Opportunistic Fungal Infections Flashcards
Which Sketchy image represents Candida albicans?
‘Candid Canadians’
Which Sketchy image represents Aspergillus fumigatus?
‘Asparagus Farm Fumigation’
Which Sketchy image represents Cryptococcus neoformans?
‘The Crypt’
Which Sketchy image represents Mucor spp. and Rhizopus spp. (mucormycetes)?
‘The Mu Car Shop and Rhizo Parts’
Which Sketchy image represents Pneumocystis jirovecii?
‘PCP Ping Pong’
Identify as many of the marked points in this image as you can.
Note: this image represents Candida albicans.
Identify as many of the marked points in this image as you can.
Note: this image represents Aspergillus fumigatus.
Identify as many of the marked points in this image as you can.
Note: this image represents Cryptococcus neoformans.
Identify as many of the marked points in this image as you can.
Note: this image represents Mucor spp. and Rhizopus spp.
Identify as many of the marked points in this image as you can.
Note: this image represents Pneumocystis jirovecii.
True/False.
Candida albicans is a dimorphic fungus in that it is a mold at 20°C and a yeast at 37°C.
False.
Candida albicans is a dimorphic fungus, but differs from other dimorphic fungi in that it forms pseudohyphae and budding yeast at 20°C (yeast form), and germ tubes at 37°C (mold form).
When will Candidia albicans be in its germ tube (mold) form?
When will Candidia albicans be in its pseudohyphae (budding yeast) form?
37°C;
20°C
(opposite of most dimorphic fungi)
True/False.
Candida albicans are urease-positive.
False.
Candida albicans are catalase-positive.
(Cryptococcus neoformans are urease-positive.)
- Candida albicans* forms germ tubes at ___°C.
- Candida albicans* forms pseudohypha at ___°C.
- Candida albicans* forms germ tubes at 37°C.
- Candida albicans* forms pseudohypha at 20°C.
Candida albicans can cause cutaneous candidiasis in areas exposed to what?
Candida albicans can cause cutaneous candidiasis in areas exposed to heat and humidity (e.g. diaper rash in infants).
Candida albicans can cause disseminated disease in immunocompromised patients (especially those with ________).
Candida albicans can cause disseminated disease in immunocompromised patients (especially those with neutropenia).
Oral thrush due to Candida albicans (which commonly presents as white patches on the lining of the mouth) is associated with what conditions or situations?
Oral or inhaled steroid use;
immunosuppression
How is oral thrush different from leukoplakia of the oral mucosa?
Oral thrush can be scraped off
How can Candida albicans infection be diagnosed?
KOH mount of oral/vaginal/skin scrapings
(microscopic examination will show budding yeast and pseudohyphae)
What form of Candida albicans infection is an AIDS-defining illness?
How does it appear?
HIV-associated esophagitis;
adherent grey/white pseudomembranes
Esophageal candidiasis is an AIDS-defining illness that generally occurs in patients with a CD4+ count
Esophageal candidiasis is an AIDS-defining illness that generally occurs in patients with a CD4+ count <200.
How does vulvovaginal candidiasis typically present?
Vulvar pruritus and a thick white vaginal discharge
Uncontrolled _________ _________ (disease), _________ (medication) use, and high _________ (hormone) levels are risk factors for vulvovaginal candidiasis.
Uncontrolled diabetes mellitus, antibiotic use, and high estrogen levels (e.g. oral contraceptives, pregnancy) are risk factors for vulvovaginal candidiasis.
What effect does vulvovaginal candidiasis have on vaginal pH?
The pH typically remains normal (3.8 - 4.5)
What fungus is sometimes found in heroin and can cause right-sided endocarditis associated with IV drug use?
Candida albicans
True/False.
Candida albicans infective endocarditis commonly affects the tricuspid valve and is associated with IV drug use, prosthetic heart valves, and indwelling lines.
True.
_______azole is effective against Candida albicans.
Fluconazole is effective against Candida albicans.
What medication should be used to treat Candida albicans infections when resistance or intolerance to preliminary antifungals is suspected or proven?
Amphotericin B
_________ is used topically to treat Candida skin infections (but is not indicated for vaginal candidiasis) and orally for thrush.
