intra-cranial infections - imaging of cns tb in hiv …...both these patients have tb meningitis...
TRANSCRIPT
Intra-cranial infections - imaging of CNS TB in HIV infected and un-
infected populations
Savvas Andronikou
The Children’s Hospital of Philadelphia
Neuro-radiologist ‘freshman’ in a developing country
Where are you working?
Have a CT scanner? Have an MRI scanner?
Two CNS Tuberculous Pathologies to Diagnose
A. Tuberculous Meningitis - TBM B. Tuberculous granuloma - Tuberculoma
TB Meningitis - Is it an emergency?
Presentation of TB Meningitis
• Altered level of consciousness
• Irritability
• Poor feeding
• Meningism
• Bulging fontanelle
• Neurologic deficits
• Cranial nerve palsies
• +/- Fever
YES this is an emergency
• For diagnosis
• Preceding CSF tapping
• Detect treatable complications
TBM Full-house for the novice
TBM Triad
• Basal Enhancement
• Infarction of deep nuclei
• Hydrocephalus
Andronikou S et al. Definitive neuroradiological diagnostic features of tuberculous meningitis in children. Pediatr Radiol. 2004 Nov;34(11):876-85
Bacterial meningitis
Most diagnostic feature - meningeal enhancement
Przybojewski S, Andronikou S, Wilmshurst J. Objective CT criteria todetermine the presence of abnormal basal enhancement in children with suspectedtuberculous meningitis. Pediatr Radiol. 2006 Jul;36(7):687-96
This is CT: normal vessels vs. meningeal enhancement
Normal Vessel Enhancement Double Lines of Abnormal Meningeal Enhancement
Enhancement of the cranial nerves
What if we have no IVI contrast?
Andronikou S, Smith B, Hatherhill M, Douis H, Wilmshurst J. Definitive neuroradiological diagnostic features of tuberculous meningitis in children.Pediatr Radiol. 2004 Nov;34(11):876-85
Treatable Complication of TBM: Hydrocephalus
TBM HydrocephalusMinority:
Non-communicating - DrainMajority:
Communicating - no drain
Non -Communicating vs. Communicating H/C
Minority: Non-communicating - DrainMajority:
Communicating - no drain
Not possible to predict which it is without air encephalography
Brainstem infarctions - not visible on CT…
van der Merwe DJ, Andronikou S, Van Toorn R, Pienaar M. Childs Nerv Syst. 2009 Aug;25(8):949-54
How does HIV affect your diagnostic ability?
• HIV makes for a higher likelihood of a child with TB getting TB Meningitis
BUT
• Less able to mount an immune response
• Less pronounced inflammatory exudate
• Less visible basal density or enhancement
• Less basal ganglia infarctions
• Less likely to get hydrocephalus
• More often atrophy – and hydrocephalus more likely communicating
Both these patients have TB meningitis
Dekker G, Andronikou S, van Toorn R, Scheepers S, Brandt A, Ackermann C. MRI findings in children with tuberculous meningitis: a comparison of HIV-infected and non-infected patients. Childs Nerv Syst. 2011 Apr 15.
Is there basal enhancement?Are there infarctions?Is there hydrocephalus?
Is there basal enhancement?Are there infarctions?Is there hydrocephalus?
Ring-enhancing lesions: TB granuloma TB abscess Neurocysticercosis
Tuberculoma is CT Iso-dense and T2 black
10 points for novice outreach radiologists:
• TBM requires urgent imaging - radiologist is critical • Diagnosis• Complications • Prior to CSF sampling
• Use CT – it may be your only tool• Work without contrast – you may not have any• Diagnostic TBM triad: basal enhancement; BG Infarcts; HC• Double lines and chiasm to detect mild basal enhancement• Hyperdense exudates are diagnostic • Avoid committing to communicating vs. non-communicating HC• BG and borderzone infarcts – CT can miss these• HIV dampens basal enhancement• TB granuloma causes seizure: CT Iso-dense and T2 black