Fungal Infection Flashcards
What are the 3 types of pathognic fungi
- Filamentous molds- multicellular, reproduce by spores
- Yeasts-Unicellular, asexual budding or hypea
- Dimorphic- Can switch between the 2 (spores and yeasts)
What type of people do fungi typically infect
Opportunistic infections
-disemminated fungal infection takes place in immunocompromised pts.
What fungi are normal commensals on humans
Malassezia furfur
Candida albicans
What are the 2 main types of fungal diseases (and sub categories)
- Fungal skin infections (superficial, cuaneous, subcutaneous)
- deep seated (endemic, opportunistic)
What are the two main steps to identify fungal infections
- KOH mount (pot. hydroxide) to detect fungal elements
2. Sabouraud dextrose agar to isolate specific type
What is the main fungal infection of the superficial mycoses, layer of skin its found, fungus its caused by
Pityriasis
Caused by malassezia furfur(dimorphic) infection of stratum corneum
What is the pathogenesis of pityriasis
produce chems that incite inflammatory rxn affecting melanin production yielding variable pigmintation
What are predisposing factors to pityriasis
Under certain conditions it will change to a mold (when there is heat and humidity*)
Younger and male due to changes in horomones (skin changes)
How to diagnose pityriasis (2)
- clinically by appearence
2. Spagetti and meatball apearence under KOH (hypea + spores)
What are 2 other forms of M furfur diseases
- Seborrheic dermatitis- inflammed flakey rash
2. Folliculis- inflammed hair follicles
What skin layer does cutaneous mycoses affect and what is an example infection called
limited to the epidermis
ex. Dermatophytosis
do dermatophytosis produce spores, what type of fungi are they what do they produce
Environmental molds (hypea)
Produce spores
Produce keratolytic enzymes that enable them to utilize keratin
transmission of dermatophytis, features that enhace infection and main symptom
Person to person contact (direct or indirect; sharing combs etc)
Trauma/heat+humitity favour infection
-scaly pruritic lesions w red vesculated borders
What is the disease called of the subcutaneous mycoses, what type of fungi is it
Sporotrichosis
dimorphic mold
How do you aquire sporotrichosis
Skin trauma after handling contaminated plant
Pathogenesis of sporotrichosis
causes subcutaneous nodule at point of entry
and will migrate up lymphatic vessels creating nodules along the way
What are the 3 main endemic mycoses
Blastomycosis
Histoplasmosis
Coccidiodomycosis
What type of fungus is endemic mycoses
Thermally dimorphic organsims (mold in cold, yeast at higher)
How is endemic mycosis transmitted
in soild then transmission thru inhalation of spores/ airborne
NO person to person transmission
pathogenesis of endemic mycoses
inhaled and lodge in mucous membrane of respiratory tree where they are phagocytosed and cause problems in immunocompromised indvs
what is the primary target organ of endemic mycoses and symptoms
Primary lung infections
(systemic symptoms- fever, fatigue, inflammation of fat under skin)
Can also be diseminated to CNS etc
What are 4 examples of opportunistic mycoses
- Systemic candidiasis
- Aspergillosis
- Crytococcosis
- Pneumocystis pneumonia
Why does candidiasis occur
usually commesal but can overgrow due to taking of antiotics (will not affect the yeast so it will grow uncontrolled)
What type of mold is candidiasis
Budding yeast
What are the virulence factors of candidiasis (5)
- Psuedohyphae
- germ tubes
- Adhesions
- Invasins (for epithelial penetration)
- Candidalysin toxin
What is the germ tube test and what is it testing for
Tests for candida albicans
Pos test- a short hyphal extension arising from a yeast cell with no constriction at the point of origin
What is candidal intertrigo
In warm moist areas between intertriginous folds of adjacent skin
What is candidal paronychia and onychomycosis
painful redness and swelling of nail folds when repeatedly immersed in water (paronychia)
Onychomycosis (thickening and loss of nails)
What is oropharyngeal candidiasis symptoms
white patches on inner cheeks, tongue, roof of mouth, tongue
What is one of the most common infections of ppl living with HIV/AIDS
Esophageal candidiasis
What are the most common symptoms of invasive candidiasis
mc symptoms are fever and chills that don’t improve after antibiotic tx
Cryptococcus- capsul?, what are the types that affect immunocompromised and non immunocompromised indvs
Have capsule
Inhaled
Immuno compro- C. neoformans (no immune)
Non immuno comrp- C gatti (good immunity)
What does cryptococcus cause in normal and HIV pts
Usually asymptomatic/ self limiting pneumia
HIV- Pneumonia, meningitis
What stain is used for cryptococcus
India-ink stain (can see the capsul)
How is aspergillosis transmitted and what is the toxin produced
Transission via inhalling spores
-produces aflatoxin
What are the symptoms of aspergillosis
- Allergic broncho pulmoary apergillosis (asthma like)
- Sinus inf
- Fungus ball in lungs
- Chronic pulmonary aspergillosis (cavities in lungs)
Pneumocytstis jirovecii transmission, who likely gets it
Spread from person to person in air
- Likely in ppl with weakened immune systems like HIV/AIDS
How to diagnose pneumocytstis jirovecci and symtoms
symptoms- fever, non productive cough, progressive dyspenia
diagnosis- By demonstration of organism in induced sputum, bronchoalveolar lavage, or endotracheal aspirate., will see cyts in xray
