Bacterial and Viral Meningitis
The infection can be caused by viral or bacterial infection, or may have aseptic causes such as cancer which spreads to the meninges, or lupus and other connective tissue disorders. The involvement of the brain makes meningitis a serious and potentially life-threatening disease.
Meningitis Symptoms and Diagnosis
The most common – and most noticeable – early symptoms of meningitis are the characteristic headache, neck stiffness, and intolerance to light. Other early symptoms include fever, confusion, and altered consciousness. Some people may experience an inability to tolerate loud noises.
In children, the disease is more difficult to diagnose as early symptoms are much more non-specific. Many children only show signs of drowsiness and irritability before they start displaying signs of serious meningitis such as the meningococcal rash.
Diagnosis of infectious meningitis may be made on the basis of a lumbar puncture. In this procedure, a sample of spinal fluid is extracted via needle. The sample is then examined in a laboratory for the presence of microorganisms.
Viral and Bacterial causes of Meningitis
Most cases of meningitis are caused by viral and bacterial infections. Other microorganisms, including amoeba and certain fungi, can also cause meningitis. Viral meningitis can be caused by a number of viruses including herpes simplex type 2, varicella zoster virus (which causes chickenpox and shingles), mumps virus, and HIV.
Many bacterial species can also cause infectious meningitis. These include group B streptococci, and Escherichia coli. These two species are common causes of infectious meningitis in newborns and premature babies. Listeria monocytogenes is also a common course of meningitis in infants, and Haemophilus influenzae type B in children under 5.
Other bacterial species that can cause meningitis include Streptococcus pneumoniae and Neisseria meningitidis. These two species are responsible for around 80% of cases of meningitis in adults.
Neisseria meningitidis, also known as meningococcal meningitis, is particularly dangerous in children. Meningococcal meningitis causes an extremely widespread and damaging skin rash which, in children, can easily cause limbs to become gangrenous.
Treatment for Infectious Meningitis
First and foremost meningitis is treated with antibiotics. Early treatment is so important that wide-spectrum antibiotics are typically administered while diagnostic test results are still being confirmed. This is crucial due to the fact that infectious meningitis can rapidly cause serious damage to the brain and body, and death can result if treatment is delayed.
More specific antibiotics are administered once the bacterial species is diagnosed. If the cause of the infection is viral, treatments are mainly supportive in nature, due to the absence of specific anti-viral treatments.
Supportive treatment for meningitis may include intravenous fluids to treat low blood pressure or shock, medication to decrease intracranial pressure, anticonvulsants to treat seizures, and steroids to suppress the inflammatory response.
Centers for Disease Control and Prevention Meningitis FAQ
National Institute of Health MedlinePlus: Meningitis Information
Robert F Kacprowicz, MD, FAAEM. Meningitis in Adults