In-depth

Acute lymphocytic leukemia

Acute lymphocytic leukemia is a type of leukemia that affects immature white blood cells. It's the most common cancer in children and adolescents.

Acute myelogenous leukemia (AML)

Acute myelogenous leukemia (AML), a form of cancer that affects the blood cells, is the most common type of leukemia.

Anthrax

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.

Brain aneurysm

Coma

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

Cough headaches

Creutzfeldt-Jakob disease

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

Dysarthria

Encephalitis

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

Exercise headaches

Febrile seizure

Guillain-Barre syndrome

Headaches in children

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

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.

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.

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.

Multiple sclerosis

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.

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.

Paraneoplastic syndromes of the nervous system

Pseudotumor cerebri

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

Reye's syndrome

Sex headaches

Thunderclap headaches

Transverse myelitis

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

West Nile virus

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

Dec. 06, 2014