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Presentation about basic learning for Meningitis.
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Oh you who believe, stay away from bad suspicion (Al - Hujurat )
Describe topographic Anatomy of Meninges
• Innervation
• Blood supply
Describe the Blood Brain Barrier (BBB)
Enlist Dural Venous Sinuses & with their function
Role of Ventricular system in CSF production, circulation
Interpret CSF report in case of meningitis
What is the causes , Clinical presentation consequences & management of meningitis
Meninges
Three layers of tissue covering brain & spinal cord:
Dura mater
Arachnoid mater
Pia mater
Two spaces:
Subdural space
Sub-arachnoid space
Dura Matter
Tough, dense connective tissue, extends to 2nd
sacral vertebra
Divides into two layers:
Periosteal layer
Meningeal layer
Falx cerebri
Tentorium cerebelli
Falx cerebelli
Diaphragma sellae
Having 4 folds
Arachnoid Matter
Thin layer, pressed
against inner wall of
Dura by
cerebrospinal fluid
pressure in
subarachnoid
space
Pia Matter
Lies on surface of brain &
spinal cord
Dural
Nerve
Supply
Branches of the trigeminal, Vagus, and
first three cervical nerves and branches
from the sympathetic system pass to the
dura.
The dura is sensitive to stretching, which
produces the sensation of headache.
Dural Blood Supply
Dural Arterial Supply
The Dura matter’s arteries supply from:
Internal carotid
Maxillary
Ascending pharyngeal
Occipital
Vertebral arteries.
From a clinical point, the most important is the middle meningeal artery(branch of Maxillary), which is commonly damaged in head injuries.
Dural Venous Drainage
The meningeal veins lie in the
endosteal layer of dura.
The middle meningeal vein
follows the branches of the
middle meningeal artery and
drains into:
• Pterygoid venous plexus
or
• Sphenoparietal sinus.
The veins lie lateral to the
arteries.
Dural Venous Sinuses
Sinus Drain into
• superior sagittal sinus confluence of sinuses
• inferior sagittal sinus unites with great cerebral vein to form straight
sinus
• straight sinus confluence of sinuses
• confluence of sinuses transverse sinuses
• transverse sinus sigmoid sinus
• sigmoid sinus internal jugular vein
• cavernous sinus superior & inferior petrosal sinuses
• occipital sinus confluence of sinuses
• inferior petrosal sinus internal jugular vein
• superior petrosal sinus sigmoid sinus
Their main function is to drain CSF
Physiology of BBB
In the brain, endothelial cells are packed
much tighter together due to the existence of
tight junctions between them, blocking the
passage of most molecules.
The BBB blocks most of the molecules except
those that cross cell membranes by means of
lipid solubility (like steroid hormones, oxygen,
carbon dioxide) and those that are allowed
by specific transport systems (like sugars and
some amino acids)
Condition in which BBM disturb
The BBB can be disturb by:
Hypertension
Hyper osmolality
Radiation
Infection
Trauma
Inflammation
Pressure
Ventricular System
Ventricle is an internal cavity
of the brain which is filled
with CSF.
Composed of:
Two lateral ventricles
Third ventricle
Fourth ventricles
All these ventricles are
connected through:
Foramen Monro
Cerebral Aqueduct
Foramen Magendie
Foramen Luschka
Formed by Choroid Plexus
Plexus is formed by invaginating of vascular pia mater into the ventricular cavity
It becomes highly convoluted & produce a spongy-like appearance
It enters the 3rd and 4th ventricles through their roofs, and the lateral ventricles through the choroid fissure
C
S
F
Choroid plexuss
Appearance Clear and colourless
Volume 130 ml
Rate of production 0.5 ml/min
Pressure 60-180 mm of H2O
Composition
protein 15-45 mg/ dL
glucose 50-85 mg/ dL
chloride 720-750 mg/100 ml
No. of cells 0-5 lymphocytes/µL
Appearance & Composition of the CSF
Glucose (mg/dL):
Normal to marked
decrease. <40
mg/dL.
Protein (mg/dL)(Marked increase) >
250 mg/dL.
WBCs (cells/µL)
>500 (usually >
1000). Early: May be
< 100.
Cell differential:Predominance of
Neutrophils (PMNs)
Culture: Positive
Opening Pressure Elevated
Glucose (mg/dL): <40 mg/dL (Low)
Protein (mg/dL)
(moderate to marked
increase) 50 -500
mg/dL
WBCs (cells/µL)Variable (10 -1000
cells/µL) <500cells/µL.
Cell differential:Predominance of
Lymphocytes
Culture: Positive for AFB
Opening Pressure Variable
Bacterial Meningitis Tubercular Meningitis
Changes In Composition In Disease
Meningitis
Inflammation of the meninges
Common causes of meningitis include:
Bacteria
Virus
Fungi
Parasites.
Organisms Causes Meningitis
Birth to 4 weeks: GBS, E.coli
4 to 12 weeks: GBS, E.coli, Pneumococcus,Salmonella, Listeria, H. Influenza
3 months to 3 years: Pneumococcus, Meningococcus, H. Influenza
3 years to adult: Pneumococcus, Meningococcus
Pathogenesis
Infection of upper respiratory tract
Invasion of blood stream
Seeding & inflammation of meninges
Increase in ICP due to inflammatory exudate
Headache
Fever
Irritability
Lethargy
Poor feeding(in child)
Convulsions
Photophobia
consequences
Hydrocephalus
Spinal & cranial nerve palsy
Hearing loss
Cortical blindness
Seizures
Intellectual deficit
Management Lumbar Puncture
Antibiotic