In-depth

Twisting the knee can cause a common knee injury known as a torn meniscus. Treatment sometimes includes surgery.

Abdominal aortic aneurysm

An abdominal aortic aneurysm is a dangerous condition in which a part of your body's main artery (aorta) is enlarged and in danger of rupturing.

Absence seizure

Absence seizures typically last only a few seconds, but can occur dozens of times a day.

ACL injury

An active life that includes sports may also include the risk of a torn ACL. Reduce your risk, and know when to get treatment.

Acoustic neuroma

Acoustic neuroma is a benign tumor that grows on the balance and hearing nerve in the head. Pressure on the nerve may cause hearing loss.

Acromegaly

Acromegaly is an uncommon hormonal disorder caused by the overproduction of growth hormone. It typically causes signs such as enlarged hands and feet.

Acute sinusitis

Acute sinusitis occurs when your sinus cavities become inflamed. Antibiotics, decongestants and corticosteroids may relieve pain and congestion and prevent development of chronic sinusitis.

Addison's disease

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

Adenomyosis

Adenomyosis can cause painful, excessive bleeding during menstrual periods. Explore symptoms and treatment.

Alcoholic hepatitis

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

Amenorrhea

Although the absence of menstruation (amenorrhea) is seldom serious, the condition can often be linked to an underlying problem requiring treatment.

Amnesia

Amnesia is much more common in fictional characters than in real people. Causes include stroke, brain inflammation and alcoholism.

Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) — often known as Lou Gehrig's disease — is a degenerative condition causing loss of control of voluntary muscles.

Anal cancer

Though anal cancer is rare, incidence of anal cancer is increasing. Find out the symptoms and causes of cancer of the anal canal.

Ankylosing spondylitis

Ankylosing spondylitis is an inflammatory arthritis that affects your spine and nearby joints. Over time, your spine may become stiff and immovable.

Aphasia

People with aphasia have difficulty speaking, comprehending speech, reading or writing. Read tips to make communication easier.

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.

Ataxia

Ataxia describes lack of muscle coordination while performing voluntary movements. A sign of an underlying condition, ataxia can affect any part of your body.

Atrial septal defect

Atrial septal defect (ASD) is an abnormal opening between the heart's upper pumping chambers. It's common and readily treated.

Atypical hyperplasia of the breast

Atypical hyperplasia is one link in the chain of progression toward breast cancer. Learn how having this condition increases your breast cancer risk.

Avascular necrosis

Loss of blood flow to a bone leads to avascular necrosis — the death of bone tissue. This most commonly affects the thighbone, causing groin pain.

Back pain

Back pain is a common reason for health care visits and missed work. Home treatment and proper body mechanics can help you feel better.

Baker's cyst

A Baker's cyst is a swollen area behind your knee. Treating the primary cause — such as arthritis or a cartilage tear — usually helps relieve pain.

Bell's palsy

Bell's palsy occurs when an impaired nerve results in facial weakness or paralysis. Most people experience a full recovery.

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.

Bladder cancer

Bladder cancer is often diagnosed early — when it's most treatable. But even with successful treatment, bladder cancer survivors need follow-up tests for years to come.

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.

Blood in urine (hematuria)

Blood in your urine isn't usually serious. But any urinary bleeding lasting more than a day or two should be checked by your doctor.

Bone cancer

Bone cancer is an uncommon type of cancer that begins in a bone. It can affect both adults and children.

Bone metastasis

Bone metastasis occurs when cancer spreads to the bones.

Bone spurs

Bone spurs can sometimes interfere with joint function or press on nerves.

Brachial plexus injury

Brachial plexus injuries affect the nerves that control your arms and hands. Serious injuries require early diagnosis for successful treatment.

Breast cancer

Breast cancer is the disease that many women fear most. But early detection and lifestyle changes may reduce your risk.

Broken ankle/broken foot

Broken leg

Broken leg — Comprehensive overview covers symptoms, diagnosis and treatment of this type of fracture.

Broken ribs

A broken rib, or fractured rib, is a common injury that occurs when one of the bones in your rib cage breaks or cracks.

Brucellosis

Brucellosis is an infectious disease that spreads from animals to people, mainly via unpasteurized dairy products. Travelers should take special care to avoid infection.

Burning mouth syndrome

Burning mouth syndrome can feel as if you scalded your mouth with hot coffee. Treatment depends on the cause, which can be difficult to identify.

Cancer

Learn about cancer, what it looks like and what causes it.

