Cryptococcal Meningitis - Symptoms, Diagnosis, and Treatment

Introduction

Cryptococcal meningitis is a fungal infection caused by Cryptococcus neoformans seen in bird droppings. When breathed in, the spore can multiply and spread from the lungs to the membrane surrounding the brain and spinal cord, resulting in meningitis. This condition is very rare in healthy individuals but easily affects people with HIV disease, whose immune system is compromised.

What Is Cryptococcal Meningitis?

Meningitis is an infection and inflammation that occurs in the meninges, a membrane that covers the brain and the spinal cord. Bacteria, fungi, or viruses can cause this condition. Two main fungi cause cryptococcal meningitis: Cryptococcus neoformans (C. neoformans) and Cryptococcus gattii (C. gattii). Cryptococcus is a fungus that is usually found in soil and bird droppings. It usually affects people with impaired immune systems.

What Are the Symptoms of Cryptococcal Meningitis?

Cryptococcal meningitis symptoms develop gradually within a few days to weeks of exposure. A person may develop various symptoms, such as:

• Headaches.

• Nausea.

• Vomiting.

• Fatigue.

• Confusion and hallucination.

• Personality changes.

• Sensitivity to light.

• Fever.

• Stiff neck.

• Blurred vision.

• Lethargy.

It may be difficult for a person to tell if they experience the symptoms of cryptococcal meningitis as many symptoms are similar to the side effects caused by the medications taken to treat the underlying conditions. However, if left untreated, it can cause more severe symptoms like:

• Fluid on the brain.

• Coma.

• Hearing loss.

• Hydrocephalus means water on the brain.

Cryptococcal meningitis can be fatal if not treated, especially in people with impaired immunity.

What Are the Causes of Cryptococcal Meningitis?

Usually, two types of Cryptococcus fungi cause cryptococcal meningitis; these are C. neoformans and C. gattii. C. neoformans cause most cryptococcal meningitis conditions. These fungi are usually found in the soil that contains bird droppings. C. gattii also causes these conditions, but these are not found in the soil. Instead, they are usually found on trees, including the eucalyptus. These usually develop in the debris at the base of the eucalyptus trees.

Cryptococcal meningitis does not occur in healthy people; it usually affects people with a compromised immune system. C. gattii usually attacks people with a healthier immune system than C. neoformans. But the conditions rarely occur in people with normal immune systems.

What Are the Risk Factors of Cryptococcal Meningitis?

Cryptococcal meningitis is a rare condition that does not occur in healthy individuals; rather, it is caused in people with a weakened immune system. People who are at higher risk of cryptococcal meningitis will have any one of these underlying conditions:

• HIV.

• AIDS.

• Diabetes.

• Leukemia.

• Cirrhosis of the liver.

• Transplantation of organs.

Cryptococcal meningitis is more likely to occur in people with reduced CD4 count. CD4 cells are T cells, a type of white blood cell (WBC), and are very significant to the immune system. People with HIV/AIDS have a reduced number of CD4 cells which makes the immune system a compromised one, which can be easily affected by Cryptococcus fungi.

How Does a Person Get Cryptococcal Meningitis?

Cryptococcal forms widespread spores, especially in the soil, bird droppings, and decaying wood. The infection occurs when these spores are inhaled, but these infections do not spread from person to person. In a person with a healthy immune system, these spores, after being inhaled, move to the lung, where the alveolar macrophages destroy them, which are the guardian white blood cells. Therefore, the pathophysiology of cryptococcal meningitis depends on the compromised immune system.

The yeast takes advantage of the compromised immune system and moves to the lymph node, where they multiply and spread, affecting the nervous system. They develop into meningitis gradually, causing symptoms.

How Is This Condition Diagnosed?

The doctor will diagnose cryptococcal meningitis by assessing a person's signs, symptoms, and medical history. If a doctor suspects cryptococcal meningitis, then a confirmatory test is performed. In the case of a confirmatory test, a spinal tap is used, which collects the cerebrospinal fluid (CSF), which is a liquid in the central nervous system that provides all the necessary nutrients and moisture.

During the test, the person should lie on the side of the knees close to the chest. Next, numb medicine is injected in an area just above the spine. After this, a spinal tap is inserted to collect cerebrospinal fluid and tested for disease-causing organisms. A blood test and CT (computed tomography) and MRI (magnetic resonance imaging) will also be performed.

How Is This Condition Treated?

Usually, people are prescribed antifungal drugs to treat cryptococcal meningitis. The most commonly used are:

1. Amphotericin B

2. Fluconazole.

3. Itraconazole.

4. Flucytosine.

The most commonly used drug is Amphotericin B, which will be prescribed daily. While a person is under this medication, the doctors will closely monitor them to prevent nephrotoxicity (the medicine can be toxic to the kidneys). Amphotericin B is directly administered intravenously (directly into the veins). Flucytosine is administered along with Amphotericin B, which helps treat the condition more quickly. The patient is under proper observation under these medications as these drugs cause severe side effects, including kidney failure.

The cerebral spinal fluid tests should be done repeatedly; if the test results are negative for cryptococcal meningitis for two weeks, the patient is asked to stop Amphotericin B and Flucytosine. After the treatment, the patient is recommended Fluconazole for about eight weeks. The success of the treatment depends on how early the condition is diagnosed and what is the underlying cause.

What Are the Complications?

The complications can be caused by cryptococcal meningitis and the treatment they receive.

Complications From Cryptococcal Meningitis Are

• Repeated infection by cryptococcus.

• Seizures.

• Hearing loss.

• Brain damage.

• Increased fluid in the brain.

Complications From the Treatment With Amphotericin B Include

• Kidney damage.

• Muscle pain.

• Joint pain.

• Fever.

• Nausea and vomiting.

What Is the Differential Diagnosis?

The differential diagnosis is based on the cause of intracranial mass lesions and infections:

1. Pyogenic, Nocardial, or Aspergillus abscess.

2. Mycobacterium tuberculosis infection.

3. Histoplasma capsulatum infection.

4. Acanthamoeba infection.

5. Neurosyphilis.

6. Lymphomas, lymphocytic meningitis, and meningeal metastases.

7. Hemorrhages.

Conclusion

Cryptococcal meningitis is a fungal infection that affects the membrane surrounding the brain and the spine. Cryptococcus fungi usually cause this, which is present in the soil and bird droppings. This condition usually affects people with a compromised immune system, like HIV/AIDS. They are treated with antifungal medications.