CNS INFECTION

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CNS INFECTION

• Dr. Basu MD

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CNS INFECTION

• Meningeal Infection meningitis
• Brain parenchymal infection encephalitis

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How we will proceed ?

• Route of CNS infection
• Meningitis
• Bacterial
• Viral
• Fungal
• Brain parenchymal Infections.
• Viral encephalitis
• Spongiform encephalopathy
• Abscess
• Rabies

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How infection enter the CNS ?

1. HAEMATOGENOUS SPREAD.
2. DIRECT IMPLANTATION TRAUMA, NEURAL TUBE
   DEFECT.
3. LOCAL EXTENTION MIDDLE EAR, SINUS Infection
4. VIA PERIPHERAL NERVE RABIES

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Meningitis

• LEPTOMENINGITIS Meningitis
• Topics of individual diseases
• Etiology
• Morphology
• Investigation
• Clinical

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LEPTOMENINGITIS Meningitis

• Definition
• Inflammation of the LEPTOMENINGES AND
  SUBARACHONOID SPACE (CSF).
• Types
• ACUTE (PURULANT) MENINGITIS
• ACUTE LYMPHOCYTIC ( VIRAL ) MENINGITIS
• Fungal
• CHRONIC MENINGITIS

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Lab diagnosis CSF
Investigations Pyogenic Meningitis Viral meningitis
Glucose Very low Normal
Pressure increased Slightly increased
Protein High High
Cells Increased Neutrophils Moderately increased Lymphocytes
Culture Often positive Negative
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ACUTE (PURULANT) MENINGITIS ETIOLOGY

1. NEONATS Escherichia Coli, GROUP B STREPTOCOCI.
2. CHILDREN gt 6MONTHS H. INFLUENZAE AND
   STREPTOCOCCUS PNEUMONIAE.

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ACUTE (PURULANT) MENINGITIS ETIOLOGY

• During Epidemics and most common in adults
  Neisseria meningitidis.
• Adult S. pneumoniae, Listeria monocytogenes.
• Following Surgery Staphylococcus aureus.

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Opaque meninges due to exudates
Neutrophil in subarachonoid space
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Complications sequel

• Edema can lead to herniation and death.
• Resolution of infection may be followed by
  adhesive arachnoiditis fibrosis ( in basal
  meninges) Obstructive hydrocephalus.
• If cerebral meninges is involved communicating
  hydrocephalous occur.

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CLINICAL SIGNS

• Clinical signs may include
• Headache,
• Neck stiffness (from irritation of spinal nerve
  roots),
• Fever, and clouded consciousness.

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• TOPIC
• Viral Encephalitis

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Viral Meningitis Aseptic meningitis

• Meningoencephalitis If Viral meningitis is
  associated with parenchymal Infection.

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Viral Encephalitis

• CNS involvement may be localized or Generalized.
• Clinical Fever, head ache.

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Viruses that can cause encephalitis

• Rabies virus
• Herpes simplex I virus encephalitis
• HIV encephalitis.
• Toxoplasmosis (infection)

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Eosinophilic Negri body, as seen here in a
Purkinje cell in hippocampus.
Rabies
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Herpes simplex virus I

• Produce hemorrhage and necrosis
• Involve temporal or frontal lobe

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HIV INFECTION Symptoms

• Progressive Disease
• AIDS-Dementia complex
• Vacuolar myelopathy of spinal cord
• Most common cause of Dementia In the Young adult
  (now-a-days) in the HIV endemic areas.
• Micro Multinucleated giant cells.

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Toxoplasma infection

• Can cause retinitis in new born.
• Develop calcification in brain.
• Can cause brain abscess.

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Fungal meningitis

• Aspergillus Vasculitis and hemorrhage.
• Cryptococcus Involve Virchow robbins
  space---soap bubble lesion.

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Toxoplasmosis ring lesionClassical for abscess
Cryptococcus-soap bubble lesion
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Chronic Meningitis

• Caused by
• Mycobacterium Tuberculosis
• Cryptococcus Neoformans
• Treponema pallidum
• Brucella.

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Mycobacterium Tuberculosis

• Seen in AIDS with atypical mycobacterium
• Involve basal surface of brain basal meningitis.

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Meningeal Syphilis

• May involve spinal Meninges produce thickening.
• Produce meningeal fibrosis and secondary
  Hydrocephalous.

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Brain Abscess

• Spread
• Hematogenous
• Contiguous
• Direct Face and nasal sinus, otitis media.
• Patient with Right to Left shunt are higher risk
  of Brain abscess.

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Morphology of abscess

• Localized collection of neutrophils.

Ring like shadow on CT
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Clinical Features and Complications

• Fever
• Increased Intracranial Pressure
• Focal Neurological Deficit.
• Complications
• Brain Herniation
• Rupture of the abscess in the subarachnoid Space
• Subdural Empyema

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Thank you !!!