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(PA school) Public Health > Lecture 2: Infectious Disease pt 2 > Flashcards

Lecture 2: Infectious Disease pt 2 Flashcards

1
Q

True or false: one species can have many forms

A

True

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2
Q

List 3 categories of fungi

A

1) Yeasts
2) Dimorphics (either yeast or mold)
3) Molds

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3
Q

1) Are yeasts unicellular or multicellular? Name 2 species.
2) Are molds unicellular or multicellular? Name 2 species

A

1) Unicellular; candida species, cryptococcus
2) Multicellular; aspergillus, mucor

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4
Q

1) How many types of Candida are there?
2) Candida is a budding yeast that forms _______________.
3) Is it common normal flora? Explain.

A

1) >50 types (C. albicans, C. tropicalis, C. glabrata, C. krusei, C. auris, etc…)
2) pseudo-hyphae
3) Common normal flora but opportunistic pathogen

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5
Q

List and describe the 3 rough categories of Candida infection

A

1) Non-significant colonization: frequently found in the GI tract, skin, tracheobronchial tree, GU tract, and of minimal significance
2) Local mucocutaneous: thrush, esophagitis, vulvovaginitis, balanitis, mastitis
3) Invasive: UTI,, meningitis, endocarditis, empyema, intraabdominal, candidemia (often line-associated), endophthalmitis

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6
Q

1) List the risk factors for Candida infection
2) How is a Candida infection treated?
3) What should you do if a pt gets frequent Candida infections?

A

1) Pregnancy, uncontrolled diabetes, broad-spectrum antibiotic use, corticosteroid use
2) Topical or oral azoles
3) Check HIV status

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7
Q

How do you dose oral and topical azoles for a Candida infection? Specify the specific azoles used.

A

1) One oral dose of 150mg of Fluconazole
200-400mg fluconazole x 14-21 days for esophageal candidiasis
2) Topical- clotrimazole 100mg x 7 days, miconazole 200mg x 3 days

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8
Q

List the clinical features of candidemia (invasive candidiasis)

A

1) Minimal fever to full-blown septic shock
2) Can resemble severe bacterial infection
3) Blood Cx positive only 50% of patients
4) (1,3)-Beta-D-glucan may be positive (even if neg blood Cx)

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9
Q

List the clinical features of invasive candidiasis

A
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10
Q

True or false: Yeasts, molds, and dimorphics are all examples of fungi

A

True

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11
Q

What is an example of a budding yeast that forms pseudo-hyphae?

A

Candida

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12
Q

What is an example of a species that is common normal flora, but also an opportunistic pathogen?

A

Candida

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13
Q

1) What is Candida endocarditis?
2) Who is it typically found in?
3) What are the symptoms?
4) How is it Dx’d?
5) How is it managed?

A

1) Most serious manifestation of candidiasis & most common cause of fungal endocarditis, results from candidemia
2) Prosthetic heart valves, IV drug users, CV catheters, prolonged funguria
3) Fever, changing or new murmurs, S/Sx heart failure; possible visual loss
4) Persistent candidemia (blood Cx), vegetation (echocardiography)
5) 3-5mg/kg/day Amphotericin B (or high-dose echinocandin) & valve replacement

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14
Q

1) What family is the most common cause of fungal meningitis? What is it an example of?
2) What type of fungus is this family?
3) How is it contracted? Where?

A

1) Cryptococcus; an invasive fungal infection primarily of lungs & CNS
2) Encapsulated yeast
3) Inhalation of C. neoformans & C. gattii (encapsulated yeasts); found in soil & dried pigeon & chicken dung

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15
Q

1) Describe subclinical cryptococcus infection
2) What presentation is seen most often in immunodeficiency?
3) What does the presentation of cryptococcus infection range from?

A

1) Common, mostly asymptomatic (incidental)
2) Progressive lung disease & dissemination
3) Range from simple nodules to widespread infiltrates leading to respiratory failure

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16
Q

1) Describe the most common imaging findings for a cryptococcus infection
2) What are some other imaging findings?

A

1) Solitary or few well-defined, noncalcified nodules that are often pleural based.
2) Lobar infiltrates, hilar and mediastinal adenopathy, and pleural effusions.

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17
Q

What is it called when Cryptococcus spreads to the CNS? What can also be involved?

