Infectious Disease > Fungus Amongus > Flashcards

Fungus Amongus Flashcards

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1
Q

Superficial fungal infections

- Dermatophyte

A
  • VERY common
  • Require keratin
  • Infect skin, hair, nails
  • Spread via contact with people, animals, soil, fomites
  • Tinea: corporals, cruris, capitis, pedis, unguium (onychomycosis)
  • DX: KOH prep, woods lamp, culture
  • Tx: oral/topical antifungals (azaleas)
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2
Q

Superficial fungal infections

- Malassezia

A
  • lipophilic yeast
  • Resides in keratin of skin and hair follicles
  • Tinea veriscolor and seborrheic dermatitis
  • Dx: KOH prep
  • TX: shampoos, azalea creams, oral meds if large area involved
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3
Q

Superficial fungal infections

- candida

A
  • Candidal intertrigo: large skin folds
  • groin/armpit, buttocks, under pendulous breasts, panes
  • KOH: pseudohyphae
  • Tx: keep dry and cool, topical antifungals, systemic anti fungal if resistant to topical
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4
Q

What is easiest way to dx fungal infections?

A
  • KOH
  • spaghetti and meatballs
  • easiest and most cost effective
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5
Q

KOH procedure

A
  • clean skin with alcohol
  • collect scale with 15 blade and place on slide
  • KOH drop and coverslip, heat gently
  • microscope
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6
Q

Subcutaneous fungal infections

- pathogenesis

A
  • introduced via skin
  • grows in dermis and subcutaneous tissue
  • may reach bone
  • orgs live in soil and live on rotting vegetation
  • usually get in skin via skin prick/injury, usually stay localized to site of implantation
  • MC in non-industrialized world
  • aka “Madura foot”
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7
Q

Subcutaneous:

Sporotrichosis

A
  • sporothrix schenkii
  • “rose gardener disease”
  • via skin through small cuts, scratch, puncture from thorn, barb, pine needles, wires
  • Usu found on decaying vegetation, rosebushes, twigs, hay, moss, mulch-rich soil
  • Not gen transmitted person to person
  • Can transmit from cat to human (scratch or bite)
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8
Q

Subcutaneous:
Sporotrichosis
- Pathophys

A
  • yeast travel along lymphatics
  • Immunocompromised, rarely can inhale spore-laden dust, leads to disseminated disease
  • Mixed pyogenic/granulomatous reaction
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9
Q

Subcutaneous:
Sporotrichosis
- Clinical presentation

A
  • Gardeners, farmers, nursery workers, landscapers
  • Lesion at site of scratch
  • Nodules under skin along lymphatic channels
  • Bone/joint destruction: subacute or chronic inflammatory arthritis 1+ joints
  • Lung involvement: severe underlying chronic lung disease, pneumonia
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10
Q

Subcutaneous:
Sporotrichosis
- Dx

A
  • Bx

- Culture and microscopy of infected tissue

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11
Q

Subcutaneous:
Sporotrichosis
- Tx

A

Tough to penetrate!

  • Itraconazole **
  • Potassium iodide solution
  • oral terbinafine
  • IV amphotericin if fail oral
  • Sx
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12
Q

What are the two main kinds of systemic fungal infections?

A
  • “true pathogens” which infect anyone

- “opportunists” which are more concerning to immunocompromised pts

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13
Q

What are the two “true pathogen” systemic fungal infections

A
  • Histoplasmosis

- Coccidioidomycosis

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14
Q

Histoplasmosis and coccidioidomycosis

- overview

A
  • Dimorphic: immature and mature forms, can be symptomatic in either form
  • respiratory acquisition
  • restricted geographic distribution: get travel history
  • Infect normal hosts
  • disease similar to TB
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15
Q

Histoplasmosis

  • Organism
  • Habitat of org
A
  • Histoplasma capsulatum
  • Soil/material contaminated with bird/bath droppings
  • Also domestic bird droppings like chickens, starlings, etc.
  • Histo belt: AR, KT, TN, WV, other parts of SE and central US. Also Africa and Australia
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16
Q

Histoplasmosis

  • pathogenesis
  • pathophys
A
  • inhalation of spores
  • spores transform to yeast in the lung, elicit cellular immunity like TB
  • Those with lower immune response (infants, children, elderly) at greater risk of severe disease
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17
Q

