The three types of meningitis

What is bacterial meningitis, and what is its treatment?

Bacterial meningitis is a serious and potentially life-threatening infection of the protective membranes covering the brain and spinal cord, known as the meninges. This condition can cause severe brain damage and is considered a medical emergency.

Causes

Bacterial meningitis is caused by various types of bacteria, including:

• Streptococcus pneumoniae (pneumococcal meningitis)
• Neisseria meningitidis (meningococcal meningitis)
• Haemophilus influenzae type b (Hib)
• Listeria monocytogenes
• Escherichia coli (especially in newborns)

Symptoms

Symptoms of bacterial meningitis can develop rapidly, often within hours. They may include:

• Sudden high fever
• Severe headache
• Stiff neck
• Nausea or vomiting
• Sensitivity to light (photophobia)
• Altered mental status (confusion or difficulty concentrating)
• Seizures
• Skin rash (especially in meningococcal meningitis)
• Sleepiness or difficulty waking

In infants, symptoms might include:

• Fever
• Constant crying
• Excessive sleepiness or irritability
• Poor feeding
• Bulging fontanel (the soft spot on a baby’s head)
• Stiffness in the baby’s body and neck

Diagnosis

Diagnosis of bacterial meningitis typically involves:

• Lumbar puncture (spinal tap): To collect and analyze cerebrospinal fluid (CSF) for signs of infection.
• Blood cultures: To identify bacteria in the bloodstream.
• Imaging tests: Such as a CT scan or MRI, to check for swelling or other complications.
• Other lab tests: To identify the specific bacteria causing the infection.

Treatment

Treatment of bacterial meningitis involves:

1. Immediate antibiotics: Prompt administration of broad-spectrum intravenous (IV) antibiotics is crucial. Once the specific bacteria are identified, the treatment may be adjusted to target the specific pathogen.
2. Corticosteroids: To reduce inflammation and swelling in the brain. These are often given along with antibiotics.
3. Supportive care: This may include fluids, oxygen therapy, and medications to manage symptoms such as seizures or pain.

Prevention

Several vaccines can prevent some types of bacterial meningitis, including:

• Pneumococcal vaccines (PCV13 and PPSV23)
• Meningococcal vaccines (MenACWY and MenB)
• Hib vaccine

Practicing good hygiene, such as regular handwashing and avoiding close contact with infected individuals, can also help reduce the risk of bacterial meningitis. In some cases, close contacts of someone with bacterial meningitis may be given antibiotics to prevent infection.

Prognosis

With prompt and appropriate treatment, many people recover from bacterial meningitis, though the risk of complications can be significant. Potential complications include hearing loss, brain damage, learning disabilities, and other neurological problems. The prognosis is generally better the sooner treatment is initiated.

What is viral meningitis, and what is its treatment?

Viral meningitis, also known as aseptic meningitis, is an inflammation of the protective membranes covering the brain and spinal cord (meninges) caused by viral infections. It is generally less severe than bacterial meningitis and often resolves without specific treatment.

Causes

Viral meningitis can be caused by various viruses, including:

• Enteroviruses: The most common cause, particularly in late summer and early fall.
• Herpes simplex virus (HSV): Particularly HSV-2.
• Varicella-zoster virus: The virus that causes chickenpox and shingles.
• Mumps virus
• Measles virus
• Influenza virus
• West Nile virus
• Lymphocytic choriomeningitis virus (LCMV)

Symptoms

Symptoms of viral meningitis can vary in severity and may include:

• Fever
• Headache
• Stiff neck
• Sensitivity to light (photophobia)
• Nausea and vomiting
• Lethargy or drowsiness
• Irritability
• Muscle aches

In infants, symptoms might also include:

• Fever
• Irritability
• Poor feeding
• Lethargy
• Vomiting
• Bulging fontanel (the soft spot on a baby’s head)

Diagnosis

Diagnosis of viral meningitis typically involves:

• Lumbar puncture (spinal tap): To collect and analyze cerebrospinal fluid (CSF) for signs of infection and to differentiate between viral and bacterial meningitis.
• Blood tests: To check for viral infections and inflammation markers.
• PCR testing: To identify viral DNA or RNA in the CSF.
• Imaging tests: Such as a CT scan or MRI, to rule out other conditions.

