Infectious Disease: Candida

Question 1

Defintion

Answer 1

Opportunistic infection = caused by the yeast-like fungus, CANDIDA ALBICANS
Candida is a part of the normal flora of the GI tract
However colonisation with Candida can occur when host defences are lowered or mucosal barriers are disrupted, leading to Candida infection (Candidiasis)

Question 2

Site of infection

Answer 2

• The majority of cases affect the oral cavity = oral candidiasis, commonly referred to as oral thrush
• The vagina = vulvovaginal candidiasis, where Candida is part of the normal flora in 13% of women
• The gastrointestinal tract = oesophageal candidiasis
  Invasive disease affecting organs or the bloodstream = invasive candidiasis

Question 3

Epidemiology

Answer 3

Older adults: weak immunity
Young children/infants: immature immunity
Immunocompromised: due to immunosupression by medication or conditions (e.g. HIV)
Smoking: seven times more likely to suffer from oral candidiasis
Broad-spectrum Abx
Pregnancy: vaginal candidiasis more common during pregnancy due to oestrogen exposure

Question 4

Pathophysiology

Answer 4

• Candida overgrowth on the mucosa causes desquamation of epithelial cells leading to the accumulation of keratin, bacteria, and necrotic tissue.
• This combination of debris leads to the formation of a pseudo-membrane (pseudomembranous candidiasis) which appears like a white plaque
• Once wiped away, erythema can be seen underneath
• In severely unwell patients , candida can enter the bloodstream either via the gastrointestinal tract, a catheter, or localised infection, resulting in invasive candidiasis.

Question 5

Signs and symptoms

Answer 5

Oral candidiasis:
- Curd-like, white or yellowish plaques can occur in the mouth, affecting the: Cheeks, Gums, Palate, Tongue

Diaper Rash:
- Red, itchy rash with raised edges and satellite lesions in skin folds, such as the neck, armpits, groin, and under the breasts.

Oesophageal candidiasis:
- Impaired eating/chewing or dysphagia/odynophagia
- May have signs of associated conditions (e.g. HIV)

Vaginal candidiasis
- Vulval itching
- Vulval soreness and irritation
- Vaginal discharge (usually white and non-offensive)
- Superficial dyspareunia
- Dysuria

Question 6

Diagnosis

Answer 6

• Clinical diagnosis
• Swabs are generally not useful as candidal organisms are commonly found in healthy people.
• For vaginal candidiasis = investigations not routinely recommended if the history indicates acute, uncomplicated vaginal candidiasis. Investigations may be required to confirm the diagnosis if there is uncertainty:
  = Vaginal pH testing : is recommended initially - a pH of <4.5 supports a diagnosis of candidiasis
  = High-vaginal swab : can be performed to identify candida fungal infection

Question 7

Oral candidiasis treatment

Answer 7

FIRST LINE =
- Miconazole oral gel for 7 days: for mild localised oral candida infection in adults
- Exclude risk factors: e.g. diabetes, nutrient deficiency such as iron and folic acid
SEOND LINE =
- Nystatin suspensions: if miconazole CI
- Oral fluconazole 50mg once daily for 7 days: for severe or extensive infections, (persistent = + another 7 days)
- biopsy = considered with people with chronic plague-like oral candidiasis that is unresponsive to treatment as certain, rare, types of oral candidiasis exist which have the potential for malignant transformation.

Question 8

Oesophageal candidiasis in HIV positive patients

Answer 8

Oral fluconazole 100 mg for 7 days: provided the person is otherwise well and is not taking prophylactic antimycotic treatment
Consider admission : if there is evidence of widespread candida infection

Question 9

Vaginal candidiasis treatment

Answer 9

FIRST LINE = Antifungal agent : antifungal can be administered by local intravaginal cream, pessary, or by oral agent
If pregnant : only local treatments (e.g. cream or pessaries) may be used; oral treatments are contraindicated

SECOND LINE:
- Confirmation of diagnosis : perform investigations to confirm the diagnosis (e.g. high vaginal swab) and investigations to exclude other diagnoses, e.g. diabetes
- Induction-maintenance regime : can be considered for recurrent vaginal candidiasis; e.g. oral fluconazole every 3 days for 3 doses (induction) followed by oral fluconazole weekly for 6 months (maintenance)

Question 10

Complications

Answer 10

• Chronic pain and/or discomfort
• Gastrointestinal effects: such as impaired eating/chewing or dysphagia/odynophagia (in the case of oesophageal candidiasis)
• Invasive candidiasis: serous infection of an organ system with candida infection has an estimated mortality of up to 79%
• Candidaemia: the manifestation of invasive candidiasis in the blood