages.

Alcohol poisoning

Alcohol poisoning occurs when you drink large amounts of alcohol in a short period of time. Potentially fatal, alcohol poisoning requires emergency medical care.

Alcoholic hepatitis

Alcohol can severely damage your liver — even moderate drinkers aren't immune. Learn more about this serious liver disease.

Alcoholism

Alcoholism is a physical and psychological dependence on alcohol that can cause serious health and social problems. But treatment can help.

Amniotic fluid embolism

Amniotic fluid embolism — Overview covers definition, symptoms and treatment of this pregnancy or post-pregnancy condition.

Anaphylaxis

Anaphylaxis is the most serious type of allergic reaction. It often occurs rapidly after exposure to an allergen and may be life-threatening.

Angina

Angina is a common type of chest pain caused by coronary artery disease. Unstable angina can be a warning sign of a heart attack.

Antibiotic-associated diarrhea

Antibiotics save lives, but they can also have side effects. The most common are mild to severe diarrhea and a serious type of colitis.

Appendicitis

Ascariasis

Ascariasis is a common type of roundworm infection found worldwide. It's spread by poor hygiene and improper sanitation. Infections are effectively treated with medication.

Autoimmune hepatitis

Autoimmune hepatitis — Early detection, medications can help.

Bee stings

Bee stings — Comprehensive overview covers prevention, treatment of bee stings.

Benign paroxysmal positional vertigo (BPPV)

Benign paroxysmal positional vertigo involves brief episodes of dizziness when your head is placed in particular positions. The condition is easily treated.

Bile reflux

Bile reflux — the backwash of bile from the small intestine into the stomach and esophagus — can cause ongoing inflammation and lead to serious complications.

Bird flu (avian influenza)

A type of influenza normally found in birds, bird flu first appeared in humans in 1997. Experts worry it could lead to a flu pandemic.

Blastocystis hominis infection

A microscopic parasite causes Blastocystis hominis infection. Experts disagree as to whether this infection causes diarrhea and other associated signs and symptoms.

Blind loop syndrome

Blind loop syndrome occurs when a portion of bowel is bypassed. The condition is most often a complication of abdominal surgery.

Botulism

Botulism, a rare and dangerous condition, is usually the result of eating food — often canned goods contaminated by bacteria that release a powerful toxin.

C. difficile

C. difficile can be a life-threatening infection. It typically develops when antibiotics destroy other bacteria in your intestines, allowing C. difficile to flourish.

Carbon monoxide poisoning

Carbon monoxide is a colorless, odorless gas. But the danger it poses is real. Consider simple tips to prevent carbon monoxide poisoning.

Carcinoid tumors

Carcinoid tumors are rare, slow-growing cancerous tumors that most often occur in the gastrointestinal tract or in the lungs.

Cardiogenic shock

Cardiogenic shock is a life-threatening complication usually of a heart attack. Cardiogenic shock treatments can be effective, but must be provided immediately.

Castleman disease

Castleman disease is a rare illness that affects your lymph nodes and other immune-cell structures of your body.

Celiac disease

Celiac disease is an immune reaction to gluten, a protein found in certain foods. As a result, the body is unable to absorb some important nutrients.

Chest pain

Chest pain can be frightening, but it doesn't always indicate a heart attack.

Cholecystitis

Cholecystitis is an inflammation of the gallbladder that's often linked to gallstones.

Cholera

Cholera causes severe diarrhea and can kill in a matter of hours, yet can be easily treated with oral or intravenous fluids.

Chronic daily headaches

Chronic daily headaches strike nearly every day. Aggressive initial treatment and steady, long-term management can help reduce pain and lead to fewer headaches.

Chronic kidney disease

Chronic kidney disease, often caused by diabetes or high blood pressure, is the gradual loss of kidney function. Early detection and treatment can help.

Chronic sinusitis

Chronic sinusitis involves long-term inflammation or infection of the sinus cavities. Medications can help, and in rare cases surgery can treat this painful condition.

