CNS INFECTION Dr Basu MD CNS INFECTION Meningeal

CNS INFECTION Dr. Basu MD

CNS INFECTION Meningeal Infection: meningitis Brain parenchymal infection { encephalitis}

How we will proceed ? Route of CNS infection Meningitis – – – Bacterial Viral Fungal Brain parenchymal Infections. – – Viral encephalitis Spongiform encephalopathy Abscess Rabies

How infection enter the CNS ? 1. HAEMATOGENOUS SPREAD. 2. DIRECT IMPLANTATION [ TRAUMA, 3. 4. NEURAL TUBE DEFECT]. LOCAL EXTENTION [ MIDDLE EAR, SINUS Infection] VIA– PERIPHERAL NERVE : RABIES

Meningitis LEPTOMENINGITIS [ Meningitis] Topics of individual diseases 1. Etiology 2. Morphology 3. Investigation 4. Clinical

LEPTOMENINGITIS [ Meningitis] Definition: Inflammation of the LEPTOMENINGES AND SUBARACHONOID SPACE (CSF). Types: 1. 2. 3. 4. ACUTE (PURULANT) MENINGITIS ACUTE LYMPHOCYTIC ( VIRAL ) MENINGITIS Fungal CHRONIC MENINGITIS

Lab diagnosis: CSF Investigations Pyogenic Meningitis Viral meningitis Glucose Very low Normal Pressure increased Slightly increased Protein High Cells Increased Neutrophils Moderately increased Lymphocytes Culture Often positive Negative

ACUTE (PURULANT) MENINGITIS : ETIOLOGY 1. NEONATS: Escherichia Coli, GROUP B STREPTOCOCI. 2. CHILDREN: > 6 MONTHS = H. INFLUENZAE AND STREPTOCOCCUS PNEUMONIAE.

ACUTE (PURULANT) MENINGITIS : ETIOLOGY 3. During Epidemics and most common in adults : Neisseria meningitidis. 4. Adult: S. pneumoniae, Listeria monocytogenes. 5. Following Surgery : Staphylococcus aureus.

Opaque meninges due to exudates Neutrophil in subarachonoid space

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.

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

TOPIC Viral Encephalitis

Viral Meningitis : Aseptic meningitis Meningoencephalitis : If Viral meningitis is associated with parenchymal Infection.

Viral Encephalitis CNS involvement may be localized or Generalized. Clinical: Fever, head ache.

Viruses that can cause encephalitis Rabies virus Herpes simplex I virus encephalitis: HIV encephalitis. Toxoplasmosis (infection)

Eosinophilic Negri body, as seen here in a Purkinje cell in hippocampus. Rabies

Herpes simplex virus I Produce hemorrhage and necrosis Involve temporal or frontal lobe

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.

Toxoplasma infection Can cause retinitis in new born. Develop calcification in brain. Can cause brain abscess.

Fungal meningitis Aspergillus: Vasculitis and hemorrhage. Cryptococcus: Involve Virchow robbins space---soap bubble lesion.

Cryptococcus-soap bubble lesion Toxoplasmosis : ring lesion Classical for abscess

Chronic Meningitis Caused by : 1. 2. 3. 4. Mycobacterium Tuberculosis Cryptococcus Neoformans Treponema pallidum Brucella.

Mycobacterium Tuberculosis Seen in AIDS with atypical mycobacterium Involve basal surface of brain: basal meningitis.

Meningeal Syphilis May involve spinal Meninges: produce thickening. Produce meningeal fibrosis and secondary Hydrocephalous.

Brain Abscess Spread : A. Hematogenous B. Contiguous C. Direct : Face and nasal sinus, otitis media. D. Patient with Right to Left shunt are higher risk of Brain abscess.

Morphology of abscess Localized collection of neutrophils. Ring like shadow on CT

Clinical Features and Complications Fever Increased Intracranial Pressure Focal Neurological Deficit. Ø Complications 1. Brain Herniation 2. Rupture of the abscess in the subarachnoid Space 3. Subdural Empyema

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