Meningitis basic to clinical
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This document discusses the anatomy and physiology of the meninges and cerebrospinal fluid (CSF). It describes the three layers of meninges - dura mater, arachnoid mater, and pia mater. It also discusses the blood-brain barrier, dural venous sinuses, ventricular system, CSF production and composition, changes in CSF in disease like meningitis, causes and clinical presentation of meningitis, and management of meningitis.
Meningitis basic to clinical
- 1. Oh you who believe, stay away from bad suspicion (Al - Hujurat )
- 2. 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
- 3. Meninges Three layers of tissue covering brain & spinal cord: Dura mater Arachnoid mater Pia mater Two spaces: Subdural space Sub-arachnoid space
- 4. Dura Matter Tough, dense connective tissue, extends to 2nd sacral vertebra Divides into two layers: Periosteal layer Meningeal layer
- 5. Falx cerebri Tentorium cerebelli Falx cerebelli Having 4 folds Diaphragma sellae
- 6. Arachnoid Matter Thin layer, pressed against inner wall of Dura by cerebrospinal fluid pressure in subarachnoid space
- 7. Pia Matter Lies on surface of brain & spinal cord
- 8. 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.
- 9. Dural Arterial Supply The Dura matters arteries supply from: Dural Blood Supply 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.
- 10. Dural Venous Sinuses Their main function is to drain CSF 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
- 13. 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)
- 15. Condition in which BBM disturb The BBB can be disturb by: Hypertension Hyper osmolality Radiation Infection Trauma Inflammation Pressure
- 16. Ventricular System Ventricle is an internal cavity of the brain which is filled with CSF. Composed of: Two lateral ventricles Third ventricle Fourth ventricles
- 17. All these ventricles are connected through: Foramen Monro Cerebral Aqueduct Foramen Magendie Foramen Luschka
- 18. 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
- 19. Appearance & Composition of the CSF 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/亮L
- 20. Changes In Composition In Disease Bacterial Meningitis Tubercular Meningitis Glucose (mg/dL): Normal to marked decrease. <40 mg/dL. Protein (mg/dL) (Marked increase) > 250 mg/dL. WBCs (cells/亮L) >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/亮L) Variable (10 -1000 cells/亮L) <500cells/亮L. Cell differential: Predominance of Lymphocytes Culture: Positive for AFB Opening Pressure Variable
- 21. Meningitis Inflammation of the meninges Common causes of meningitis include: Bacteria Virus Fungi Parasites.
- 22. 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
- 23. Pathogenesis Infection of upper respiratory tract Invasion of blood stream Seeding & inflammation of meninges Increase in ICP due to inflammatory exudate
- 24. Headache Fever Irritability Lethargy Poor feeding(in child) Convulsions Photophobia
- 25. consequences Hydrocephalus Spinal & cranial nerve palsy Hearing loss Cortical blindness Seizures Intellectual deficit
- 26. Management Lumbar Puncture Antibiotic