of Medicine | Cryptococcosis
is an infection caused by inhaling the fungus Cryptococcus neoformans. It is one
of the diseases most often affecting AIDS patients. Cryptococcosis may be limited
to the lungs, but frequently spreads throughout the body. Although almost any
organ can be infected, the fungus is often fatal if it infects the nervous system
where it causes an inflammation of the membranes covering the brain and spinal
fungus causing cryptococcus, C. neoformans, is found worldwide in soil contaminated
with pigeon or other bird droppings. It has also been found on unwashed raw fruit.
Cryptococcosis is a rare disease in healthy individuals, but is the most common
fungal infection affecting people with AIDS.
with Hodgkin's disease or who are taking large doses of drugs that suppress the
functioning of the immune system (corticosteroids, chemotherapy drugs) are also
more susceptible to cryptococcal infection. Cryptococcosis is also called cryptococcal
meningitis (when the brain is infected), Busse-Buschke disease, European blastomycosis,
torular meningitis, or torulosis.
the cryptococcal fungus reaches the lungs, three things can happen. The immune
system can heal the body without medical intervention, the disease can stay localized
in the lungs, or it can spread throughout the body. In healthy people with normally
functioning immune systems, the body usually heals itself, and the infected person
notices no symptoms and has no complications (asymptomatic). The disease does
not spread from one person to another.
is an opportunistic infection that puts people with immune system diseases at
higher risk of developing more serious forms of the disease. In the United States,
610% of all patients with AIDS get cryptococcosis.
the body does not heal itself, the fungus begins to grow in the lungs and form
nodules that can be seen on chest x rays. In the early stages of infection, an
individual usually only exhibits symptoms of a respiratory infection, such as
a dry cough, so the disease is rarely diagnosed.
fungus can remain dormant in the lungs and produce an active infection later if
the immune system is weakened. If the disease becomes active, it can cause cryptococcal
pneumonia in the lungs. Unfortunately, however, cryptococcal pneumonia has symptoms
similar to other pneumonias (cough, chest pain, difficulty breathing), making
it difficult to accurately diagnose. The infection can spread to other parts of
the body, particularly the brain and central nervous system.
patients are not diagnosed as having cryptococcosis until they show signs of cryptococcal
meningitis, or infection of the membranes surrounding the brain and spinal cord.
Symptoms appear gradually over a period of two to four weeks. Fever and headache
are the most common symptoms, occurring in about 85% of patients. Nausea, vomiting,
unwanted weight loss, and fatigue are also common. Other symptoms seen in 2530%
of patients are blurred vision, stiff neck, aversion to light, and seizures. Since
the symptoms of classic meningitis, such as stiff neck and aversion to light,
do not occur in many patients, diagnosis is often delayed. In addition to meningitis,
inflammation of the brain (encephalitis) and brain lesions called cryptococcomas
or tortulomas can also develop.
addition to the brain, the cryptococcal infection can spread to the kidneys, bone
marrow, heart, adrenal glands, lymph nodes, urinary tract, blood, and skin. Often
times preceding the development of cryptococcal meningitis, painless rashes and
lesions that mimic other skin diseases, such as molluscum contagiosum, may develop.
A small percentage of patients with brain infections show infections in other
organs as well.
who regularly work with AIDS patients have the most experience in diagnosing cryptococcosis.
The preferred methods of diagnosis use simple and very accurate blood and cerebrospinal
fluid (CSF) tests that detect the presence of an antigen produced by the fungus.
The cerebrospinal fluid test is generally more sensitive to detecting the meningitis
form of the infection. CSF is collected during a procedure called a lumbar puncture,
during which an anesthetic is applied to a small area of the back near the spine
and a needle is used to withdraw a sample of cerebrospinal fluid from the space
between the vertebrae and the spinal cord. Once obtained, a small amount of ink
(called India ink) is added to a sample of CSF or a sample prepared from skin
lesions. If the fungus is present, it will become visible when the ink binds to
the capsule or covering that surrounds the fungus. Faster results are obtained
with the India ink test, but it is less accurate than the blood test (7585%
accuracy compared to 99% accuracy with the blood test) because some strains are
not visible using this method. Antigen tests are routinely recommended for non-symptomatic
patients with advanced AIDS.
way to diagnose cryptococcosis is to culture a sample of sputum, tissue from a
lung biopsy,or CSF in the laboratory to isolate the fungus. Cultures are also
done to assess the effectiveness of treatment.