Churg-Strauss syndrome

Churg-Strauss syndrome is a rare disorder marked by blood vessel inflammation that affects organs throughout the body. Asthma is the most common sign.

Concussion

Concussions can be serious injuries that need sufficient time to heal.

Congenital adrenal hyperplasia

Congenital adrenal hyperplasia is a genetic condition affecting the adrenal glands and interfering with normal growth and development in boys and girls.

Constipation in children

Constipation in children is common. Often, simple changes in diet and routine are helpful.

Cryptosporidium infection

Cryptosporidium infection may cause diarrhea in healthy people, but for people with HIV/AIDS and weakened immune systems, the illness can cause serious complications.

Cyclic vomiting syndrome

Cyclic vomiting syndrome can last for hours or days and shares many triggers with migraines.

Cyclospora infection

Cyclospora infection is an uncommon foodborne intestinal infection that causes diarrhea. Outbreaks have been linked to contaminated water and produce.

Dengue fever

Dengue fever is a sometimes fatal viral disease spread by mosquitoes in tropical and subtropical areas of the world. Learn how to protect yourself.

Diabetes insipidus

Diabetes insipidus is a rare condition characterized by intense thirst and the excretion of large amounts of urine.

Diabetic coma

A diabetic coma is a medical emergency. Minimize the effects with prompt treatment.

Diabetic ketoacidosis

Diabetic ketoacidosis is a serious diabetes complication. Learn the warning signs — and know when to seek emergency care.

Diabetic neuropathy

Diabetes can damage nerves throughout your body — a condition known as diabetic neuropathy. Nerve damage can cause pain, disability and other serious complications.

Drug allergy

Drug allergy can occur with many medications. Find out what you can do to recognize and avoid potentially dangerous reactions.

Dumping syndrome

Dysphagia

Difficulty swallowing can be painful and may indicate a serious medical problem.

Ear infection (middle ear)

Ear infections are common in children. These bacterial or viral infections of the middle ear can cause mild to severe ear pain.

Ebola virus and Marburg virus

Ectopic pregnancy

An ectopic pregnancy can't continue normally — but prompt treatment can help prevent life-threatening blood loss.

Egg allergy

Egg allergy can cause a serious reaction in children and adults. Here's how to recognize egg allergy symptoms, and what to do if a severe reaction occurs.

Ehrlichiosis

Ehrlichiosis is a tick-borne disease that causes flu-like symptoms. When you're outdoors, be aware of steps to prevent tick bites.

Encephalitis

Encephalitis is inflammation of the brain usually caused by a viral infection. Severe cases can cause brain damage, even death.

Endometriosis

Endometriosis is a common and often painful disorder in which tissue that normally lines the inside of your uterus grows outside your uterus.

Enlarged liver

You can get an enlarged liver from a number of medical problems or personal habits. Treatment depends on what's causing the enlargement.

Esophagitis

Several conditions can cause esophagitis. Learn what they are and how to get relief.

Exercise headaches

You know exercise is good for you. But did you know that exertion can leave you with a pounding headache?

Food allergy

Food allergy symptoms can make you miserable. Unfortunately, there's no cure — but there are steps you can take to keep your symptoms in check.

Food poisoning

Food poisoning has many forms, and some can be serious. Here's how to recognize food poisoning and ways to prevent getting sick.

Giardiasis

Giardia infection is a common waterborne illness. Learn the symptoms and reduce your risk.

Glaucoma

Glaucoma is a group of eye conditions that, left untreated, can seriously damage your optic nerve and lead to blindness.

Hangovers

Hangovers are the unwelcome result of drinking too much alcohol. However unpleasant, most hangovers go away on their own within eight to 24 hours.

Hantavirus pulmonary syndrome

Hantavirus pulmonary syndrome is initiated by a rodent-carried virus that infects the lung tissues, bringing on flu-like symptoms, respiratory problems and even death.

