Definition

The definition of meningoencephalitis (ME) can be understood from its components. The meninges are thin layers that protect the brain. If the meninges become inflamed, it is called meningitis. Encephalitis is inflammation that occurs in the brain. When both conditions occur simultaneously, it is called meningoencephalitis. 

Meningitis and encephalitis have different symptoms, but when they occur together, they can cause symptoms such as headaches, fever accompanied by impaired consciousness, or seizures. In 2020, The Lancet published data on the spread of meningitis in Indonesia, noting that Indonesia has the highest incidence of cases in Southeast Asia. The most common cause of meningoencephalitis is a virus. The disease is difficult to transmit but can cause severe symptoms. It can occur at any age, especially in very young children and adults who have risk factors for meningoencephalitis.

Causes

The inflammation can be caused by various microorganisms, from viruses to fungi. Inflammation can occur acutely (within days) or chronically (over years). Some known causes of meningoencephalitis include:

• Virus. The most common viruses causing meningoencephalitis are herpes and HIV. Herpes virus is the most frequent cause of ME.
• Fungi. Fungi can spread through the bloodstream and cause meningoencephalitis. Individuals with weakened immune systems, such as those with HIV or taking steroid medications, are more susceptible to fungal meningoencephalitis.
• Bacteria. This condition is life-threatening and very dangerous, potentially causing severe complications such as permanent paralysis.
• Parasites. The most common route of infection is through food.
• Secondary infections. These infections initially occur in other parts of the body and then spread to the brain or its membranes.
• Amoeba infection.  A rare form of meningoencephalitis caused by the amoeba Naegleria fowleri.
• Japanese encephalitis. A type of encephalitis caused by a virus commonly found in Asia.

Risk factor

Risk factors for meningitis include:

• Missing vaccination schedules as recommended.
• Young age, with most cases occurring in children under 5 years old.
• Living in densely populated areas.
• Pregnancy, as the risk of infection increases during pregnancy.
• Having a weakened immune system, such as with diabetes mellitus or HIV infection.
• Taking medications that suppress the immune system.

Symptoms

Meningoencephalitis can cause symptoms of both meningitis and encephalitis. Initial symptoms may include:

• Sensitivity to light
• Persistent headache
• Neck stiffness
• Confusion, seizures, or a tendency to sleep
• Fever
• Behavioral changes
• Visual and auditory hallucinations
• Loss of consciousness
• Red lesions, indicating a herpes virus cause

Symptoms can develop slowly, starting with flu-like symptoms. In infants, symptoms can worsen within 4-11 days.

Diagnosis

Diagnosing meningoencephalitis involves three key components: medical history, physical examination, and laboratory or radiological tests. Initially, the doctor will seek the source of infection causing meningoencephalitis. They will then interview the patient about the history and duration of symptoms. Additional tests that can help confirm the diagnosis include:

• Blood culture: This test aims to identify the type of microorganism causing the symptoms, especially bacteria.
• Radiological examinations: CT scans and MRIs can show conditions such as brain inflammation or swelling and detect infections around the head not visible through physical examination.
• Spinal fluid examination: This invasive test can diagnose meningitis and help determine the type of bacteria causing meningoencephalitis.

Blood culture and spinal fluid examination can take some time. Meanwhile, the doctor will provide treatment to alleviate the symptoms of meningoencephalitis.

Management

Treatment for meningoencephalitis is specific to the causative microorganism. Bacterial infections require intravenous antibiotics and corticosteroids to alleviate inflammation symptoms, preventing complications such as brain swelling and seizures.

For viral infections, the treatment includes:

• Complete bed rest
• Ensuring adequate fluid intake
• Taking medications to reduce fever and relieve pain

In some cases, treatment also aims to alleviate inflammation symptoms, so corticosteroids may be given. The doctor may administer antibiotics and other medications while awaiting laboratory results. With appropriate treatment, symptoms will improve within days. Early treatment can prevent severe complications.

Complications

If left untreated, meningoencephalitis can be fatal. Other potential complications include:

• Impaired thinking, hearing, or movement, possibly permanent.
• Long-term medication use.
• Kidney failure.
• Recurrent seizures.
• Memory and learning difficulties.
• Shock.
• Mobility issues due to paralysis or limb weakness.

Prevention

Prevention can start in infancy with vaccinations such as MMR, chickenpox, pneumococcal, and Haemophilus influenzae type b (Hib) vaccines. Contact health officials for information and vaccination schedules for your baby.

For sexually active adults, preventive measures against meningoencephalitis include:

• Using protection during sexual intercourse.
• Avoiding sexual contact with individuals who have had a herpes infection.
• Consider cesarean delivery to prevent direct infection to the baby if the mother has herpes and is pregnant.

Daily actions to prevent the spread of microorganisms causing meningoencephalitis include:

• Frequent handwashing.
• Maintaining health and immune system strength.
• Covering the mouth when coughing or sneezing.
• Being cautious with food consumption, especially for pregnant women, who should eat well-cooked red meat and avoid unpasteurized cheese.

When to see a doctor?

Meningitis is a medical emergency that requires immediate treatment. Meningoencephalitis can start from non-threatening infections. Always monitor and consult a doctor if symptoms do not improve with treatment. Meningoencephalitis symptoms can resemble other illnesses, making the initial symptoms appear mild. Return to the doctor if symptoms do not improve within a week for further examination. Seek medical attention immediately if you or a close one experiences any of the following symptoms:

• Persistent headache
• Recurrent seizures
• Fever
• Neck stiffness
• Decreased consciousness, such as a tendency to sleep or confusion
• Hearing and vision disturbances
• Fatigue
• Mobility issues and limb movement difficulties