Term
| what are the endemic mycoses? what kind of fungi are they? |
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Definition
| coccidioidomycosis, histoplasmosis, and blastomycosis; all of which are dimorphic fungi (infectious mold in soil @ 25 C and yeast in tissue @ 37 C) |
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Term
| how are most fungi transmitted? |
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Definition
| inhalation of spores from the environment - not person to person |
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Term
| what is the range of clinical manifestations associated with fungal infection? |
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Definition
| asymptomatic or mild, acute pulmonary disease, chronic pulmonary disease (often associated with COPD), and disseminated disease (more common in immunocompromised pts - AIDS defining illnesses) |
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Term
| how are fungal infections diagnosed? |
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Definition
| clinical presentation, demonstration of the organism in the tissue (usually solid for dx), cx (gold standard, but slow), serology (>4x increase in IgG titer in acute & convalescent serum confirms dx), and skin test (positive result is not diagnostic as it indicates past or present infection and most individuals living in an endemic area are skin test positive. there is also cross reactivity between coccidiodin & histoplasmin) |
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Term
| where is coccidioimycosis found in its environment? how is it found? what form does it take in humans? |
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Definition
| as a mold in the soil in its *arthroconidia (septated hyphae, infectious) form in dry arid areas, southern CA, AZ, etc. in tissue, coccidioidomycosis take its *spherule form which contains endospores (both empty and full spherules are seen in clinical specimens) |
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Term
| when is a common time to see coccidioimycosis outbreaks? |
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Definition
| when a lot of soil is disturbed such as in a construction site |
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Term
| what % of coccidioides cases are mild/asymptomatic? what is the incubation period? |
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Definition
| 50-60%. the incubation period is 10-26 days and the infection usually resolves in 3 wks to 3 mos |
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Term
| what are the symptoms of coccidioides infection? |
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Definition
| fever, chest pain, malaise, night sweats and a productive cough |
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Term
| can coccidioides cause skin lesions? |
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Definition
| yes due to an allergic response, ~20% of pts present with erythema nodosum and erythema multiforme (upper trunk & extremities). this occurs mostly in females. |
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Term
| what % of pts will develop a chronic coccidioides infection? |
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Definition
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Term
| when is a coccidioides infection considered chronic? how do pts with a chronic coccidioides infection present? |
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Definition
| coccidioides infections are considered chronic if they last > 3 mos and pts with it present with *calcified nodules, which are 1-3 cm granulomatous rxns, often asymptomatic seen on CXR. *cavitary lesions may also develop in the periphery of the lungs, where the walls are thin. many cavitary lesions are asymptomatic and half spontaneously resolve in 2 yrs. symptoms of these cavitary lesion include a productive cough w/hemoptysis, chest pain, malaise and fever |
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Term
| what is a chronic progressive pulmonary coccidioides infection? |
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Definition
| where coccidioidal infiltrates spread throughout the lung, resulting in a more severe illness w/symptomatic pts, cavities or nodules. symptoms include a productive cough w/hemoptysis, chest pain, malaise, fever, night sweats, weight loss, and anorexia |
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Term
| can coccidioides infections become disseminated? |
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Definition
| yes, and risk factors for this include: immunocompromised pts (HIV, DM, neutropenia), darker-skinned pts, pregnant women, the very young or very old. |
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Term
| where are the most common sites of dissemination w/coccidioides? what is usually associated with dissemination? |
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Definition
| the skin, bones, joints, and meninges. progressive pulmonary disease is usually associated with dissemination. |
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Term
| what characterizes the effects of disseminated coccidioides infections in the skin, musculoskeletal, and meningal areas? |
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Definition
| cutaneous infection: 40%, large verrucous lesions (papules, pustules, nodules, abscesses, ulcers - NOT rash-like) musculoskeletal infection: 20% mainly seen in the vertebral column, pelvis, metacarpal & metatarsal bones, lower extremities. meningitis: 33% seen 3-6 mos after primary infection and presents w/headaches, fever, weakness, confusion, and seizures |
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Term
| where is histoplasma found in its environment? how is it found? what form does it take in humans? |
