HIV and Opportunistic - Fungal Flashcards by Donald Rees

What is the most common fungal infection to get a hold of the immunocompromised?

Candida

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Discuss the lab findings for Candida

Catalase Positive, so those with chronic granulomatous infection are at risk for infection

extracellular pathogen (on epithelial surfaces) that DOES NOT change the pH

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When do we see candidiasis thrush in patients?

Candidal esophagitis- AIDS defining illness (CD4+ less than 100)

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Other presentations of Cancida besides scraping white plaques?

Cutaneous: Kids& Diaper rash

IV drug user- Endocarditis and Tricuspid valve damage

Eyes - Retinitis

Bones: Vertebral osteomyelitis

mucosal - can wipe away, underlying red, painful

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Two histology features for candida

KOH prep= hyphae, germ tubes

necrotic squamous epithelium w yeast overlying inflamed submucosa

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Cold vs. warm candida and general structure we will look for

Cold temp = pseudohyphae = yeast form

Warm = germ tubes = mold form

Structure: Budding yeasts and pseudohyphae

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Who is at risk besides AIDS patients for getting Candida?

Diabetes, Antibiotics (kill micro-flora in the gut, so Candida can take over), Birth Control

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How do we treat Candida?

Azoles for minor infection like diaper rash

Amphotericin or Capsofungin (echinocandin) (if resistant to ampho) for severe disseminated infection in immunocompromised

oral/esophageal candidiasis = Nystatin

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What count do we think of for PCP?

Less than 200

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PCP symptoms in compromised vs normal health

Asymptomatic in healthy people.

Immune compromised = PCP Pneumonia (CD4+

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Chest X ray for PCP

CXR: Ground glass appearance (diffuse interstitial infiltrates, bilateral, perihilar)

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Discuss the lab findings of PCP

microscopy= trophozoites/cysts in sputum or bronchoalveolar Lavage.

Anemia with nonspecific increase in LDH.

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Histology for PCP

Histo: methamine silver stain= Disc shaped yeast. Foamy exudate with “dented ball” alveolar damage. No inflammatory response.

Direct fluorescent antibody test (DFA) shows antibodies, sensitive, better than giemsa stains

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PCP treatment

Bactrim (TMP/SMX, Trimethoprine and sulfamethaxazole), active sx and prophylaxis (CD435)

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Leading cause of AIDS death?

Respiratory illness! Never forget PCP!

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Discuss the structure of Cryptococcus Neoformans

HEAVILY encapsulated with repeating polysaccharide antigens (antiphagocytic), urease positive

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Where do we get cryptococcus from? Discuss transmission and where it goes INSIDE OF YOU

CD4Lung –> Blood –> CNS

patho: Latency in macrophages of lung granulomas like TB, then acute infection in the lungs

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Symptoms of cryptococcus infection

Lungs- Cough, dyspnea, pneumonia

CNS: common* fungal meningitis (spread via CSF): visible exudate unlike viral, AMS, diplopia, ataxia/palsy, Sz, meningismus, CN palsies, acute memory loss

Const: Fever, Headache, malaise
other: skin lesions, eye, prostate

Discuss lab stuff for cryptococcus

Sensitivity: culture>antigen>microscopy

Blood Culture can grow c. neoformans
(+) cryptococcal antigen test:( CRAG) = latex agglutination= cryptococcal polysaccharide antigen: done on blood/ CSF* (most sensitive)
direct microscopy of any body fluid

Discuss the histology for crypto

histo: india ink stain= large clear capsules around budding yeast (cryptococcal halos), background is dark
meningeal tissue shows fibrosis, expanded virchow-robin space with organism aggregates, no reactive gliosis, reactive CT can lead to obstruction and hydrocephalus,

other stains: red mucicarmine or silver methanamine

Discuss imaging for crypto

Imaging: Soap bubble lesions in gray matter, basilar meningitis

Discuss treatment and prognosis for crypto

Tx: Amphotericin B and flucytosine followed by maintenance with fluconazole (which we also use if there is only mild disease)
repeated LP’s to decrease ICP

prognosis: severe, death >60%

Discuss the structure and transmission of coccidiomycosis

Trans: Inhalation of spore dust - widespread fevers with earthquakes and dust clouds.

