Cryptococcosis

Definition

Cryptococcosis is infection with the fungi Cryptococcus neoformans or Cryptococcus gattii.

Alternative Names

C. neoformans var. neoformans infection; C. neoformans var. gatti infection; C. neoformans var. grubii infection

Causes

C neoformans and C gattii are the fungi that cause this disease. Infection with C neoformans is seen worldwide. Infection with C gattii has mainly been seen in the Pacific Northwest region of the United States, British Columbia in Canada, Southeast Asia, and Australia. In the United States, sporadic cases have been seen in many states including Washington, Oregon, California, Idaho, Hawaii, Georgia, Rhode Island, and Florida. Cryptococcus is the most common fungus that causes serious infection worldwide.

Both types of fungi are found in soil. If you breathe the fungus in, it infects your lungs. The infection may go away on its own, remain in the lungs only, or spread throughout the body (disseminate). C neoformans infection is most often seen in people with a weak immune system, such as those who:

Are infected with HIV/AIDS
Take corticosteroid medicines
Cancer
Are on chemotherapy medicines for cancer
Have Hodgkin disease
Have had an organ transplant

C gattii may affect people with normal immune system.

C neoformans is the most common life-threatening cause of fungal infection in people with HIV/AIDS.

People between 20 to 40 years of age are the most common age group that has this infection.

Symptoms

The infection may spread to the brain in people who have a weakened immune system. Neurological (brain) symptoms start slowly. Most people have swelling and irritation of the brain and spinal cord when they are diagnosed. Symptoms of brain infection may include:

Fever and headache
Neck stiffness
Nausea and vomiting
Blurred vision or double vision
Confusion

The infection can also affect the lungs and other organs. Lung symptoms may include:

Difficulty in breathing
Cough
Chest pain

Other symptoms may include:

Bone pain or tenderness of the breastbone
Fatigue
Skin rash, including pinpoint red spots (petechiae), ulcers, or other skin lesions
Sweating -- unusual, excessive at night
Swollen glands
Unintentional weight loss

People with a healthy immune system may have no symptoms at all.

Exams and Tests

The health care provider will perform a physical exam and ask about symptoms and travel history. The physical exam may reveal:

Abnormal breath sounds
Fast heart rate
Fever
Mental status changes
Stiff neck

Tests that may be done include:

Blood culture to differentiate between the two fungi
CT scan of the head
Sputum culture and stain
Lung biopsy
Bronchoscopy and bronchoalveolar lavage
Spinal tap to obtain a sample of cerebrospinal fluid (CSF)
Cerebrospinal fluid (CSF) culture and other tests to check for signs of infection
Chest x-ray
Cryptococcal antigen test (looks for a certain molecule that is shed from the cell wall of the Cryptococcus fungus into the bloodstream or CSF)

Treatment

Fungal medicines are prescribed for people infected with cryptococcus.

Medicines include:

Amphotericin B (can have severe side effects)
Flucytosine
Fluconazole

Outlook (Prognosis)

Central nervous system involvement often causes death or leads to permanent damage.

When to Contact a Medical Professional

Contact your provider if you develop symptoms of cryptococcosis, especially if you have a weakened immune system.

References

Kauffman CA, Chen SC-A. Cryptococcosis. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 317.

Perfect JR. Cryptococcosis (Cryptococcus neoformans and Cryptococcus gattii). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 262.

Robles WS, Ameen M. Cryptococcosis. In: Lebwohl MG, Heymann WR, Murrell DF, eds. Treatment of Skin Disease: Comprehensive Therapeutic Strategies. 6th ed. Philadelphia, PA: Elsevier; 2022:chap 49.