Encephalitis and Meningitis

  • Medical Author:
    Jerry R. Balentine, DO, FACEP

    Dr. Balentine received his undergraduate degree from McDaniel College in Westminster, Maryland. He attended medical school at the Philadelphia College of Osteopathic Medicine graduating in1983. He completed his internship at St. Joseph's Hospital in Philadelphia and his Emergency Medicine residency at Lincoln Medical and Mental Health Center in the Bronx, where he served as chief resident.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

What is encephalomyelitis?

Encephalomyelitis is inflammation of both the brain and spinal cord. Encephalomyelitis can be caused by a variety of conditions that lead to irritation of the brain and spinal cord. Among the common causes of encephalomyelitis are viruses that infect the nervous tissues (for example, herpes zoster virus). People with encephalomyelitis can exhibit combinations of the various symptoms of either encephalitis or meningitis.

What are the risk factors for encephalitis and meningitis?

Patients with a suppressed immune system, either because of medications (organ transplant recipients, etc.) or from a disease that suppresses the immune system (HIV, for example), are at increased risk for encephalitis and meningitis.

What specialties of doctors treat encephalitis and meningitis?

Encephalitis and meningitis usually needs to be treated in the hospital. A family practice or general internal-medicine physician or an infectious-disease specialist will usually be treating those with meningitis or encephalitis.

How do health-care professionals diagnose encephalitis and meningitis?

Encephalitis or meningitis is suggested when the symptoms described above are present. The doctor diagnoses encephalitis or meningitis after a completing a thorough history (asking the patient questions) and examination. The examination includes special maneuvers to detect signs of inflammation of the membranes that surround the brain and spinal cord (meninges). These signs and symptoms can include neck stiffness, headache, and fever. Based on the history and examination, the doctor suggests specific tests to further help in determining the diagnosis.

Tests that are used in the evaluation of individuals suspected of having encephalitis or meningitis include evaluation of the blood for signs of infection and possible presence of bacteria, brain scanning (such as CT scan or MRI scan), and cerebrospinal fluid analysis.

A lumbar puncture is the most common method of obtaining a sample of the fluid in the spinal canal (the cerebrospinal fluid or CSF) for examination. A lumbar puncture (LP) is the insertion of a needle into the fluid within the spinal canal. It is termed a "lumbar puncture" because the needle goes into the lumbar portion of the back (the lower portion of the back). The needle passes between the bony parts of the spine until it reaches the cerebral spinal fluid. A small amount of fluid is then collected and sent to the laboratory for examination. The evaluation of the spinal fluid is usually necessary for the definitive diagnosis and to help make optimal treatment decisions (such as the appropriate choice of antibiotics).

The diagnosis is confirmed by abnormal spinal fluid results and, in the case of an infection, by identifying the organism causing the infection. In patients with meningitis, the CSF fluid often has a low glucose (sugar) level and increased white blood cell count. In addition, the fluid can be used to identify some viral causes of meningitis (PCR or polymerase chain reaction) or be used to culture bacterial organisms causing the meningitis.

Medically Reviewed by a Doctor on 9/8/2016
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