Headaches in children

Children of all ages experience headaches, but the causes aren't all the same. Here's how to help your child.

Heart attack

Heart failure

Heart failure means your heart can't efficiently pump blood throughout your body. Medications, and sometimes devices or surgery, can help you manage this condition.

Heat exhaustion

Heat exhaustion occurs when your body overheats, usually as a result of hot, humid weather. It's preventable, but can be dangerous if not treated.

Hemolytic uremic syndrome (HUS)

Hemolytic uremic syndrome is an uncommon condition that can cause life-threatening kidney failure, especially for children and older adults.

Hemophilia

Hemophilia occurs when your body lacks one of several clot-forming proteins called clotting factors. The result is prolonged bleeding, which can be life-threatening.

Henoch-Schonlein purpura

Henoch-Schonlein purpura causes inflammation of small blood vessels (vasculitis) and often a purplish rash. It's most common in children ages 2 to 6.

Hepatitis A

Hepatitis A virus causes a highly contagious liver infection. Find out how to recognize it and when treatment is required.

Hepatitis B

Having hepatitis B increases your risk of serious liver disease. Protect yourself with a hepatitis B vaccine.

Hepatitis C

Hepatitis C is a highly infectious disease that's usually contracted from contaminated blood.

Hirschsprung's disease

Hirschsprung's disease, a disease of the colon, is present at birth and can cause serious problems passing stool.

Hydrocele

A hydrocele is a generally harmless fluid-filled sac that surrounds a testicle, causing scrotal swelling. However, it may indicate a more serious condition.

Hyperglycemia in diabetes

Hyperglycemia in diabetes — Comprehensive overview covers causes, symptoms and treatments of high blood sugar.

Hyponatremia

Indigestion

Indigestion can ruin meals and make you feel uncomfortable. Take steps to prevent symptoms like upset stomach, bloating and pain.

Infant reflux

Spit up happens. Often, changes in feeding technique help keep reflux under control.

Intestinal ischemia

Intestinal ischemia occurs when the blood supply to your digestive system is reduced. Abdominal pain is a common symptom. Several treatment options are available.

Intestinal obstruction

Intestinal obstruction — a serious condition that requires prompt medical attention — occurs when a blockage of the intestine prevents food or fluid from passing through.

Intussusception

A rare but serious disorder, intussusception occurs when one part of the intestine slides into an adjacent part, often causing intestinal obstruction.

Kawasaki disease

Kawasaki disease — the leading cause of acquired coronary disease in children — causes artery wall inflammation throughout the body. It affects children younger than age 5.

Kidney stones

Kidney stones often recur. Find out what causes kidney stones and how to prevent them.

Krabbe disease

Krabbe disease is a rare, inherited disorder — most often affecting infants — that impairs functioning of the central nervous system and usually leads to early death.

Lactose intolerance

Lactose intolerance means you can't fully digest milk sugar (lactose). Though it's generally not dangerous, the symptoms can be uncomfortable.

Legionnaires' disease

Legionnaires' disease, a severe form of pneumonia, is caused by bacteria that can live in water in air conditioning systems, showers and spas.

Listeria infection

Most people exposed to listeria don't become ill. But for those at risk of a listeria infection — a foodborne illness — the consequences can be severe.

Liver cancer

The risk of liver cancer may be reduced by protecting yourself from serious liver diseases such as cirrhosis and hepatitis B and C.

Liver hemangioma

Liver hemangioma is the most common type of noncancerous (benign) liver mass. Learn how doctors treat liver hemangioma.

Low blood pressure (hypotension)

Low blood pressure (hypotension) can be a sign of good health or of a life-threatening condition. Find out more about hypotension's causes and treatment options.

Malaria

Malaria is one of the oldest diseases on Earth and is still one of the leading killers.

Meningitis

Fever, headache and stiff neck are common signs and symptoms of meningitis — an infection of the membranes and fluid surrounding the brain and spinal cord.