A

Cryptococcal meningitis; skin and bones
(most common cause of fungal meningitis)

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18
Q

What are the two tests for cryptococcus infection? Describe their sensitivities and specificities

A

1) Cryptococcal antigen test aka CrAg:
-93-99% sensitive, 93-98% specific, and fast.
2) India Ink Staining
-Traditional but not as sensitive

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19
Q

What are the lumbar puncture CSF values for a Cryptococcal meningitis infection? (glucose, protein, WBC, & opening pressure)

A

Glucose: normal
Protein: Mildly Elevated
WBC: Less than 20
Opening Pressure: Increased

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20
Q

What 3 things do you use to treat cryptococcal meningitis?

A

1&2) Amphotericin B 3-4mg/kg/day IV x 2-8 weeks
AND
Flucytosine 100mg/kg/day x 2-8 weeks
3) Followed by Fluconazole 400mg/day PO x 12 months

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21
Q

How do you treat Cryptococcus if no CNS involvement and pt is immunocompetent?

A

Fluconazole 400mg PO x 6-12 months

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22
Q

1) What is the etiology of histoplasmosis?
2) What type of fungus is histoplasmosis? Explain.

A

1) Inhalation of conidia spores from soil contaminated by bird & bat droppings.
2) Dimorphic endemic fungus
-Exist as a mold in the soil and “narrow based budding yeast” in the body

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23
Q

Describe the clinical features (most cases asymptomatic or mild) of histoplasmosis:
1) What is indicative of past infection?
2) What is most common?
3) What is a complication of pulmonary histoplasmosis?
4) What are some other features?

A

1) Incidental pulmonary & splenic calcifications
2) Acute pulmonary histoplasmosis
3) Progressive disseminated histoplasmosis
4) Cough, fever, myalgias

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24
Q

1) What does acute histoplasmosis infection mimic?
2) What can a CXR have?
3) How is it diagnosed? Desc. the sensitivity and specificity of this test.

A

1) Pneumonia
2) Diffuse infiltrates and conspicuous hilar adenopathy
3) Urine histo antigen:
~70-85% sensitive, but false-positive from blastomycosis, aspergillus, and a few others

25
Q

1) Chronic pulmonary histoplasmosis is seen in what groups the most often?
2) What is it characterized by?
3) What does it show on a CXR/ CT?
4) What does serology show?
5) How do you differentiate it from TB?

A

1) Older pts with chronic lung disease, smokers
2) Productive cough, dyspnea, CP, fatigue, fever, sweats
3) Complex apical cavities, infiltrates, nodules (TB?)
4) Usually positive
5) Sputum or BAL fluid Cx or lung Bx

26
Q

1) Progressive disseminated histoplasmosis makes 1 in ____________ pts with acute infection.
2) Who is most likely to get a progressive disseminated infection?

A

1) 2000
2) HIV, immunosuppressive disorders & meds (TNFa-I, steroids, anti-rejection meds)

27
Q

What are the two types of progressive disseminated histoplasmosis? Describe the symptoms/ locations of each, and who each was most common in

A

1) Acute (infants, immunocompromised): fever, fatigue, hepatosplenomegaly, pancytopenia
2) Chronic (older pts, men): pancytopenia, hepatosplenomegaly, transaminitis, oropharyngeal or GI lesions
-Other sites: skin, brain, adrenal glands

28
Q

How is mild-to moderate Histoplasmosis treated?
2) What about disseminated histoplasmosis?
3) What may be needed after initial therapy? For who?

A

1) Itraconazole 100-200 mg/day PO BID for weeks to months
2) Amphotericin B 3mg/kg/day
3) Suppressive therapy for AIDS patient or itraconazole after initial therapy

29
Q

1) What is Coccidiomycosis also called? What is its etiology?
2) Where is it endemic to? Why is it expanding?

A

1) “Valley fever”; Mold in the soil, yeast in the body
(Coccidioides immitis, C. posadasii)
2): Endemic to the Southwest United States, Mexico, central America and South America (42.6 cases per 100,000 in endemic regions)
-Has increased 7 fold in the past 13 years
-Expanding territory/warming climate

30
Q

1) ______% of histoplasmosis infection are subclinical, but it can form __________ and be latent / reactivate
2) It’s more severe in __________________ hosts
3) Where is it endemic to?

A

1) 90%; granulomas
2) immunocompromised
3) Mississippi River Valley area

31
Q

1) How is Coccidiomycosis “Valley Fever” spread?
2) What is its incubation?
3) Describe its course. What prevents reinfection?