Carcinoid tumors

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

Castleman disease

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

Cerebral palsy

Cerebral palsy — Comprehensive overview covers symptoms, causes and treatment of this movement disorder.

Cervical cancer

Cervical cancer is a common and often preventable reproductive cancer. Find out what cervical cancer is and how it's treated.

Cervical dystonia

Cervical dystonia is a neurological movement disorder affecting your neck. This painful condition occurs in children and adults and is most common in women.

Cervical spondylosis

Cervical spondylosis is a chronic degeneration of the bones and disks of the neck, most likely caused by aging and wear and tear.

Chest pain

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

Chiari malformation

Chiari malformation is an uncommon condition in which brain tissue extends into the spinal canal, causing headaches and other potentially serious symptoms.

Childhood schizophrenia

Childhood schizophrenia is confusing and heart wrenching. Learn about managing this serious psychotic disorder.

Chondromalacia patella

Chondromalacia patella is a knee condition that plagues many runners. It's often caused by overuse or injury.

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 exertional compartment syndrome

Don't ignore exercise-related pain, pressure or numbness, because it may indicate chronic exertional compartment syndrome. Proper treatment can get you back to your favorite sport.

Chronic pelvic pain in women

Chronic pelvic pain is pain in your pelvic region — the area below your bellybutton and between your hips — that lasts six months or longer.

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.

Claudication

Don't ignore leg pain that starts when you exercise and stops when you rest. It could be claudication. Understand its causes and treatments.

Cluster headache

Cluster headaches usually occur repeatedly on one side of your head and cause intense pain that feels like a stabbing sensation in your eye.

Coarctation of the aorta

Coarctation of the aorta is a cardiovascular defect resulting in a narrowing of the aorta, the blood vessel that delivers oxygen-rich blood to your body.

Coma

Coma is often a complication from a severe brain injury that leaves a person unconscious and unresponsive. Many people recover from this condition.

Complex regional pain syndrome

Complex regional pain syndrome is a chronic, painful disease that typically affects an arm or leg that was recently injured or infected.

Conjoined twins

Conjoined twins are identical twins most often joined at the chest, head or pelvis. In some cases, conjoined twins can be surgically separated.

Cough headaches

Cough headaches — so named because they're triggered by coughing — are sometimes harmless, but they may be a symptom of a serious condition.

Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease is a rare cause of dementia that progresses rapidly once symptoms develop.

Cushing syndrome

Cushing syndrome is caused by an excess of the hormone cortisol, originating from your adrenal glands or from corticosteroid medications you're taking for another illness.

Cyclic vomiting syndrome

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

Cystic fibrosis

Earlier detection and better treatments have improved the outlook for people with cystic fibrosis.

Deep vein thrombosis

Dementia

Dementia — Comprehensive overview covers symptoms, causes and treatments of this mental deterioration.

Diabetes insipidus

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

Diffuse idiopathic skeletal hyperostosis (DISH)

DISH most often occurs in the spine, but it can affect other joints in your body. Get the basics on this condition.

Dilated cardiomyopathy

Dislocated shoulder

Dislocation

A blow to your joint can dislocate the bones that meet at that joint. Don't try popping them back into place yourself. Get medical help.

Dizziness

Dizziness is one of the most common health concerns. However, few cases of dizziness are due to serious conditions.

Double uterus

Double uterus is a rare condition that sometimes goes undiagnosed throughout a woman's life. Find out how a double uterus can affect your reproductive health.

Dwarfism

Dwarfism — an adult height of 4 feet 10 inches (147 centimeters) or less — is caused by a medical or genetic condition.

Dysarthria

Dysarthria is a speech disorder caused by an inability to control or coordinate the muscles used for speaking.

Dystonia

Dystonia causes involuntary, sustained muscle contractions, resulting in repetitive movements, twisting and abnormal posture.

Ebstein's anomaly

Ebstein's anomaly is a rare heart defect. Some people may not have any symptoms, but others may need treatment, including surgery.

Eisenmenger syndrome

Eisenmenger syndrome, a complication of congenital heart defects, can be life-threatening if not properly treated. Find out more.

Encephalitis

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

Enlarged heart

Enlarged heart is often a sign of a serious heart condition. Find out causes and treatments for enlarged heart.

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.

Enlarged spleen

An enlarged spleen is usually a sign of an underlying problem. Treatment varies, depending on what's causing the enlargement.

