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75 Cards in this Set
- Front
- Back
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Dimorphic fungi
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Mycelia, fruiting bodies, spores in environs
Yeast in body |
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Histoplasma capsulatum
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Intracellular organism
Pathology similar to TB |
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Histoplasma geographic
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Mississippi/Ohio River Valley
SE US St Lawrence valley Grows in soil (esp enriched in nitrogren) Soils lacking montmorillonite clay Soil enriched with bird droppings |
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Histo in colony
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Moist creamy colonies that produce fuzzy edges in a few days
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Histo pathogenesis
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Intracellular growth of tiny yeasts w/in macrophages
Epitheloid granulomatous cellular rxn resembling TB, plus abundant FIBROSIS and rare caseation necrosis Cell mediated immune mechanisms: INFgamma activates macros to kill yeasts, chemokines stimulate cell rxn to wall off infect |
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Histoplasma primary infection syndrome
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Frequently asympto or mild
May be flu-like w/ cough, fever, malaise, hilar adenopathy Can lead to mediastinal fibrosis in a sm no of pts- an immunologic reaction containing a few organisms |
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Reinfection syndrome with Histo
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Exposure to lg numbers of aerosolized spores in a previously infected individualsmay result in febrile illness with ACUTE pulmonary infiltrates
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Mediastinal fibrosis in histo
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Rare complication
Hard to treat because its really an immune reaction, so killing the bug does not help too much Surgery difficult |
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Chronic cavitary pulmonary histo
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Progressive fibrous and nodular apical infiltrates, which cavitate
Clinical findings of cough, fever, weight loss in men >40 |
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Disseminated histoplasmosis
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Acute infection disseminates
Immunosuppressed Chronic progressive disease in AIDS |
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Diagnosing histo
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Culture - yeast form can be grown from respiratory specimens
Yeast converts to mycelia in room temp, characteristic fruiting bodies Macrocondia Biopsy showing intracellular yeast, granulomas, etc Serology - not good for acute Urine - histo antigen in urine useful for active disease, esp in HIV |
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Urine antigen in histo
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Detection of polysaccarides in urine
Useful in active disease, esp HIV Not going to pos in mild or asymptomatic pulmonary disease |
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Therapy of histoplasma
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Not all infections require
AmphoB - severe, progressive forms Itraconaozle - treatment as well as chronic suppression to in immunosuppressed |
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Geography in blastomyces
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Major river valleys of Midwest
South central US Scattered worldwide Moist soils, river and pond edges Less common than histo |
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Epi in blastomyces
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M > F
Outdoor occupation risk Dogs can be infected and are symptomatic |
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Pathogenesis of blastomycoses
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Extracellular yeast
May also be seen after phagocytosis in macrophages Thick walled yeast with broad based buds Noncaseating, loose granulomas with lots of PMNs Epi hyperplasia prominent |
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Blasto skin lesions are mistaken for?
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SCC
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Blastomycoses clinical presentation
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Pulmonary - primary site - most common, sometimes asymptomatic - infiltrate on CXR
Skin - uncommon, looks like SCC Bone - one of the only fungi to go for bone Disseminated - GU, CNS |
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Diagnosing blasto
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Stain of pus/tissue, histopath to show yeast forms
Culture - myceial forms in days to weeks - lollypop hyphae structure (fruiting body) Serology not useful |
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Treating blasto
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Amphotericin B for serious/progression
Iatraconazle for others |
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Coccidiodes
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Southwestern US, Ca
Dry, alkaline soils Also in Central, SA |
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Valley fever
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Caused by cocciodes
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Coccidiodes pathology
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Inhalation of arthrospores
Pulmonary infection w/ possible hematogenous dissemination Granulomatous response Endospores in chacteristic spherules varying in size, no yeast forms In areas exposed to air, pts can have mycelial form in lung |
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Coccidiodes life cycle
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No yeast form
Mycelial form produces athroconidia (like a spore but not) Breathe in Differentiates into spherule Division w/in the spherule makes lots of endospores |
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Coccidiodies clinical
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Primary pulmonary - Valley fever
febrile illness with highincidence of athralgias Disseminated - bone, skin, meningies higher risk in preg, AAs, Filipino pps AIDS |
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CXR in cocciodies
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Coin lesion
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Skin finding in coccidiodies
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Erythema nodosum
Raised tender nodules, shins Immunologic rxn, no organisms here A marker for having immunologically controlled diease |
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Coccidiodies diagnosis
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Serology - useful in following progression
Culture - sputum/tissue sample, white fluffy mycelia appear w/in week. Barrel shaped athrospores easily aerosolized (watch out!) Histo - endopsores w/in granulonatous rxn |
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Complement fixation assay in coccidiodies
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High is bad
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Coccidioidomycosis Rx
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Most not treated
Ampho B for progressive primary and immunosuppressed Meningitis - itrathecal AmphoB Fluc/iatroconazole for the prevention, less serious |
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Sporothrix geography
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Worldwide
Rotting wood, sphagnum oss, potting soil, rose plants |
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Sporotrichosis pathology
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Local inoculation, frequently upper limb
Pyrogranulomatous response in dermis Lymphangitic spread |
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Sporotrichosis appearance
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Cigar shaped
Elongated Difficult to find on biopsy |
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Sporotrichosis clinical
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Cutaneous lymphangitis with nodules
Somtimes has osteoartercular involvement and tenosynovitis Pulmonary, uncommon Disseminated in immunosuppressed Prefers colder body temp sites (skin) |
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Sporothrichosis diagnosis
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Culture - yeast like colonies in a week, convert o mycelia at RT
Cigar shaped yeast, difficult to find on biopsy No useful serology |
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Fruiting body of sporotrix
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Stalks with flowers
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Sporotrichosis therapy
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Azole
KI - may work by increasing macrophage intracell killing mecah Local heat |
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Penicillium marneffei
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Emerging disease
SE Asia Respiratory and disseminated systemic infections in immunosuppresed |
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Diagnosis of pencilliosis marneffei
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Growth of mold with diffusible RED PIGMENT
Penicillum fruting structures in culture, yeast-like forms with binary fission in tissue |
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Treating penicilliosis marneffei
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Amph B
Possibly iatraconazole, voriconazole |
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How does P marneffi divide in tissue?
