Cryptococcosis

Contents

What is cryptococcosis?

Cryptococcosis is a fungus infection caused by inhaling the fungus Cryptococcus neoformans, which is mainly found in soils enriched with pigeon droppings. In the fall of wet or dried pigeons, C. neoformans it can remain viable for 2 years or more.

Two varieties of C. neoformans exist - neoformans and gattii. C. neoformans var neoformans is the most common variety and mainly affects immunosuppressed patients such as those with human immunodeficiency virus (HIV) infection and AIDS. C. neoformans var gattii it is much less common, but mainly affects immunocompetent people. This variety is restricted to subtropical and tropical areas and the fungus is found in eucalyptus trees and in the surrounding air.

What are the causes and risk factors for cryptococcosis?

The most common cryptococcosis infections (C. neoformans var neoformans) affect people with immunodeficiency, for example, patients with high doses of corticosteroids, Cancer chemotherapy patients organ transplant patients and patients with acquired immunodeficiency (AIDS) and HIV infection. With the global rise of AIDS, cryptococcosis is now one of the most common life-threatening fungal infections in these patients.

The infection is mainly through inhalation of cryptococcus spores released from soil and bird droppings. It occurs in both humans and animals, but animal-to-human and human-to-human transmission through respiratory droplets has not been documented. Transmission by organ transplantation has been reported when organs from infected donors were used. Infection from cuts through the skin is not common, but it can occur.

What are the clinical features of cryptococcosis?

The signs and symptoms of the disease are dependent at the site of infection. There are several main sites of infection.

Site of infection	Characteristics
Lung	In immunocompetent patients there can be no signs or symptoms. Often these patients will recover spontaneously without any medication. Immunosuppressed patients may present with mild to moderate symptoms, including fever, discomfort, dry cough, chest pain. Severe infection can lead to pneumonia or respiratory distress in adults syndrome.
Central Nervous System (CNS)	Meningitis It is the most common presentation. Signs and symptoms include headache, altered mental status, confusion, lethargy, nausea and vomiting, blurred or double vision, seizures, and coma. This form of infection is fatal without proper therapy. Death can occur from 2 weeks to several years after the onset of symptoms.
Disseminated (extended, involving other organs)	In severe infections, pulmonary and CNS disease is often associated with disseminated disease. The most commonly affected organs include the skin, the prostate, and the medullary cavity of the bones.

Cryptococcal infection of the skin

Skin infection occurs in 10 to 15% of patients infected with C. neoformans.
In immunocompetent patients, the skin may be the only site of infection.
In immunosuppressed patients, especially those with HIV infection or AIDS, skin infection is usually a sign of disseminated disease.
Skin infection presents as:
- Papules, pustules, nodules and ulcers
- Bleeding into the skin, presenting as petechiae or ecchymosis.

How is cryptococcosis diagnosed?

The following laboratory and radiology tests are performed to aid in the diagnosis of cryptococcal disease.

Sputum culture and stain
Lung biopsy
Bronchoscopy
CSF culture and staining
Chest x-ray

The skin biopsy shows characteristics histopathology.

What is the treatment for cryptococcosis?

Treatment of cryptococcal disease depends on the patient. immune status and site of infection. It is based on the following categories of infection.

Pulmonary cryptococcosis in an immunocompetent patient
Pulmonary cryptococcosis in an immunosuppressed patient
CNS cryptococcosis
Non-pulmonary disseminated cryptococcosis, non-CNS

Immunocompetent patients with asymptomatic Lung disease usually does not require any treatment. If the disease does not resolve spontaneously, the antifungal fluconazole can be given for 3 to 6 months.

Treatment goals for categories 2, 3, and 4 differ depending on whether the patient also has HIV / AIDS. The goal in HIV / AIDS infected patients is first control infection, followed by lifelong treatment to suppress C. neoformans. For patients with cryptococcal disease uncomplicated by HIV / AIDS, the goal of treatment is to eradicate the fungi and achieve a permanent cure.

Various antifungal medications are used.

Intravenous amphotericin B is the drug of choice for the initial therapy of disseminated, pulmonary, and CNS cryptococcosis.
Flucytosine should be used in conjunction with amphotericin B.
Oral fluconazole can be used for less serious infections and is used for lifelong treatment to prevent relapses.