cns infections. infection of cns coverings dura – pachymeningitis leptomeninges - leptomeningitis...
TRANSCRIPT
CNS Infections
CNS Infections
Infection of CNS coverings Dura – pachymeningitis Leptomeninges - leptomeningitis
Infections of neural tissue Brain – encephalitis Spinal cord – myelitis
Ventricles - ventriculitis
CNS Infections
Pachymeningitis Sources
Direct spread from chronic suppurative infections of sinuses, ear, mastoid or compound fracture
Manifestations Usually localised +/- overlying
osteomyelitis Extradural abscess Subdural empyaema Spinal epidural abscess.
CNS Infections
Leptomeningitis (commonly purulent) Sources
Haematogenous (most common) Direct from adjacent inflammatory lesion ? Through cribriform plate Iatrogenic eg. spinal tap
Microbiology
CNS Infections
Pathology Gross
Swollen, congested brain (acute inflammation)
Purulent CSF (filling sulci & basal cisterns) Micro
Purulent exudate in subarachnoid space, extending into perivascular spaces
Some cortical oedema +/- degeneration in chronic cases
Brain & Cord:
Purulent meningitis
Brain: Purulent meningitis
Brain: Purulent meningitis
Brain: Purulent meningitis
Brain: Purulent meningitis
Brain: Purulent meningitis
Brain: Purulent meningitis
Spinal cord:
Purulent meningitis
CNS Infections
Acute lymphocytic meningitis Causes
Viruses: ECHO, Coxsackie, Herpes simples II, E-B virus.
Manifestations Similar to bacterial meningitis – less severe Gross: acute inflammation, clear CSF Micro: lymphocytic cellular exudate in CSF
and subarachnoid space
CNS Infections
Chronic meningitis Causes
Mycobacterium tuberculosis - TB Treponema pallidum – syphilis Brucella – brucellosis Fungi – Candida, Cryptococcus, Histopasma Protozoa – Toxoplasma, Amoebae
Micro: Largely mononuclear inflammation with
granulomas
Brain:
Tuberculous meningitis.
Brain: Tuberculous meningitis
Tuberculous meningitis
CNS Infection
Chronic meningitis Complications
Obstructive hydrocephalus Focal infarctions/microinfarcts due to
endarteritis oblitrerans Formation of intracranial mass Cranial nerve palsies
CNS Infections
Infections associated with formation of intracranial mass Tuberculosis – tuberculoma Syphilis – gumma Amoebiasis – amoeboma Aspergillosis – aspergilloma, Crryptococcosis - toruloma. Parasites – cysticercosis, hydatid cyst.
Tuberculoma
Brain: Toruloma
CNS Infections
CNS syphilis (tertiary) Meningoencephalitis
(meningovascular syphilis) Gumma General paresis of the insane (GPI) –
focal infarcts, atrophy and dementia Tabes dorsalis.
CNS syphilis
Brain: Syphilis
CNS Infections
Cerebral abscess Sources
Direct spread (sinusitis, mastoiditis) Haematogenous.
Manifestations Mass effect Complications: spread into ventricles or
subarachnoid space – ventriculitis or meningitis
CNS Infections
Cerebral abscess Pathology
Localised suppuration Surrounding pyogenic membrane Surrounding brain:
Oedema – vasogenic Inflammatory infiltrate rich in plasma cells and
lymphocytes. Gliosis – astrocytes mainly.
CNS: Abscess
Cerebral abscess
Cerebral abscess
Brain: cerebellar abscess.
Encephalitis
Primary encephalitis Acute/subacute viral infections Persistent viral infections Slow viral infections
Secondary encephalitisPost-infectious encephalomyelitis
CNS Infections
Primary viral encephalitisHerpesviruses – HSV 1 and 2Enteroviruses – PoliovirusArbovirusesRabiesvirusPersistent virus infections (SSPE,
PMLE)HIV-1 infection
Encephalitis
Primary encephalitis – morphology Gross
Focal/generalised inflammation +/- necrosis Micro
Mononuclear inflammatory infiltrate with perivascular extension (lyphocytes, plasma cells)
Neuronal destruction + neuronophagia Proliferation of microglia – rod cells Reactive gliosis – astrocytosis Inclusion bodies Demyelination.
Viral encephalitis: Preferred sites for various viruses
Brain: Encephalitis
Viral encephalitis: Histological lesions
Viral encephalitis: Neuronophagia
Encephalitis: Perivascular infiltrate
Encephalitis: Types of inclusion bodies
CNS infection:
Rabies
Brain: Herpes simplex encephalitis
Brain: Herpes encephalitis: vessel necrosis + inflam. cells
Encephalitis: Intranuclear inclusions
CNS: Poliomyelitis
Encephalitis
Primary encephalitis Persistent viral encephalitis
Subacute sclerosing panencephalitis (SSPE) Chronic infection Result of measles virus infection Affects older children Brain shows loss of myelin + gliosis + perivascular
lymphocytic infiltration CSF contains high titres of measles antibody and
viral antigen Expression of aberrant T-cell response to presence
of virus in brain.
Encephalitis
Primary encephalitis Slow virus infections
Progressive multifocal leucoencephalopathy (PMLE)
Infection by papovavirus group (JC virus) In immunosuppressed patients (HD,
chemotherapy for malignancies) Focal demyelination in white matter, basal
ganglia Gitter cells in affected areas + atypical
astrocytes + abnormal oligodendrocytes (contain virions as inclusions)
Brain: Progressive multifocal leukoencephalopathy
Encephalitis
Secondary encephalitis Bacterial eg Brucella Spirochaetal eg Treponema Rickettsial eg. Borrelia Parasitic
Protozoa – Toxoplasma, Plasmodium, Trypanosoma
Metazoa – Schistosoma, Cysticercus, Hydatid.
Viral eg Mumps, Yellow fever
Encephalitis
Postinfectious encephalomyelitisMeaslesRubellaVaricella-ZosterVacciniaInfluenzaVariola.
CNS Changes in HIV Infection
Aseptic meningitis 1-2 weeks after seroconversion in 10%. HIV
1 antibodies in CSF.
Meningoencephalitis Gross
Diffuse cortical atrophy Micro
Chronic inflammation, focal necrosis + gliosis, endarteritis, microglial nodules +/- giant cells, multifocal/diffuse demyelination + gliosis
CNS Changes in HIV Infection
Vacuolar myelopathy (20-30%) Similar to subacute combined
degeneration Immunosuppression (not due to HIV)
Inflammatory myopathy Muscle fibre necrosis + phagocytosis Interstitial infiltration with HIV-
positive macrophages
CNS Changes in HIV Infection
Cranial and peripheral neuropathies Acute & chronic demyelinating
polyneuropathy Distal symmetrical polyneuropathy Polyradiculopathy Mononeuritis multiplex Sensory neuropathy due to
ganglioneuritis (rare)
CNS in Childhood AIDS
Neurological manifestations in 1 year: Microcephaly + mental retardation + delay of
motor development
Micro: Calcification in basal ganglia or deep cortical
white matter (blood vessels) Foci of tissue destruction in grey/white matter Loss or delay in myelination Opportunistic CNS infections (rare in children)