Menstrual cramps

A monthly period is bad enough. Add in painful menstrual cramps, and you may be cursing this thing called womanhood. How do you get relief?

Mesenteric lymphadenitis

Mesenteric lymphadenitis is an inflammation of the lymph nodes in the tissue that attaches various organs to your abdominal wall (mesentery). It mainly affects children.

Migraine

A migraine isn't an ordinary headache. In addition to severe head pain, it can cause nausea, vomiting, and extreme sensitivity to light and sound.

Molar pregnancy

Molar pregnancy — Comprehensive overview covers symptoms, treatment of this tumor in the uterus.

Morning sickness

Morning sickness is common in pregnancy. Learn what to expect and how to relieve your symptoms.

Multiple myeloma

Multiple myeloma is cancer of your bone marrow plasma cells. The disease can make you prone to infections and damage your bones and kidneys.

Myocardial ischemia

Myocardial ischemia is a heart problem that occurs when blood flow to your heart muscle is decreased, reducing the heart's oxygen supply.

Naegleria infection

Summertime freshwater swimming may put you at risk of this rare but often fatal infection. Learn more about your risks and how to protect yourself.

Nonulcer stomach pain

Nonulcer stomach pain, a type of indigestion, commonly causes pain or discomfort in your upper abdomen.

Norovirus infection

Noroviruses cause an intestinal flu-like illness that typically resolves within days. Norovirus infection is highly contagious, especially in closed settings like hospitals and cruise ships.

Orchitis

Orchitis, a painful inflammation of one or both testicles, may be caused by the mumps virus or a bacterial infection.

Orthostatic hypotension (postural hypotension)

Orthostatic hypotension (postural hypotension) is a form of low blood pressure that occurs when you stand up.

Ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) — Comprehensive overview covers symptoms, treatment of this complication of infertility treatment.

Pancreatic cysts

Most cysts in the pancreas aren't malignant, but tests are needed to determine the best course of treatment.

Pancreatitis

The pain of pancreatitis, an inflammation of the pancreas, can last for days, or in chronic cases, for years. Pancreatitis can lead to serious complications.

Panic attacks

Panic attacks can make you feel like you're having a heart attack. Learn how to manage these intense bursts of fear.

Parvovirus infection

Parvovirus infection is a common childhood illness with a distinctive cheek rash. In some adults, including some pregnant women, it can be serious.

Peanut allergy

Peanut allergy can be serious. Find out what you need to know to prevent a life-threatening reaction.

Peptic ulcer

Peptic ulcers are painful sores that commonly affect the lining of your stomach and upper small intestine. The most frequent cause is a treatable infection.

Peritonitis

Peritonitis is an infection of the membrane that lines your inner abdominal wall and covers the organs within your abdomen (peritoneum).

Pinworm infection

Pinworms are intestinal parasites common in children and easily spread within families. Effective treatments include medications and good hygiene.

Pituitary tumors

Pituitary tumors are abnormal growths in the pituitary gland in the brain. Most are noncancerous (benign). Some may cause overproduction of hormones and associated problems.

Plague

Plague is a disease carried by rats and other rodents. The risk of developing plague is low, and most cases occur in Africa.

Polio

One of the most feared diseases of the 20th century, polio has been eradicated from the developed world but remains a threat in less developed nations.

Polymorphous light eruption

Polymorphous light eruption is a sun-induced skin rash affecting people who develop a sensitivity to sunlight.

Porphyria

Porphyria is a group of inherited disorders that result from buildup of natural chemicals call porphyrins, which can cause nervous system and skin problems.

Postpartum preeclampsia

Postpartum preeclampsia — Comprehensive overview covers symptoms and treatment of this post-pregnancy condition.

Pseudomembranous colitis

Pseudomembranous colitis is an inflammation of the colon that occurs most often in people using antibiotics.

