Meningitis is characterized by inflammation of the membranes (meninges) around the brain or spinal cord. The disorder can occur in three different forms: adult, infantile, and neonatal. This inflammation may be caused by different types of bacteria, viruses, fungi, or malignant tumors. Chemical reactions to certain injections into the spinal canal can also cause Meningitis. This inflammation can begin suddenly (acute) or develop gradually (subacute). Adult forms of Meningitis are characterized by fever, headache, and a stiff neck, sometimes with aching muscles. Nausea, vomiting and other symptoms may occur. Treatment with antibiotics is usually effective against the infection.
Meningitis in adults and children is often preceded by respiratory illness or a sore throat. In its acute form, the disorder is characterized by fever, headache, a stiff neck, and vomiting. Adults may become seriously ill within 24 hours. In children, the course of the infection may be even shorter. Symptoms among older children and adults may progress from irritability through confusion, drowsiness, and stupor, possibly leading to coma. Dehydration often occurs, and collapse of the blood vessels may lead to shock (Waterhouse-Friderichsen Syndrome), especially when the Meningitis is caused by meningococcus bacteria which spreads to the blood (septicemia). Paralysis of one side of the body (hemiparesis) is uncommon early in the course of Meningitis, but may occur later as a result of tissue death in the brain (cerebral infarction). Meningitis may recur even after treatment with antibiotics.
Infantile Meningitis: The course of the disorder is less predictable among infants between 3 months and 2 years of age. Fever, vomiting, irritability, and convulsions usually occur. A high-pitched cry, and a bulging or tight soft spot (fontanel) on the crown of the head (where the parts of the still unhardened bones join) may also occur. Since the incidence of Meningitis is highest among this age group, any unexplained fever needs to be closely watched. Cerebral fluid may accumulate just inside the tough outer membrane covering the brain (subdural effusions) after several days. Typical signs of Meningitis include seizures, a persistent fever, and an enlarging head size. A brain abscess or subdural pus accumulation may also occur. Water accumulating in the brain (hydrocephalus), deafness and slowed mental and physical development are possible effects of Meningitis on the central nervous system.
Neonatal Meningitis: Meningitis in newborn babies can begin during the first 4 weeks of life. It may be caused by infections in parts of the body other than the brain or spine. Some cases may arise from complications occurring at birth. The disorder is characterized by subtle and non-specific signs such as jitteriness, interrupted breathing (apnea), vomiting, diarrhea, and a yellowish skin color (jaundice). Usually signs of infection elsewhere in the body (e.g. middle ear infection) are also present. The cerebrospinal fluid can be tested for a definite diagnosis.
Meningitis due to Group B pneumococcus bacteria may be present in the first 10 days of life, when it frequently accompanies a lung illness. Usually, however, this form of Meningitis occurs after 10 days of age as an isolated illness. Neonatal Meningitis is also characterized by symptoms such as fever, drowsiness, and seizures.
Meningitis can be caused by different bacteria, viruses and organisms such as Neisseria meningitis, Hemophilus influenzae b, Streptococcus (Diplococcus) pneumoniae, Group A Streptococcus, Escherichia coli or other gram-negative organisms (chiefly Pseudomonas), and Staphylococcus aureus.
Recurrent Meningitis occurs in special situations: 1) When there is a communication between the brain and the exterior that may be inborn or occur after an injury; 2) When infection occurs in areas close to the meninges as in mastoid infection, sinus infection, brain abscess, accumulation of pus under the outer meninge (subdural empyema), or spinal epidural abscess; 3) When the patient has impaired immunity against bacteria or other causes of illness.
Aproximately 3,000 cases of Meningitis have been reported in 1997. Meningitis caused by Hemophilus influenzae occurs most often in children before the age of five to six years.
Neonatal Meningitis usually occurs during the first four weeks of life, and predominantly affects infants of low birth weight who have had complications at birth. This form of the disorder occurs in approximately two out of 10,000 full-term infants, and in two out of 1,000 low birth weight infants. This form of Meningitis predominantly affects males.
Meningitis is usually treated with different types of antibiotics used against the specific bacteria causing the infection. These may include ampicillin, chloramphenicol, gentamicin, penicillin, moxalactam, nafcillin, or in tuberculosis cases isoniazid.
Children more than two years of age can be immunized against Meningitis with the Haemophilus influenzae type b polysaccharide vaccine.
A vaccine composed of attenuated bacteria with added protein, has been approved for use in children under two years of age to protect them against Haemophilus influenzae type B Meningitis.
The Food and Drug Administration (FDA) approved Prevnar vaccine for the treatment of meningitis. Because of the high cost of the drug, the FDA limited the potential recipients to children less than two years of age and children from high risk groups (i.e., Native Americans, African Americans, Alaskan Americans, and individuals with HIV, sickle cell anemia, and immunodeficiency disorders.
The orphan product, Amphotericin B Lipid Complex, has been sponsored by the Bristol-Myers Squibb Co., P.O. Box 4000, Princeton, NJ, 08543, for the treatment of Cryptococcal Meningitis.
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