Inflammations & infections
of CNS
and Cerebrospinal fluid
Dr Aarathi Rau
Infections of the CNS
Meninges,brain,both
 Meningitis Pachymeningitis:Epidural and subdural
infections
 Leptomeningitis-Subarachnoid
 Brain Cerebral abscess-focal inflammation
 Encephalitis-diffuse inflammation
Formation,circulation,function of
CSF
 Formation-500
ml/day
 Ultrafilteration & secretion –choroid
plexus, ependymal lining of ventricles
 Circulation: ventricular system-foraminasubarachnoid space
Function of CSF
 Protects,
lubricates the brain
 Provides nutrients, removes waste
90-150 ml adult
10-60 ml in newborn
Blood brain barrier –
homeostasis;electrolytes
Urea,glucose ,protein,creatinine passively
along concentration gradient
Normal CSF
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Thin, colourless, clear fluid
Pressure 90-180mm WATER (10-100 neonates)
0-5 WBC’s /mm3 (neonates 0-30/ mm3 )
Lymphocytes & monocytes
Occasional ependymal or choroid plexus cells
Protein 15-45mg/dl
Glucose 50-80mg/dl
Chloride 113-130 mEq/L
Sterile
Meningitis
Def: inflammatory process of the
leptomeninges & CSF within the
subarachnoid space
 Meningoencephalitis =+inflammation of
brain parenchyma
 Classification
 Acute
 Aseptic
 Chronic
Pyogenic meningitis pathogenesis
 Blood
borne
 Direct-sinuses,mastoid,middle ear,dural
venous sinuses,direct trauma,fracture skull
 Neonates:E Coli,Strep pneumoniae,
Adolescents: N Meningitides, H influenzae
 Adults: N Meningitides, Strep pneumoniae
type 3
 Elderly :Listeria monocytogenes,strep
pneumoniae type 3
Clinical features
 General
 Headache,altered
 Neck
stiffness
consciousness,vomiting
Gross
 Pus
in the subarachnoid space
 Meningeal vessels engorged
 Location-Pneumococcal-convexities
 Tracks along vessels, ventriculitis
 Microscopy
 PMN in SA space,> meningial vessels
 Thrombosis of superficial vessels &
 Cerebral ischemic damage
CSF in Pyogenic Meningitis
 Increased
pressure
 Purulent/cloudy
 ↑protein
 ↓ glucose
 Leucocytosis
 Neutrophils ++
 Gram stain
 Culture
Sequele
 Resolution
 Cerebritis,hemorrhagic
 Fibrosing
infarction of brain
meningitis
 Hydrocephalus
 Chronic adhesive arachnoiditis
(Aseptic)Lymphocytic meningitis
 Viral
usually (Coxsackie, EBV, ECHO)
Less fulminant than bacterial
 Usually recover
 Few specimens
 Mild lymphocytic infiltrate of the meninges
CSF in Viral meningitis
Clear appearance
Mild pleocytosis
Lymphocytes +
Protein↑
Glucose –WNL
Culture sterile
Virological exam-Coxsackie, EBV, ECHO
Tubercular meningitis
 Hematogenic
spread
 Gross:Thickening & opacity of
leptomeniges
 Basal meningitis, encasing cranial N’s
 Discrete white granules on the meninges
+/ Microscopy-granulomas, lymphoplasmacytic infiltrate
 Obliterative endarteritis
Tubercular meningitis
 Sequele-adhesive,
fibrous, arachnoiditis,
 Hydrocephalus
 Infarction
following endarteritis
 Tuberculoma-intraparenchymal
CSF in Tubercular meningitis
 Moderate
pleocytosis
 Lymphocytosis (early –neutrophilia)
 Glucose ↓ (< pyogenic )
 Protein +++
 Cobweb appearance /clot
 AFB, culture, PCR.
 Atypical mycobacteria
Syphilis
Meningovascular neurosyphilis:Chronic
meningitis
Base of brain
Cerebral convexities+/-,
Spinal leptomeninges
Cerebral Gumma
Microscopy-endarteritis obliterans (Heubner
arteritis) with plasma cell cuffing
Cerebral abscess
 Def:
Focal inflammation of the
parenchyma of the brain
 Routes of infection
 Secondary to meningitis
 Local spread (middle ear,mastoid)
 Hematogenous-BE,cyanotic heart
disease,bronchiectasis
 Trauma
GROSS MORPHOLOGY
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Ill defined local
swelling
 preferred sites frontal
lobe,parietal lobe
cerebellum
depending on aetiology
 C/S fibrous capsule
soft central
liquefactive necrosis
surrounding oedema
Morphology
 Microscopy
 Abscess
containing necrosis surrounded
by granulation tissue ,fibrosis & gliosis
 Microbiology:mixed bacteria + anaerobes
Encephalitis
 Diffuse
brain inflammation
 Causative org: viral,rickettsia,bacteria
(listeria)
 Death of neurons
HIV associated Neurologic
disorders
 Primary:
 CNS
 Primary
HIV encephalopathies
 Giant cell encephalitis,
leucoencepalopathy, gray matter disease
 Myelopathy
 Lymphocytic Meningitis-seroconversion
 PNS
 Skeletal muscle myositis
HIV associated Neurologic
disorders
 Associated
with immune supressed
condition
 Opportunistic infections
 Lymphoma
CSF in AIDS
 Aseptic
HIV meningitis-lymphocytic
meningitis
 Infections
 M. tuberculosis less reactive
 Mycobacterium avium intracellulare
 Cryptococci
 Neurosyphilis
 Malignancies
OTHER INFECTIONS
 Prion
disease (CJD)
 Fungal infections
 Parasitic infections malaria,
toxoplasmosis,Echinococcus,cysticercosis
Typical Cerebrospinal Fluid Findings in Various Types of
Meningitis
Test
Bacterial
Viral
Fungal
Tubercular
Opening
pressure
Elevated
Usually
normal
Variable
Variable
White blood
cell count
>=1,000 per
mm3
<100 per mm3
Variable
Variable
Cell
differential
Predominance Predominance
of PMNs
of
lymphocytes
Predominance Predominance
of
of
lymphocytes
lymphocytes
Protein
Mild to
marked
elevation
Normal to
elevated
Elevated
Elevated
CSF-to-serum
glucose ratio
Normal to
marked
decrease
Usually
normal
Low
Low
Intracranial hemorrhage
 Intracerebral
hematoma-associated with
hypertension,(AV malformations,tumour )
 Subarachnoid hemorrhage
 Any age group
 Associated with rupture of Berry aneurysm
Hemorrhagic tap
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Traumatic
 Clear supernatant
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Clearing from tube 1
to 3
 Fresh RBC’s
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Subarachnoid
hemorrhage
 Xanthochromia>4 hrs
upto 2-4 weeks
 Same appearance in
1,2 & 3
 Crenated RBC’s
Lumbar puncture
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Diagnostic
Meningitis;bacterial,TB,fungal, viral *,syphilis
encephalitis
Guillain Barre Syndrome
Matastasis lymphoma,leukaemia,breast,lung
Haemorrhage
Any disorder affecting the nervous system!
Therapeutic
Administer dye for imaging studies
Administer medications eg CT,anaesthesia
Processing
 Method
of collection
 3 sterile bottles
 Biochemistry & immunology-blood glucose
 Microbiology
 Cell count,cytology
 Send QUICKLY