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Opportunistic Infections: Cryptococcoses

Basic Information

Cryptococcoses, an infection which is the most common cause of meningitis in patients with advanced HIV disease, is caused by the yeast Cryptococcoses neoformanf--a harmless fungus that lives in soil, especially in soil fertilized by bird droppings.

But Cryptococcoses neoformanf is not only present in soil but in the excrement of pigeons and other birds. Fungal spores that are inhaled are believed to initially cause infection. After infection occurs these spores are transported by blood to other sites in the body.

Unfortunately it is difficult for HIV-infected patients to avoid this fungus altogether but risk of exposure may be lessened by avoiding places thought to be contaminated with the fungus. That would include places that are defiled by pigeon excrement. In Africa, data is stronger connecting the infection to pigeons than it is in the U.S. -- 40% of HIV-infected patients in Africa stated that they had had contact with pigeons. At any rate, the fungus is not spread from person to person contact.

This fungus is found the world over and when inhaled by a normal host it is contained in the lungs, but when inhaled by an HIV-infected person it can cause infection in:

  • the pulmonary system
  • the retina
  • the central nervous system
  • the skin
  • bones
  • lymph nodes
  • other disseminated areas

But in immunosuppressed patients the most commonly seen and the most serious manifestation is meningitis and the most common infection site is the brain.

It is estimated that 6% to 10% of HIV-infected patients in the U.S. will develop cryptococcal meningitis during the course of HIV disease. But generally it develops in patients with advanced HIV disease whose CD4 lymphocyte count is below 100 cells per mm -- a sign of meaningful immune system impairment.

Cryptococcal meningitis occurs when the membranes surrounding the brain (or the meninges) become infected, however the infection can occur in the brain itself.

Cryptococcoses has been associated with significant mortality rates in HIV-infected individuals, especially if treatment for the infection is not begun promptly after diagnosis. Early treatment is key. Treatment begun early enough has shown to be effective.

Symptoms

Headache, which can be severe, is usually the first symptom of meningitis. As the disease progresses, other symptoms appear and can include:

  • confusion
  • changes in mental status
  • lethargy
  • sensitivity to light
  • blurred vision
  • fever
  • nausea
  • vomiting
  • speech difficulties
  • cranial nerve abnormalities

Diagnosis/Treatment

A cryptococcal antigen test can confirm active infection with cryptococcal meningitis if the test for the causative fungal organism is positive. Many patients with advanced HIV disease exhibit the antigen in both cerebrospinal fluid and serum. A patient's history and physical exam is indicated with an eye towards evaluating the patient's neurological status.

Other diagnostic tools include:

  • lumbar puncture
  • CT and/or MRI
  • fungal culture
  • cerebrospinal fluid for India ink examination

Mental status may be an important indicator at time of diagnosis. Patients who are confused and lethargic generally respond less favorably than patients whose mental status is not impaired.

Untreated, cryptococcal meningitis can lead to coma and mortality but aggressive treatment begun early has improved the prognosis, though chronic suppressive therapy (maintenance antifungal therapy) is important because of recurrences in more than 50% of cases following treatment.

Drug therapy with fluconazole may be indicated for:

  • patients with mild disease
  • patients with spinal fluid antigens less than 1:128
  • patients with unimpaired mental status

Amphotericin B may be indicated for all other patients, at least initially, but once stability has occurred it may be possible to change to fluconazole.

Itraconazole may be substituted for fluconazole in patients who are unable to tolerate it. Reduction of frequency of disease has been found to be associated with use of fluconazole and itraconazole.

Drug therapy tailored to the individual and recommendations about prolonged amphotericin B therapy are in a state of change. A patient is best served being treated by a health care provider and medical team experienced at treating this infection.

In patients whose CD4 count is lower than 50 cells per mm, prophylaxis is an option but there may be mitigating factors that argue against it. Your health care provider and medical team will be able to evaluate you and explain benefits and risks of prophylaxis.

We at Always Your Choice are experienced at diagnosing and treating cryptococcoses. If you have symptoms of this opportunistic infection or have questions about it we will be glad to see you.