Fungus Amongus Flashcards
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)
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
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
4
Q
What is easiest way to dx fungal infections?
A
- KOH
- spaghetti and meatballs
- easiest and most cost effective
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
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”
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)
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
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
10
Q
Subcutaneous:
Sporotrichosis
- Dx
A
- Bx
- Culture and microscopy of infected tissue
11
Q
Subcutaneous:
Sporotrichosis
- Tx
A
Tough to penetrate!
- Itraconazole **
- Potassium iodide solution
- oral terbinafine
- IV amphotericin if fail oral
- Sx
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
13
Q
What are the two “true pathogen” systemic fungal infections
A
- Histoplasmosis
- Coccidioidomycosis
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
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
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
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
18
Q
Histoplasmosis
- Chronic disease
A
- MC in pts with underlying lung dz
- cough up blood, weight loss, malaise, fever, dyspnea
- similar to TB
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
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
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
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
23
Q
Coccidioidomycosis
- pathogenesis
A
- Inhalation of spores while outdoor (MC)
- Puncture wound with infected object
- Organ transplant/sexual transmission from infected person (rare)
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
25
Q
Coccidioidomycosis
- Clinical Acute
A
- 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
Q
Coccidioidomycosis
- Disseminated dz
A
- pregnancy, dark-skinned people, immunocompromised
- Skin: erythema nodosum, erythema multiforme
- bone: arthralgias
- CNS sx
27
Q
Coccidioidomycosis
- Dx
A
- 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
Q
Coccidioidomycosis
- Tx
A
- mild: supportive care
- Moderate: -azole
- Severe: posaconazole or amphotericin B. May last months to years
29
Q
Overview of opportunist infections
A
- omnipresent
- yeasts or molds
- many routes, widely variable
- host response varies
- no lasting immunity
30
Q
List the opportunistic infections
A
- Cryptococcosis
- Candidiasis
- Aspergillosis
- Mucormycosis
31
Q
Cryptococcosis
- organism
- org habitat
A
- Cryptococcus neoformans
- Soils with pigeon droppings
- In certain conditions, may remain viable for 2+ years
32
Q
Cryptococcosis
- pathogenesis
- pathophysiology
A
- inhalation of yeast
- occurs in immunodeficient pts
- Transient colonization, acute/chronic lung dz, or CNS invasion
33
Q
Cryptococcosis
- Clinical
A
- Usu asx, recover spontaneously
- mild to mod sx: fever, HA, malaise, dry cough, chest pain
- Severe: pneumonia or ARDS
34
Q
Cryptococcosis
- CNS
A
- 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
Q
Cryptococcosis
- Disseminated dz
A
- Most involve skin, prostate, medullary cavity of bones
- Can develop papules, pustules, nodules, ulcers
- petechiae or ecchymoses
36
Q
Cryptococcosis
- Dx
A
- Sputum culture and stain
- lung bx
- bronchoscopy
- CSF culture and stain
- CXR
- skin bx
37
Q
Cryptococcosis
- Tx
A
- 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
Q
Candidiasis
- organism
- org habitat
A
- MC type!!
- candida albicans
- Normally in intestinal tract, mucous membranes and skin. Overgrowth = sx
39
Q
Candidiasis
- pathogenesis
A
- colonized area: overgrowth
- non-colonized areas: invasion
40
Q
Candidiasis
- pathogenesis
A
- breach in skin or mucousal integrity
- Pulmonary: opportunistic infection, usu have widespread systemic involvement
- Invasive: enters bloodstream and spreads throughout body “candida septicemia”
41
Q
Candidiasis
- name when in throat
A
- thrush
- oropharyngeal candidiasis
42
Q
Candidiasis
- name when in vagina
A
yeast infection
43
Q
Candidiasis
- Clinical settings
A
- 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
Q
Invasive Candidiasis
- overview
A
- one of the MC causes of bloodstream infections in hospitalized patients in the US
- often = long hospital stays, high med $$, poor outcome…
45
Q
Invasive Candidiasis
- sx
A
- 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
Q
Invasive Candidiasis
- Dx
A
- hx
- PE
- blood cultures
47
Q
Invasive Candidiasis
- Tx
A
- aggressive!!
- IV Echinocandin, fluconazole, amphotericin B, other antifungals
48
Q
Aspergillosis
- organism
- org habitat
A
- Aspergillus fumigateurs (and others?)
- mold without a yeast phase
- found everywhere indoors and outdoors
49
Q
Aspergillosis
- Pathogenesis
A
- inhalation of spores
- most people inhale them every day without a problem
- Weakened immune system or lung disease = higher risk of health problems
50
Q
Black molds (2)
A
- 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
Q
Aspergillosis
- Pathophysiology
A
spores in lung:
- elicit allergy
- grow
- invade vasculature and disseminate
52
Q
Aspergillosis
- Clinical presentation
A
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
Q
Aspergillosis
- Dx
A
- CXR/CT of chest
- Sputum culture
- tissue bx
54
Q
Aspergillosis
- Tx
A
- Allergic or sinusitis: oral itraconazole +/- corticosteroids
- Invasive: oral voriconazole
55
Q
Mucormycosis
- org
- org habitat
A
- many fungi can cause
- Mucoraceae family MC
- Mucor. Rhizopus MC org
- mold without a yeast phase
- Soil and decaying matter, found everywhere
56
Q
Mucormycosis
- Pathogenesis
A
- 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
Q
Mucormycosis
- pathophys
A
- 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
Q
Mucormycosis
- Clinical
A
- 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
Q
Mucormycosis
- Dx
A
- 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
Q
Mucormycosis
- Tx
A
- Tx underlying dz (DKA, neutropenia)
- IV very high dose amphotericin B
- 2nd line posaconazole