Treatment

Treatment for viral meningitis is generally supportive and focuses on relieving symptoms. It may include:

1. Rest: Allowing the body to recover.
2. Hydration: Ensuring adequate fluid intake to prevent dehydration.
3. Pain and fever relief: Using over-the-counter pain relievers like acetaminophen or ibuprofen.
4. Antiviral medications: In certain cases, such as meningitis caused by herpesviruses, antiviral medications like acyclovir may be prescribed.

Prevention

Preventive measures for viral meningitis include:

• Vaccination: Vaccines for measles, mumps, rubella (MMR), and varicella can help prevent viral infections that may lead to meningitis.
• Good hygiene: Regular handwashing, avoiding close contact with infected individuals, and disinfecting surfaces can reduce the risk of infection.
• Avoiding insect bites: Using insect repellent and wearing protective clothing can help prevent infections from mosquito-borne viruses like West Nile virus.

Prognosis

Most people with viral meningitis recover fully within 7 to 10 days without long-term complications. However, some viruses, like the herpes simplex virus, can cause more severe illness and may require prolonged treatment. The prognosis is generally good, especially with proper supportive care.

What is fungal meningitis, and what is its treatment?

Fungal meningitis is a rare but serious infection of the protective membranes covering the brain and spinal cord, known as the meninges, caused by fungal organisms. This type of meningitis can develop when a fungal infection spreads from another part of the body to the brain or spinal cord.

Causes

Fungal meningitis can be caused by several types of fungi, including:

• Cryptococcus: The most common cause of fungal meningitis, often affecting people with weakened immune systems, such as those with HIV/AIDS.
• Histoplasma: Found in environments with bird or bat droppings.
• Blastomyces: Found in soil and decaying organic matter.
• Coccidioides: Found in soil in certain areas of the United States (e.g., the Southwest) and parts of Central and South America, causing “Valley fever.”
• Candida: Typically affects hospitalized patients or those with compromised immune systems.

Symptoms

Symptoms of fungal meningitis can develop slowly, over weeks to months, and may include:

• Fever
• Headache
• Stiff neck
• Nausea and vomiting
• Sensitivity to light (photophobia)
• Confusion or altered mental status
• Seizures

Diagnosis

Diagnosing fungal meningitis involves:

• Lumbar puncture (spinal tap): To collect and analyze cerebrospinal fluid (CSF) for the presence of fungi.
• Blood tests: To check for fungal infections and inflammation markers.
• Imaging tests: Such as CT scans or MRIs, to detect complications and rule out other conditions.
• Fungal cultures and antigen testing: To identify the specific type of fungus causing the infection.

Treatment

Treatment for fungal meningitis typically involves:

1. Antifungal medications: The specific medication and duration of treatment depend on the type of fungus involved. Common antifungal drugs include:

• Amphotericin B: Often used initially for severe infections.
• Fluconazole or itraconazole: Used for less severe infections or as a follow-up to initial treatment with amphotericin B.
• Voriconazole or posaconazole: May be used for certain types of fungal infections or when other treatments are not effective.

1. Management of underlying conditions: Addressing any underlying health issues, such as HIV/AIDS or immunosuppression, is crucial for effective treatment.

Prevention

Preventing fungal meningitis involves:

• Avoiding environments where fungi are common: Such as areas with bird or bat droppings, especially for people with weakened immune systems.
• Using antifungal medications preventatively: For high-risk individuals, such as those with HIV/AIDS or those undergoing certain medical treatments.
• Maintaining a healthy immune system: Through proper nutrition, regular medical care, and managing chronic health conditions.

Prognosis

The prognosis for fungal meningitis varies depending on the individual’s overall health, the type of fungus involved, and how quickly treatment is started. Early diagnosis and appropriate antifungal treatment improve the chances of recovery, though some individuals may experience long-term complications or require prolonged treatment. Fungal meningitis can be life-threatening, particularly for those with weakened immune systems.