Transcript Document

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.
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–
–
–
Viral encephalitis
Spongiform encephalopathy
Abscess
Rabies
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
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
High
Cells
Increased
Neutrophils
Moderately increased
Lymphocytes
Culture
Often positive
Negative
ACUTE (PURULANT) MENINGITIS : ETIOLOGY
1. NEONATS: Escherichia Coli, GROUP B
STREPTOCOCI.
2. CHILDREN: > 6MONTHS = H. INFLUENZAE
AND STREPTOCOCCUS PNEUMONIAE.
ACUTE (PURULANT) MENINGITIS : ETIOLOGY
During Epidemics and most common in
adults : Neisseria meningitidis.
4. Adult: S. pneumoniae, Listeria
monocytogenes.
5. Following Surgery : Staphylococcus
aureus.
3.
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.

1.
2.
Complications
Brain Herniation
Rupture of the abscess in the subarachnoid
Space
3. Subdural Empyema
Thank you !!!