Epilepsy

Epilepsy disrupts the normal electrical activity inside your brain. Symptoms and causes can vary, but medication is usually very effective.

Esophageal varices

Esophageal varices — enlarged veins in the esophagus — are a serious complication of liver diseases such as cirrhosis.

Exercise headaches

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

Eye melanoma

Although melanoma is commonly a type of skin cancer, it can also occur in your eye. Eye exams can often detect this rare cancer.

Fibromuscular dysplasia

Fibromuscular dysplasia is a rare, but treatable, condition in which the arteries to your kidneys, brain or abdomen narrow, reducing blood flow to your organs.

Foot drop

Foot drop is a general term used to describe difficulty lifting the front part of the foot. Treatment depends on the underlying cause.

Frontal lobe seizures

Frontal lobe seizures can produce many odd behaviors, including bicycle pedaling motions and pelvic thrusting. Seizures often occur during sleep.

Frostbite

Frostbite — Comprehensive overview covers causes, symptoms and treatments of this cold injury.

Frozen shoulder

Frozen shoulder, also known as adhesive capsulitis, is a condition characterized by stiffness, pain and limited motion in the shoulder joint.

Galactorrhea

Galactorrhea is a milky discharge from the nipple not associated with the normal milk production of breast-feeding.

Gallstones

Gallstones often don't cause symptoms. But if you have a gallbladder attack, you're not likely to forget it.

Ganglion cyst

Ganglion cysts are noncancerous fluid-filled lumps (cysts) that sometimes develop in the tendons or joints of the wrist, hand or foot.

Golfer's elbow

The pain of golfer's elbow doesn't have to keep you off the course. Here's how to get back into the swing of things.

Growth plate fractures

Growth plate fractures can interfere with your child's normal bone growth, resulting in a stunted or twisted limb. Prompt, proper care is essential.

Gynecomastia

Gynecomastia, enlarged breasts in males, is a common problem. Find out about treatments and how to cope.

Hamstring injury

Hamstring injury — Comprehensive overview covers symptoms, treatments, self-care, prevention of this leg muscle injury.

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 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.

Heart murmurs

This whooshing sound in your heart is usually harmless, but in some cases heart murmurs can alert your doctor to specific heart conditions.

Hemochromatosis

Hemochromatosis causes your body to store large amounts of iron, which can cause life-threatening complications. The simple treatment is to regularly remove blood.

Herniated disk

Back pain may mean you have a herniated disk — but not always. In fact, you can have disk herniation without pain. Here are the facts.

Hiccups

Caused by contractions of your diaphragm, hiccups are usually harmless. But rarely, hiccups may signal an underlying medical condition that requires treatment.

High potassium (hyperkalemia)

High potassium (hyperkalemia) has many possible causes, including reduced kidney function. Hyperkalemia can be life-threatening if not treated.

Hip fracture

A hip fracture is a serious injury, potentially life-threatening. But many people are able to make a good recovery.

Hodgkin's lymphoma

Hurthle cell cancer

Hurthle cell cancer is a rare type of thyroid cancer. Surgical removal of the thyroid gland is usually required.

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.

Hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is a genetic disorder in which heart muscle becomes abnormally thick. It's the most common cause of sudden cardiac death in young people.

Hypopituitarism

In hypopituitarism, your pituitary gland produces too little — or none — of one or more hormones. Disruption of any number of routine body functions can result.

Incompetent cervix

Incompetent cervix — Overview covers symptoms, risks and treatment of weak cervical tissue during pregnancy.

Inflammatory bowel disease (IBD)

Inflammatory bowel disease can be painful and debilitating, and it can cause life-threatening complications. Find out more about treating this digestive system disorder.

Inflammatory breast cancer

Inflammatory breast cancer occurs when cancer cells clog lymphatic vessels in the skin of the breast. It's a rare but deadly form of cancer.

Invasive lobular carcinoma

Invasive lobular carcinoma is a form of breast cancer that develops in a milk-producing lobule of breast tissue.

Kidney cancer

When kidney cancer is diagnosed and treated early, the chances for recovery are better.

Knee bursitis

Knee pain

Find out what could cause knee pain.

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.

Left ventricular hypertrophy

Left ventricular hypertrophy, thickening of the wall of your heart's main pumping chamber, increases your risk of cardiovascular diseases.

Legg-Calve-Perthes disease

Legg-Calve-Perthes disease is a rare childhood hip condition that requires specialty care.

Lewy body dementia

This type of dementia often causes hallucinations, delusions and fluctuating alertness.

