Health Encyclopedia

Meningitis - gram-negative

Definition

Gram-negative meningitis is an infection of the membranes covering the brain and spinal cord (meninges) caused by gram-negative bacteria (bacteria that turn pink when exposed to a special stain).

Alternative Names

Gram-negative meningitis

Causes, incidence, and risk factors

Acute bacterial meningitis, which can be caused by gram-negative bacteria, is very serious and should be treated immediately to prevent permanent damage. Bacteria causing gram-negative meningitis include Pseudomonas aeruginosa, Escherichia coli, Enterobacter aerogenes, Proteus morganii, and Klebsiella pneumoniae.

Gram-negative meningitis is much more common in infants than adults.

Risk factors in adults and children include recent brain surgery and recent injury to the head. The infection is sometimes connected to spinal fluid shunt placement after brain surgery. Spinal abnormalities, urinary tract abnormalities, a local infection, or urinary tract infection may make children vulnerable to this type of meningitis.

Symptoms

Fever
Severe headache
Nausea and vomiting
Stiff neck
Sensitivity to light (photophobia)
Mental status changes
Symptoms suggesting infection of bladder, kidney, intestines, or lungs, which might be the source of the spinal fluid infection

Signs and tests

For any patient with meningitis, it is important to perform a lumbar puncture (spinal tap). In a lumbar puncture, doctors take a sample of the patient's spinal fluid (known as cerebrospinal fluid, or CSF) for testing.

Low blood pressure
Fast heart rate
Stiff neck
Elevated white blood cell count in blood
Spinal fluid showing increased white blood cells, low glucose, high protein
Special stain of the spinal fluid showing white blood cells and sometimes gram-negative bacteria
CSF culture growing gram-negative bacteria
Blood culture growing gram-negative bacteria
CT scan of the brain (usually normal)

Treatment

It is important to recognize the symptoms of this kind of meningitis, and seek treatment as soon as possible. Early treatment may prevent serious illness or death. Antibiotic treatment through an IV usually starts right away.

Expectations (prognosis)

Many people recover completely, but a large number of people suffer permanent brain damage or die from this type of meningitis. Between 40% and 80% of patients with gram-negative meningitis do not survive, although these numbers may be improving. The likelihood of survival depends on the patient's age, other medical conditions that may be present, and how quickly the infection is treated.

Complications

Shock with organ damage
Brain abscess (collection of bacteria in the brain itself)
Brain damage
Seizures

Calling your health care provider

Go to the emergency room or call the local emergency number (such as 911) if you notice symptoms that indicate meningitis. This condition can be very serious and needs immediate treatment.

Prevention

Prompt treatment of related infections may reduce the risk of meningitis.

Review Date:9/6/2006
Reviewed By:Hilary M. Babcock, M.D., Medical Director of Occupational Infection Control, Barnes-Jewish and St. Louis Children's Hospitals; Instructor of Medicine, Infectious Disease Division, Washington University School of Medicine, St. Louis, MO. Review provided by VeriMed Healthcare Network.

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