Cryptococcosis
A | Head trauma | |
B | Primary gastrointestinal infection | |
C | Hematogenous spread of fungus from the lung | |
D | Orthopedic surgery |
A | Head trauma | |
B | Primary gastrointestinal infection | |
C | Hematogenous spread of fungus from the lung | |
D | Orthopedic surgery |
C. neoformans causes cryptococcus, especially cryptococcal meningitis. C. neoformans is an oval, budding yeast surrounded by a large polysaccharide capsule. It occurs widely in nature and grows abundantly in soil containing bird droppings. The organism is most often inhaled and spread hematogenously from the lungs. Lung infections range from asymptomatic to pneumonia. Cryptococcosis is the most common encapsulated infection in the immunocompromised host. The organism disseminates hematogenously to the central nervous system (meningitis) andother organs. It can be cultured from cerebral spinal fluid (CSF) or diagnosed by serologic tests for either antibody or antigen. Amphotericin B and flucytosine are used to treat cryptococcal meningitis.
Latex agglutination study of the antigen in CSF helps in the diagnosis of –
A |
Cryptococcus |
|
B |
Candidiasis |
|
C |
Aspergillosis |
|
D |
Histoplasmosis |
Ans. is ‘a’ i.e., Cryptococcus
Capsular antigen is detected in CSF or serum by latex agglutination.
Which is false regarding cryptococcus neoformans‑
A |
Grows at 5°C and 37°C |
|
B |
It has 4 serotypes |
|
C |
Urease negative |
|
D |
Causes superficial skin infection |
Ans. is ‘c’ i e., Urease negative
Cryptococcus neoformans is distinguished from other non-pathogenic crvptococci by ‑
– Ability to grow at 37°C
Lack of fermentative ability
– Ability to hydrolyze urease (urease positive)
– Formation of brown pigment on niger seed agar
– Ability to assimilate inositol
Ability to produce phenole oxidase.
A | Skin | |
B |
Bone |
|
C |
Brain |
|
D |
Kidney |
Ans. is ‘d’ i.e., Kidney
Crvptococcosis
- Acquired by inhalation of the fungus into the lungs.
- Rarely acquired through skin or mucosa.
- Pulmonary infection has a tendency toward spontaneous resolution and is frequently asymptomatic.
- Silent hematogenous spread to the brain occurs, especially in basal ganglia or the head of the caudate nucleus.
- C/Fs – Self limiting pulmonary infection Most common form of cryptococcosis (Green wood) Meningoencephalitis (most patients have at the time of diagnosis)
Pulmonary symptoms
Skin lesions (10%)
Osteolytic lesions in bone (4%)
Remember
- Cryptococcus in AIDS patient has less signs and symptoms.
- Focal lesion called cryptococcomas are more common in previously normal patient.
- Self limiting pulmonary infection is the most common form of cryptococcosis, but most patient present with meningoencephalitis.
- Headache is the most common symptom.
- Cryptococcal lung lesions do not calcify.
A | Renal transplant recipient | |
B |
Agammaglobulinemia |
|
C |
Neutropenia |
|
D |
IgA deficiency |
Ans. is ‘a’ i.e., Renal transplant recipient
Predisposing factors for crvptococcus
- AIDS (most common) -4 when CD, T cells <200/ L • Sarcoidosis
- Glucocorticoids therapy • Lymphoma
- Solid organ transplantation (Renal transplant) • Idiopathic CD4 + lymphocytopenia
A | Cryptococcus neoformans | |
B |
Penicillium marneffi |
|
C |
Penicillium marneffi |
|
D |
Candida albicans |
Ans. is ‘a’ i.e., Cryptococcus neoformans
- Maltese cross pattern under palarized light is seen in :- Babesia, Cryptococcus, Aspergillus nidulans, starch granules and lipid (cholesterol) droplets.
“Fungal ball due to Aspergillus nidulans have a propensity to produce pale staining thick walled non-viable null cells that show maltese cross bifringence when examined under polarized light”.
“On polarized light the spores in cryptococcus give maltese cross appearance”. – Atals of deep mycosis
“Babesia microti is associated with maltese cross forms and ring forms”. – Barbara J. Bain
“Starch granules and fat (cholesterol) droplets produce maltese cross pattern in polarized light”.
March 2009 & March 2013
A | Blastomyces | |
B |
Cryptococcus neoformans |
|
C |
Histoplasma |
|
D |
Coccidioidomycosis |
Ans. B: Cryptococcus neoformans
Chronic meningitis is usually due to infection, most commonly tuberculosis. Infectious organisms invade the brain or the subarachnoid space and multiply slowly over weeks or months.
Such organisms include the bacteria that cause tuberculosis or syphilis and fungi such as Cryptococcus neoformans or Coccidioides immitis.
These fungi are more likely to cause chronic meningitis in people with a weakened immune system, such as those with human immunodeficiency virus (HIV) infection or acquired immunodeficiency syndrome (AIDS).
March 2007
A | Pentostatin | |
B |
Amphotericin B |
|
C |
Zidovudine |
|
D |
Clotrimazole |
Ans. B: Amphotericin B
Cryptococcus neoformans is an encapsulated yeast-like fungus. It causes meningitis, especially as a secondary infection in AIDS patients.
Cryptococcosis that does not affect the central nervous system can be treated with fluconazole alone.
Cryptococcal meningitis should be treated for two weeks with intravenous Amphotericin B and oral flucytosine. Main disadvantage of Amphotericin B includes nephrotoxicity.
September 2009
A | Histoplasmosis | |
B |
Cryptococcus |
|
C |
Candida albicans |
|
D |
Coccidiomycosis |
Ans. B: Cryptococcus
In immunocompetent patients, cryptococcal infection is usually asymptomatic, self-limited, and confined to the lungs.
In persons with advanced HIV infection (e.g., those with CD4 counts
In HIV-infected patients, Cryptococcus can infect almost all organs in the body, but most commonly causes meningitis or meningoencephalitis.
A | Primarily infects lung | |
B |
Urease negative |
|
C |
India-ink is used |
|
D |
All are true |
Ans. is `b i.e., Urease negative
CRYPTOCOCCUS NEOFORMANS
-
The only pathogenic yeast
-
Four capsular serotypes – A, B, C and D
-
It has polysaccharide capsule
-
Most infections in immunocompromised patients are caused by serotype A.
-
Pigeon droppings commonly contain serotype A and D.
-
Eucalyptus trees contain serotype B.
-
It is positively positive.
Mode of transmission
-
By inhalation of the fungus into the lung (most common)
-
Through skin or mucosa (some times).
A | Gram Stain | |
B |
Wright-Giemsa |
|
C |
India ink |
|
D |
Toluidine blue |
Ans. is ‘c’ i.e., India ink
Unstained wet preperations of CSF mixed with drop of India ink or nigrosine demonstrate the capsule as a clear halo.
Methenamine silver or periodic acid-Schiff are used for staining a tissue sample.