Lipoma

A lipoma is a fatty tumor located just below the skin. Treatment usually isn't necessary.

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.

Lung cancer

Smoking increases your risk of lung cancer. Quit now and reduce your risk.

Lymphedema

Lymphedema causes swelling in an arm or a leg. It occurs when an obstruction in your lymphatic system causes a backup of lymph fluid.

Meniere's disease

Meniere's disease is an inner ear disorder that causes vertigo, hearing loss and other sensory problems. Treatment and self-care tactics can lessen its effects.

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?

Mesothelioma

Mesothelioma is a type of cancer closely linked to asbestos exposure. Find out the signs and symptoms of malignant mesothelioma and how to protect yourself.

Microcephaly

Microcephaly — Comprehensive overview covers causes and management of this rare neurological condition.

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.

Migraine with aura

Migraine with aura is a usually severe headache that's accompanied by visual disturbances, such as flashes of light, zigzagging patterns or blind spots.

Mild cognitive impairment (MCI)

Mild cognitive impairment (MCI) is a transition stage between the cognitive changes of normal aging and dementias such as Alzheimer's disease.

Morton's neuroma

Morton's neuroma is a growth of nerve tissue in your foot that may be caused by pressure or irritation. It can be painful.

Mouth cancer

Mouth cancer includes cancer that occurs in the mouth or on the lips.

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.

Myasthenia gravis

Myasthenia gravis is a condition of muscle weakness caused by a breakdown in communication between nerves and muscles. Treatments can help relieve muscle weakness.

Myelofibrosis

In myelofibrosis, healthy bone marrow is replaced with scar tissue, leading to severe anemia and fatigue.

Myocarditis

Myocarditis is a disease in which the heart muscle becomes inflamed and swollen, often as the result of an infection.

Myoclonus

Myoclonus refers to involuntary muscle jerks. Examples range from simple hiccups to the jerking movements common in epileptic seizures or cognitive disorders.

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.

Nasal polyps

Nasal polyps, inflammation-related growths in the nasal passages or sinuses, can block the flow of air and fluid in your nose.

Nasopharyngeal carcinoma

Nasopharyngeal carcinoma is rare in the United States but more common in some other parts of the world.

Neck pain

Although often eased with simple techniques at home, neck pain can sometimes be a symptom of a more serious problem requiring medical treatment.

Neuroblastoma

Neuroblastoma most commonly affects children age 5 and younger. It's the most common form of cancer in babies.

Neurofibromatosis

Neurofibromatosis — Comprehensive overview covers symptoms, diagnosis and treatment of this genetic disorder.

Nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease is associated with obesity and diabetes. Lifestyle changes may prevent it from becoming serious.

Non-Hodgkin's lymphoma

Non-Hodgkin's lymphoma is cancer originating in the lymphatic system. It's caused by abnormal white blood cells, and often the only sign is swollen lymph nodes.

Optic neuritis

Optic neuritis is an inflammation of the optic nerve, the structure that transmits visual information to your brain. Optic neuritis usually causes temporary vision loss.

Osteoarthritis

The wear and tear of aging may take a toll on your joints. Find out how to manage osteoarthritis.

Osteochondritis dissecans

Osteochondritis dissecans occurs when a piece of and bone loosens and separates from the bone.

Osteomyelitis

Osteomyelitis is a bone infection that commonly affects the long bones in the arms and legs in children, and the spine and pelvis in adults.

Paget's disease of the breast

Paget's disease of the breast is a form of breast cancer that involves the nipple. Understand treatment options for this rare breast cancer.

Pancreatic cancer

Pancreatic cancer is often fatal. Find out which new treatments offer hope.

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.

Patellar tendinitis

Don't let the common term "jumper's knee" fool you. Patellar tendinitis can affect anyone — no matter how frequently or infrequently you jump.

Patent ductus arteriosus (PDA)

Patent ductus arteriosus (PDA) is a persistent, abnormal opening between the aorta and pulmonary artery. If it doesn't resolve on its own, it's readily treated.

Pericardial effusion

Pericardial effusion, the accumulation of excess fluid in the sac-like structure around the heart, can decrease heart function and can be life-threatening.

Peripheral neuropathy

Peripheral neuropathy symptoms can range from annoying to disabling. Learn how to deal with the burning, numbness and tingling.

Pinched nerve

A pinched nerve occurs when pressure is applied by surrounding tissues. This pressure disrupts the nerve's function, causing pain, tingling or numbness.

