Cryptococcosis

Overview

Cryptococcosis is a chronic, subacute to acute pulmonary, systemic or meningitic disease, initiated by the inhalation of basidiospores and/or desiccated yeast cells of Cryptococcus neoformans. Primary pulmonary infections have no diagnostic symptoms and are usually subclinical. On dissemination, the fungus usually shows a predilection for the central nervous system, however skin, bones and other visceral organs may also become involved. Although C. neoformans is regarded as the principle pathogenic species, C. albidus and C. laurentii have on occasion also been implicated in human infection.

source: mycology

Symptoms

  • Blurred vision or double vision (diplopia)
  • Bone pain or tenderness of the breastbone (sternum)
  • Chest pain
  • Confusion
  • Cough -- dry
  • Fatigue
  • Fever
  • Headache
  • Nausea
  • Skin rash -- pinpoint red spots (petechiae)
  • Sweating -- unusual, excessive at night
  • Swollen glands
  • Unintentional weight loss
  • Weakness

Note: People with a normal immune system may have no symptoms at all.

source: NIH

Causes

Cryptococcus is an encapsulated basidiomycete yeast-like fungus with a predilection for the respiratory and nervous system of humans and animals. Two species, C. neoformans and C. gattii are distinguishable biochemically and by molecular techniques.

In humans, C. neoformans affects immunocompromised hosts predominantly and is the commonest cause of fungal meningitis; worldwide, 7-10% of patients with AIDS are affected. AIDS associated cryptococcosis accounts for 50% of all cryptococcal infections reported annually and usually occurs in HIV patients when their CD4 lymphocyte count is below 200/mm3. Meningitis is the predominant clinical presentation with fever and headache as the most common symptoms. Secondary cutaneous infections occur in up to 15% of patients with disseminated cryptococcosis and often indicate a poor prognosis. Lesions usually begin as small papules that subsequently ulcerate, but may also present as abscesses, erythematous nodules, or cellulitis. This variety is found worldwide.

In contrast, the distribution of cryptococcosis due to Cryptococcus gattii is geographically restricted, non-immunocompromised hosts are usually affected, large mass lesions in lung and/or brain (cryptococcomas) are characteristic and morbidity from neurological disease is high. Human disease is endemic in Australia, Papua New Guinea, parts of Africa, the Mediterranean region, India, south-east Asia, Mexico, Brazil, Paraguay and Southern California.

source: mycology

Prevention

Take the lowest doses of corticosteroid medications possible. Practice safe sex to reduce the risk of getting HIV and the infections associated with a weakened immune system.

source: NIH

Diagnosis

  • Sputum cultureSputum culture and stain
  • Lung biopsyLung biopsy
  • BronchoscopyBronchoscopy
  • Cerebrospinal Fluid cultureCerebrospinal Fluid culture and stain for Cryptococcus
  • Chest x-rayChest x-ray
  • Cryptococcal antigen test (looks for a certain molecule that the Cryptococcus fungus can shed into the blood)

source: NIH

Prognosis

Cryptococcosis is a defining opportunistic infection for AIDS. Other conditions which pose an increased risk include certain lymphomas (e.g. Hodgkin's lymphoma), sarcoidosis, and patients on long-term corticosteroid therapy.

Distribution is worldwide. The prevalence of cryptococcosis has been increasing over the past 20 years for many reasons, including the increase in incidence of AIDS and the expanded use of immunosuppressive drugs.

In humans, C. neoformans causes three types of infections:

  • Wound or cutaneous cryptococcosis
  • Pulmonary cryptococcosis, and
  • Cryptococcal meningitis.

Cryptococcal meningitis (infection of the meninges, the tissue covering the brain) is believed to result from dissemination of the fungus from either an observed or unappreciated pulmonary infection. Cryptococcus gattii causes infections in immunocompetent people (those having a functioning immune system), but C. neoformans v. grubii, and v. neoformans usually only cause clinically evident infections in persons who have some form of defect in their immune systems (immunocompromised persons). People who have defects in their cell-mediated immunity, for example, people with AIDS, are especially susceptible to disseminated cryptococcosis. Cryptococcosis is often fatal, especially if untreated.

source: wikipedia

Treatment

Some infections require no treatment. Even so, there should be regular check-ups for a full year to make sure the infection has not spread. If there are lung lesions or the disease spreads, antifungal medications are prescribed. These drugs may need to be taken for a long time.

Medications include:

  • Amphotericin B
  • Flucytosine
  • Fluconazole

Expectations (prognosis):

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

Complications:

  • Infection comes back
  • Meningitis
  • Permanent brain or nerve damage
  • Side effects of medications (such as Amphotericin B) can be severe

source: MarylandUni