theme 1: fungal pathogens

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are fungi prokaryotic or eukaryotic?
eukaryotic
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how do fungi reproduce?
asexually/sexually, spore formation
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what are the 3 classes of fungi based on lifestyle?
1)saprophytes (decay organic matter) 2)plant pathogen 3)animal pathogen
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what are the growth forms of fungi?
-hyphal=macroscopic, -yeast=single celled
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what are fungi cell walls made of?
glucan-chitin
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what are the 3 types of fungal disease?
1) superficial, 2) subcutaneous, 3) systemic
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where can fungal superficial infections occur? give examples of the fungi causing these (3)
-skin, hair, nails, mucocutaneous tissue, -dermatophytes, candida, malassezia
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what event is subcutaneous infection more likely to follow after and what countries?
-after traumatic implantation, tropical countries
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what does systemic infection affect and give examples of the fungi causing them (2)?
-deep seated organs, -candida, aspergillus
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where does tinea barbae affect?
face skin-shaved
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which groups of people are fungal nail infection, athletes foot and scalp ringworm more common in?
-fungal=common in adults, more in elderly, -athletes foot= common in sportsmen and adults (not young people), -scalp ringworm=common in prepubertal kids
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is athletes foot more common than fungal nail infection, how common is fungal nail infection and scalp ringworm
-athletes is more common than fungal, fungal=2-25%, scalp ringworm=6.6% of US kids, 200 million cases globally
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whats the medical name of athletes foot?
tinea pedis
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how does tinea pedis affect uni/bi-laterally the foot?
-itching, flaking, fissuring of the skin, dry and scale soles, if whole foot affected=moccasin foot
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what fungi causes tinea pedis?
trichophyton rubrum
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what increase severity of tinea pedis?
hyperhidrosis (excessive sweating)
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what 2 things can happen after being infected by tinea pedis?
1) secondary bacterial infection 2) can spread to infect toe nails
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what is the medical name of fungal nail infection and where does it affect?
tinea unguium (onychomycosis), affects nails (toe/finger)
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what happens to the nails in tinea unguium?
-thickening, discolouring, dystrophy
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what 2 fungi can cause tinea unguium?
1) trichophyton rubrum 2)t. interdigitale
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what are the 4 types of tinea unguium?
1) lateral/distal subungal (nail bed/plate), 2)Superficial white (white islands in superficial layers of plate, affects immunocompromised), 3)proximal, 4)total nail dystrophy
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what is the medical name for jock itch?
tinea cruris
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what gender is tinea cruris more prevalent in? think who is grimmer
men
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how does tinea cruris present?
itching, scaling, erythematous plaques with distinct edges (red), poss satellite lesions too (extra splotches)
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where can tinea cruris spread to?
buttocks, back, lower abdomen
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what fungi causes tinea cruris, and revision, what else does it cause?
t.rubrum, -tinea pedis, tinea unguium,
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what is the medical name for scalp ringworm?
tinea capitis
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what people are likely to present with tinea capitis and what symptoms will they have?
-pre-pubescent children, -slight inflammation to severe inflammation, scaly patches, alopecia, black dots, grey patches
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tinea capitis symptoms are much worse when it is zoophilic dermatophytes, why is this and give an example of a reaction from a zoophilic dermatophyte
-body recognises zoophilic is from animals and body response more severe than anthro dermatophyte, -kerion celsi= boggy inflamed lesions
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a severe symptom of tinea capitis is favus, what symptoms are present with favus?
cup shaped crusts (scutula)
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whats the medical name for ringworm?
tinea corporis
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what areas does tinea corporis affect, and where can it spread from?
-limb/torso skin, can spread from scalp/groin
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what will a patient present with if they have tinea corporis?
-circular, single/multiple erythematous plaques, can get Majoccis granuloma (invasion of the follicle)
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what type of dermatophytes cause tinea corporis?
anthrophilic or zoophilic
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how would you investigate a dermatophyte infection?
microscopy and culture
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what treatment would you suggest for a mild dermatophyte infection?
-topical antifungal therapy, e.g. terbinafine, clotrimazole
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what treatment would you give for a severe dermatophyte infection?
-systemic antifungal therapy
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IMPORTANT: what must ALL cases of tinea capitis be treated with and give examples
-systemic oral antifungals (as kids dont respond to topical, topical just reduces this spread not cure),-griseofulvin, terbinafine, itraconazole
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2 point summary of dermatophytes
-infects skin, hair, nails, -low morbidity and high incidence
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what type of infections do the genus of yeasts:malassezia cause?
-superficial
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where is malassezia normally found?
-part of normal flora in humans after birth, on head and trunk mainly
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what diseases does malassezia cause/have a role in?
-pityriasis versicolor, -seborrhoeic dermatitis, -atopic eczema
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if suspect someone of pityriasis versicolor what would they present with?
-hyper/hypopigmented lesions on upper trunk
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what age and area are most likely to present with pityriasis versicolor?