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Definition
| histoplasma capsulatum is found as a mold in soil containing *bird/bat guano. this mold has sepate, branching hyphae and is referred to as tuberculate macroconidia. the form of histoplasma found in humans *does not have a capsule, it proliferates intracellularly within *macrophages and clinical speciments demonstrate *intracellular yeast |
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Term
| where is histoplasmosis endemic? |
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Definition
| along the ohio and mississippi river valleys |
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Term
| what is the pathogenesis of histoplasmosis? |
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Definition
| the spores are inhaled and develop into yeast cells in the airways. macrophages then ingest the yeast and migrate to the mediastinal lymph nodes and RES (liver & spleen). caseous lesions then develop and calcify - typically in the lungs, lymph nodes, liver and spleen |
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Term
| what are the clinical manifestations of histoplasmosis? |
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Definition
| acute pulmonary histoplasmosis (usually mild & self limiting), chronic pulmonary histoplasmosis, disseminated disease (infants, immunosuppressed pts, pts on steroids), and mediastinal granulomas |
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Term
| what characterizes the acute pulmonary disease due to histoplasma? |
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Definition
| acute pulmonary disease is asymptomatic or presents as mild cold-like in 60-90% of pts. a minority may develop fever, headache, chills, nonproductive cough, malaise and anorexia. pts may have hepatosplenomegaly, adeonopathy, rashes (erythema nodosum or multiforma). there may be residual lung calcification and or a positive skin test and anti-fungal meds are usually not necessary |
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Term
| what characterizes chronic progressive pulmonary disease due to histoplasma? |
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Definition
| this usually occurs in elderly males as a complication of underlying pulmonary disease such as emphysema. it may start as an interstitial pneumonia and then form cavitations w/caseation in the lungs (resembles TB). symptoms include: fever, chills, weight loss, malaise, and a productive cough (hemoptysis) |
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Term
| how does disseminated disease occur with histoplasma infections? |
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Definition
| histoplasma spreads via the lymphatics and blood within macrophages through the tissue of the RES (spleen, liver, lymph nodes, and bone marrow). |
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Term
| what is acute disseminated histoplasmosis? |
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Definition
| acute disseminated histoplasmosis is seen primarily in infants, involves extensive RES involvement and presents with fever, severe hepatosplenomegaly, lymphadenopathy, weight loss, nausea, vomiting, and diarrhea. |
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Term
| what is subacute disseminated histoplasmosis? |
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Definition
| sub acute disseminated histoplasmosis involves moderate RES involvement, focal lesions in different organs (GI and oropharyngeal ulcers) |
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Term
| what is chronic disseminated histoplasmosis? |
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Definition
| chronic disseminated histoplasmosis is seen primarily in adults and features the mildest RES involvement, mildest symptoms including oropharyngeal ulcers, gradual weight loss, and fatigue |
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Term
| where is blastomyces found in its environment? how is it found? what form does it take in humans? |
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Definition
| blastomyces grows as a mold in nature but is hard to isolate. in tissue it grows as an extracellular yeast that is thick walled and broad-budding |
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Term
| where is the endemic area for blastomyces? |
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Definition
| most of the histoplasma area, though farther north |
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|
Term
| what are the clinical manifestations of blastomycosis? |
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Definition
| acute and chronic pneumonia and disseminated disease affecting the skin (most common), bones, joints, GU, and CNS |
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Term
| what characterizes an acute blastomyces infection? chronic? |
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Definition
| acute blastomyces infection: an incubation period of 21-100 days followed by nothing or symptoms of pneumonia (fever, chills, myalgias, chest pain, nonproductive cough) and an inflammatory response that may form a *noncaseous granuloma* that can reactivate. chronic blastomyces infection: productive cough, hemoptysis, weight loss, chest pain, and low-grade fever |
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Term
| how often will cutaneous blastomycosis disseminate to the skin if it disseminates? what characterizes this event? |
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Definition
| cutaneous blastomycosis disseminates to the skin 40-80% of the time, generally accompanied by active pulmonary disease. subcutaneous nodules may ulcerate form - along with verrucous lesions (small papulopustular lesions that spread and crust over) and ulcerative lesions (pustules w/raised borders, red tissue that bleeds easily) |
