CryptococcosisIntroduction:
This condition is also known under the alternative diagnostic
names "tolurosis" or "blastomycosis". It is a fungal infection,
which is transmitted by Cryptococcus
neoformans that is found in soil worldwide. Some patients are very
sensitive to this pathogen, particularly AIDS patients, but also patients with
Hodgkins lymphoma, patients on longterm high doses of corticosteroids or sarcoidosis
patients. The encapsulated yeast form of C. neoformans enters the body
through inhalation of dust contaminated with the pathogen. In the lungs of a healthy
host a self-limited cryptococcal infection would ensue. However, in a patient
whose immune system is paralyzed such as with AIDS a severe pneumonia will develop.
The infection then spreads throughout the system with skin lesions, subcutaneous
nodules and disease in liver, kidneys, spleen, joints, bones, prostate and other
organs. Even the central nervous system is often affected in AIDS patients with
cryptococcal meningitis. Signs
and symptoms: During the acute lung infection phase symptoms would
include coughing, chest wall pain and difficulties breathing. Skin involvement
looks quite varied with pustules, papules, acne like and even with basal cell
cancer-like appearance of lesions. This is shown here with two
images, before and after treatment (be patient, loads slowly). If the
physician is in doubt what the lesions are, one or two of them could be biopsied
for analysis by the pathologist. Single lesions in bone, abdominal organs or kidney
may not give any symptoms, because they are pain free and are self-limiting in
a person with a normal immune system. Headaches, blurred vision, behavioral changes,
confusion, agitation and depression can all be symptoms of a beginning cryptococcal
meningitis. Diagnostic tests: Mostly the diagnosis
is made by culture from body fluid samples such as urine, blood, phlegm or cerebrospinal
fluid (CSF). Smears of biopsy specimens can be examined after special staining
techniques by an experienced laboratory physician or technician. The characteristic
encapsulated budding yeasts of C.neoformans with cryptococcal capsular polysaccharide
have a unique appearance that can readily be distinguished from other pathogens
by the experienced observer. Finally there is a latex test for capsular antigen,
which is a specific blood test, particularly, if the titers are higher than 1:8.
For pulmonary lesions X-rays, CT scans, bronchoscopy with biopsy are employed
to lead to a diagnosis. With any palpable lesion such as in skin or in the subcutaneous
tissue skin biopsy would be considered. With meningitis lumbar puncture to obtain
CSF has to be done in order to diagnose the condition. Treatment:
Treatment has to be individualized according to the situation. It depends
whether the patient is immuno-competent or immunocompromised as in an AIDS patient. The
patient with a normal immune system may not need treatment for a localized lung
infection with cryptococcus, as it would often be self limiting. However, in order
to be certain that the assumption of "localized disease" is correct
it is wise for the physician to examine and culture the CSF (to rule out meningitis),
the urine (rule out kidney involvement) and examine the skin for any abnormal
lesions. Patients with a normal immune system can be treated for mild disease
with fluconazole (brand name: Diflucan) orally. More severe infection would have
to be treated with flucytosine (brand name: Ancobon) orally, but side-effects
(kidney and bone marrow toxicity) has to be monitored. Some centers can measure
flucytosine levels, which would be desirable to avoid toxic levels. Serious disease
is treated with intravenous amphotericin B in combination with or followed by
oral flucytosine. In AIDS patients responses are often incomplete. Treatment
is therefore often combined antifungal drug therapy and the course is longer or
ongoing. The physician starts with intravenous amphotericin B and oral flucytosine
(brand name: Ancobon). If after two weeks the cryptococcosis is cured, a preventative
maintenance dose of fluconazole (brand name: Diflucan) is given orally. Blood
tests are usually done to show that the antigen titers for cryptococcosis are
negative before treatment can be stopped (Ref. 1, p.1220). |
