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30 Cards in this Set
- Front
- Back
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Describe the appearance of Candida. Where is it found endogenously?
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*oval yeast, pseudohyphae may be present
*skin and mucous membranes, esp. skin folds, oral cavity, and female GU tract |
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How can pseudohyphae be differentiated from normal hyphae?
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The walls of pseudohyphae are not parallel.
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What does Candida look like on culture?
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Not fluffy but rather appear as bacterial colonies.
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Name 7 factors which can dispose someone to fulminant infection be Candida.
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1.Antibiotic treatment - especially females
2.Maceration of tissues - diaper rash 3.Immunosuppressive steroid tx 4.Catheters 5.Pregnancy 6.DM pts 7.HIV and CA pts |
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What manifestation of Candida infection can signal a low CD4+ count in HIV pts?
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Oral thrush
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What manifestations of Candida are seen in IV drug abusers?
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Fundal endocarditis and endophthalmitis
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CA pts with profound immunosupression and Candidemia may present with what symptom?
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Microabscesses in the RES.
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In diagnosing a Candida infection, why is it important to differentiate between C. albicans and other species?
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C. albicans is susceptible to fluconazole, whereas other species will need to be treated with amphoteracin.
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What factors may confound diagnosis of Candida?
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*b/c it is endogenous, presence may not indicate infection
*pts with candidemia may have negative blood cultures |
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Describe the appearance of cryptococcus.
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Encapsulated round yeast.
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What environmental factor stimulates growth of cryptococcus? How is it acquired?
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*bird feces
*inhalation of yeast |
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What patient population most frequently presents with fulminant infection by cryptococcus?
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*those with defects in T-cell immunity
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What is the most common manifestation of Cryptococcus in HIV/AIDS pts? What part of the structure facilitates this?
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*asceptic meningitis
*capsule allows movement into CNS |
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What is the best means of diagnosing cryptococcus infection? What kind of sensitivity does this method offer?
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*detection of antigen in CSF or serum
*90% sensitivity |
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What asymptomatic manifestation of cryptococcus may appear in immunocompetent patients?
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A cryptocoma in the lungs.
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What treatment is recommended for HIV patients presenting with cryptococcal infections?
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Lifetime fluconazole prophylaxis.
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Describe the appearance of Aspergillus. Where is it found in nature?
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A mold with septate hyphae that shows acute right-angle branching in tissue. The fungus is ubiquitous and found nearly everywhere.
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List the 3 disease states associated with aspergillus.
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1.Allergic bronchopulmonary aspergillosis
2.Aspergilloma 3.Invasive aspergillosis |
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What is ABPA? What patient population does it occur most often in?
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*allergic bronchopulmonary aspergillosis
*hypersensitivity reaction to spores *no tissue invasion *most common in pateinst with reactive airway disease, like CF or asthma |
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How is aspergillus acquired?
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Inhalation of spores.
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Aspergillus can form a "fungus ball". What is this and how is it treated?
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*aspergilloma
*grows in cavity spaces in lungs *because of avscularity, rx are often ineffective and surgery is required |
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What patient populations are most susceptible to invasive aspergillosis? What is the mortality in these patients?
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*HIV, bone marrow and solid organ transplant pts.
*for BM transplants, mortality is 70-100% *severity of disease correlated with degree of immunosupression |
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What occurs in invasive aspergillosis?
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*invasion of lung tissue and vasculature
*hemoptysis due to massive pulmonary hemorrhage *septic emboli may cause extra-pulmonary disease |
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Describe the appearance of the Zygomycetes.
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*wide, aseptate ribbony hyphae with right-angle branching
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What patient populations are most susceptible to rhinocerebral zygomycosis?
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*poorly controlled DM pts
*neutropenic pts |
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What symptoms does rhinocerebral zygomycosis present with? What are the dangers of this infection?
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*H/A, facial pain, periorbital swelling
*penetration into brain has 100% mortality |
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What treatment is indicated for rhinocerebral zygomycosis?
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Aggressive surgical treatment, with debridement to continue until margins are clear.
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How is PCP usually identified?
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*not able to be cultured
*By direct examination *induced sputum or bronchoscopic exam |
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What kind of symptoms are caused by PCP? What part of the organism's pathogenesis contributes to this?
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*pneumonia with non-productive cough
*airway fills with foamy exudate which interferes with gas exchange |
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What are the two recommended rx for tx of PCP?
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*SMZ-TMP
*pentamidine |