Histoplasmosis

- presentation

A
  • 90% asx
  • Sx 3-14 days after exposure
  • Acute: flu like sx
  • maybe: dyspnea, chest pain, cough, respiratory sx
  • 5-6% skin lesions and joint pain, mainly in females
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18
Q

Histoplasmosis

- Chronic disease

A
  • MC in pts with underlying lung dz
  • cough up blood, weight loss, malaise, fever, dyspnea
  • similar to TB
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19
Q

Histoplasmosis

- disseminated dz

A
  • immunocompromised
  • Sx vary depending on duration of illness
  • GI, CNS, Cardiac sx as progresses
  • 50-60% mouth and gum pain dt mucosal ulcers**
  • fatal if not treated
  • 1-10% have ocular involvement, may = blind
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20
Q

Histoplasmosis

- Dx

A
  • Sputum culture: positive in 10-15% acute and 60% chronic
  • blood culture: 50-90% positive in progressive disseminated dz
  • CXR and CT scan (looks like pneumonia)
  • tissue bx
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21
Q

Histoplasmosis

- Tx

A
  • MC acute infection with normal immunity will recovery without treatment
  • mild sx: monitor
  • Prolonged/severe sx: antifungals
  • Chronic/disseminated: Amphotericin B
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22
Q

Coccidioidomycosis

  • aka
  • org
  • org habitat
A
  • “valley fever”
  • coccidides immitis and occidioides posadaii
  • lower Sonoran life zone: NM, TX, AZ, NV, northern Mexico and CA San Joaquin Valley. Places with a mild winter and arid summer
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23
Q

Coccidioidomycosis

- pathogenesis

A
  • Inhalation of spores while outdoor (MC)
  • Puncture wound with infected object
  • Organ transplant/sexual transmission from infected person (rare)
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24
Q

