Neuro OI Flashcards
(79 cards)
Differentials for SOL on imaging
Toxoplasmosis, primary CNS lymphoma, TB, cryptococcus, non-Hodgkin lymphoma, syphillitis gummae
Possible causes of encephalitis
HIV, VZV, HSV, syphilis
Causes of meningitis
HIV seroconversion, cryptococcus, TB, syphilis, bacterial (eg strep pneumoniae)
Different causes of spastic paraparesis
HIV-vacuolar myelopathy, transverse myelitis from VZV, HSV, HTLV-1, toxoplasmosis, syphilis
Causes of polyradiculitis
CMV, NHL
What organism is most commonly associated with HIV related cryptococcal disease in the UK?
Cryptococcus neoformans var grubii (serotype A)
2nd most is cryptococcus neoformans bar neoformans (serotype D)
Where is c. neoformans var neoformans found?
Bird (primarily pigeon) droppings
(Non avian sources are also found)
Where is c. Neoformans var gatii found?
Eucalyptus trees
Therefore infections mainly in tropical and subtropical regions
What does cryptococcal skin disease look like?
Molluscum
Pathway of cryptococcus through the body
Inhaled into lungs.
May then cause localised disease.
Spreads to blood and diseminates.
Prostate can be a sanctuary site.
Symptoms of cryptococcal meningitis
Headache, fever
Meningism variable
Raised ICP may cause nausea, vomitting, confusion, coma
What might you see on CXR in pulmonary cryptococcal disease
Variable but include -
Widespread infiltration, nodular disease, isolated abscess formation, pleural effision
Rarer presentations of cryptococcal disease
Ocular palsy, papilloedema, chorioretinitis, osteolytic bone lesions
How to diagnose cryptococcal disease
Serum CrAg - generally if negative this excludes disseminated disease
If CrAg positive needs LP with manometry (after CT/MRI)
Fungal culture
Possible causes of false positive serum CrAg
Rheumatoid factor, heterophile antibodies
What should CSF be sent for if suspecting cryptococcal disease?
CrAg
Microscopy - India ink stain
Culture
What would you expect to see on India ink stain?
Clear around the wall of the yeast as the carbon grains cannot penetrate the capsule
(Cryptococcus)
What role do fungal sensitivities play in tx of cryptococcal disease?
ONLY if not responding to treatment can be used to guide a switch
Factors indicating poor prognosis in cryptococcal disease
Blood culture positive
Low white cells in CSF
High CSF CrAg
Confusion
Raised ICP
What is the induction treatment for neuro cryptococcal disease?
Liposomal Amphotericin B (ambisome) 4mg/kg/day IV (preferred)
Plus flucytosine 100mg/kg/day
Historically amphotericin B deoxycholate 0.7-1mg/kg/day used
Role of flucytosine in cryptococcal meningitis treatment
Speeds rate of sterilisation of CSF
Reduces incidence of relapse in patients not on HAART
Associated with enhanced toxicity in some studies, no impact on mortality
Why do we use ambisome rather than standard amphotericin B?
At least equivalent efficacy
Less nephrotoxicity
What would be an alternative therapy for cryptococcal meningitis if ambisome not tolerated?
Fluconazole 400mg/day +/- flucytosine
May be used as first line if good prognostic factors as easier to administer
Treatment of refractory cryptococcal meningitis
If all normal meds not tolerated can try newer Azoles voriconazole and posaconazole - expensive.