Lecture 10 Fungal Infections

Question 1

What type of patients are susceptible to fungal infections

Answer 1

Affecting patients with an impaired immune system (Immunodeficient, HIV/AIDS, neutropenia, premature neonates)

Affecting patients with chronic lung diseases (asthma, CF,COPD)

ICU patients

Question 2

What are the causes of mucocutaneous candidiasis

Answer 2

Antibiotic use
Moist areas
Inhalation steroids
Neonates <3 months

Question 3

Presenting symptoms of Mucocutaneous

Answer 3

Neutropenia
Low CD4+ T cells
Impaired IL-17 Immunity

Question 4

What are the causes of Invasive Candidiasis

Answer 4

Gut commensal

Infections mostly endogenous origin

Question 5

Risk Factors of Invasive Candiasis

Answer 5

Broad-spectrum antibiotics Intravascular catheters
Total parenteral nutrition
Abdominal surgery

Question 6

How is Invasive Candidiasis diagnosed

Answer 6

Blood culture or culture from normally sterile site

Question 7

How is Aspergillus transmitted

Answer 7

Sporulation
Hydrophobic conidia
Airborne/inhalation

Question 8

What are the clinical features of acute invasive pulmonary aspergillosis

Answer 8

Rapid and extensive hyphal growth
• Thrombosis and hemorrhage
• Angio-invasive and dissemination
• Absent or non-specific clinical signs and symptoms
• Persistent febrile neutropenia despite broad-spectrum antibiotics

Question 9

What are the clinical features of (Sub) acute invasive pulmonary aspergillosis

Answer 9

 Non-angioinvasive
 Limited fungal growth
 Pyogranulomatous infiltrates
 Tissue necrosis
 Excessive inflammation
 Non-specific clinical signs and symptoms  Mild to moderate systemic illness

Question 10

How is Pulmonary Aspergillosis diagnosed in non-neutropenic patients

Answer 10

Cultures of sputum and/or bronchoalveolar lavage, and/or biopsy
• Aspergillus specific IgG and IgE in chronic and allergic pulmonary aspergillosis

Question 11

How is Pulmonary Aspergillosis diagnosed in neutropenic patients

Answer 11

High resolution CT-chest
 ‘halo-sign’ and ‘air-crescent sign’
• Molecular markers in blood: galactomannan and PCR-Aspergillus (high NPV and are suited for screening purposes)
• BAL and biopsies if clinical condition allows

Question 12

How is cryptococcus transmitted

Answer 12

Inhalation

Found on the bark of a variety of tress, bird faeces and organic matter

Question 13

Clinical presentation of cryptococcus infection

Answer 13

Headache
Confusion
Altered behaviour
Visual disturbance
Coma

Question 14

What is the diagnosis of cryptococcal disease

Answer 14

CSF- high protein and low glucose

Bood culture- cryptococcus antigen

Question 15

Name antifungal agents to treat invasive fungal infections

Answer 15

Amphotericin B formulations (iv)
Azoles (iv, oral)
Echinocandins (iv)
Flucytosine (iv, oral)

Question 16

What is the action of Amphotericin B formulations (iv)

Answer 16

Acting on ergosterol > lysis

Cryptococcal meningitis

Question 17

What is the action of Azoles

Answer 17

Inhibiting ergosterol synthesis

Invasive aspiergillosis

Question 18

What is the action of Echinocandins

Answer 18

Inhibiting glucan synthesis

Invasive candidiasis

Question 19

What is the action of Flucytosine (iv, oral)

Answer 19

Inhibiting fungal DNA synthesis

Cryptococcal meningitis