Glossary of Micro - opportunistic fungi
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- Describe the appearance of Candida. Where is it found endogenously?
- *oval yeast, pseudohyphae may be present
*skin and mucous membranes, esp. skin folds, oral cavity, and female GU tract
- How can pseudohyphae be differentiated from normal hyphae?
- The walls of pseudohyphae are not parallel.
- What does Candida look like on culture?
- Not fluffy but rather appear as bacterial colonies.
- Name 7 factors which can dispose someone to fulminant infection be Candida.
- 1.Antibiotic treatment - especially females
2.Maceration of tissues - diaper rash
3.Immunosuppressive steroid tx
7.HIV and CA pts
- What manifestation of Candida infection can signal a low CD4+ count in HIV pts?
- Oral thrush
- What manifestations of Candida are seen in IV drug abusers?
- Fundal endocarditis and endophthalmitis
- CA pts with profound immunosupression and Candidemia may present with what symptom?
- Microabscesses in the RES.
- In diagnosing a Candida infection, why is it important to differentiate between C. albicans and other species?
- C. albicans is susceptible to fluconazole, whereas other species will need to be treated with amphoteracin.
- What factors may confound diagnosis of Candida?
- *b/c it is endogenous, presence may not indicate infection
*pts with candidemia may have negative blood cultures
- Describe the appearance of cryptococcus.
- Encapsulated round yeast.
- What environmental factor stimulates growth of cryptococcus? How is it acquired?
- *bird feces
*inhalation of yeast
- What patient population most frequently presents with fulminant infection by cryptococcus?
- *those with defects in T-cell immunity
- What is the most common manifestation of Cryptococcus in HIV/AIDS pts? What part of the structure facilitates this?
- *asceptic meningitis
*capsule allows movement into CNS
- What is the best means of diagnosing cryptococcus infection? What kind of sensitivity does this method offer?
- *detection of antigen in CSF or serum
- What asymptomatic manifestation of cryptococcus may appear in immunocompetent patients?
- A cryptocoma in the lungs.
- What treatment is recommended for HIV patients presenting with cryptococcal infections?
- Lifetime fluconazole prophylaxis.
- Describe the appearance of Aspergillus. Where is it found in nature?
- A mold with septate hyphae that shows acute right-angle branching in tissue. The fungus is ubiquitous and found nearly everywhere.
- List the 3 disease states associated with aspergillus.
- 1.Allergic bronchopulmonary aspergillosis
- What is ABPA? What patient population does it occur most often in?
- *allergic bronchopulmonary aspergillosis
*hypersensitivity reaction to spores
*no tissue invasion
*most common in pateinst with reactive airway disease, like CF or asthma
- How is aspergillus acquired?
- Inhalation of spores.
- Aspergillus can form a "fungus ball". What is this and how is it treated?
*grows in cavity spaces in lungs
*because of avscularity, rx are often ineffective and surgery is required
- What patient populations are most susceptible to invasive aspergillosis? What is the mortality in these patients?
- *HIV, bone marrow and solid organ transplant pts.
*for BM transplants, mortality is 70-100%
*severity of disease correlated with degree of immunosupression
- What occurs in invasive aspergillosis?
- *invasion of lung tissue and vasculature
*hemoptysis due to massive pulmonary hemorrhage
*septic emboli may cause extra-pulmonary disease
- Describe the appearance of the Zygomycetes.
- *wide, aseptate ribbony hyphae with right-angle branching
- What patient populations are most susceptible to rhinocerebral zygomycosis?
- *poorly controlled DM pts
- What symptoms does rhinocerebral zygomycosis present with? What are the dangers of this infection?
- *H/A, facial pain, periorbital swelling
*penetration into brain has 100% mortality
- What treatment is indicated for rhinocerebral zygomycosis?
- Aggressive surgical treatment, with debridement to continue until margins are clear.
- How is PCP usually identified?
- *not able to be cultured
*By direct examination
*induced sputum or bronchoscopic exam
- What kind of symptoms are caused by PCP? What part of the organism's pathogenesis contributes to this?
- *pneumonia with non-productive cough
*airway fills with foamy exudate which interferes with gas exchange
- What are the two recommended rx for tx of PCP?
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