Infection

Question 1

Candidiasis - Definition & Presentation

Answer 1

Main types are Oral & Systemic

Systemic candidiasis is an infection of blood or other normally sterile site with Candida species
Oral candidiasis is an oral infection resulting from yeasts of the genus Candida -> More common in infants and those who use inhalers

Presentations:
(Systemic = features of sepsis)
- Fever
- tachycardia
- tachypnoea
- hypotension
- poor capillary refill
- confusion
- decreased urine output

(Oral)
- Creamy white/yellow plaques in mouth
- Burning oral pain
- Cracks, ulcers, or crusted fissures radiating from angles of the mouth
- Unpleasant taste in mouth

Question 2

Candidiasis - Aetiology & Risk Factors

Answer 2

Candida species are present as normal flora in humans

So, Systemic candidiasis often has an endogenous source of infection, primarily the gastrointestinal (GI) tract

Pathological colonisation is linked to factors including age extremes and compromised immunity

Most cases of oropharyngeal candidiasis are due to Candida albicans

Risk Factors:
(Systemic)
- Use of Central Venous Catheter -> Most important
- Exposure to broad-spec antibiotics
- Parenteral nutrition
- Surgery -> Mucosal breakage allowing Candida in
- Immunosuppressants
- Haemodialysis

(Oral)
- hyposalivation
- poor oral hygiene
- extremes of age
- Exposure to broad-spec antibiotics

-> reduced immune response:
- malabsorption and malnutrition
- advanced malignancy
- Chemo
- HIV
- Immunosuppressive agents

Question 3

Candidiasis systemic - Differentials

Answer 3

1) Bacterial Sepsis
-> No differentiating signs/symptoms between fungal and bacterial causes of sepsis
-> Blood culture pos. for bacteria instead of fungus

2) Drug-induced fever
->Hx of a causative drug use

3) PE
->Patients may present with pleuritic chest pain, dyspnoea, hypoxia, and hypotension

Question 4

Candidiasis systemic - Investigations

Answer 4

1) Blood culture -> test if fungal infection. Positive = fungal infection. Negative = probably not a fungal infection but don’t rule it out

2) FBC -> WBC

Should be performed if sepsis suspected:
3) ABG -> hypoxaemia, hypercapnia

4) Lactate levels -> high

5) Coagulation studies

6) Renal function tests -> creatinine twice normal

7) LFT

8) Serum glucose -> low

Question 5

Candidiasis systemic - Management

Answer 5

1) Antifungal therapy: Caspofungin: 70 mg intravenously as a loading dose, followed by 50 mg once daily
+ Supportive care for Sepsis

If Systemic Candida is confirmed:

2) Consider switching to Fluconazole: 400 mg orally once daily. Can switch to intravenous at higher dose if patient is critically ill

+ If the patient has an intravascular catheter present, removal is recommended.

If neutropenia:
2) Stick with step 1)

If neutropenia w/ complications:
2) Prolonged antifungal therapy:

–> Endocarditis: Amphotericin B lipid complex: 3-5 mg/kg/day intravenously

–> Endophthalmitis: amphotericin B lipid complex: 3-5 mg/kg/day intravenously & Flucytosine: 25 mg/kg/day orally given in 4 divided doses

–> Renal candidiasis: fluconazole: 400 mg intravenously/orally once daily

Question 6

Candidiasis systemic - Prognosis & Complications

Answer 6

Attributable mortality to candidemia ranges from 5% to 70%

Poor prognosis factors:
- Presence of complications (endocarditis, septic shock… Etc)
- Neutropenia, Comorbidity, Underlying diseases
- C tropicalis and C glabrata species
- Delay in therapy may increase mortality

Complications:
1) Septic shock

Question 7

Candidiasis oral - Differentials

Answer 7

1) Chemical burns
-> Hx of chemical agent, most commonly from topical use of aspirin for toothache
-> White plaques cannot be scraped off
-> Resolves on its own between 7-14 days

2) Reactive keratosis
-> Lesions are usually asymptomatic
-> Definitive diagnosis is always through biopsy and histological evaluation of the lesion

3) Hairy leucoplakia
-> Lesions are asymptomatic
-> Definitive diagnosis is always through biopsy and histological evaluation of the lesion

4) Plaque-type lichen planus
-> Lesions are asymptomatic
-> Definitive diagnosis is always through biopsy and histological evaluation of the lesion

5) Erosive lichen planus
-> Lesions are painful, but mostly when eating, whereas erythematous candidiasis may be associated with constant burning pain

Question 8

Candidiasis oral - Investigations

Answer 8

1) Superficial smear of lesion for microscopy -> results indicate positive for Candida hyphae

Consider:
1) biopsy of lesion
2) culture of mouth rinse sample
3) upper GI endoscopy with or without biopsy of lesions
4) urinalysis, random or fasting blood glucose, or glucose tolerance test to exclude diabetes

Question 9

Candidiasis oral - Management

Answer 9

If Mild/Moderate:
1) topical antifungal: Clotrimazole oropharyngeal: 10 mg orally (dissolved in the mouth) five times daily for 14 days

If Severe:
1) systemic antifungal treatment: Fluconazole: 200 mg orally on day one, followed by 100-200 mg once daily for at least 2 weeks

+ (both) If there are removable dentures, aggressive disinfection of them

Question 10

Candidiasis oral - Prognosis & Complications

Answer 10

The course of pseudomembranous candidiasis is usually acute and the associated symptoms are minimal

Erythematous oral candidiasis may be acute or chronic

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

Complications:
1) Oesophageal candidiasis
-> In a severely immunocompromised host, Candida may become focally invasive
-> Clinically, dysphagia and odynophagia may develop

2) Hepatotoxicity associated w systemic Azole antifungal therapy
-> LFTs are monitored frequently in patients taking systemic azoles