Meningoencephalitis: Symptoms, Causes & Treatment

Meningoencephalitis is inflammation of the brain and meninges. It can cause symptoms such as headache, fever, nausea, difficulty speaking, disorientation, changes in behavior and/or personality, and seizures in some cases.

This inflammation can be caused by viruses, fungi, bacteria, or parasites that reach the central nervous system and begin to multiply.

Treatment for meningoencephalitis should be started as soon as possible and is usually guided by an infectious disease specialist or neurologist. The goal is to treat the infection, prevent inflammation from worsening, and reduce the risk of life-threatening complications.

Main symptoms

The main symptoms of meningoencephalitis are:

• Headache

• Neck stiffness, with difficulty touching the chin to the chest

• Fever

• Nausea or vomiting

• Increased sensitivity to light

• Excessive sleepiness or fatigue

• Confusion or disorientation

Other symptoms may also occur, such as difficulty swallowing or speaking, changes in behavior and/or personality, hallucinations, amnesia, or seizures.

According to the CDC, anyone with symptoms of meningitis should seek medical care right away so a healthcare provider can identify the cause and determine the best treatment.

Confirming a diagnosis

Meningoencephalitis is diagnosed by an infectious disease specialist or neurologist based on symptoms, health history, a physical and neurological exam, laboratory tests, and imaging studies.

The doctor may order imaging tests such as a CT scan or MRI, as well as blood tests. In some cases, an electroencephalogram (EEG) may also be used to evaluate brain activity.

A lumbar puncture may also be performed to analyze cerebrospinal fluid (CSF), the fluid that surrounds the brain and spinal cord. CSF analysis can help detect infection and identify the infectious agent causing the inflammation.

According to the World Health Organization (WHO), this test helps diagnose meningitis, although it should not delay antibiotic treatment if bacterial meningitis is suspected.

Possible causes

Meningoencephalitis can be caused by viruses, bacteria, fungi, or parasites that lead to inflammation of the brain and meninges, resulting in symptoms.

Meningoencephalitis can happen when an infectious agent reaches the nervous system and multiplies. It can also occur as a complication of viral meningitis or appear a few weeks after an infection or vaccination.

It is important for the cause of meningoencephalitis to be properly identified so that the doctor can recommend the most appropriate treatment.

Main types

The main types of meningoencephalitis are:

1. Herpetic meningoencephalitis

Herpetic meningoencephalitis is caused by herpes simplex virus types 1 and 2, which can cause cold sores or genital herpes, for example.

This type of meningoencephalitis usually occurs when the virus is reactivated. The virus can remain “dormant” in the nerves and become active again when the immune system is weakened.

2. Viral meningoencephalitis

In addition to herpes virus, viral meningoencephalitis can be caused by other viruses, such as enteroviruses, varicella-zoster virus, adenovirus, respiratory syncytial virus (RSV), or influenza (flu) virus, for example.

3. Bacterial meningoencephalitis

Bacterial meningoencephalitis can be caused by bacteria such as Mycoplasma pneumoniae, Listeria monocytogenes, Mycobacterium tuberculosis, Treponema pallidum, or Rickettsia prowazekii, for example.

This type of meningoencephalitis is considered serious and can cause life-threatening complications if it is not diagnosed and treated quickly.

4. Primary amebic meningoencephalitis

Primary amebic meningoencephalitis is caused by the amoeba Naegleria fowleri, also known as the brain-eating amoeba. This is another serious type of meningoencephalitis.

This amoeba can be transmitted through contact with contaminated freshwater, such as lakes, rivers, and hot springs. It can enter the body through the lining of the nose and reach the brain and meninges, causing inflammation.

5. Parasitic meningoencephalitis

In addition to the amoeba Naegleria fowleri, parasitic meningoencephalitis can also be caused by other parasites, such as Acanthamoeba species, Toxoplasma gondii, or Plasmodium falciparum, for example.

6. Fungal meningoencephalitis

Fungal meningoencephalitis can be caused by fungi such as Cryptococcus neoformans, Coccidioides species., Penicillium species., or Histoplasma capsulatum, for example.

When these fungi enter the body, they can reach the bloodstream and travel to the brain and meninges, causing meningoencephalitis.

This type of meningoencephalitis is usually more common in people with a weakened immune system, such as people with HIV or cancer, or those taking immunosuppressive medications.

Treatment options

Treatment for meningoencephalitis should be guided by an infectious disease specialist or neurologist. It can vary depending on the cause of the inflammation, and medication is usually recommended.

The main medications for meningoencephalitis are:

• Antivirals, such as acyclovir or ganciclovir, depending on the virus involved

• Antibiotics, for bacterial meningoencephalitis

• Antifungal medications, for fungal infection

• Antiparasitic medications, to fight parasites

• Alkylphosphocholines, such as miltefosine, or other medications such as amphotericin B, for primary amebic meningoencephalitis

Anticonvulsants, such as phenytoin, may also be prescribed for seizures. Pain relievers or sedatives may be used to control pain, and corticosteroids and diuretics may be prescribed to reduce intracranial pressure.

In general, meningoencephalitis treatment is done in the hospital so the person can be monitored. This helps prevent complications, ensure the infectious agent is properly treated, and relieve symptoms.

Potential complications

Complications of meningoencephalitis are more likely in severe cases or when treatment is delayed. They can include brain or nerve damage and coma, and may be life-threatening.

In some cases, even after recovery, a person may have memory problems, difficulty with motor coordination, difficulty speaking or swallowing, trouble concentrating or paying attention, personality changes, or seizures.