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Term
| how often will blastomycoses disseminate to the bone/joint if it disseminates? GU? CNS? |
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Definition
| blastomycoses will disseminate to the bone and joint 10-50% of the time (generally painless), to the GU 30% of the time (prostate+epididymis in men), and to the CNS 5-10% of the time manifesting as *brain abscesses* w/headaches, confusion, coma, seizures |
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Term
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Definition
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Term
| what are the 3 kinds of fungal sinusitis? |
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Definition
| noninvasive (seen in immunocompetent pts), invasive (seen in immunocompromised pts, spreads through direct bone invasion, often w/intracranial and orbital involvement - rhinocerebral disease), and allergic fungal sinusitis (host immune response rxn) |
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Term
| who usually gets allergic fungal sinusitis? |
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Definition
| young adults w/asthma & allergies severe enough to cause obstruction of sinuses and recurrent nasal polyps |
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Term
| what characterizes allergic fungal sinusitis? how is it diagnosed? |
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Definition
| the allergic rxn is comprised of mucin secretion, an inflammatory response, IgE, and immune complexes against the fungal antigens. bone erosion and deformites may occur and allergic fungal sinusitis is diagnosed by histologic staining of clinical specimens (eosinophilic infiltrates & fungal hyphae confirmed by cx) |
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Term
| what is the most common fungal cause of sinusitis? |
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Definition
| aspergillus, which can cause rhinocerebral disease in neutropenic pts |
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Term
| what fungi commonly causes rhinocerebral disease in DM pts? |
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Definition
| zygomycetes or mucor (rhizopus, absidia, and rhizomucor are all related) |
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Term
| what kind of fungi cause phaeohyphomycoses? |
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Definition
| dematiaceous fungi, which are brown/black fungi found in the soil and primarily opportunistic |
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Term
| where is aspergillis found? what form does it take? what kinds of infections can it cause? |
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Definition
| aspergillis is a ubiquitous mold found in soil and plants, frequently isolated from ventilation systems. it has septated hyphae w/chains of conidia on conidiaphore. the types of infections it causes include: allergic, chronic, and invasive. it is only a mold - not dimorphic, so what you see in nature will be seen on a clinical specimen |
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Term
| what characterizes allergic aspergillosis? |
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Definition
| inhaled spores settle in the bronchi and trigger an asthmatic response mediated by IgE, leading to rhinitis and wheezing. approx 40% of pts develop a positive skin test |
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Term
| what characterizes acute sinusitis due to aspergillis? |
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Definition
| this can occur in pts w/allergic rhinitis, chronic nasal congestion, and recurrent sinusitis - it may also co-exist w/bacterial sinusitis |
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Term
| can acute sinusitis due to aspergillis become invasive? |
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Definition
| yes, in neutropenic pts, aspergillis spreads from nasal mucosa or sinuses to adjacent structures resulting in vascular invasion and necrosis causing headache, sinus pain, proptosis, and monocular blindness |
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Term
| what is allergic bronchopulmonary aspergillosis (ABPA)? |
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Definition
| this hypersensitivity rxn to aspergillus antigen occurs in pts w/asthma and is a chronic inflammatory response consisting of an intermittent fever & productive cough (brown mucus containing hyphae). it is however, not invasive. pts w/this may develop a steroid-dependent asthma or COPD |
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Term
| what are the criteria for diagnosing ABPA? |
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Definition
| episodic bronchial obstruction (asthma), eosinophilia, a positive skin test to aspergillus antigens (type 1 hypersensitivity), increased IgE and IgG antibodies to aspergillus antigens, a hx of pulmonary infiltrates and episodic bronchial plugging leading to bronchietasis |
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Term
| what is an aspergilloma? does it require anything to form? |
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Definition
| colonization of the pulmonary cavity/dead areas in the lung or sinuses, forming a fungus ball consisting of hyphae, mucus, host tissue/debris and some inflammatory cells. it may be asymptomatic or cause a productive cough w/hemoptysis and CXRs will show a mass separated from the cavity wall by an air space. *to form it requires pre-existing conditions include TB, CA, sarcoidosis, histoplasmosis, emphysema, and bronchiectasis to form.* |
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Term
| what is the course of a pulmonary aspergillosis? |
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Definition
