MI: Fungal Infections Pt.2

Question 1

List the aetiological agents that can cause Aspergillus infection.

Answer 1

• Aspergillus fumigatus
• Aspergillus flavus
• Aspergillus niger
• Aspergillus niduland
• Aspergillus terreus

Question 2

What is the mainstay of diagnosis of Aspergillus infection?

Answer 2

Microscopy - looking at fungal spores

Question 3

List some investigations used in the diagnosis of Aspergillus infection.

Answer 3

• Blood test
  
  • Beta-D glucan
  • Serology
    
    • Check IgE for allergic response in ABPA
    • Aspergillus IgG for invasive disease
  • Antigen detection (galactomannan) - in blood and BAL
  • PCR
• Blood/tissue culture
• Imaging (CXR/CT for ABPA and aspergilloma)

Question 4

What is the treatment for aspergillosis?

Answer 4

• ABPA - itraconazole plus steroids
• Aspergilloma - surgery plus itraconazole
• Invasive aspergillosis - voriconazole (amphotericin B second line)

Question 5

List some examples of dermatophyte infections.

Answer 5

• Ringworm
• Tinea
• Nail infections

Question 6

What is tinea pedis caused by?

Answer 6

• Tricophyton rubrum
• Tricophyton interdigitale
• Epidermophyton floccosum

Question 7

What is tinea cruris caused by?

Answer 7

• Tricophyton rubrum
• Epidermophyton floccosum

Question 8

What is tinea corporis caused by?

Answer 8

• Tricophyton rubrum
• Tricophyton tonsurans

Question 9

What is onychomycosis caused by?

Answer 9

• Tricophyton spp.
• Epidermophyton spp.
• Microsporum spp.

Question 10

How is onychomycosis treated?

Answer 10

• Nail lacquers
• If unsuccessful, systemic treatment with terbinafine
• Itraconazole is also an option

Question 11

How are dermatophyte infections diagnosed?

Answer 11

Skin scarpings and microscopy

Question 12

What is pityriasis versicolor caused by?

Answer 12

Malassezia furfur

Question 13

What is mucormycosis?

Answer 13

Group of moulds that cause very severe and invasive disease

transmitted by direct inoculation or inhalation

Question 14

Which groups of patients are affected by mucormycosis?

Answer 14

• Immunocompromised patients
• Patients with poorly controlled diabetes

Question 15

What is the characteristic clinical manifestation of mucormycosis?

Answer 15

Cellulitis of the orbit and face which progresses with discharge and black pus from the palate and nose

NOTE: black eschars may be seen as the fungus destroys the tissues

can also cause pulmonary/cutaneous manifestations

Question 16

What can retro-orbital extension of mucormycosis lead to?

Answer 16

Proptosis, ophthalmoplegia and blindness

Question 17

What is the term used to describe the invasion of the brain by mucormycosis?

Answer 17

Rhinocerebral mucormycosis

Question 18

List three aetiological agents that can cause mucormyocosis.

Answer 18

• Rhizopus spp.
• Rhizomucor spp.
• Mucor spp.

Question 19

How is mucormycosis managed?

Answer 19

• SURGICAL EMERGENCY
• Refer to ENT for debridement
• May need high-dose amphotericin

Question 20

What are the three targets of antifungals?

Answer 20

• Cell membrane
• DNA/RNA synthesis
• Cell wall