Candidiasis (I)

Question 1

What is candidiasis?

Answer 1

Infection by yeasts of the genus Candida, mostly C albicans

Question 2

What pathogen is candidiasis most commonly caused by?

Answer 2

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)

Question 3

Where does Candida albicans usually live?

Answer 3

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

Question 4

Who does Candida albicans cause disease in?

Answer 4

High risk patients

Ability of Candida to colonise and infect tissues requires local and systemic defects in host immune responses e.g. immunocompromised

Question 5

What is pseudomembranous candidiasis?

Answer 5

• 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)

Question 6

What is erythematous candidiasis?

Answer 6

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

Question 7

What are the two ways candidiasis infection can occur?

Answer 7

• local infection - imbalance in local flora leading to overgrowth of C. albicans
• systemic infection - breach of skin barrier leading to direct invasion of bloodstream

Question 8

What are the different types of disease Candida can cause? (4)

Answer 8

• oral thrush (pseudomembranous candidiasis) - oropharyngeal lesion
  
  • erythematous candidiasis
• oesophageal candidiasis - associated with AIDS
• vulvovaginitis - vaginal yeast infection
• systemic candidiasis

Question 9

What are the clinical features of oral thrush (pseudomembranous candidiasis)? (3)

Answer 9

• white plaque in oral cavity that can be scraped off leading to inflamed areas
• feels cottony in mouth
• fissuring at mouth corners (angular cheilitis)

Question 10

What medication can cause oral thrush?

Answer 10

ICS (beclomethasone) in asthma

Question 11

How does erythematous candidiasis (type of oral candidiasis) present? (4)

Answer 11

• atrophic fiery red flat lesions
• patchy areas of loss of filiform papillae on tongue dorsum
• spotty red areas on buccal mucosa
• burning oral pain

Question 12

What symptom does oesophageal candidiasis lead to?

Answer 12

Odynophagia (retrosternal pain on swallowing)

Question 13

How does vulvovaginitis (candidiasis) present? (4)

Answer 13

• cottage cheese, non-offensive discharge
• dysuria
• dyspareunia
• pruritic

Question 14

What are some symptoms of systemic candidiasis? (4)

Answer 14

• fever
• fatigue
• skin rash
• neurological deficits e.g. altered mental state

Question 15

How does candidaemia (disseminated candidiasis) present?

Answer 15

Persistent fever despite Abx therapy

Question 16

What are some general risk factors for candidiasis? (3)

Answer 16

• immunosuppression - HIV, diabetes, steroid use
• imbalance in local flora - Abx, steroid use
• compromised skin

Question 17

What are some specific risk factors for oral candidiasis? (11)

Answer 17

• 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

Question 18

What is the first-line investigation for candidiasis?

Answer 18

Superficial smear of lesion for microscopy - positive for Candida hyphae

Question 19

What are some differential diagnoses for candidiasis? (8)

Answer 19

• chemical burns
• thermal burns
• hairy leukoplakia
• pre-malignant leukoplakia
• plaque-type lichen planus
• erosive lichen planus
• reactive keratosis
• migratory glossitis

Question 20

What topical antifungals are there for mild-moderate candidiasis? (3)

Answer 20

• clotrimazole (main one)
• miconazole
• nystatin

Question 21

What do we give for severe candidiasis?

Answer 21

Systemic antifungal treatment - fluconazole

Question 22

What do we give for vaginal candidiasis?

Answer 22

Oral fluconazole

Local miconazole/clotrimazole creams

Question 23

What can we give to those severely immunocompromised as prophylactic therapy for candidiasis?

Answer 23

Suppressive therapy with fluconazole

Question 24

What are some complications of candidiasis? (5)

Answer 24

• oral candidiasis –> oesophageal candidiasis
• disseminated candidiasis (sepsis)
• meningoencephalitis (obstructive hydrocephalus, calcifications, thrombosis)
• pyelonephritis
• abscess in multiple organs

Question 25

What is the prognosis like for oral candidiasis?

Answer 25

Patients tolerate repeated episodes of oropharyngeal candidiasis without difficulty, but aggressive treatment is effective in preventing recurrent infections