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.

Placenta accreta

Placenta accreta — Comprehensive overview covers symptoms and treatment of this serious pregnancy condition.

Placenta previa

Placenta previa is a pregnancy complication that can cause excessive bleeding before or during delivery. Treatment may include bed rest or a C-section birth.

Plantar fasciitis

Plantar fasciitis is a common cause of heel pain. It generally clears up with the help of simple treatments for pain and inflammation.

Posterior cruciate ligament injury

Less common than an ACL knee injury, a torn posterior cruciate ligament can be painful and sideline you for months. Find out more.

Posterior prolapse (rectocele)

A posterior prolapse (rectocele) occurs when the supportive tissue between the rectum and vagina weakens, allowing the rectum to bulge into the vagina.

Precocious puberty

Precocious puberty is a rare condition in which the physical signs of puberty begin to develop too early in children.

Primary biliary cirrhosis

Primary biliary cirrhosis begins with inflammation in the liver's small bile ducts, but eventually can lead to damage and scarring in the liver itself.

Primary lateral sclerosis (PLS)

Primary lateral sclerosis (PLS) — Comprehensive overview covers symptoms, diagnosis of uncommon motor neuron disease.

Primary progressive aphasia

Primary progressive aphasia is a rare neurological syndrome that slowly and progressively impairs language capabilities.

Progressive supranuclear palsy

Progressive supranuclear palsy — a syndrome with many similarities to Parkinson's disease — has no effective treatment, but certain medications and self-care measures can help.

Prolactinoma

Prolactinoma is a tumor in the pituitary gland that causes overproduction of the hormone prolactin. Too much prolactin can cause infertility or sexual dysfunction.

Prostate cancer

Prostate cancer is a common cancer affecting men. But with early detection, you improve your chances of successful treatment.

Pseudotumor cerebri

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

Psoriatic arthritis

Some people with psoriasis may develop joint pain called psoriatic arthritis. Get the basics here.

Pulmonary embolism

Pulmonary embolism occurs when one or more arteries in your lungs become blocked. Surgery, cancer, family history and long airplane trips may place you at risk.

Pulmonary hypertension

High blood pressure affecting only the arteries in your lungs is known as pulmonary hypertension. Discover the symptoms, risk factors and treatment for this condition.

Pulmonary valve stenosis

Pulmonary valve stenosis is a narrowing of the valve that controls blood flow from your heart to your lungs. It's usually present at birth.

Rectovaginal fistula

Rectovaginal fistula — Comprehensive overview explains treatment of this complication due to childbirth, Crohn's disease, cancer or other causes.

Retinoblastoma

Retinoblastoma is a cancerous tumor of the eye that generally affects young children. If retinoblastoma is detected early, a cure is possible.

Rett syndrome

Parenting a child with Rett syndrome can be challenging. Here's what to expect and steps you can take to help your child.

Rotator cuff injury

A rotator cuff injury is a painful shoulder condition often caused by lifting, falling or repetitive motions. Explore treatments including exercise therapy, medications and surgery.

Sacral dimple

A sacral dimple is an indentation in the skin on the lower back — usually just above the crease between the buttocks.

Sacroiliitis

Sacroiliitis is one cause of low back pain and discomfort. It's an inflammation of the sacroiliac joints, which connect the lower spine and pelvis.

Salivary gland cancer

Salivary gland cancer is a rare form of cancer that often begins with a painless lump in the mouth, throat or neck.

Schizophrenia

Schizophrenia causes delusions, hallucinations and behavior changes. The good news is that new medications can often effectively manage schizophrenia symptoms.

Sciatica

The pain of acute sciatica can be excruciating, but it usually goes away in about six weeks. Learn how to feel better in the meantime.

Scoliosis

Scoliosis is an abnormal curvature of the spine. Most cases are mild, but severe cases may require treatment with braces or surgery.

Sex headaches

Sex headaches are usually nothing to worry about. But they can sometimes be associated with bleeding problems inside and around the brain.

Shaken baby syndrome

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

Sheehan's syndrome

Sheehan's syndrome is a rare pituitary gland disorder that occurs in women usually as a result of severe blood loss during childbirth.

Sinus headaches

Sinus headaches are often confused with migraines. Proper diagnosis and treatment are the keys to relief.

Small vessel disease

If you have symptoms of heart disease, but your doctor doesn't see any blocked major arteries, small vessel disease may be the cause.