-between puberty and middle age, more common in tropics
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whats frustrating about pityriasis versicolor for the patient?
relapsing
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how would pityriasis versicolor be diagnosed? what would be seen and why is this preferred over the other method
-microsopy= yeast cells and hyphal segments -> spag and meatballs, -dont use culture as hard and uninterpretable
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how would you treat someone with pityriases versicolor? what are lines of treatment if this fails?
-topical antifungal (e.g. clotrimazole), -if fail, use oral fluconazole or itraconazole
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what is candida a genus of?
yeasts
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candida can be present in 3: healthy, superficially, systemic, explain where and what
1) healthy people-mucosal surface and GI tract, 2)superficially-mucosal disease (thrush)(oral/vaginal), skin disease, keratitis (eye cornea) 3) systemic-if in circulatory system can infect most organs
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give some examples of candida species:
c.albicans, c.glabrata, c.parapsilosis, c.krusei
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name the 4 types of superficial candida infection of oral mucosa
1)acute pseudo-membranous, 2) chronic atrophic, 3)angular cheilitis, 4)chronic hypoplastic
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what people are likely to present with acute pseudo-membranous candidiasis and how would they present?
-white plaques (can wipe off), -low cd4 count (<200 cells/ul), younger, asthma with steroid inhalers
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what people are likely to present with chronic atrophic candidiasis and how would they present?
-red/raw (erythema), -older
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a patient presents with swollen red patches on the corner of mouth, whats the diagnosis?
angular cheilitis
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a person presents with white leathery patches (dont easily rub away) on inside of cheek, on gum, on/under tongue, whats the diagnosis and why are you concerned?
chronic hypoplastic, could become malignant
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why are you worried for someone who has HIV/AIDS or is using antibiotics and their risk of oral candidosis?
-HIV/AIDS=need t cell immunity to prevent mucosal candidosis (happens even with antiretrovirals), -antibiotics=suppress normal bacterial flora-> less competition for yeast
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why are you worried for someone who has head/neck cancer or is in hospital?
-head/neck=radio/chemo affects salivary glands, -hospital= increases risk of oral disease (bro come let go hospital and get thrushhhhh)
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the other type of superficial fungal infection is candida vulvovaginitis: how common is it, can it be recurrent, who has it worse off?
-70-80% woman (childbearing age) get it at least once, -10% have recurrent, -pregs have more intense infections
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what symptoms does someone have to make you diagnose candida vulvovaginitis?
-pruritis (itching), burning sensation, +/- discharge, *** epithelium inflammed can spread to labia majora
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for most superficial candidosis how would you diagnose it and what kind of treatment would you use?
-clinical diagnosis (based off history/examination), -empirical therapy
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when would you do further testing for superficial candidosis, what testing is this?
-if recurrent infection, -culture= identify the fungus and antifungal sensitivity testing
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what treatment would you use for superficial candidosis of a non pregnant person?
-oral azoles (e.g. fluconazole but resistance in c.albicans/c.krusei is an issue)
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IMPORTANT-if a patient is pregnant with superficial candidosis, what treatment must you not use and why and what is used instead?
-NO oral azoles (no no no oral fluconazole)-> increases chance of tetratologies, -use topical azoles e.g. clotrimazoles
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where is the candida involved in systemic candidosis acquired from and whats the common species?
-colonised skin, mucosal site, GI tract, -c.albicans
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what type of host is it more likely to get systemic candidosis?
-compromised host
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what can you tell from a blood culture from a systemic candidosis patient?
-disseminated disease (spread through body)
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someone with HIV presents with pain/difficulty on eating/swallowing, whats the diagnosis? what other group has some chance of getting this diagnosis ?
-candida oesophagitis, common in HIV, 10-20% of oropharyngeal disease
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how to diagnose candida oesophagitis?
-endoscopy with biopsy
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what is candidaemia and is it an issue for hospital?
-candida in blood culture, -3.3 cases per 1000 icu admissions
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how do you respond to candidaemia?
-remove lines, -start antifungal therapy, -check eyes and heart
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part of the response to candidaemia is checking eyes and heart, why check eyes?
-risk of getting occular candidosis after candidaemia is 3-25%
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what two types of occular candidosis exist? and which requires intravitreal antifungals (into eye)
-chorioretinitis (75%), endophthalmitis (25%)
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part of the response to candidaemia is checking eyes and heart, why check heart? and what happens to heart?
-2-3% get candida endocarditis, get vegetations (masses) on heart valves
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an IV drug abuser who had undergone a valve replacement surgery presents with fever, weight loss, fatigue, heart murmur, what do they have and why were they more at risk of it?
-candida endoarditis, -iv drug abuser and valve replacement=inc risk
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whats the way to treat our poor iv drug abuser valve replaced patient with candida endocarditis?
-valve replacement
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an immunocompromised premature neonate presents with fever, abdominal pain, oliguria (small amounts of urine), anuria (no urine), what is the diagnosis?
renal candidosis
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how does renal candidosis occur in a patient?
-candida lodges in kidney tissue during filtration
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where does the candida come from to cause urinary tract candida infection?
-ascends from genital tract infection/catheters
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who is urinary tract candida infection?