x rays are useful in assessing lung damage and may reveal a single mass or multiple
distinct nodules, but the x ray alone does not lead to a definitive diagnosis
cryptococcosis is diagnosed, treatment begins with amphotericin B (Fungizone),
sometimes in combination with 5-flucytosine (Ancobon). Amphotericin B is a powerful
fungistatic drug with potentially toxic side effects,
such as kidney toxicity and lower concentrations of an important blood component
called hemoglobin. This medication can also cause fever, chills, nausea and vomiting,
diarrhea, headache, and muscle aches. Treatment is generally given intravenously
during a hospital stay and continues until the patient is stable or improving
(no more than two to three weeks). 5-flucytosine is given orally. Patients may
also receive other medication to minimize the side effects from these drugs.
B, with or without 5-flucytosine, is given for several weeks until the patient
is stable, after which the patient receives oral fluconazole (Diflucan). Fluconazole
is a broad-spectrum antifungal drug with few serious side effects. Patient with
AIDS must continue taking fluconazole for the rest of their lives to prevent a
relapse of cryptococcosis. Sometimes fluconazole is given to patients with advanced
AIDS as a preventative (prophylactic) measure.
of the high cost of fluconazole, the manufacturer of the drug, Pfizer, has established
a financial assistance plan to make the drug available at lower cost to those
who meet certain criteria. Patients needing this drug should ask their doctors
about this program.
cryptococcosis is always fatal. The acute mortality rate for patients with AIDS
is 1025%. Most deaths are attributable to cryptococcal meningitis and occur
within two weeks after diagnosis. For AIDS patients who do not receive continued
suppressive therapy (fluconazole), the relapse rate is 5060% within six
months and a shortened life expectancy. Once the cryptococcosis infection has
been successfully treated, individuals may be left with a variety of neurologic
symptoms, such as weakness, headache, and hearing or visual loss. In addition,
fluid may accumulate around the brain (hydrocephalus).
best way to prevent cryptococcosis is to stay free of HIV infection. People with
suppressed immune systems should try to stay away from areas contaminated with
pigeon or other bird droppings, such as the attics of old buildings, barns, and
areas under bridges where pigeons roost.
for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. (800)
311-3435, (404) 639-3311. <http://www.cdc.gov>.
Aids Clearinghouse. 800-458-5231.
Aids Hotline. 800-342-AIDS.
Inform. 205 13th Street, #2001, San Francisco, CA 94103. (800) 822-7422. <http://www.projinf.org>.
William G. "Cryptococcosis." Journal of the International Association
of Physicians in AIDS Care. July 1996 <http://www.iapac.org/diseases/fungi/cocc.html>.
Inform Cryptococcal Infections Fact Sheet." Project Inform. 21 May 1996 <http://www.projinf.org>.
glandA pair of organs located above the kidneys. The outer tissue of the
gland produces the hormones epinephrine (adrenaline) and norepinephrine, while
the inner tissue produces several steroid hormones.
B (Fengizone)An antifungal medication, prescribed for topical or systemic
use in treating fungal infections.
specific protein produced by the immune system in response to a specific foreign
protein or particle called an antigen.
foreign protein or particle capable of eliciting an immune response.
who carry a disease but who do not exhibit symptoms of the disease are said to
removal of a tissue sample for diagnostic purposes.
fluid (CSF)The clear fluid that surrounds the spinal cord and brain and
acts as a shock absorber.
group of hormones produced naturally by the adrenal gland or manufactured synthetically.
They are often used to treat inflammation. Examples include cortisone and prednisone.
of the brain.
diseaseA disease that causes chronic inflammation of the lymph nodes, spleen,
liver and kidneys. It is also called malignant lymphoma.
of fluid around the brain.
state in which the immune system is suppressed or not functioning properly.
ink testA diagnostic test used to detect the cyptococcal organism C. neoformans.
A dye, called India ink, is added to a sample of CSF fluid, and if the fungi is
present, they will become visible as the dye binds to the capsule surrounding
punctureAlso called a spinal tap, a procedure in which a thin needle is
used to withdraw a sample of cerebrospinal fluid for diagnostic purposes from
the area surrounding the spine.
of the membranes covering the brain and spinal cord called the meninges.
contagiosumA disease of the skin and mucuous membranes, caused by a poxvirus
and found all over the world.
infectionAn infection that is normally mild in a healthy individual, but
which takes advantage of an ill person's weakened immune system to move into the
body, grow, spread, and cause serious illness.
of the lungs, typically caused by a virus, bacteria, or other organism.