orofacial fungal infections Flashcards
what % of healthy individuals is candida species found in?
35-55%
what other fungi species can be found in healthy individuals that rarely cause disease?
saccharomyces
geotrichum
cryptococcus
are candida harmless?
usually harmless but under certain conditions may switch to pathogenic form and cause disease
name some e.g of candida species
C albicans (most common/principal)
C glabrata
C tropicalis
C kefyr
C krusei
(all pathogenic)
name some e.g of other rare fungal species
Aspergillus spp
Cryptococcus spp
Geotrichum spp
Saccharomyces spp
when does candida cause problems ?
when it overgrows due to e.g dry mouth, antibiotics, immunosuppressed pts
what word describes candida existing in diff shapes/morphology
pleomorphic
what’s the main form of C albicans?
ovoid
what filamentous forms does C albicans change to due to environmental changes?
hyphae
pseudohyphae (elongated, not true hyphae)
name e.g of environmental changes that cause a morphological change in C albicans
decrease in pH
increase in temp
increase in CO2
increase in nutrients e.g glucose
what are ovoid cells well suited to do in immunosuppressed pts?
haematogenous spread
what are hyphal cells adapted to do and how?
invasion, colonisation and avoiding macrophages
due to elongated form
what is tongue coating caused by and how is it managed?
-build up of food + bacteria deposits in filiform papillae on dorsum of tongue
-manage by increasing fluid intake & roughage in diet + gentle tongue brushing
where is candida mainly found?
dorsum of tongue
in who does candida increase?
pregnant women
smokers
poorly controlled diabetics
denture wearers
list general predisposing factors of pathogenic C albicans
broad spectrum antibiotics
corticosteroids
cytotoxics (chemo)
poorly controlled diabetes
xerostomia
nutritional deficiencies
immunosuppression
list local predisposing factors of pathogenic C albicans
trauma e.g ill fitted dentures
tobacco smoking
reduced salivary flow
carb rich diet
how do broad spectrum antibiotics affect candida levels
cause change in oral microflora which control candida levels by competing for dietary substrates and epithelial cell adhesion
how do xerogenic agents affect candida levels
cause reduction in salivary flushing and antifungal salivary components
why is oral candidosis sometimes the first presentation of immunodeficiency?
bc cell mediated immunity & humoral immunity are important in prevention + elimination of fungal infections
what is a predisposing haematological factor of candidosis & how?
blood type o -> increased H antigen which is a receptor for C albicans
what is a predisposing dietary factor of candidosis & how?
-malnutrition/deficiencies (iron, vit b12, c) -> reduced host defences + mucosal integrity allowing hyphal invasion and infection
-CHO rich diet -> can increase adherence of candida to epithelilal cells
is candidosis usually a local or systemic infection?
local
symptoms of oral candidosis
altered taste
oral dryness
dysphagia (if oesophageal infection occurs)
what are the acute forms of candidosis
pseudomembranous (‘thrush”)
erythematous/atrophic
what are the chronic forms of candidosis
chronic hyperplastic candidosis (CHC)
erythematous (denture stomatitis)
what are the secondary forms of candidosis
median rhomboid glossitis
angular cheilitis
chronic mucocutaneous candidosis
clinical features of thrush (pseudomembranous candidosis)
detachable creamy-white/yellowish patches on oral mucosal surfaces
wipes off & has erythematous base
asymptomatic lesions
who is thrush classically found in?
immunocompromised (HIV, extremes of age, DM)
what is thrush frequently associated with?
angular cheilitis
oesophageal candidosis (in HIV)
management of thrush
improve OH
smoking cessation
investigate & treat systemic issues (e.g immunosuppression, DM, anaemia)
live active yogurt
topical agents -> chlorhexidine m/w, anti-fungal agents (nystatin, miconazole gel)
clinical features of erythematous candidosis
painful erythematous patches
commonly on dorsum of tongue & palate
associated with chronic use of broad spectrum antibiotics (‘antibiotic sore mouth’) & corticosteroids
found in HIV
clinical features of CHC (chronic hyperplastic candidosis)
white/erythematous raised lesions that don’t rub off
usually on buccal mucosa bilaterally towards commissures
may have associated angular cheilitis
may be nodular/speckled -> more prone to malignancy OR white plaque like
generally asymptomatic
who is CHC most commonly found in
middle-aged male smokers
what is CHC a form of
chronic hyperkeratosis (in which candida is identified)
management of CHC
biopsy to recognise if premalignant
check iron/folate/vit b12 levels
remove predisposing factors (smoking, controlled DM)
systemic anti-fungals (oral fluconazole 2-4+ weeks)
clinical features of chronic erythematous candidosis ( denture stomatitis)
marked erythema of palatal mucosa with sharply defined margins
if relief area present, may result in underlying spongy granular change
asymptomatic (except angular cheilitis)
rarely involves lower arch
cause of denture stomatitis
denture fit excludes saliva from supporting mucosa allowing candida to overgrow
inadequate OH/ denture hygiene
poorly fit dentures
affects 65%
describe newtons classification
