Influenza (flu) is a very contagious viral infection that affects the air passages of the lungs. It causes a high fever, body aches, a cough, and other symptoms.

Detailed information on ingrown hairs, including symptoms, diagnosis, and treatment

A hernia is when a part of the intestine pushes through a weak spot in the belly (abdominal) muscles. The hernia creates a soft lump or bulge under the skin.

An inguinal hernia is when part of your intestine pushes through a weak spot in your lower belly (abdominal) wall. This area is called the groin. The hernia creates a lump in your groin. Over time, the hernia may get bigger.

A hernia occurs when a part of the intestine pushes through a weakness in the belly (abdominal) muscles. A hernia in the groin area is called an inguinal hernia.

Detailed information on bee stings and other insect stings, including symptoms and treatment

Insect stings can occur anywhere on the body and can be painful and frightening for a child. Most insect stings cause only minor discomfort. Most stings are from honeybees or yellow jackets, also called ground hornets.

Insomnia is trouble falling to sleep or staying asleep. One in 3 adults has bouts of insomnia.

Tumors on your pancreas, called insulinomas, make extra insulin, more than your body can use. This causes blood sugar levels to drop too low. This can cause symptoms of low blood sugar or hypoglycemia.

Intensity modulated radiation therapy is a type of radiation therapy for treating hard-to-reach tumors. It uses 3-D imaging technology, allowing doctors to adjust the radiation beam and strength based on a tumor's size, shape and ...

Intensive behavioral therapy is a treatment for obesity. Through this treatment

Interstitial cystitis is an inflamed or irritated bladder wall. It can lead to scarring and stiffening of the bladder. The bladder can’t hold as much urine as it did in the past. It is an ongoing (chronic) disorder.

Interstitial lung disease is the name for a group of more than 200 chronic lung disorders. These diseases inflame or scar the lungs. The inflammation and scarring make it hard to get enough oxygen. The scarring is called pulmonary ...

Intestinal malrotation is a birth defect. It happens when your baby’s intestinal tract doesn’t form as it should during pregnancy. Malrotation happens when your baby’s intestine doesn’t turn like it should.

If your healthcare provider determines that you have an intestinal obstruction, it means that something is blocking your intestine. Food and stool may not be able to move freely. Read on to learn more about this condition, including ...

An intra-abdominal abscess is a collection of pus or infected fluid that is surrounded by inflamed tissue inside the belly.

An intra-aortic balloon pump (IABP) is a type of therapeutic device. It helps your heart pump more blood. You may need it if your heart is unable to pump enough blood for your body.

Intracranial stenosis, also known as intracranial artery stenosis, is the narrowing of an artery in the brain, which can lead to a stroke. The narrowing is caused by a buildup and hardening of fatty deposits called plaque. This process ...

Spontaneous intracranial hypotension is probably an under diagnosed cause of headache, even though its estimated to affect only about one in 50,000 individuals. The symptoms may include headache, neck stiffness and arm pain.

Intraoperative radiation therapy is radiation treatment that takes place in the operating room immediately after tumor removal. Patients receive their entire course of radiation therapy in one dose, while still under anesthesia. Doctors ...

An intravenous pyelogram is an imaging test used to look at the kidneys and ureters. The ureters are the narrow tubes that carry urine from the kidneys to the bladder.

Intraventricular hemorrhage (IVH) is bleeding inside or around the ventricles in the brain. The ventricles are the spaces in the brain that contain the cerebral spinal fluid.

Intussusception is a serious problem in the intestine. It occurs when one part of the intestine slides inside another part. The intestine then folds into itself like a telescope. This creates a blockage or obstruction. It stops food that...

Invasive ductal breast cancer (IDC), also known as infiltrating ductal carcinoma, is the most common form of invasive breast cancer and represents 80 percent of breast cancer cases. The condition begins with abnormal cells forming in the...

Invasive lobular breast cancer (ILC), also known as infiltrating lobular carcinoma, is the second most common form of invasive breast cancer. It makes up 10 to 15 percent of breast cancer cases. The condition begins when abnormal cells ...

Iritis is the inflammation of your iris and the anterior chamber of your eye. Iritis can lead to serious problems. It can cause severe vision loss and even blindness.

Iron deficiency and anemia are common after a gastric bypass or other weight-loss surgery, especially in women. In fact, iron deficiency can occur in more than half of women who are past menopause when they have this surgery.

The most common cause of anemia is a lack of iron. This is called iron deficiency.

Anemia is a common health problem in children. The most common cause of anemia is not getting enough iron. A child who is anemic does not have enough red blood cells or enough hemoglobin.

Irritable bowel syndrome (IBS) is a disorder that affects your large intestine or colon. When you have IBS your colon looks normal. But it does not work the way it should.