Coccidioidomycosis

- pathophysiology

A
  • In soil, grows as mold with long filaments that break off into airborne spores when soil is disturbed
  • spores are small and carry hundreds of miles in the wind.
  • Once inside lungs, spores reproduce, perpetuating life cycle of disease
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25
Coccidioidomycosis | - Clinical Acute
- 65% asx - Low grade fever w/chills and night sweats - fatigue - pain - cough with poss sputum/hemoptysis - Anorexia - lower limb/food swelling - rattling of the chest
26
Coccidioidomycosis | - Disseminated dz
- pregnancy, dark-skinned people, immunocompromised - Skin: erythema nodosum, erythema multiforme - bone: arthralgias - CNS sx
27
Coccidioidomycosis | - Dx
- Sputum smear (KOH test) - Blood test: look for coccidioides species - Culture, histology, serological testing - CXR - Severe dz: lung, liver, lymph node, bone bx, spinal tap, bronchoscopy with lavage
28
Coccidioidomycosis | - Tx
- mild: supportive care - Moderate: -azole - Severe: posaconazole or amphotericin B. May last months to years
29
Overview of opportunist infections
- omnipresent - yeasts or molds - many routes, widely variable - host response varies - no lasting immunity
30
List the opportunistic infections
- Cryptococcosis - Candidiasis - Aspergillosis - Mucormycosis
31
Cryptococcosis - organism - org habitat
- Cryptococcus neoformans - Soils with pigeon droppings - In certain conditions, may remain viable for 2+ years
32
Cryptococcosis - pathogenesis - pathophysiology
- inhalation of yeast - occurs in immunodeficient pts - Transient colonization, acute/chronic lung dz, or CNS invasion
33
Cryptococcosis | - Clinical
- Usu asx, recover spontaneously - mild to mod sx: fever, HA, malaise, dry cough, chest pain - Severe: pneumonia or ARDS
34
Cryptococcosis | - CNS
- Meningitis is MC presentation ** - HA, nuchal rigidity, AMS, confusion, malaise, n/v, blurred vision, seizure, coma - Fatal within 2W to several years w/o tx
35
Cryptococcosis | - Disseminated dz
- Most involve skin, prostate, medullary cavity of bones - Can develop papules, pustules, nodules, ulcers - petechiae or ecchymoses
36
Cryptococcosis | - Dx
- Sputum culture and stain - lung bx - bronchoscopy - CSF culture and stain - CXR - skin bx
37
Cryptococcosis | - Tx
- asx: no tx - mild pulm dz: fluconazole 6-12 mo - pulm/CNS: IV Amphotericin B + Flucytosine. - Oral fluconazole can be used for less severe infections and is used for life long tx to prevent relapse - HIV/AIDs: life long tx to suppress the fungus
38
Candidiasis - organism - org habitat
- MC type!! - candida albicans - Normally in intestinal tract, mucous membranes and skin. Overgrowth = sx
39
Candidiasis | - pathogenesis
- colonized area: overgrowth | - non-colonized areas: invasion
40
Candidiasis | - pathogenesis
- breach in skin or mucousal integrity - Pulmonary: opportunistic infection, usu have widespread systemic involvement - Invasive: enters bloodstream and spreads throughout body "candida septicemia"
41
Candidiasis | - name when in throat
- thrush | - oropharyngeal candidiasis
42
Candidiasis | - name when in vagina
yeast infection
43
Candidiasis | - Clinical settings
- very young/very old - warm climate - occlusion - use of broad spectrum abx - high estrogen contraceptive pills/pregnancy - DM, Cushing's, other endocrine disorders - Immunodeficiency - Chemotherapy or marrow ablation
44
Invasive Candidiasis | - overview
- one of the MC causes of bloodstream infections in hospitalized patients in the US - often = long hospital stays, high med $$, poor outcome...
45
Invasive Candidiasis | - sx
- often already sick from other conditions, hard to tell what is candidiasis - Fever and chills that don't improve on abx - other sx as spreads throughout body
46
Invasive Candidiasis | - Dx
- hx - PE - blood cultures
47
Invasive Candidiasis | - Tx
- aggressive!! | - IV Echinocandin, fluconazole, amphotericin B, other antifungals
48
Aspergillosis - organism - org habitat
- Aspergillus fumigateurs (and others?) - mold without a yeast phase - found everywhere indoors and outdoors
49
Aspergillosis | - Pathogenesis
- inhalation of spores - most people inhale them every day without a problem - Weakened immune system or lung disease = higher risk of health problems
50
Black molds (2)
- Stachybotrys chartarum: infamous for ARDS and infant deaths in Ohio in 90s - Aspergillus niger: toxic black mold that produces mycotoxins (people may confuse aspergillus niger with aspergillus fumigatus which is less dangerous)
51
Aspergillosis | - Pathophysiology
spores in lung: - elicit allergy - grow - invade vasculature and disseminate
52
Aspergillosis | - Clinical presentation
Depends on type of aspergillosis - Allergic broncho-pulmonary: similar to asthma, wheezing, cough, SOB, fever - Chronic pulmonary: MC in those with COPD, TB, sarcoidosis - "fungus ball": cough, hemoptysis, SOB - Invasive + pneumonia/other end-organ dz: fever, chest pain, cough, hemoptysis, SOB
53
Aspergillosis | - Dx
- CXR/CT of chest - Sputum culture - tissue bx
54
Aspergillosis | - Tx
- Allergic or sinusitis: oral itraconazole +/- corticosteroids - Invasive: oral voriconazole
55
Mucormycosis - org - org habitat
- many fungi can cause - Mucoraceae family MC - Mucor. Rhizopus MC org - mold without a yeast phase - Soil and decaying matter, found everywhere
56
Mucormycosis | - Pathogenesis
- People with weakened immune systems - Affects sinus or lung after inhaling fungal spores from air or after ingestion - Fungus can enter skin via cut, scrape, burn, other trauma
57
Mucormycosis | - pathophys
- Most acute and fulminant fungal infection known* - molds in environment that become hyphal form in tissue - once spores grow, fungal hyphae invade blood vessels - results in tissue infarction, necrosis, thrombosis
58
Mucormycosis | - Clinical
- Severe infection of sinuses, can extend into brain abscess - Rhinocerebral swelling, HA, congestion, black lesions on upper oral cavity - 50% in DKA pts - Pulmonary: fever, cough, chest pain, SOB. MC in neutropenic pts (chemo, leukemia) - Cutaneous: ulcers/blisters, black skin - GI: abd pain, n/v, GI bleeding - Disseminated: usu sick already from something else. Brain infection, coma
59
Mucormycosis | - Dx
- CT scan of paranasal sinuses and nasal endoscopy if suspect rhino cerebral dz - tissue bx: pathology and culture - Pulm dz: bronchoalveolar lavage +/- bx - Cutaneous: skin bx for pathology and culture - CBC, CMP, ABG, iron studies, CSF
60
Mucormycosis | - Tx
- Tx underlying dz (DKA, neutropenia) - IV very high dose amphotericin B - 2nd line posaconazole
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