Viral meningitis (VM) is an inflammation of the meninges, the membranes that cover the brain and spinal cord. This condition occurs when a viral infection spreads to the central nervous system, causing swelling. It is the most frequent form of meningitis diagnosed in the United States and is the least severe type. Distinguishing VM from bacterial meningitis is important, as the viral form is rarely life-threatening and typically resolves without specific intervention.
Recognizable Symptoms
Symptoms of viral meningitis typically appear within three to seven days following initial exposure to the virus. The presentation can resemble a severe case of the flu, but specific neurological signs emerge as the condition progresses. The classic triad of symptoms includes high fever, a severe headache, and a stiff neck.
Patients may also experience photophobia, which is an increased sensitivity to bright light. Nausea and vomiting are common, and individuals often report feeling tired, lethargic, or unable to concentrate. These symptoms typically peak and then gradually improve as the body fights off the infection.
Recognizing the signs in infants and young children requires special attention, as they may not display the classic symptoms. Instead, a baby might show increased irritability, poor feeding, or an inability to be comforted. A bulging soft spot, known as the fontanelle, on a baby’s head indicates increased pressure within the skull. Any suspicion of meningitis in a child warrants immediate medical evaluation.
Contagion and Transmission Pathways
The viruses responsible for viral meningitis are highly contagious and spread easily from person to person. Enteroviruses are the most common cause, accounting for up to 90% of all identified cases.
Enteroviruses primarily transmit through the fecal-oral route, meaning the virus passes when microscopic amounts of an infected person’s stool are ingested. This often happens due to poor hand hygiene after using the restroom or changing a diaper, followed by touching the mouth, nose, or eyes. The virus can also spread through respiratory secretions when an infected person coughs or sneezes, releasing droplets into the air.
Other Viral Causes
Other viruses can also lead to viral meningitis, each having its own transmission pathway. Mumps and measles viruses spread through airborne respiratory droplets. Herpes Simplex Virus (HSV) can be transmitted through close contact, including sexual contact, particularly in the case of HSV-2. Certain arboviruses, like the West Nile Virus, are spread through the bites of infected insects rather than person-to-person contact. Preventing transmission involves diligent handwashing, avoiding close contact with sick individuals, and taking precautions against mosquito bites.
Diagnosis and Management
A diagnosis of viral meningitis begins with a physical examination and a review of the patient’s symptoms. Because the symptoms closely mimic the signs of the dangerous bacterial form, distinguishing between the two is a top priority. The definitive test to confirm a diagnosis and rule out bacteria is a lumbar puncture.
During this procedure, a small sample of cerebrospinal fluid (CSF) is collected from the lower back and analyzed. The appearance and contents of the CSF, such as the white blood cell count and glucose levels, help determine if the cause is viral or bacterial. Further testing, including polymerase chain reaction (PCR) assays on the CSF, blood, or stool samples, can identify the specific type of virus involved.
Treatment for viral meningitis is supportive, as antibiotics are ineffective against viruses. Management focuses on alleviating symptoms while the body fights the infection. This involves rest, maintaining adequate hydration, and using over-the-counter medications for pain and fever relief.
Hospitalization may be necessary if a patient is severely dehydrated or if the diagnosis is uncertain, particularly in infants. Antiviral medications are only prescribed when the meningitis is confirmed to be caused by a virus like Herpes Simplex, which responds to drugs like acyclovir. Most individuals experience a full recovery within seven to ten days without long-term complications.