A

1) Inhalation of airborne spores; no known person-to-person or zoonotic spread
Rarely solid organ transplant
2) 3 weeks after inhalation of spores
3) Subclinical and spontaneous resolution in 50% of patients
-Lifelong immunity after infection typically prevents recurrent infections

32
Q

What are the 3 categories of symptoms of Coccidiomycosis (valley fever)? Describe each

A

1) General: Fever, fatigue, headache, night sweats, weight loss, arthralgias
2) Chest: Productive cough, dyspnea, hemoptysis, pleuritic chest pain
3) Rash: Erythema nodosum, Erythema multiform

33
Q

slide 35

A
34
Q

Testing for Coccidiomycosis is challenging, but:
1) What two values are abnormal?
2) What two titers should you draw?
3) How often is spinal fluid culture positive?
4) What do you need to test for?

A

1) Moderate leukocytosis and eosinophilia
2) IgM and IgG titers (complement fixing)
3) 30% of cases
4) Blood complement-fixing antibodies

35
Q

1) Describe imaging for Coccidiomycosis
2) Describe its treatment (3 options)

A

1) Varies, might find patchy pulmonary infiltrates
2) -Uncomplicated cases resolve spontaneously
-Itraconazole 200mg PO BID x 6 months
-If progressive: Amphotericin B IV until titers decrease

36
Q

1) What type of fungi is Blastomyces?
2) What is its etiology?
3) Describe its pathophysiology (include its incubation period)

A

1) Dimorphic endemic
2) Blastomyces dermatidis, mold in soil/water; broad-based budding yeast in the body
3) Exposure to contaminated soil or decomposing timber
Inhalation of spores
-Traumatized, non-intact skin exposure (Cutaneous Blastomycosis)
-Incubation 30-45 days

37
Q

1) Where is Blastomyces endemic?
2) What are its signs and symptoms?
3) Where does it disseminate? (6 places)

A

1) Ohio River Basin, Mississippi River Basin, Great Lakes, St. Lawrence River
2) Pulmonary involvement: initially asymptomatic in 50% of cases
-Fever, sweating, cough, nocturnal joint pain
3) Bone, nervous system, lungs, liver, spleen, kidney

38
Q

Describe blastomyces:
1) Imaging (& its sensitivity)
2) Labs (3)

A

1) Chest xray: 66% sensitivity, may see Osteolytic lesions
3) -Microscopy: Broad-based budding
-Skin biopsy
-Bone Marrow Aspirate

39
Q

1) How is Blastomyces treated?
2) What about if severe?

A

1) Itraconazole 200-400mg/day PO x 6-12 months
2) Amphotericin B 3-5mg/kg/day IV

40
Q

1) What type of fungus is Aspergillus?
2) What is its etiology?
3) Describe its pathophysiology

A

1) Mold
2) Aspergillus genus (many species…several hundred).Most pathogenic are A. Fumigatus and A. Flavus, Spore-forming
3) Produces aflatoxin and grows into surrounding tissue; can form an aspergilloma **“fungus ball.” **
-Invasive aspergillosis: usually in the lungs, but can cause severe disease in the sinuses, CNS, eyes, or elsewhere

41
Q

Describe the diagnosis of aspergillus

A

1) Common in respiratory tree. Positive cultures alone not enough to dx.
2) Galactomannan antigen detection
3) Allergic Bronchopulmonary Aspergillosis: Hypersensitivity to Aspergillus spores, causing inflammation of bronchioles and eosinophilia

42
Q

What are the two ways to treat Aspergillus based on its two different forms?

A

1) Allergic forms: Itraconazole 200mg PO QD x 16 weeks and Prednisone 0.5mg/kg/day x 4-6 months
Can also use Voriconazole
2) Invasive Aspergillus: Voriconazole 6mg/kg IV BID x 12 weeks
+Surgical debridement for sinusitis and focal pulmonary lesions

43
Q

1) What type of fungus is Mucormycosis?
2) What is its etiology? Give examples
3) List risk factors
4) What are its signs/ symptoms?

A

1) Mold
2) Infections from several different molds, otherwise called “zygomycosis”
-Mucor, rhizopus, and others; “Black Fungus”
3) Diabetes, cancer, immunosuppression, steroids
4) Commonly infects sinuses, eyes and brain and leads to tissue death (Invades blood vessels)

44
Q

Mucormycosis:
1) How is it diagnosed?
2) How is it treated?
3) What is its prognosis?

