Candidiasis (I) Flashcards
What is candidiasis?
Infection by yeasts of the genus Candida, mostly C albicans
What pathogen is candidiasis most commonly caused by?
Candida albicans (type of dimorphic fungus):
- opportunistic microbe, normally found throughout body (skin/mucous membranes)
- penetrate epithelial tissue by secretion of protease enzymes (secretory aspartyl proteinases and phospholipase B)
Where does Candida albicans usually live?
Although Candida are considered normal flora in GI and GU tracts, healthy skin and oropharyngeal cavity, they are capable of:
- local infection of mucous membranes - oropharyngeal candidiasis, oesophagitis, vulvovaginitis
- focal invasion - endophthalmitis, meningitis, endocarditis
- dissemination - candidaemia
Who does Candida albicans cause disease in?
High risk patients
Ability of Candida to colonise and infect tissues requires local and systemic defects in host immune responses e.g. immunocompromised
What is pseudomembranous candidiasis?
- oral thrush - most common oral candidiasis
- lesions on palate, buccal mucosa, and on lateral borders and dorsum of tongue
- due to weakened immune system = destruction of stratified epithelium layer = white lesions (looks like cottage cheese that can be scraped away to leave behind a red mucosal base)
What is erythematous candidiasis?
Due to change in levels of microbial competition keeping Candida in check –> overgrowth of Candida –> increased blood flow to affected tissue with red painful lesions
What are the two ways candidiasis infection can occur?
- local infection - imbalance in local flora leading to overgrowth of C. albicans
- systemic infection - breach of skin barrier leading to direct invasion of bloodstream
What are the different types of disease Candida can cause? (4)
- oral thrush (pseudomembranous candidiasis) - oropharyngeal lesion
- erythematous candidiasis
- oesophageal candidiasis - associated with AIDS
- vulvovaginitis - vaginal yeast infection
- systemic candidiasis
What are the clinical features of oral thrush (pseudomembranous candidiasis)? (3)
- white plaque in oral cavity that can be scraped off leading to inflamed areas
- feels cottony in mouth
- fissuring at mouth corners (angular cheilitis)
What medication can cause oral thrush?
ICS (beclomethasone) in asthma
How does erythematous candidiasis (type of oral candidiasis) present? (4)
- atrophic fiery red flat lesions
- patchy areas of loss of filiform papillae on tongue dorsum
- spotty red areas on buccal mucosa
- burning oral pain
What symptom does oesophageal candidiasis lead to?
Odynophagia (retrosternal pain on swallowing)
How does vulvovaginitis (candidiasis) present? (4)
- cottage cheese, non-offensive discharge
- dysuria
- dyspareunia
- pruritic
What are some symptoms of systemic candidiasis? (4)
- fever
- fatigue
- skin rash
- neurological deficits e.g. altered mental state
How does candidaemia (disseminated candidiasis) present?
Persistent fever despite Abx therapy
What are some general risk factors for candidiasis? (3)
- immunosuppression - HIV, diabetes, steroid use
- imbalance in local flora - Abx, steroid use
- compromised skin
What are some specific risk factors for oral candidiasis? (11)
- hyposalivation/xerostomia (reduced/absent saliva)
- poor oral hygiene (e.g. denture wearers)
- malabsorption and malnutrition
- advanced malignancy
- chemotherapy and radiotherapy
- HIV
- endocrine disturbance (DM, hypoparathyroidism, pregnancy, hypoadrenalism)
- immunosuppressive agents (local/systemic corticosteroids)
- current/recent use of broad-spectrum or multiple narrow-spectrum Abx
- extremes of age
- inhaled corticosteroids
What is the first-line investigation for candidiasis?
Superficial smear of lesion for microscopy - positive for Candida hyphae
What are some differential diagnoses for candidiasis? (8)
- chemical burns
- thermal burns
- hairy leukoplakia
- pre-malignant leukoplakia
- plaque-type lichen planus
- erosive lichen planus
- reactive keratosis
- migratory glossitis
What topical antifungals are there for mild-moderate candidiasis? (3)
- clotrimazole (main one)
- miconazole
- nystatin
What do we give for severe candidiasis?
Systemic antifungal treatment - fluconazole
What do we give for vaginal candidiasis?
Oral fluconazole
Local miconazole/clotrimazole creams
What can we give to those severely immunocompromised as prophylactic therapy for candidiasis?
Suppressive therapy with fluconazole
What are some complications of candidiasis? (5)
- oral candidiasis –> oesophageal candidiasis
- disseminated candidiasis (sepsis)
- meningoencephalitis (obstructive hydrocephalus, calcifications, thrombosis)
- pyelonephritis
- abscess in multiple organs
