cns infection intro

8/9/2019 CNS Infection Intro

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y Frequency and emergency condition

Pathogens

-Bacteria - Tuberculosis-Virus - Prion [CNS only]-Fungus - Parasite


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y Hematogenous spread : most common

Direct invasion : trauma, surgery

Adjacent area: sinus ,mastoid ,middle ear

Placenta : rubella ,toxoplasmosis

Peripheral nerve : rabies


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y , 1.

2. ,,

,,3.

4.

Polymerase chain reaction(PCR)


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y 3 y Dura matery Arachnoidy

Pia mater


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y Lepto meninges (pia + arachnoid)

y Coverbrain, spinal cord, proximalCranial nervesandPeripheral nerve


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y The blood-brain barrier (BBB) is a separation ofcirculating blood and cerebrospinal fluid (CSF)maintained by the choroid plexus in the central

nervous system(CNS).


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It is composed of endothelial cells, which are packed verytightly in brain capillaries

Tight junction

Astrocyte cell projections called astrocytic feet (also

known as "glial limitans") surround the endothelial cells ofthe BBB


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y Endothelial cell restrict the diffusion ofmicroscopic objects (e.g. bacteria) and large orhydrophillic molecules into the CSF, while allowingthe diffusion of small hydrophobic molecules (O

2,

hormones, CO2).

Cells of the barrier actively transport metabolic

products such as glucose across the barrier withspecific proteins.


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y This "barrier" results from the selectivity of the tightjunctions between endothelial cells in CNS vessels thatrestricts the passage of solutes.


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Blocking massive molecules >500 dalton

y Preventing toxins, viruses, and bacteria

y Preventing ATB enter CNS


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y Blood brain barrier1.small molecules

2.lipid soluble molecules

3.small protein binding

Meningeal inflammation (meningeal inflammation)


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1. ANATOMICAL BARRIER

Scalp, skull, dura, leptomeninges

Blood brain barrier and Blood CSF Barrier

2. IMMUNOLOGICALDEFENSEHumoral response, Phagocytic cellular response

and Complement-No WBC, onlymicloglia-Immunoglobulin and complement


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y GENERAL SYSTEMIC SYMPTOM

FOCAL NEUROLOGICALDEFICIT

AL

TE

RATI

ON OF CONCI

OUSNE

SS MININGISMUS:FEVER,STIFF NECK,PHOTOPHOBIA

FEVER

SEIZ

URE

PAIN,HEADACHE

SIGN OF INCREASEDINTRACRANIALPRESSURE :HEADACHE,BLURR VISION,VOMITING


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Thank you for attention


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cns infection intro

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