A

1) Biopsy, culture, imaging. (Challenging, can look like other organisms)
2) Amphotericin B IV and surgical debridement
3) Poor, over 50% fatal

45
Q

1) What category does Pneumocystis (Pneumocystis jiroveci) belong to?
2) What are its risk factors?

A

1) Defies Classification (both protozoan and fungal characteristics)
2) HIV with CD4 count less than 200
-Solid organ or Stem cell transplant recipients
-High dose corticosteroids
-Cancer chemotherapy patients
-Rheumatological diseases

46
Q

Describe the initial (1-2 wks) and pronounced symptoms of pneumocystis

A

1) Fever, malaise, non-productive cough
2) Sputum production, chest pain, chills, exertional dyspnea (w/hypoxia)

47
Q

1) What imaging is done for Pneumocystis and how does it appear?
2) How is it treated? For how long?

A

1) CXR: diffuse Bilateral Interstitial Infiltrates, “Bat winging” appearance
2) 21 days of Trimethoprim-Sulfamethoxazole

48
Q

What are the two ways to diagnose Pneumocystis? Describe each

A

1) Sputum Sample: PCR
2) Blood test: Beta-D-glucan
-High False positive rate

49
Q

Even though they’re both eukaryotes, what is a huge difference between fungal cells and human cells?

A

Fungal cell walls

50
Q

List 4 systemic fungal agents

A

1) Azoles
2) Amphotericin
3) Flucytosine
4) Fungins (echinocandins)

51
Q

1) What is the MOA of Amphotericin B? How does this explain why it has side effects?
2) Describe its spectrum

A

1) Bind to sterols, primarily ergosterol, causing pores that leak cellular components
-Targets are not unique to fungi; human cells have sterols too
2) Broad. Most yeast, all dimorphics, and molds

52
Q

What are the side effects of Amphotericin B?

A

1) Kidney injury (>20%)
2) Low electrolytes common
3) Transfusion reaction: tachycardia, resp. distress, N/V, fever…

53
Q

1) What is the MOA of Flucytosine?
2) What are its side effects?

A

1) Penetrates cells, converted to fluorouracil, which competes with uracil, interfering with RNA synthesis
2) hematologic (leukopenia and thrombocytopenia)

54
Q

1) Give examples of azoles
2) What is their MOA?

A

1) Fluconazole, itraconazole, voriconazole, posaconazole, isavuconazole
2) Inhibiting a cytochrome P450 enzyme necessary for ergosterol

55
Q

Which azole is being described?:
1) Has good yeast coverage. Good CSF penetration. Great bioavailability, no levels
2) Targets yeasts and dimorphics, no molds. Only PO, inconsistent bioavailability (need to check levels), doesn’t reach CSF
3) Covers yeast, dimorphics, and some molds (aspergillus, not mucor). Variable bioavailability (check levels). Good CSF penetration

A

1) Fluconazole
2) Itraconazole
3) Voriconazole

56
Q

Which azole is being described?:
1) Covers yeasts, dimorphics, and molds, but only oral and absorption can be problematic. Rarely levels
2) Similar spectrum to the above, (yeast, dimorphics, and molds); better bioavailability; causes QTc shortening (unlike all the other azoles, which cause QTc prolongation)

A

1) Posaconazole
2) Isavuconazole

57
Q

1) What is a con to using azoles? What do you need to monitor?
2) What is an azole side effect?
3) ___________azole classically causes visual hallucinations as a side-effect when levels are too high

A

1) All the azoles have significant drug-drug interactions
Hepatotoxicity: monitor ALT/AST
2) Prolonged QTc (except isavuconazole, which weirdly shortens QTc)
3) Voriconazole

58
Q

1) List 3 Fungins (echinocandins)
2) What is their MOA? What is noteworthy about this?
3) Describe its coverage

A

1) Micafungin, caspofungin, anidulafungin
2) Target fungal cell glucan synthesis
-Purely fungal; less side effects! (but only IV)
3) Often used for invasive candidiasis and empiric fungal coverage in neutropenic fever
-No dimorphics

59
Q

72yoM presents with fever and lower back pain. On exam, he has 4/5 strength in his lower extremities and saddle anesthesia. On further history, you learn that he has chronic back pain, and has been receiving regular spinal injections of methylprednisolone contaminated with mold.
What is the causative agent? (hint: this was a major outbreak in 2012)

A

Exserohilum rostratum

(PA school) Public Health (3 decks)

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