Nystatin is used topically to treat Candida skin infections (but is not indicated for vaginal candidiasis) and orally for thrush.
Nystatin can be used to treat what forms of Candida infections?
How?
Cuteaneous (topical) (but is not indicated for vaginal candidiasis);
thrush (oral)
___________/micafungin (echinocandins antifungals) can be used to treat oral, esophageal, and systemic candidiasis.
Caspofungin/micafungin (echinocandins antifungals) can be used to treat oral, esophageal, and systemic candidiasis.
True/False.
Aspergillus spp. fungi are catalase-positive.
True.
Aflatoxins produced by Aspergillus flavus can be found in what foods?
Nuts, legumes, wheat, and other crops
Aflatoxins of Aspergillus flavus have been linked to ________ ________.
Aflatoxins of Aspergillus flavus have been linked to hepatocellular carcinoma.
Aflatoxins of Aspergillus _______ have been linked to hepatocellular carcinoma.
Aflatoxins of Aspergillus flavus have been linked to hepatocellular carcinoma.
Aspergillus spp. have ________ (septate / non-septate) hyphae that form ≤ _____-degree angle branches.
Aspergillus spp. have septate hyphae that form ≤ 45-degree angle branches.
Aspergillus is transmitted via what mechanism?
Inhalation of spores
(contained in fruiting bodies)
Allergic bronchopulmonary aspergillosis (a type __ hypersensitivity reaction) presents with migratory _________ infiltrates, wheezing, and increased serum Ig__ (most commonly in cystic fibrosis and asthma patients).
Allergic bronchopulmonary aspergillosis (a type II hypersensitivity reaction) presents with migratory pulmonary infiltrates, wheezing, and increased serum IgE (most commonly in cystic fibrosis and asthma patients).
Where do the ‘fungus balls’ associated with colonization of Aspergillus in the lung usually form?
(May cause fever, hemoptysis, and cough.)
In old pulmonary cavities
(from past infections or other pulmonary damage)
____________ (“fungus balls”) typically develop in old pulmonary cavities (from tuberculosis, sarcoidosis, emphysema, etc.).
Aspergillomas (“fungus balls”) typically develop in old pulmonary cavities (from tuberculosis, sarcoidosis, emphysema, etc.).
Aspergillomas (“fungus balls”) typically develop in old pulmonary cavities (i.e. following tuberculosis) and classically appear as radio______ (-paque / -lucent) structures that shift with change in position on chest X-ray (_______-dependent).
Aspergillomas (“fungus balls”) typically develop in old pulmonary cavities (i.e. following tuberculosis) and classically appear as radiopaque structures that shift with change in position on chest X-ray (gravity-dependent).
What are the three main categories of infection with Aspergillus spp.?
- _________ _________ aspergillosis
- _________omas
- _________ _________ aspergillosis
- Allergic bronchopulmonary aspergillosis
- Aspergillomas
- Invasive pulmonary aspergillosis
Invasive pulmonary aspergillosis is _______invasive, and ________-centered. It typically occurs in immunosuppressed and ______penic patients.
Invasive pulmonary aspergillosis is angioinvasive, and airway-centered. It typically occurs in immunosuppressed and neutropenic patients.
A key point of the pathophysiology of invasive pulmonary aspergillosis is that it is what?
It is angioinvasive
In severely immunocompromised and neutropenic patients, Aspergillus spp. can invade blood vessels and spread hematogenously to the ________, ________, ________, skin, and paranasal sinuses, causing infection and _________.
In severely immunocompromised and neutropenic patients, Aspergillus spp. can invade blood vessels and spread hematogenously to the kidneys, endocardium, brain, skin, and paranasal sinuses, causing infection and infarction.
True/False.
Invasive pulmonary aspergillosis occurs in immunocompromised/neutropenic patients and can present with some combination of fever, cough, hemoptysis, chest pain, and dyspnea.
True.
How can severe aspergillosis cause renal failure in immunocompromised and neutropenic patients?
Hematogenous spread to the kidneys
(which may result in infarction and renal failure)
True/False.
Both Candida albicans and Aspergillus spp. can cause endocarditis in severe infections.