| inhalation of conida (macrophages try to clear spores), the conidia form hyphae, complement is activated (neutrophil chemotatic factors are released leading to an influx of neutrophils), and invasive disease results if neutrophils are unable to conatain the hyphae |
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Term
| what are the symptoms of invasive pulmonary aspergillosis? |
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Definition
| fever, non-productive cough or hemoptysis, tachycardia, and pulmonary infiltrates seen on x-ray. |
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Term
| can invasive pulmonary aspergillosis lead to pulmonary infarcts? |
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Definition
| yes, if the blood vessels are invaded, pulmonary infarcts are possible - resulting in chest pain and pleuritic rubs. a CT scan may reveal ring-enhancing lesions as a halo surrounding a denser consolidated area |
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Term
| can invasive pulmonary aspergillosis become chronic? |
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Definition
| yes chronic pulmonary aspergillosis can progress to a necrotizing pulmonary lesion, accompanied by persistent fever and hemoptysis. this is seen most often in AIDs pts, diabetics, and those with chronic granulomatous disease |
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Term
| what are the risk factors for invasive aspergillosis? |
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Definition
| immunosuppression (esp neutropenia), use of broad spectrum antimicrobials, corticosteroid use, bone marrow & solid organ transplantation |
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Term
| what happens when hyphae invade blood vessels? |
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Definition
| angioinvasion leads to obstruction, ischemia, infarction, tissue necrosis and may seed other organs (other parts of the lung, brain, liver, heart, spleen, and skin) |
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Term
| what is a dx of invasive aspergillosis based on? |
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Definition
| clinical symptoms and histopathology: demonstration of branching, septate hyphae in clinical specimen - sputum/transtracheal aspirate/bronchial/lung bx. a cx from sputum doesn't necessarily mean the disease is invasive - hyphae needs to be seen in the tissue for that dx (consider the pts risk for invasive aspergillosis). indirect testing for invasive disease: galactomannan ELISA and fungitell assays are also available |
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Term
| when should presumptive invasive aspergillosus be treated? |
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Definition
| high risk pts (neutropenic, aspergillus isolated in clinical specimen, fever, CXR/CT consistent with aspergillosis) should be treated. low risk pts (solid organ transplants, CA, chronic granulomatous disease, and HIV) can be bxed first |
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Term
| what is important for IDing aspergillus in sputum? |
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Definition
| its acute angle branching septated hyphae b/c it is a mold |
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Term
| what organisms cause zygomycosis? |
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Definition
| zygomycosis or mucormycosis is caused by: mucor, rhizopus, absidia, and rhizomucor - which are all zygomycetes |
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Term
| where are zygomycetes/mucor found? |
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Definition
| they are ubiquitous - found on bread and spoiled food |
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Term
| what is the shape of zygomycetes/mucor? |
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Definition
| broad, *nonseptate hyphae* (differentiates zygomycetes from aspergillus) |
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Term
| how is zygomycosis contracted? |
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Definition
| zygomycetes/mucor colonize nasal, oropharyngeal or respiratory mucosa when spores are inhaled |
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Term
| how do zygomycetes/mucor invade the tissue? who is at risk for this? |
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Definition
| hyphae invade the lumen and walls of blood vessels most commonly of granulocytopenic and acidotic pts (esp diabetics) who are at high risk for invasive disease |
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Term
| what is another difference beside hyphae between zygomycetes and aspergillus? |
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Definition
| zygomycetes have round spores, while aspergillus has condidia radiating out |
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Term
| what are the types of infections seen with zygomycetes? |
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Definition
| *rhinocerebral (seen in DM pts), pulmonary, abdominal/pelvic & gastrointestinal, primary cutaneous, and disseminated disease |
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Term
| when does zygomycetes usually cause rhinocerebral disease? how does the infection occur? what is the clinical course? |
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Definition
| in acidotic DM pts via an initial infection in the nasal region which spreads the sinuses, eye, brain, and meninges. the infection results in fever, facial pain, headaches, nasal congestion, visual disturbances, and lethargy - can be fatal in 2 wks |
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Term
| who does zygomycetes commonly cause pulmonary disease in? how does the infection occur? what is the clinical course? |