Pseudotumor cerebri

Pseudotumor cerebri — Comprehensive overview covers symptoms, causes, treatment of increased pressure inside the skull.

Pyloric stenosis

Comprehensive overview covers symptoms, treatment of this uncommon digestive condition in infants.

Radiation sickness

Radiation sickness is the effect of high doses of radiation on the body. The severity of illness depends on how much radiation the body absorbs.

Rocky Mountain spotted fever

Rocky Mountain spotted fever is a potentially serious bacterial infection transmitted to humans by tick bites. Prompt medical treatment is necessary.

Rotavirus

Rotavirus causes severe diarrhea in infants and children. Most cases can be treated at home with extra fluids.

Ruptured eardrum

A ruptured eardrum causes hearing loss and can give bacteria easy access to your middle ear. A ruptured eardrum usually heals without treatment.

Salmonella infection

Salmonella infection will cause only diarrhea and stomach pain in some people, but for infants and immunocompromised people, this bacterial illness can cause life-threatening complications.

Scarlet fever

Scarlet fever is a bacterial infection that causes a rash, fever and sore throat and usually affects children and adolescents.

Shaken baby syndrome

Shaken baby syndrome — Comprehensive overview covers symptoms, treatment of this serious brain injury.

Shellfish allergy

Smallpox

Social anxiety disorder

Intense fear and avoidance of social situations can be debilitating. Take action to avoid long-term consequences caused by worry and isolation.

Spider bites

Spider bites — Comprehensive overview covers symptoms, complications, treatment of spider bites.

Spinal headaches

Spinal headaches may occur after a spinal tap or spinal anesthesia. The pain can be severe, but treatment is available.

Spontaneous coronary artery dissection

Find out about this rare cause of heart attack in young, healthy people.

Stomach cancer

Reduce your risk of stomach cancer by eating more fruits and vegetables.

Strep throat

Strep throat is a bacterial throat infection. It typically causes a very sore throat and is treated with antibiotics.

Sudden cardiac arrest

Sudden cardiac arrest is a medical emergency. Rapid treatment improves your chances of survival.

Swine flu (H1N1 flu)

Swine flu — Comprehensive overview covers swine flu symptoms, tests, treatment and prevention.

Tapeworm infection

Tapeworms most commonly enter your body through contaminated food or water. Symptoms aren't always present, but the prognosis is good with prompt diagnosis and treatment.

Testicular torsion

Testicular torsion blocks blood flow to a testicle. Know the signs of this painful condition — and when to see a doctor.

Thunderclap headaches

Thunderclap headaches strike suddenly. Immediate medical attention is essential. Some thunderclap headaches signal a life-threatening condition.

Toxic hepatitis

Toxic hepatitis is liver damage that occurs when your liver isn't able to break down certain toxins — including common pain relievers such as Tylenol.

Traumatic brain injury

While mild traumatic brain injury generally results in few long-term problems, more severe injury can cause several physical, emotional, behavioral, communication and cognitive problems.

Traveler's diarrhea

Traveler's diarrhea is unpleasant. Find out how to avoid this travel-related health problem.

Tularemia

Tularemia is a rare, highly infectious disease spread by insects and wild animals. Landscapers, hunters and laboratory workers are especially at risk.

Vasovagal syncope

Vasovagal syncope (fainting) is a sudden and brief loss of consciousness that occurs when the blood flow to your brain is markedly reduced.

Ventricular fibrillation

Ventricular fibrillation is a life-threatening heart rhythm disturbance that requires immediate treatment. Find out more.

Whooping cough

Whooping cough is a serious lung infection that's especially dangerous in young infants.

Wilson's disease

In Wilson's disease, the body doesn't metabolize copper properly, causing excess amounts to accumulate in the liver and other organs.

Zollinger-Ellison syndrome

In Zollinger-Ellison syndrome, tumors in the pancreas or duodenum secrete a hormone called gastrin that leads to excessive stomach acid and ulcers.

May. 14, 2011