Snoring

Snoring may be just a nighttime annoyance, or it may indicate a more serious health condition. It can also disrupt your life and relationships.

Soft tissue sarcoma

Soft tissue sarcomas are uncommon cancers that originate in the soft tissues of your body.

Spinal cord injury

A spinal cord injury affects the nerves that carry impulses to and from your brain. Permanent disability commonly results.

Spinal headaches

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

Spinal tumor

A spinal tumor can cause back pain, loss of sensation — even paralysis. But recent advances offer more treatment options than ever before.

Sprains and strains

Sprains and strains — damage to ligaments, tendons and muscles — can result from overdoing physical activities. Learn ways to prevent this damage.

Stress fractures

Stress fractures are tiny cracks in a bone. Simple steps can help prevent this common overuse injury.

Stroke

Stroke occurs when the blood supply to part of your brain is interrupted, depriving brain tissue of oxygen and nutrients. Stroke is a medical emergency.

Syringomyelia

Syringomyelia is the development of a fluid-filled cyst within your spinal cord. It can cause a variety of neurological symptoms, including pain, weakness and stiffness.

Takayasu's arteritis

Takayasu's arteritis is an uncommon form of vasculitis that affects the large arteries.

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.

Tennis elbow

Tennis elbow usually results from repetitive contraction of the forearm muscles — causing pain where the muscles attach to the elbow. Rest and pain relievers may help.

Tension headache

A tension headache is the most common form of headache. A number of treatments are available to help you deal with the pain.

Thoracic outlet syndrome

Thoracic outlet syndrome is a group of disorders that occur when the nerves or vessels in the shoulder area (thoracic outlet) are compressed.

Throat cancer

The most common throat cancers are linked to smoking and excessive alcohol use.

Thrombophlebitis

Thrombophlebitis occurs when a blood clot and swelling develop in a vein, typically in your leg. The cause often is prolonged inactivity or bed rest.

Thumb arthritis

Thumb arthritis (basal joint arthritis) occurs when the joint at your wrist and the base of your thumb develops osteoarthritis.

Thunderclap headaches

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

Tinnitus

Head noise — also called ringing in the ears (tinnitus) — is common. Although often annoying, tinnitus is rarely a warning of a serious health problem.

TMJ disorders

TMJ disorders are painful conditions centered where your jawbone attaches to your skull. The pain may be temporary or chronic.

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.

Toxoplasmosis

Toxoplasmosis is an infection caused by a parasite. It doesn't make most people ill, but infants and people with HIV/AIDS are at risk of complications.

Transverse myelitis

Transverse myelitis — inflammation of the insulating material that covers nerve cells in your spine (myelin) — causes pain, muscle weakness and other problems.

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.

Trigeminal neuralgia

Trigeminal neuralgia is a very painful condition of a large nerve that provides sensation to most of your face. Treatment involves medications and, sometimes, surgery.

Tuberous sclerosis

Tuberous sclerosis is a rare genetic disease. With appropriate treatment, many people who have tuberous sclerosis lead full, productive lives.

Undescended testicle

Undescended testicle is a testicle that hasn't moved into its proper position in the scrotum prior to birth. The condition often corrects itself.

Uterine fibroids

Uterine fibroids are noncancerous tumors of the uterus. Medical therapy and surgical procedures can shrink or remove uterine fibroids.

Uterine prolapse

A sensation of sitting on a small ball or something falling out of your vagina could mean you have uterine prolapse.

Vaginal cancer

Vaginal cancer is a rare cancer that typically occurs in older women.

Vascular dementia

Vasculitis

Vasculitis is an inflammation of the blood vessels. It can affect people of any age. Treatment depends on the type of vasculitis.

Ventricular fibrillation

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

Vocal cord paralysis

Vocal cord paralysis occurs when one or both of your vocal cords don't open or close properly.

Vulvar cancer

Cancer of the vulva, the outer part of the female genitalia, is rare. It occurs most often in older women.

Water on the knee

Water on the knee refers to excess fluid inside or around your knee joint. Find out what causes this common knee problem.

West Nile virus

West Nile virus infection usually resolves on its own, but occasionally it can be serious.

Whiplash

Whiplash is a neck injury often linked to auto accidents. Discover which treatments work and which don't.

Wilms' tumor

Wilms' tumor is a rare kidney cancer that primarily affects children.

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.

Wrist pain

Sometimes it really is all in the wrist. Learn more about what causes wrist pain and how it's treated.

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.

Aug. 17, 2013