-women, diabetics, abnormal urinary tracts, ICU patients
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what is candiduria and is it significant?
-candida present in urine, -may/may not be significant
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why is urinary tract candida infection a bit of a ***** to treat?
-a few antifungals get weed out alas
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what are the two causes of candida peritonitis?
1)complication of peritoneal dialysis, 2) perforation of bowel in surgery get a yummy mix of bacterial and yeast infection
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what would someone with candida peritonitis present with?
-fever, abdo pain, nausea, vomiting
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how to diagnose and treatment of specifically candida peritonitis?
-culture of candida from peritoneal fluid, -drainage and antifungals
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what form of candidosis is hepatosplenic candidosis?
-disseminated form (we be spreADing)
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how does hepatosplenic candidosis occur? (2 events then smth)
-leukaemia/neutropenia (less wbc), during neutrophil recovery=yeasts lodge in liver/spleen
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someone presents with abscess formation (bulls eye sign), fever, liver function disturbance, whats the diagnosis?
-hepatosplenic candidosis
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why is antifungal therapy not effective in hepatosplenic candidosis?
- the dead fungus can keep triggering inappropriate inflammatory responses
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what are the two potential ways of diagnosing systemic candidosis?
1) cultures (from blood, peritoneal fluid, sterile site) 2)imaging (e.g. valve vegetation)
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what does the treatment of systemic candidosis depend on?
-candida species, sensitivity, severity, need for oral agent
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what are the 3 types of treatment of systemic candidosis?
-echinocandins (e.g.anidulafungin IV), -azoles (oral fluconazole), -liposomal amphotericin B (IV)
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what is aspergillus a genus of?
-moulds
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what is the structure of the aspergillus moulds? and what do they make?
-filamentous fungi, make airborne spores
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how are people universally exposed to aspergillus and what part of the body can it colonise?
-inhale the airborne spores, -colonise airways
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what 4 examples of medically important aspergillus species?
-a.fumigatus, a.niger, a.flavus, a.terreus
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people can have 4 different ways of reacting to inhaling aspergillus. what is the general name of a reaction to aspergillus?
-aspergillosis
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what is aspergilloma?and where does it form?
- solid balls of fungus, -space occupying/non invasive
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what cavities can aspergilloma form in?
-cavities from previous TB, sarcoid (nodules in lung/lymph nodes/bone/skin), surgery
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IMPORTANT: what can happen to an aspergilloma that are normally indolent (grow slowly)?
can break up causing haemoptysis, poss fatal
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how to treat aspergilloma?
resection of the lung
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what name is given to the 2 allergic reactions to aspergillosis?
-allergic bronchopulmonary aspergillosis, -allergic sinus disease
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who tends to get the allergic reactions to aspergillus and what are their symptoms/signs?
-asthma/cf peeps, -wheezing, breathlessness, loss of lung function, bronchiectasis, airway inflammation, igE/igG start wylin
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how to treat allergic bronchopulmonary aspergillosis/allergic sinus disease?
-steroids/antifungal therapy
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whats the chronic reaction to aspergillus called?
chronic pulmonary aspergillosis (CPA)
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who is likely to present with chronic pulmonary aspergillosis and what symptoms would they have?
-people with chronic obstructive pulmonary disease, -chronic resp symptoms, cough, wheezing, breathlessness, chest pain
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if someone has chronic pulmonary aspergillosis, what would CT/sputum or BAL (squirt fluid into lungs then recollect it) cultures/bloods show?
-chest ct=consolidation, cavitation, -culture=positive for aspergillus, bloods=positive for aspergillus igG
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what are the two conditions of invasive aspergillosis?
-invasive pulmonary aspergillus, -invasive aspergillus sinusitis
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who is likely to present with invasive aspergillosis and what signs will they have?
-haemotological malignancy, stem cell/solid organ transplant, -signs=low neutrophil counts, angioinvasion of lung tissue (enters vessels), halo and air crescent signs on CT, 25% can disseminate to extrapulmonary sites
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so you blast the invasive aspergillosis with aggresive antifungal therapy, hows the prognosis looking doc?
-moderate to poor rip
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what are the 3 general methods of diagnosis of aspergillosis?
-culture, serology (fluids for antibodies), imaging
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how to treat CPA and invasive aspergillosis?
antifungals-> itraconazole, voriconazole, amphotercin B
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summary of malassezia:what group and what do they cause?
-yeasts part of normal flora, cause of pityriasis versicolor
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summary of candida: what type of disease it causes, what it can infect, where does infection usually arise from in patients
Causes both superficial and systemic disease Can infect any organ in the body Infection usually from patients own colonised mucosa
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summary of aspergillus: what can it cause, how do you get it, what does effect depend on?
Causing pulmonary or sinus disease Inhalation of Aspergillus spores Effect depends on host reaction, or lack of reaction, from allergy to invasive disease
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important reminders:3
1) tinea capitis-oral medicine (on yer head, in yer mouth) 2) pregant? congrats, remember all the Ts, treat thrush topically, 3)aspergilloma-not always indolent, having a (fungal ball), watch for the bleed
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