Structure: Cocci forms spherules filled with endospores inside lungs in the warm body, mold form in the cold

These spherules are larger than RBCs

location: SW US, california valley

Discuss the symptoms of coccidio

sx: chronic pneumonia, lung granulomas, meninges, valley fever (rash,joint pain, fever, cough), erythema nodosum on shins in healthy people due to exaggerated immune response

Discuss the histology of coccidio

histo: Cx which takes a while, KOH prep, IgM titers, eosinophilia

Discuss the imaging for coccidio

Imaging: Radiography shows either nothing or cavities or nodules

Discuss the treatment for coccidio

Tx: Azole drugs (ketoconazole) for lung infections. Amphotericin B in systemic infection

Discuss the treatment for histoplasmosis

Structure: Smaller than RBCs. Dimorphic: Cold/Soil = Mold form, Body/heat = yeast form

Discuss transmission of histoplasmosis

Trans: Bird/Bat droppings (recently in a cave) or chicken coops, transmit via respiratory spores being ingested by macrophages

Histology for Histoplasmosis

Histo: Macrophages with intracellular ovoid bodies often in coin lesion produced by granulomatous inflammatory process, KOH prep, Rapid Histoplasma blood or urine antigen test

Where do we find histoplasmosis

Location: Midwestern and Central U.S. along the Mississippi and Ohio River valleys

What happens to a person with histoplasmosis?

Sx:Pneumonia if granulomas present, Chronic pulmonary issues if granulomas calcify and fibrose Can mimic TB! Erythema nodosum on shins due to exaggerated immune response Immune Compromised - Disseminated = hepatosplenomegaly with calcifications due to targeting macrophages

Treatment for Histoplasmosis

Tx: Local/mild = Fluconazole, Ketoconazole. Systemic = Amphotericin B (lots of side effects)

What dos this Aspergillus thing look like and what do our labs show us?

Structure: Hyphae at acute angles with septations (tree like). Make conidiaphores with fruiting bodies that bud off and are inhaled Lab: Catalase positive Diagnose: Serum galactomannan for early screening

Symptoms of Aspergillus (4 main pathways. Don't kill me, yes this card is long but it's basic explanations. You'll be fiiiiiiiiiiiiiiiiiiiiiiiiiine)

Sx: spectrum based on immune response 1) Allergic bronchopulmonary aspergillosis= allergic sinusitis (Type 1 hypersensitivity rxn= elevated IgE; wheezing, fever, recurrent asthma, pulmonary infiltrates) 2) Aspergilloma- solid balls of fungus in lower lungs (especially in pre-existing fibrocavitary lung disease, TB and cancers) 3) angioinvasive aspergillosis- immunocompromised, (invades blood vessels and disseminates) which presents with hemoptysis 4) invasive aspergillosis- systemic involvement ( kidney failure, endocarditis, ring enhancing lesions in brain on CT, necrosis of nose)

What toxin do we see with Aspergillus

toxin: aflatoxin - Very carcinogenic especially for hepatic carcinoma in aspergillus flavus

Histology for Aspergillus

histo: fungal septa hyphae branch at 45*

What do we associate with Aspergillus?

a/w: peanut crops and wheat crops, african liver cancer, neutropenic patients

Treatment for Aspergillus

Tx: Less serious use Voriconazole, systemic use amphotericin. Aspergilloma = surgical resection. ABPA = corticosteroids with antifungals (itraconazole)

Structure of mucormycosis

Structure: broad, nonseptated hyphae (ribbon like), right angle (90 degrees) branching unlike Aspergillus (45 degrees)

Discuss the transmission of Mucormycosis and who is at risk

Risk: Diabetics and immunocompromised. Found in bread (rhizopus) Transmission: Spore inhalation, proliferate in blood vessel wall where there is high glucose and ketones (think DKA). Breaks through the cribriform plate to get to the brain

Symptoms we see with mucormycosis

Sx: Rhinocerebromucormycoses (black eschar around nose and eyes = very bad prognosis = extensive necrosis) disseminated disease (basal ganglia, cutaneous tissue, kidney, respiratory tract, etc.)

Treatment of Mucormycosis

Tx: surgical debridement, liposomal amphotericin B (usually doesn’t matter, prognosis dismal - 67%), posaconazole