Meningitis and Encephalitis

Seizures associated with fever may represent a benign event or be symptomatic of central nervous system infection. Simple febrile seizures are generalized seizures associated with fever, occurring in 2% to 5% of children 6 months to 5 years of age, lasting less than 15 minutes and not recurring within 24 hours. Thus a focal or prolonged seizure or a seizure that is complicated by Todd's (postictal) paralysis raises suspicion of underlying cerebral disease. Between 2% and 5% of children with fever and seizures have meningitis, whereas 13% to 16% of children with meningitis have seizures. Information about antibiotic use should be solicited, since antibiotics can mask symptoms and signs of meningitis.

Early administration of antibiotics in the ED after blood and urine cultures are obtained (but often before LP if there will be any delay) is indicated. Symptoms and signs of meningitis may he minimal or absent in children under 12 months and subtle in children between 12 and 18 months. Postictal state is usually very short in simple febrile seizures; a prolonged altered level of consciousness suggests another cause, In addition to bacterial causes of meningitis, viral, mycobacterial, and fungal CNS infections can cause seizure. It is particularly important to consider herpes encephalitis in patients with a CSF pleocytosis with negative gram stain, especially in children with focal neurologic findings or coma, since early antiviral treatment is indicated. Mycobacterial or fungal infection should be suspected in patients with a very low CSF glucose without an identifiable bacterial cause.

Causes

Meningitis & encephalitis are usually caused by viruses. Most often, the body’s immune system is able to contain and defeat an infection. But if the infection passes into the blood stream and then into the cerebrospinal fluid that surrounds the brain and spinal cord, it can affect the nerves and travel to the brain and surrounding membranes, causing inflammation. This swelling can harm or destroy nerve cells and cause bleeding in the brain.

Symptoms

• Altered level of consciousness
• Paradoxic irritability
• Vomiting
• Complex seizure features (focal, prolonged, or recurrent)

Signs

• Fever
• Lethargy +++
• Irritability +++
• Vomiting +++
• Nuchal rigidity ++
• Bulging fontanel ++
• Kernig's sign ++
• Brudzinski's sign ++
• Petechiae ++
• "Toxic appearing" ++
• Headache ++
• Apnea +
• Coma +
• Central nervous system infection may also present with focal neurologic signs, cyanosis, hypotension, grunting respirations, or rash.

Treatment

Antiviral medications may be prescribed for encephalitis caused by the herpes virus. Antibiotics are prescribed for bacterial infections. Anticonvulsants are used to prevent. Corticosteroids are used to reduce brain swelling and inflammation. Sedatives may be needed for irritability or restlessness. Over-the-counter medications may be used for fever and headache.

Individuals with bacterial meningitis are usually hospitalized and treated with antibiotics intravenously. Antiviral drugs may also be prescribed.