True.
How does cerebral Aspergillus in immunocompromised / neutropenic patients appear on imaging?
Ring-enhancing lesions
In immunocompromised and neutropenic patients, Aspergillus can spread hematogenously to the ________ sinuses, which may lead to tissue necrosis.
In immunocompromised and neutropenic patients, Aspergillus can spread hematogenously to the paranasal sinuses, which may lead to tissue necrosis.
____________ is an effective treatment against most cases of aspergillosis.
What should be given for severe cases?
Voriconazole is an effective treatment against most cases of aspergillosis.
Amphotericin B
__________ __________ yeast cells are encapsulated by a thick polysaccharide layer with antiphagocytic properties.
Cryptococcous neoformans yeast cells are encapsulated by a thick polysaccharide layer with antiphagocytic properties.
True/False.
Cryptococcus neoformans is unique in that it has a very thick peptide capsule that is anti-phagocytic.
False.
Cryptococcus neoformans is unique in that it has a very thick polysaccharide capsule that is anti-phagocytic.
Where is Cryptococcus neoformans typically found?
Bird (especially pidgeon) droppings
and soil
How is Cryptococcus neoformans typically introduced into the body?
Inhalation
Cryptococcus neoformans fungi are ________-positive.
Cryptococcus neoformans fungi are urease-positive.
Cryptococcus neoformans is an opportunistic fungi that more commonly affects what kind of patients?
Cryptococcus neoformans is an opportunistic fungi that more commonly affects immunocompromised patients (i.e. HIV patients).
True/False.
Pulmonary cryptococcosis is often asymptomatic.
True.
(but may present with coughing and dyspnea)
The most common manifestation of Cryptococcus neoformans infection is __________.
The most common manifestation of Cryptococcus neoformans infection is meningitis (particularly in immunocompromised patients).
Microscopic examination of bronchoalveolar lavage prepared with __________ or __________ stain can be done to diagnose pulmonary cryptococcosis.
Microscopic examination of bronchoalveolar lavage prepared with mucicarmine or methenamine stain can be done to diagnose pulmonary cryptococcosis.
Microscopic examination of _________ _________ prepared with mucicarmine or methenamine stain can be done to diagnose pulmonary cryptococcosis.
Microscopic examination of bronchoalveolar lavage prepared with mucicarmine or methenamine stain can be done to diagnose pulmonary cryptococcosis.
Bronchoalveolar lavage can be prepared with mucicarmine (_____) or methenamine (_____) stain for diagnosis of pulmonary cryptococcosis.
Bronchoalveolar lavage can be prepared with mucicarmine (red) or methenamine (silver) stain for diagnosis of pulmonary cryptococcosis.
In cryptococcal meningitis, what staining of cerebrospinal fluid will show a wide clear zone (capsular “haloes”) around Cryptococcus neoformans yeast cells on a dark background?
India ink staining
In _________ meningitis, india ink staining of cerebrospinal fluid will show a wide clear zone (capsular “haloes”) around _________ _________ yeast cells on a dark background.
In cryptococcal meningitis, india ink staining of cerebrospinal fluid will show a wide clear zone (capsular “haloes”) around Cryptococcus neoformans yeast cells on a dark background.
The _________ _________ test detects the polysaccharide capsule antigen of Cryptococcus neoformans in the serum and cerebrospinal fluid for diagnosis of cryptococcosis.
The latex agglutination test detects the polysaccharide capsule antigen of Cryptococcus neoformans in the serum and cerebrospinal fluid for diagnosis of cryptococcosis.
Cryptococcal meningoencephalitis may present with what brain lesions on MRI?
‘Soap bubble’ lesions
Initial treatment of cryptococcal meningitis is a combination of _________ and _________ (followed by long-term therapy with ______azole).
Initial treatment of cryptococcal meningitis is a combination of amphotericin B and flucytosine (followed by long-term therapy with fluconazole).
Name two fungal species that can cause mucormycosis.
- Mucor spp.*;
- Rhizopus* spp.
Mucomycosis is strongly associated with what two patient populations?
The immunocompromised;
those with DKA
Certain species of Rhizopus spp. are common _______ molds.
