Meningitis - gram-negative
Gram-negative meningitis is an infection of the membranes covering the brain and spinal cord (meninges) from bacteria that turn pink when exposed to a special stain (Gram-negative bacteria).
Causes, incidence, and risk factors
Acute bacterial meningitis can be caused by Gram-negative bacteria. Bacteria causing Gram-negative meningitis include:
- Acinetobacter baumannii
- Enterobacter aerogenes
- Escherichia coli
- Klebsiella pneumoniae
- Pseudomonas aeruginosa
Gram-negative meningitis is much more common in infants than adults.
Risk factors in adults and children include:
- Fever and chills
- Mental status changes
- Nausea and vomiting
- Sensitivity to light (photophobia)
- Severe headache
- Stiff neck (meningismus)
- Symptoms of a bladder, kidney, intestine, or lung infection
Other symptoms that can occur with this disease:
- Bulging fontanelles
- Decreased consciousness
- Poor feeding or irritability in children
- Rapid breathing
- Unusual posture, with the head and neck arched backwards (opisthotonos)
Signs and tests
A physical examination will usually show:
- Fast heart rate
- Mental status changes
- Stiff neck
For any patient who is suspected of having meningitis, it is important to perform a lumbar puncture ("spinal tap"), in which spinal fluid (known as cerebrospinal fluid, or CSF) is collected for testing.
Tests that may be done include:
Treatment with antibiotics should be started as soon as possible. Ceftazidime or Cefepime is one of the most commonly used antibiotics for this type of meningitis, but other antibiotics may be used, depending on the type of bacteria.
If you have a shunt, it may be removed to get rid of the infection.
Early treatment improves the outcome. Between 40% and 80% of patients with Gram-negative meningitis do not survive. Young children and adults over age 50 have the highest risk of death.
Many people recover completely, but a large number of people have permanent brain damage or die from this type of meningitis. The likelihood of survival depends on:
- How quickly the infection is treated
- Other medical conditions that may be present
- The patient's age
Calling your health care provider
Call the local emergency number (such as 911) or go to an emergency room if you suspect meningitis in a young child who has the following symptoms:
- Feeding problems
- High-pitched cry
- Persistent unexplained fever
Call the local emergency number if you develop any of the serious symptoms listed above. Meningitis can quickly become a life-threatening illness.
Prompt treatment of related infections may reduce the risk of meningitis.
Swartz MN. Meningitis: bacterial, viral, and other. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 437.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Jatin M. Vyas, PhD, MD, Assistant Professor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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