type 1 - pinpoint hyperaemia (red spots)
type 2 - diffuse erythema limited to denture fit surface
type 3 - nodular appearance of palatal mucosa
management of denture stomatitis
improve denture hygiene
eliminate tissue trauma (tissue conditioners)
miconazole gel applied to denture fit surface (caution as absorbed systemically & can interact with drugs e.g warfarin)
if lack of resolution consider systemic issues
clinical features of angular cheilitis
symmetrical erythematous fissuring in commissures
decreased vertical dimension with maceration of underlying skin (assoc with saliva pooling)
predisposing aetiological factors in angular cheilitis
lip morphology
reduced haematinic levels (B12, iron)
malabsorption disorders e.g chrons
immunosuppression
DM
broad spectrum antibiotics
xerostomia
management of angular cheilitis
correct predisposing factors
correct vertical dimension
improve OH and denture hygiene
treat intraoral candida with topical agents
miconazole gel to corners of mouth
if chronic, trimovate cream
who does angular cheilitis mainly affect
elderly edentulous with denture stomatitis
people with thrush, CHC
clinical features of median rhomboid glossitis
localised candidal infection with atrophy of filiform papillae
asymptomatic diamond shaped smooth area anterior to circumvallate papillae
what is median rhomboid glossitis strongly associated with
smoking
corticosteroid inhalers
management of median rhomboid glossitis
smoking cessation
address inhaler technique
check for predisposing factors
systemic anti-fungal (fluconazole)
aetiology/cause of chronic mucocutaneous candidosis (CMC)
impaired cellular immunity to candida
what is CMC associated with
rare congenital disorders e.g APS-1
what is APS-1 (autoimmune polyendocrine syndrome type 1)
rare monogenic autosomal recessive disease with varied onset (0-18yrs)
CMC usually first major feature
clinical features of CMC in APS-1
initially presents as as oral thrush with angular cheilitis
becomes more chronic with atrophy and leukoplakia
painful with acidic/spicy food
how is oral candidosis diagnosed
usually clinically (with thrush and denture stomatitis)
if possible take microbial sample (to identify, quantify and assess resistance)
which candida species are more resistant to some anti-fungal agents
C glabrata
C krusei
what are 6 diff candidal sampling methods & their adv/disadv
1) whole saliva culture
+ gives fungal load
- not suitable in xerostomia
2) concentrated oral rinse
+ gives fungal load
- requires specialised lab
3) sponge imprint culture
+ gives fungal load, site specific
- requires specialised lab
4) swab
+ site specific
- doesn’t give load
5) smear
+ no lengthy culture required
- doesn’t give species
6) biopsy
+ indicated for CHC
- doesn’t give load or species, MOS procedure
4 types of anti-fungal agents
1) polyenes (nystatin, amphoterecin)
2) azoles (fluconazole, miconazole, ketoconazole)
3) 5-flucytosine
4) echinocandins (caspofungin, micofungin, anidulafungin)
MoA (mechanism of action) & administration of polyenes
disrupts fungal cell membrane (fungicidal)
topical
MoA & adminsitration of azoles
inhibition of ergosterol synthesis (fungistatic)
topical/ systemic
MoA & adminsitration of 5-flucytosine
inhibition of protein & DNA synthesis
systemic
MoA & administration of echinocandins
inhibition of B1,3 D-glucan synthesis
intravenous
therapeutic indications for topical anti-fungal agents
superficial infection
denture wearers, AB drug use, diabetics
therapeutic indications for systemic anti-fungal agents
immunosuppressed
candidal leukoplakia (e.g CHC)
MoA of nystatin, dose & adverse effects
MoA - prevents fungal membrane ergosterol synthesis
dose - oral suspension 4x day for 1-2 weeks
effects - oral irritation, sensitisation, nausea
MoA of amphotericin, dose & adverse effects
MoA - binds with fungal membrane ergosterol -> cell death
dose - lozenges 10mg 4x day 10-15 days
effects - mild GI disturbances
MoA of azoles
inhibit lanosterol demethylase -> no ergosterol synthesis
why is there azole resistance
overproduction/altered lanosterol demethylase
compensation by other sterol synthesis enzymes
2 types of azoles and e.g
1) imidazoles (miconazole, ketoconazole, clotrimazole)
2) triazoles (fluconazole, itraconazole, voriconazole, posaconazole)
how is miconazole used & dose
gel applied to affected area (e.g denture fit surface, dentures can be left in)
has anti-staphylococcal activity
dose - gel 25mg, 4x day for 2 weeks after meals
how is ketaconazole used & dose
systemic
non-specific (inhibits testosterone & cortisol synthesis)
dose - 200mg 1x for 2 weeks
contraindications for ketoconazole
not used in in pts with liver disease or alcoholics as hepatotoxic
contraindications for fluconazole
pregnancy
breast feeding
side effects of fluconazole
nausea/vomitting
diarrhoea, flatulence
rashes
hepatitis
what drugs does fluconazole affect & how?
reduces metabolism of several drugs by inhibiting CYP3A
-benzodiazepines
-calcium channel blockers
-ciclosporin
-warfarin
results in increased conc and toxicity
which candida species may show decreased susceptibility/frank resistance to fluconazole
C glabrata
C dublinensis
what has been developed to combat resistant species
echinocandins
(C parapsilosis and C guillermondii often resistant)
