Differences Between Meningitis and Encephalitis

Key takeaways:

• The difference between meningitis and encephalitis is in the site of occurrence: Meningitis is the swelling of the tissues around the brain and spinal cord, while encephalitis is the swelling of the brain itself. 
• Both conditions share similar symptoms, but while meningitis may cause sensitivity to or dislike of bright lights, encephalitis typically doesn't.
• The only way to tell whether you have meningitis or encephalitis is by seeking medical attention. Your doctor will run a proper test to determine if you have either of them and recommend the right treatment.

Meningitis and encephalitis are life-threatening diseases that affect the brain. However, both conditions affect different parts of the brain.

Meningitis is the inflammation of the meninges, a membrane surrounding the brain and spinal cord. In contrast, encephalitis is a condition in which the brain is swollen. 

Both conditions are typically caused by infectious agents like bacteria, viruses, and fungi, although parasites can also be involved in rare cases. Non-infectious causes such as autoimmune disorders or drug reactions are less common.

Meningitis and encephalitis may affect anyone at any age, but very young or elderly persons are at increased risk.

People can contract these diseases through contact with an infected person’s saliva, nasal discharge, feces, or respiratory or throat secretions (kissing, coughing, sharing a drinking glass, eating utensils, or personal items) and always present with flu-like symptoms.

Differences between meningitis and encephalitis

As much as meningitis and encephalitis may seem similar, a few differences set them apart. These include:

The site of occurrence

Although they are both inflammations affecting the central nervous system with similar symptoms, their primary difference lies in the part of the central nervous system they affect. 

As explained earlier, meningitis affects the membrane surrounding the brain and spinal cord, known as the meninges, whereas encephalitis affects the brain itself. 

Symptoms

Symptoms like headache, fatigue, and high fever are common in both meningitis and encephalitis. However,  in meningitis, you may experience a sensitivity to or dislike of bright lights, which is absent in encephalitis.

Also, in severe cases of encephalitis, you may notice difficulty in speech, hearing, hallucinations, or personality changes.

Symptoms of meningitis

Meningitis often presents with flu-like symptoms that develop over 1-2 days. The symptoms of meningitis depend on the underlying cause of the disease. 

Here are some common symptoms that may indicate meningitis:

• High temperature
• Headache
• A dark purple or red rash
• Nausea and vomiting
• Neck stiffness
• Confusion or altered mental status
• Sensitivity to bright lights
• Drowsiness
• Seizure

Symptoms of encephalitis

Similar to meningitis, encephalitis begins with flu-like symptoms and progresses to more severe symptoms over time. Some common symptoms of encephalitis include:

• Fever
• Headache
• Change in behavior
• Confusion and disorientation
• Stiffness of the neck

In severe cases, you may experience:

• Hallucinations
• Double visions
• Speech or hearing problems
• Loss of consciousness
• Seizures
• Impaired judgment
• Memory loss
• Partial paralysis in arms and legs
• Muscle weakness
• Coma

Causes of meningitis

Meningitis and encephalitis share similar causes. That said, here are the causes of meningitis: 

1. Bacterial meningitis

When bacteria invade the body and travel through the bloodstream to the brain, it affects the meninges directly. These bacteria begin by infecting the upper respiratory tract and can subsequently spread to the brain.

Bacterial meningitis is rare but fatal and can cause stroke, hearing loss, and permanent brain damage.

Bacteria that cause meningitis are:

• Streptococcus pneumonia
• Neisseria meningitidis
• Haemophilus influenza
• Streptococcus agalactiae
• Listeria monocytogenes

2. Viral meningitis

Viral meningitis is the most common form of meningitis, and its primary cause is a common type of virus called enteroviruses. 

This virus enters through the mouth and nose and is present in mucus, saliva, and feces. Children younger than five have an increased risk of contracting viral meningitis. 

Despite viral meningitis being more common than the others, most cases resolve naturally without medical intervention.

Meningitis can also be caused by other viruses, such as:

• Arboviruses
• Herpes viruses
• Influenza virus
• Measles virus
• Mumps virus
• Non-polio enteroviruses
• Lymphocytic choriomeningitis virus

3. Fungal meningitis

Immunocompromised individuals (for example, those who have HIV/AIDS, cancer, or taking long-term corticosteroid medication) are at higher risk for fungal meningitis. However, healthy individuals can also have it.

The most common cause of fungal meningitis is the fungus Cryptococcus neoformans, which is found in dirt or bird droppings. Fungal meningitis is curable, although it has an increased chance of reoccurring in roughly half of the affected individuals. 

Other fungi that might cause meningitis include:

• Coccidioides immitis
• Aspergillus
• Candida
• Mucormycosis (common in patients with diabetes mellitus and those receiving transplants)

4. Parasites

Some parasites known to cause meningitis include tapeworms (cysticercosis), Plasmodium falciparum (which causes cerebral malaria), and, in rare cases, amoebas associated with freshwater swimming. Amoebic meningitis can be rapidly fatal.

Risk factors for meningitis

Conditions that may increase your risk of meningitis include:

• Conditions that suppress the immune system (e.g., HIV/AIDS, transplant recipients)
• Alcohol use disorder
• Sickle cell anemia
• Splenectomy
• Travels to endemic environments
• Exposure to mosquitoes and ticks
• Living in crowded conditions
• Undervaccination
• Very young or very old persons
• Chronic medical conditions
• Intravenous drug use

Risk factors for encephalitis

Here are some risk factors for or people at higher risk of developing encephalitis:

• People with weak immunity
• Contact with bodily fluids of infected persons (saliva, feces, nasal discharge, respiratory and throat secretions).
• Very young or very old persons
• Exposure to mosquitoes and ticks
• Travels to endemic environments

Outlook for meningitis and encephalitis

When detected and treated promptly, mild cases of encephalitis and meningitis can quickly resolve. However, the recovery process may be prolonged for more severe cases.

Unlike bacterial meningitis, viral meningitis may resolve on its own and rarely cause long-term complications. 

However, some people never make a full recovery and suffer from complications like memory loss, frequent seizures, behavioral changes, persistent tiredness, and problems with attention due to damage to the brain.

Treatment for meningitis and encephalitis

Both meningitis and encephalitis are serious conditions that require immediate medical attention. 

Treatment for meningitis and encephalitis varies depending on the underlying cause. Potential treatment options include:

• Antiviral medicines
• Antibiotic medications
• Antifungal medication
• Painkillers to ease discomfort and reduce fever
• Medications to minimize seizures and fits
• Oxygen through a face mask for respiratory distress

When to see a doctor

If you suspect you have meningitis or encephalitis, seek immediate medical attention. In addition, if you're planning international travel, consult your doctor about necessary vaccinations and potential health risks, including meningitis and encephalitis.

Final words

Pinpointing meningitis and encephalitis may be challenging without the assistance of a skilled health practitioner and running the necessary tests to rule out other diseases, so it is best not to guess or apply self-medications. 

Furthermore, meningitis and encephalitis are life-threatening, and early detection significantly improves treatment outcomes.