Free Living Ameoba Flashcards
Skin lesion -> meningitis, free living ameoba organism most likely?
Ballamuthia
What clinical syndrome does N.Fowleri cause?
Primary amoebic meningoencephalitis
Rx of choice (most important) in Naegleri?
Ampho B, miltefosine (pt on round also on rifampicin and albendazole and fluconazole)
Who gets acanthamoeba? Clinical syndrome?
Immunosuppressed
Causes disseminated disease
Granulomatous meningitis
Through eyes (Keratitis - ppl with contact lens get this) OR eyes or sinuses
Infective stage of Naegleri fowleri?
Trophozoite -> cribriform plate
Mode of transmission of acanthameoba?
trophozoite / cyst enters via nasal passage / eye / broken skin
Which of the free living amoebas do you see trophozoites in the CSF on microscopy?
N.Fowleri
∆∆ for leish (cutaneous) not responding to Rx?
Free living ameoba
What do you see on microscopy in free living ameoba?
Look for Giant cells and trophozoite on direct smear with wet mount
Rx of acanthamoeba?
pentamidine, sulfadiazine, flucytosine, and either fluconazole or itraconazole.
Lots of Rx options as per CDC
Mode of acquisition of naegleria fowleri?
exposure to warm fresh water - often swimming pool and lagoons - summer months, transmitted by olfactory epithelium
Countries and epidemiology of free living ameobas?
- USA, South America and some in Thailand/USA
- Naergleria fowleri - more common in children and immunocompetent,
- Balamuthia - hispanic
- Acanthameoba - often immunosuppressed
- Predominance of all strains in males
Which free living ameoba is associated with contact lens use?
Acanthamoeba keratitis (AK)
Associated with contact lens use
Occurs in immunocompetent people
Clinical features of ballamuthia mandrillaris
- Painless facial or cutaneous lesion, several weeks incubation, slow growing, mostly nasal
- Lesions in oral cavity
- Causes granulomatous meingoencephalitis, insidious onset
- Cervical lymph nodes
How does acanthameoba present?
Insidious onset, meningoencephalitis - granulomatous encephalitis
Immunocompromised
Sometimes have cutaneous skin lesions
How do you ∆ ballamuthia mandrillaris?
Tissue biopsy: granulomatous inflammation, with giant cells, lymphocytes, and visible amoeba
How does meningitis occur from naergleri fowleri?
Transmitted to brain through olfactory nerve via cribriform plate
Rx of naergleri fowleri?
IV amphotericin B + miltefisine + rifampicin
(+ azithro + fluconazole + albendazole)
Differential diagnosis of central facial lesion?
Bacteria: rhinosceroderma (klebsiella), NOMA (borrerai), TB, NTM (chelonae, abscessans)
Fungi: paracocci, histo, zygomyces
Parasite: leish, free living ameoba
Non inf: lukaemia
Investigations for naegleria fowleri?
CSF - aseptic on gram stain
- wet mount - see the ameoba
- WCC and protein will be raised
How do you contract ballamuthia mandrillaris?
Break in skin, contact with fresh water
What are the free living amoebas that cause disease in humans?
Ballamuthia mandrillaris, Naegleria fowleri, Acanthamoeba
What is this?
Ballamuthia Mandrillasis
How is B.mandrillasis transmitted?
Skin and sinuses
When do patients with free living amoeba present with fever?
When they have CNS parasites -> leptomeningitis
Management of ballamuthia mandrillaris?
9-12 months of Rx
Albendazole + Itraconazole
+ Miltefosine
+ Amphotericin B for 1st month
Clinical features of naegleria fowleri?
Acute aseptic haemorrhagic meningoencephalitis (Primary amoebic meningoencephalitis, PAM)
- headache, fever
- acute and fulminant
What is this?
Acanthameoba trophozoite - spine like projections
What is this?
N.Fowleri
