Tropical Fungal Diseases Flashcards
What is Mycetoma?
An infection that can be either fungal or bacterial, which causes a slow insidious destruction of skin, soft tissue and bones and nodular masses with sinus and ‘grain’ formation
What is the epidemiology of Mycetoma?
Europe, Asia, Africa, Latin America
**MEXICO AND SUDAN
Associated with areas of long dry season
Associated with thorny bushes –> people who spend their time working outside are most at risk
What causes Mycetoma?
BACTERIA –> actinomyocytes, like nocardia spp.
FUNGAL –> Madurella spp.
How does Mycetoma present?
A painless slow growing nodule, usually on the foot, which eventually spreads along the skin and soft tissue and causes the formation of sinuses
What are the complications of Mycetoma?
- Disseminated infection –> amputation, death etc.
**Very insidious onset which means people are very slow to present with it
How is mycetoma diagnosed?
FNA and microscopy
PCR
Clinical diagnosis
Relevant imaging looking for bony destruction
How is mycetoma managed?
- Bacterial –> Co-trimoxazole + Streptomycin
- Fungal –> Ketoconazole 400mg OD for 1-2 years
What is a major side effect of long-term anti-fungal use?
Hepatic toxicity
What is Sporotrichosis?
A fungal sub-cut infection which frequently infects and spreads along lymph nodes
Found in SA
Associated with HIV
Rx with Antifungals
What is histoplasmosis?
Fungal infection primarily assocaited with HIV, which behaves very similarly to TB
What is the epidemiology of Histoplasmosis?
North America, South America, Africa
French Guiana (exam!) –> leading cause of HIV deaths
What is the main risk factor for developing histoplasmosis?
HIV +ve
What is the causative organism of histoplasmosis?
Histoplasma Capsulatum
2 varieties: African and Classical
How does Histoplasmosis present?
95% Asymptomatic
Acute infection: Fever, cough, malaise, lymphadopathy
Progressively worsens –> unrelenting pneumonia, weight loss, night sweats, hepatomegaly
How is histoplasmosis diagnosed?
- CXR
- Aspirate (Bone Marrow or Liver) –> microscpoy and culture
- Antigen testing
What might you see on a histoplasmosis x-ray?
Cavitating areas
Apical Lesions
Miliary Pattern
(i.e. TB es el mismo)
What is your main DDx of histoplasmosis?
TB
How do you manage Histoplasmosis?
- Liposomal Amphotericin B is recommended in disseminated illness
Itraconazole if non-severe disease (i.e. no end organ involvement, such as O2 requirement, renal impairment, hepatic failure)
What is paracoccidiomycosis?
Paracoccidioidomycosis is a granulomatous systemic infection caused by the fungus Paracoccidioides.
This fungus lives in parts of Central and South America.
Most often affects men who work outdoors in rural areas.
What is Talaromycosis?
An invasive fungal disease which predominantly occurs in Asia and affects HIV +ve people
How does Talaromycosis present?
Diffuse papular skin lesions with necrotic centre
How do you treat Talaromycosis?
Amphotericin B or L-AMB
NOT A QUESTION JUST AN IMPORTANT FACT:
Basically with the fungal infections - chuck them into your DDx whenever you have an HIV +ve patient with some weird systemic disease and rash
Testing is through Antigen testing usually
Management is usually long term
Differentiate these by their location more than anything (because for example, talaromycosis, histomplasmosis and paracoccidiomycosis present almost the same, but have different global epidemiology)
What are the side effects of Amphotericin B?
Highly toxic
Renal toxicity
Anaemia
Rigors
Needs to be given IV - challenging for long courses of medication
What is the biology of Cryptococcus?
Encapsulated yeast-like fungus
Cryptococcus neoformans spp.
How is cryptococcus spread?
Aerosolised droplets
What is the epidemioliogy of Cryptococcus?
Commonest cause of meningitis in Zimbabwae and Malawi
Assocaited with HIV with CD4 <100
What is the main risk factor for developing Cryptococcus?
HIV with CD4 <100 (OI!)
Who should you screen for Cryptococcus?
All HIV patients with CD4 <100 should be screened with serum CrAg…
If Positive: LP and repeat
If negative: Prophylactic Fluconazole therapy until CD4 count improves
How does Cryptococcus present?
CNS Disease –> Meningitis
Respiratory Disease –> TB like pneumonia
How do you diagnose Cryptococcus
HIV test in all patients
LP –> CSF, Opening pressure
- Culture
- India ink stain
CrAg** (ideally CSF but can do serum too!)
How would you expect the CSF to be in Cryptococcus
HIGH opening pressure
High lymphocytes
Low glucose
High protein
What are the complications of Cryptococcal meningitis?
Very high ICP –> can be cause of death (and does not respond to roids or mannitol)
Untreated Cryptococcus = death
How do you manage Cryptococcus?
NEWEST GUIDANCE (2022 from WHO; Lecture outdated)
Liposomal Amp B 10mg/kg STAT
+ 14/7 Flucytosine
+ 14/7 Fluconazole 1200mg
+ additional 8/52 of fluconazole 800mg
ART
When should you start ART in Cryptococcal meningitis?
if not already established, wait 4-6 weeks after initiating Rx for Crypto because, like TB, it can cause IRIS
What is chromoblastomycosis?
Chromoblastomycosis is a chronic fungal infection of the skin and subcutaneous tissue, most commonly of hands, feet and lower legs.
It is typically caused by traumatic percutaneous inoculation of the genera Fonsecaea, Phialophora and Cladophialophora which are found in plant debris or forest detritus.
Infection occurs worldwide but is most common in rural tropical and subtropical areas e.g. SEA
Male agricultural workers are most commonly affected.
How does Chromoblastomycosis present?
Painless lesions develop slowly over years from the site of inoculation as verrucous nodules or plaques, gradually spreading centripetally by lymphatic or cutaneous dissemination.
Typical complications are ulcerations, bacterial superinfection and chronic lymphoedema, which may be confused with elephantiasis in regions co-endemic with lymphatic filariasis.
How is Chromoblastomycosis diagnosed?
Microscopy: detection of pathognomonic sclerotic cells in skin scrapings (‘Medlar bodies’, fumagoid or muriform cells)
How is chromoblastomycosis managed?
Itraconazole +/- trbinafine +/- Abx for concurrent bacterial infection
