Fungal Pathogens

Question 1

What are fungi?

Answer 1

Kingdom
Eukaryotic
Single or multi-celled
Mainly hyphal or yeast formations
Glucan-chitin wall
Asexual and/or sexual reproduction
Saprophytic
Plant pathogens and very rarely animal pathogens

Question 2

Types of fungal disease

Answer 2

Superficial
Subcutaneous
Systemic

Question 3

Superficial infection

Answer 3

Affects skin, hair, nails and mucocutaneous tissue

Dermatophytes, Malassezia, Candida

Question 4

Subcutaneous infection

Answer 4

Subcutaneous tissue affected, usually following traumatic implantation

Question 5

Systemic infection

Answer 5

Affects organs

Candida and Aspergillus

Question 6

Dermatophytes

Answer 6

Slow growing moulds causing superficial infection

Originate in soil, other animals or humans

Question 7

Tinea pedis

Answer 7

Athlete's foot
Uni or bilateral
Itching, flaking, fissuring of skin
Typical cause Trichophyton rubrum
Mainly in adults

Question 8

Tinea ungulum

Answer 8

Fungal nail disease
Also called onychomycosis
Four main types
Trichophyton rubrum and T. interdigitale

Question 9

Tinea cruris

Answer 9

Jock itch (groin area)
More prevalent in men
Itching, scaling, erythematous plaques with distinct edges
May extent to buttocks, back and lower abdo
T. rubrum

Question 10

Tinea corporis

Answer 10

Ringworm

Question 11

Tinea capitis

Answer 11

Scalp ringworm
Mainly in pre-pubescent children
Ranges from slight inflammation, to scaly patches, alopecia, black dots, grey patches, to severe inflammation

Question 12

Tinea barbae

Answer 12

Face skin (shaved)

Question 13

Kerion celsi

Answer 13

Boggy, inflamed lesion within tine capitis, usually from zoophilic dermatophytes

Question 14

Investigation for treatment of dermatophyte infection

Answer 14

Microscopy and culture

Question 15

Treatment of mild disease

Answer 15

Topical antifungals (terbinafine, clotrimazole)

Question 16

Treatment of severe disease

Answer 16

Systemic antifungals

Question 17

Treatment of any tinea capitis

Answer 17

Systemic antifungals (griseofulvin, terbinafine, itraconazole)
Topical will not be curative (role in reducing spread)

Question 18

Malassezia

Answer 18

Genus of yeasts
Part of normal skin flora
Most frequent on head and trunk

Question 19

Pityriasis versicolor

Answer 19

Hyper or hypo-pigmented lesions
Upper trunk
Puberty - middle age
More common in tropics
Tends to relapse

Question 20

Diagnosis of pityriasis versicolor

Answer 20

Microscopy - culture difficult and not interpretable

Question 21

Treatment of pityriasis versicolor

Answer 21

Topical antifungals, if that fails then oral

Question 22

Candida

Answer 22

Large genus of yeasts
Causes thrush (oral and vaginal) and also occasionally skin disease and keratitis
Can affect almost any organ

Question 23

Acute-pseudomembranous superficial candida infection of the oral mucosa

Answer 23

Classical oral thrush
Low CD4 count
Younger patients
Asthma with steroid inhalers

Question 24

Chronic atrophic superficial candida infection of the oral mucosa

Answer 24

Older patients

Erythema

Question 25

Candida vulvovaginitis

Answer 25

Vaginal thrush Affects 70-80% of women at least once during child-bearing years Pruritis, burning sensation, possible discharge Inflammation Often worse during pregnancy Approx. 10% will have recurrent infections Diagnosis by +ve culture

Question 26

Treatment of candida

Answer 26

Usually oral azoles, though resistance can be an issue

Question 27

Azoles in pregnant women

Answer 27

Only use topical as oral azoles can be a teratogen

Question 28

Systemic candidosis

Answer 28

Defined by site | Usually from colonised skin, mucosal sites or GI

Question 29

Candida oesophagitis

Answer 29

Mainly in HIV Pain/difficulty on swallowing Diagnosed with endoscopy with biopsy

Question 30

Candidaemia

Answer 30

Candida in blood culture Remove lines where possible Start antifungal therapy Check eyes and heart

Question 31

Ocular candidosis

Answer 31

3-25% following candidaemia | Mainly candida chorioretinitis and secondarily candida endophthalmitis (which requires intravitreal antifungals)

Question 32

Candida endocarditis

Answer 32

2-3% following candidaemia IV drug abusers, valve surgery Vegetations seen on heart valves - normally need valve replacements Fever, weight loss, fatigue, heart murmur

Question 33

Renal candidosis

Answer 33

Candida infecting kidney from blood | Immunocompromised premature neonates

Question 34

Urinary tract candida

Answer 34

Common to have candida but does not necessarily mean UTI | Difficult to treat as most antifungals not excreted in urine

Question 35

Candida peritonitis

Answer 35

Peritoneal dialysis complication Bowl perforation Treatment by source control/drainage and antifungals

Question 36

Diagnosis of systemic candidosis

Answer 36

Culture, ideally from sterile site, blood, peritoneal fluid etc Imaging

Question 37

Treatment of systemic candidosis

Answer 37

Depends on sensitivity, severity, need for oral agent Echocandins (IV) Azoles (oral) Liposomal amphotericin B (IV)

Question 38

Bullseye sign

Answer 38

Bullseye appearance of cysts on spleen

Question 39

Aspergillus

Answer 39

Genus of moulds Produces airborne spores Universal exposure Airways may be colonised

Question 40

Reactions to aspergillus inhalation

Answer 40

If healthy: nothing Cavities from other conditions: fungal ball Asthma, CF: Allergic bronchopulmonary aspergillosis, allergic sinus disease Chronic lung disease: Chronic pulmonary aspergillosis Immunocompromised: Invasive pulmonary aspergillosis, invasive aspergillus sinusitis

Question 41

Aspergilloma

Answer 41

Solid balls of fungus | Often indolent but may break up causing haemoptysis which can be fatal

Question 42

Halo and air crescent sign

Answer 42

CT scan signs | Associated with invasive aspergillosis

Question 43

Aspergillosis diagnosis

Answer 43

Culture Serology Imaging

Question 44

Aspergillosis treatment

Answer 44

Aspergilloma, resection Allergic aspergillosis, steroids +/- antifungals CPA and invasive aspergillosis, antifungals