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Definition
| pts w/leukemia, severe neutropenia (neutrophils are important for clearing fungi) or on steroid therapy. it starts as bronchtis/lobular pneumonia and progresses to a fever, productive cough w/hemoptysis, chest pain and SOB. through invasion of the blood vessels and destruction of lung tissue, zygomycetes can spread via blood to the CNS, liver, kidney, spleen, heart, and skin - causing necrosis and abscess formation |
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Term
| who does zygomycetes tend to cause GI infections in? |
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Definition
| malnourished pts or those w/renal failure. this leads to necrotic ulcers in the stomach and colon |
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Term
| who does zygomycetes tend to cause cutaneous infections in? |
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Definition
| usually burn pts or as a result of disseminated disease. usually single lesions develop into necrotic ulcers w/dark centers |
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Term
| what are the predisposing conditions for zygomycetes causing rhinocerebral disease, pulmonary disease, cutaneous infection, and GI infection? |
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Definition
| rhinocerebral disease-> DM pts, pulmonary disease_->neutropenic pts, cutaneous infection->burn pts, and GI infection-> malnutrition |
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Term
| what do the hyphae look like for zygomycetes? |
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Definition
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Term
| what are the 3 forms of pneumocystis jiroveci? how is it spread? what is the rate of exposure? |
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Definition
| pneumocystis jiroveci comes in 2 forms cysts and trophs. the cysts are larger and more prevalent in clinical symptoms and have 8 intracystic bodies that can rupture and release the intracystic bodies as trophs. trophs are haploid and can split by fission or fuse and form cysts. it is spread person to person via aerosol and can be dormant in the lung. >50% of the population is seropositive by 2-4 yrs of age. it is considered an AIDS defining illness and pneumocystis jiroveci may simply reactivate in these immunocompromise pts |
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Term
| what are the in situ pneumocystis jiroveci cysts often described as? |
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Definition
| "collapsed ping pong balls" |
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Term
| what are some of the symptoms of pneumocystis pneumonia? |
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Definition
| fever, dyspnea, dry/productive cough, hypoxemia, and diffuse bilateral infitrates on a CXR |
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Term
| what characterizes pneumocystis pneumonia as an AIDS defining illness? can it disseminate? |
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Definition
| ~80% of AIDS pts have it at some point, it was a leading cause of death in AIDS before prophylaxis and it can disseminated to the spleen, lymph nodes and bone marrow |
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Term
| what is the DOC for pneumocystis pneumonia? other drugs? |
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Definition
| trimethoprim-sulfamethoxazole, which disrupts the synthesis of *tetrahydrofolic acid. it is used as tx or prophylaxis in AIDS or neutropenic pts. echinocandins are also active against pneumocystis jiroveci via inhibition of glucan synthase, which disrupts cell wall synthesis (primary drug for candida) |
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Term
| what kind of pathogen is penicillium marneffi? |
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Definition
| penicillium marneffi is a dimorphic fungus endemic to SE asia (mold in soil/vegetation, intracellular yeast in macrophages). the bamboo rat is thought to be the animal reservoir and it most frequently infects the lung and liver. it is an AIDS defining illness in thailand |
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Term
| what are the clinical symptoms associated with penicillosis? |
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Definition
| fever, cough, lymphadenopathy, pulmonary infiltrates, hepatosplenomegaly, *subcutaneous abscess, and *papular skin lesions |
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Term
| what is seen histologically in a clinical specimen from a pt w/penicillosis? |
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Definition
| small, oval yeast cell withing macrophages or extracellular sausage-like forms wtih septa |
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Term
| what is the treatment for penicillosis? |
|
Definition
| amphotericin B (2 wks) then itraconazole (10 wks) |
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Term
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Definition
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|
Term
| what is a potentially lethal fungus moving south from canada? |
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Definition
| cryptococcus gattii (related to cryptococcus neoformans which caused meningitis in immunocompromised pts) infects healthy people who have contact w/soid or trees |
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Term
| what are the clinical symptoms of pts infected with cryptococcus gattii? tx? |
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Definition
| coughing, night sweats, pneumonia, wt loss over wks, possibly meningitis. tx is 6-8 wks of IV antifungals (amphotericin B) and up to 6 mos of oral fluconazole |
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