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Cranial meninges
The document discusses the cranial meninges, which are the three protective membranes that cover the brain - the dura mater, arachnoid mater, and pia mater. It describes the layers and their functions in protecting the brain. It also discusses subarachnoid hemorrhage (SAH), which is bleeding under the arachnoid layer caused by a ruptured brain aneurysm. Treatment for SAH involves stabilizing the patient, preventing rebleeding by clipping or coiling the aneurysm, and preventing complications like vasospasm. The standard treatment is microsurgical clipping or endovascular coiling of the aneurysm as soon as possible to prevent rebleeding and improve outcomes.
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Cranial meninges
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- 2. Protection of theBrain • The Skull • Cranial meninges • Cerebrospinal fluid • Blood brain barrier
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- 4. 1. Dura Mater- Composed of two layers: a) Periosteal – outer layer, attaches to bone. b) Meningeal – inner layer, closer to brain. Cranial Meninges - 3 layer protective membrane Two layers fused, except to enclose the dural sinuses 3. Pia Mater - delicate, follows convolutions. 2. Arachnoid Layer - ‘spider’ web like.
- 5. Coronal section ofthe upper part of the head Endosteal layer Meningeal layer They are closely united except along certain lines; they are separated to form venous sinuses Superior sagittal sinus (Dural venous sinus) Dura mater Subdural space
- 6. Sagittal section showingthe duramater 1) Falx cerebri 2) Tentorium cerebelli 3) Falx cerebelli 4) Diaphragma sellae
- 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 BLOOD SUPPLY The middle meningeal artery supplies most of the blood for the dura mater, though the meningeal branches of the posterior and anterior ethmoidal artery also contribute.
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- 11. Subdural space Potential spacebetween dura and arachnoid mater. Cranial Meningeal Spaces Epidural space Potential space superior to dura. Subarachnoid space Filled with CSF Contains the blood vessels supplying brain.
- 13. SUBARACNOID SPACE Relativelynarrow over the surface of cerebral hemisphere, but sometimes becomes much wider in areas at the base of the brain, the widest space is called subarachnoid cisterns.
- 14. Median sagittal sectionto show the subarachnoid cisterns & circulation of CSF Superior cistern Interpeduncular cistern Cerebellomedullary cistern Chiasmatic cistern Pontine cistern
- 15. PIA MATER Piamater functions to cover and protect the central nervous system (CNS), to protect the blood vessels and enclose the venous sinuses near the CNS, to contain the cerebrospinal fluid (CSF) and to form partitions with the skull. The CSF, pia mater, and other layers of the meninges work together as a protection device for the brain, with the CSF often referred to as the fourth layer of the meninges.
- 17. PATHOLOGY There are threetypes of hemorrhage involving the meninges: An epidural hematoma arise after an accident or spontaneously A subdural hematoma is a hematoma (collection of blood) located in a separation of the arachnoid from the dura mater. The small veins that connect the dura mater and the arachnoid are torn, usually during an accident, and blood leaks into this area A subarachnoid hemorrhage is acute bleeding under the arachnoid; it may occur spontaneously or as a result of trauma.
- 18. Other medicalconditions that affect the meninges include meningitis (usually from fungal, bacterial, or viral infection) and meningiomas that arise from the meninges, or from meningeal carcinomatoses (tumors) that form elsewhere in the body and metastasize to the meninges.
- 20. CRANIAL VENOUS SINUSES The dural venous sinuses (also called dural sinuses, cerebral sinuses, or cranial sinuses) are venous channels found between layers of dura mater in the brain. They receive blood from internal and external veins of the brain, receive cerebrospinal fluid (CSF) from the subarachnoid space, and ultimately empty into the internal jugular vein.
- 21. Name Drains to Inferiorsagittal sinus Straight sinus Superior sagittal sinus Typically becomes right transverse sinus or confluence of sinuses Straight sinus Typically becomes left transverse sinus or confluence of sinuses Occipital sinus Confluence of sinuses Confluence of sinuses Right and Left transverse sinuses Sphenoparietal sinuses Cavernous sinuses Cavernous sinuses Superior and inferior petrosal sinuses Superior petrosal sinus Transverse sinuses Transverse sinuses Sigmoid sinus Inferior petrosal sinus Sigmoid sinus Sigmoid sinuses Internal jugular vein
- 22. ARTERIES TO SPECIFICBRAIN AREAS Corpus striatum Middle & lateral striate Anterior & Middle cerebral arteryInternal capsule Thalamus PComA, basilar, PCA Midbrain PCA, supCerebellarA, basilar Pons Basilar, Ant, inf, supCerebellarA, Medulla oblongata Vertebral, ASA,PSA,PICA, basilar Cerebellum supCerebellar, AICA,PICA
- 23. BLOOD SUPPLY OFTHE BRAIN VERTEBRAL Basilar Posterior cerebral artery INTERNAL CAROTID Middle cerebral Anterior cerebral Anterior communicating artery Posterior communicating artery CIRCLE OF WILLIS
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- 29. SYMPTOMS Headache (suddenonset, greater severity) Nausea and vomitting Loss or impairment of consciousness (may progress to coma and death) Confusion and irritability Meningial irritation and nuchal rigidity (stiff neck) Focal neurological deficits (may indicate site of lesions).