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Binary fission of yeasts
Not budding |
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Penicillium fruiting body
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Paint bring mycoses
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Opportunistic infections
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Take advantage of defect in immune system
Usually not pathogenic |
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Diagnosing opportunistic infections
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Gold standard is histology
Seeing it causing disease in infection |
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Risks for thrush
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Recent antibiotics
Defects in cell mediated immunity: HIV infection Diabetes Steroid inhaler |
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Confirming diagnosing
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Scrape for KOH
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Nystatin
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Swish and spine
Topical antifungal Not going to get to the esophagus |
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Candida diagnosis
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Culture - bottle and agar plates
Gram stains Speciation is desirable for watching out for resistance Take seriously a positive culture from a normally sterile site |
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CMV comes up with which immune dysfnc?
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T cell
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Short term neutrophil dysfnc?
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Worry abotu candida
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Risk factors for disseminated candiasis
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Neutrophil dysfnc
Neutropenia Transplant recipient Leukemia Central line for TPN |
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HIV and candidiasis
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Mucosal candidiasis (thrush, etc)
It does not disseminate because they have neutrophils |
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Treating disseminated candida
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Antimicrobials - micafungin/caspofungin
or ampho B fluconazole Remove lines Surgery for abscesses |
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What do you do when you find yeast in the urine?
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Change the foley
Cystitis from yeast happens w/ constant foley and long term Abx If changing the foley fails Then start an antifungal |
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Diagnosing aspergillus
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Histology
Culture sputum (not diagnostic b/c could be colonize, but in right setting) Culture of biopsy specimen Serum galactomannan test |
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Galactomannan test
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Blood test, BAL specimen, CSF
Tests for aspergillous antigen Species specific cell wall antigen |
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Opportunistic fungi
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Candida
Aspergillus Zygomycoses (Mucor) Cryptococcus |
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Pathology in aspergillus
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Vascular invasions
Infarction Necrosis Edema Hemorrhage Culture grows aspergillus fumigatus |
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Aspergillus host defenses
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Phagocytic cells
and Cell mediated immunity |
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Who gets aspergillus?
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transplant patients
HIV patients immune defects |
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Treating aspergillus
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Voriconazole is first choice
AmpoB - second line Caspofungin - third line |
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Sinus infection in pt with DKA?
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Worry about mucor
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Zygomycosis (mucor)
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Ubiquitous fungi
Low virulence Opportunistis presumed due to combinationof defects of macros and PMNs serever immuncompromise, DM, lyphoma, leukemia, burns --rare |
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Mucor pathology
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Hyphae invade tissue with affinity to blood vessels
Necrosis and thrombosis |
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Zygomycosis treatment
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Surgery is necessary
Reverse underlying problem Medical -- amphoB, posaconazole Prognosis is poor |
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HIV pt with new onset MS change and normal labs?
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Do a spinal tap
Do an MRI Worry about crypto, toxo |
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Cryptococcal diagnosis
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Culture CSF
Cryptococcal antigen (from CSF, blood) Yeast! Elevated opening pressure on spinal tap |
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Does cryptococcus have hyphae?
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No
Its a thick walled yeast with a capsule |
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Why high opening pressure in crypto menigitis?
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Gums up the ventricles
Cannot resorb CSF appropriately |
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Crypto on CSF
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Elevated opening pressure
May be decreased glucose, increased preotin, low WBC India ink positive |
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Crypto antigen test
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Latex agglutination
Blood or CSF Sensitive and specific Titer indicative or burden of disease |
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How do you get crypto?
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Pigeon poop inhalation
Initially typically assymptomatic Walled off by macros in lung Disease due to reactivation Cell medated immunity important, can occur in competent hosts Can disseminated, predilicaiton for the CNS |
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Clincal crypto
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Lung
Skin - umblicated lesion Disseminated |
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Treatment for crypto
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Mild - fluconazole
Serious - amphotericin B and flucytosine + 6 weeks of fluconazole Improve immune status in AIDS, prevent immune reconstitution inflammatory syndrome Increased intracranial pressure serial lumbar puncture to remove CSF lumbar drain placement more permanent shunt may be necessary |
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Prognosis of crypto meningitis
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Depends on underlying illness
Reversibility of the immune suppression Residual defects: CN palsy, decrease mental fnc, hydrocephalus, visual loss |