Certain species of Rhizopus spp. are common bread molds.
Mucor spp. and Rhizopus spp. enter the body through ___________.
Mucor spp. and Rhizopus spp. enter the body through inhalation.
The mold forms of Mucor spp. and Rhizopus spp. form _________ (septate / non-septate) hyphae that branch at ___° angles.
The mold forms of Mucor spp. and Rhizopus spp. form non-septate hyphae that branch at 90° angles.
In what tissue do Mucor spp. and Rhizopus spp. proliferate?
Blood vessel walls
How do Mucor spp. and Rhizopus spp. enter the brain?
Via the cribriform plate
Rhinocerebral mucormycosis can lead to necrosis of what?
The nasal cavity, presenting as a black eschar on the palate or turbinates
Treatment of mucormycosis includes what?
Amphotericin B and surgical debridement
What is the most prevalent opportunistic infection in HIV patients and is an AIDS-defining illness?
Pneumocystis jiroveci (carinii) pneumonia
(known as PJP or PCP)
True/False.
Pneumocystis jiroveci (carinii) is an opportunistic fungi that affects immunocompromised patients almost exclusively.
True.
True/False.
Disease caused by Pneumocystis jiroveci (carinii) in immunocompetent patients happens fairly often.
False.
Although immunocompetent individuals may be asymptomatic carriers of P. jiroveci (carinii), it rarely causes disease.
HIV patients with a CD4+ count < _____ are at risk of developing Pneumocystis jiroveci (carinii) pneumonia.
HIV patients with a CD4+ count 200 are at risk of developing Pneumocystis jiroveci pneumonia.
How does Pneumocystis jiroveci (carinii) pneumonia present on CXR?
“Ground glass” infiltrates
What is the updated term for Pneumocystis carinii?
Pneumocystis jiroveci
___________ examination or PCR of ________ ________ fluid or induced ________ sample can be used to diagnose Pneumocystis jiroveci (carinii) pneumonia.
Microscopic examination or PCR of bronchoalveolar lavage fluid or induced sputum sample can be used to diagnose Pneumocystis jiroveci (carinii) pneumonia.
____________ ________ stain of lung biopsy or bronchoalveolar lavage fluid shows disc-shaped yeast-like cells in Pneumocystis jiroveci (carinii) pneumonia.
Methenamine silver stain of lung biopsy or bronchoalveolar lavage fluid shows disc-shaped yeast-like cells in Pneumocystis jiroveci (carinii) pneumonia.
Methenamine silver stain of lung biopsy or bronchoalveolar lavage fluid shows ______-shaped ______-like cells in Pneumocystis jiroveci (carinii) pneumonia.
Methenamine silver stain of lung biopsy or bronchoalveolar lavage fluid shows disc-shaped yeast-like cells in Pneumocystis jiroveci (carinii) pneumonia.
Yeast-like cells of Pneumocystis jiroveci (carinii) have an ovoid or “_______________” appearance on microscopic examination of methenamine silver stained lung tissue or bronchoalveolar lavage fluid.
Yeast-like cells of Pneumocystis jiroveci (carinii) have an ovoid or “crushed ping pong ball” appearance on microscopic examination of methenamine silver stained lung tissue or bronchoalveolar lavage fluid.
What is used in HIV patients for prevention (given prophylactically when CD4+ count is <200) and treatment of Pneumocystis jiroveci (carinii) pneumonia?
Bactrim (trimethoprim-sulfamethoxazole)
In addition to bactrim (trimethoprim-sulfamethoxazole), ____________ can be used in HIV patients for prevention (given prophylactically when CD4+ count is < ____) of Pneumocystis jiroveci (carinii) and it can also be given for treatment of Pneumocystis jiroveci (carinii) pneumonia when bactrim (trimethoprim-sulfamethoxazole) is not tolerated.
In addition to bactrim (trimethoprim-sulfamethoxazole), pentamidine can be used in HIV patients for prevention (given prophylactically when CD4+ count is 200) of Pneumocystis jiroveci (carinii) and it can also be given for treatment of Pneumocystis jiroveci (carinii) pneumonia when bactrim (trimethoprim-sulfamethoxazole) is not tolerated.