- 30. DIFFERENTIAL DIAGNOSIS Meningitis Migraine Intracerebral hemorrhage Ischemic stroke
- 34. Grade Signs andsymptoms Survival 1 Asymptomatic or minimal headache and slight neck stiffness 70% 2 Moderate to severe headache; neck stiffness; no neurologic deficit except cranial nerve plasy 60% 3 Drowsy; minimal neurologic deficit 50% 4 Stuporous; moderate to severe hemiparesis; possibly early decerebrate rigidity and vegetative disturbances 20% 5 Deep coma; decerebrate rigidity; moribund 10% Hunt and Hess classification
- 35. TREATMENT Stabilizing patient. Prevention of rebleeding by obliterating the bleeding source. prevention of a phenomenon known as vasospasm and, prevention and treatment of complications.
- 36. PREVENTING RE-BLEEDING Upto 14% of SAH patients may experience re-bleeding within 2 hours of the initial hemorrhage Re-bleeding was more common in those with a systolic blood pressure >160mm Hg Anti-fibrinolytic therapy may reduce re- bleeding but has not been shown to improve outcomes 1/24/2015©2009, AmericanHeart Association.Allrights reserved.
- 37. SURGICAL AND ENDOVASCULAR MANAGEMENTOF SAH Surgery – clip aneurysm base Endovascular – coiling Should be performed within 2 days of hemorrhage. 1/24/2015©2009, AmericanHeart Association.Allrights reserved.
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- 39. LEFT IMAGE ARROW-ANGIO WITH LARGE ANEURYSM RIGHT IMAGE ARROW – ANGIO SHOWING ANEURYSM POST CLIPPING 1/24/2015©2009, AmericanHeart Association.Allrights reserved. Angio Image Courtsey: The University of Texas Health Science Center at San Antonio – Department of Neurosurgery
- 40. SURGICAL AND ENDOVASCULAR MANAGEMENTOF SAH Combined morbidity and mortality was significantly greater in surgically treated patients than in those treated with endovascular techniques (30.9% vs. 23.5%; absolute risk reduction 7.4%) During the short follow-up period, the re- bleeding rate for coiling was 2.9% versus 0.9% for surgery There have been no randomized comparisons of coiling versus clipping for unruptured aneurysms 1/24/2015©2009, AmericanHeart Association.Allrights reserved.
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- 42. COIL SYSTEM EMBOLIZATION: IMMEDIATERESULT 1/24/2015©2009, AmericanHeart Association.Allrights reserved. Angio showing large ICA aneurysm Same aneurysm - Post GDC Coiling Angio Image Courtsey: The University of Texas Health Science Center at San Antonio – Department of Neurosurgery
- 44. PREVENTING VASOSPASM Theuse of calcium channel blockers, thought to be able to prevent the spasm of blood vessels by preventing calcium from entering smooth muscle cells, has been proposed for the prevention of vasospasm. The oral calcium channel blocker nimodipine improves outcome if administered between the fourth and twenty-first day after the hemorrhage.
- 45. PREVENTING OTHER COMPLICATIONS If medication don’t help, then angiography may be attempted to identify the sites of vasospasms and administer vasodilator medication (drugs that relax the blood vessel wall) directly into the artery. Angioplasty (opening the constricted area with a balloon) may also be performed.
- 46. SUMMARY AND CONCLUSIONS The current standard of practice calls for microsurgical clipping or endovascular coiling of the aneurysm neck whenever possible Treatment morbidity is determined by numerous factors, including patient, aneurysm, and institutional factors 1/24/2015©2009, AmericanHeart Association.Allrights reserved.
- 47. SUMMARY AND CONCLUSIONS Favorable outcomes are more likely in institutions that treat high volumes of patients with SAH, in institutions that offer endovascular services, and in selected patients whose aneurysms are coiled rather than clipped Optimal treatment requires availability of both experienced cerebrovascular surgeons and endovascular surgeons working in a collaborative effort to evaluate each case of SAH 1/24/2015©2009, AmericanHeart Association.Allrights reserved.