Meningitis

Overview

Meningitis is inflammation (swelling) of the meninges, membranes that cover the brain and spinal cord. This inflammation can be caused by a viral, bacterial, or fungal infection of the fluid surrounding these membranes. The trademark signs of meningitis are stiff neck, headache, and fever, although symptoms may vary according to the type of meningitis. Both viral and bacterial meningitis can be spread by coughing, sneezing, or sharing items such as toothbrushes. Although viral meningitis is not usually serious, bacterial infection can be fatal if it not treated quickly. The best way to prevent meningitis is to practice good hygiene and stay up-to-date on routine vaccinations.

Symptoms and Diagnosis

Meningitis may occur suddenly or develop after an illness. Symptoms of meningitis depend on the type of infection, but may at first resemble those of the flu (influenza). The most common symptoms include stiff neck, high fever, lethargy, severe headache, sensitivity, and skin rash. Bacterial meningitis progresses quickly and can be deadly if left untreated. Fungal meningitis is less common and not contagious. Symptoms of meningitis can be different in infants. They may have high fever with constant crying, sleepiness or tiredness, poor feeding, stiffness in the body and neck, and a bulge on top of the head. Serious complications can occur from meningitis the longer someone goes without treatment, including hearing loss, learning disabilities, brain damage, seizures, kidney failure, and death.

Meningitis is diagnosed with a physical exam to check for signs of infection and diagnostic tests. A diagnosis of meningitis can be confirmed through a spinal tap (lumbar puncture). Meningitis is present if the cerebrospinal fluid collected during the spinal tap shows low glucose (sugar) levels, a high white blood cell count, and increased protein. Blood cultures can detect bacteria that cause meningitis, while imaging tests can reveal inflammation in the body.

Causes

Meningitis can be caused by bacterial, viral, or fungal infection. Viruses cause the majority of meningitis cases; these infections are typically not serious. Enteroviruses are the most common source of viral meningitis. Other viruses include herpes simplex virus, HIV, mumps, and West Nile virus. Bacterial meningitis occurs when bacteria get into the bloodstream and travel to the brain and spinal cord. Less often, bacteria can infect the meninges after an ear or sinus infection, a skull fracture, or some surgeries. The bacterium most likely to cause meningitis is Streptococcus pneumoniae (pneumococcus), which is also a common source of pneumonia or ear and sinus infections. Neisseria meningitides (meningococcus) is another common source of meningitis that occurs when bacteria from an upper respiratory infection get into the bloodstream. Meningococcus is extremely contagious and is commonly diagnosed in students and military personnel housed in close quarters. Another bacterium, Haemophilusinfluenzae type b (haemophilus), was once the primary cause of bacterial meningitis in children but has since become less common due to routine Hib vaccines. Both viral and bacterial meningitis can be spread by sharing utensils, food, or drinks, or through germs spread by coughing and sneezing.

Occasionally, a fungal infection can result in chronic meningitis, although this is rare. Cryptococcal meningitis is a type of fungal meningitis that can be harmful to people with weakened immune systems. Meningitis can also be caused by drug allergies, some types of cancer, and some inflammatory diseases. Continue reading for Prevention and Treatment Information . . .

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