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- 1. CEREBROSPINAL FLUID (C.S.F) By : Dr Uffaq Zeb (PT) DPT (RMI-KMU) MSNMPT* (RIU) 1
- 2. CSF OBJECTIVES Physiological Anatomy Location Composition Functions Formation Circulation Reabsorption CSF Pressure Diseases Cerebral blood flow Perivascular Space Lymphatic system Cerebral Vascular Resistance Cerebral Microcirculation Protective mechanisms of brain Blood-CSF and Blood- Brain Barriers Brain metabolism 2
- 3. CSF C.S.F LOCATION Ventricles of brain Cisterns around outside of brain Subarachnoid around Brain Spinal cord All these chambers are connected with one another Constant pressure 3
- 4. CSF VENTRICLES OF BRAIN (RIGHT LATERAL ASPECT) 4
- 5. CSF VENTRICLES OF BRAIN (ANTERIOR ASPECT) 5
- 7. CSF CHARACTERISTICS OF CSF 1. Clear, colorless, transparent 2. Reaction: Alkaline 3. 500 – 700 ml/day (0.2 ml/min) 4. Total 100 – 160 ml 7
- 8. CSF COMPOSITION OF CSF Water: 99.13% Solids: 0.87 % Organic Inorganic Cells 8
- 9. CSF COMPOSITION OF CSF 1. GLUCOSE is 30% less (64mg%) 2. Protein. Only 20-25mg% as compared to 7500mg% in plasma 3. Cells. Very few lymphocytes (1-5 cell/mm3) 4. osmotic pressure equal to plasma; 5. sodium ion equal to plasma; 6. chloride ion 15 percent greater than plasma; 7. potassium ion 40 per cent less; 9
- 10. CSF FUNCTIONS OF C.S.F 1. Acts as fluid buffer (cushioning the CNS against injury) 2. Acts as reservoir to regulate the contents of the cranium 3. May act as a medium of nutrient exchange in the CNS; However brain carries out its metabolic exchanges directly with blood. 4. Clinical - DIAGNOSTIC Therapeutic 10
- 11. CSF FORMATION OF CSF Sites: >2/3 by Choroid plexus <1/3 by Ependymal surfaces arachnoidal membrane perivascular spaces (A small amount also comes from brain itself) Choroid plexus: Cauliflower like growth of blood vessels covered by thin epithelium, projecting into all ventricles 11
- 16. CSF CIRCULATION OF C.S.F 16 Lateral Ventricles Monro 3rd Ventricle Aqueduct of Sylvius (Mesencephalic Aqueduct) 4th Ventricle Subarachnoid Space 2 – Luschka (lat.) 1 – Magendie
- 18. CSF 18
- 19. CSF ABSORPTION To the venous system by bulk fluid through arachnoid granulations, located in the superior sagital sinus by pressure gradient. (Arachnoid villi function like Valves and allow one-way flow) Arachnoid granulations : Projections of arachnoidal membrane in venous sinuses:- Arachnoid villi (Microscopic) Collection of Arachnoid villi:- Arachnoidal Granulations (Macroscopic) Endothelial cells cover the villi 19
- 20. CSF DRAINAGE OF A PERIVASCULAR SPACE INTO THE SUBARACHNOID SPACE 20 Lymphatic system
- 21. CSF REGULATION OF CSF PRESSURE Balance between Formation and Reabsorption 21
- 23. CSF CEREBRAL BLOOD FLOW (CBF) 15% of Cardiac Output 750-900 ml/min 23
- 24. CSF AUTOREGULATION OF CBF Definition of Autoregulation: The process by which blood flow to the tissues is maintained at relatively constant level despite changes in perfusion pressure Extremely well autoregulated between arterial pressure limits of 60 and 140 mmHg In hypertensives, upto 160-180 mmHg Roll of Sympathetic Nervous System in exercise Very high mean arterial pressure Sympathetic stimulation causes vasoconstriction of brain arteries to prevent vascular hemorrhage 24
- 26. CSF CEREBRAL MICROCIRCULATION Capillaries are much less “leaky” No fenestrations (few exceptions) Mechanism: Glial feet by the surrounding Glial cells surround the capillaries 26
- 27. CSF PROTECTIVE MECHANISMS OF BRAIN 1. Trauma Skull bones CSF 2. Blood flow in case of high arterial pressure Autoregulation Sympathetic nervous system e.g. in exercise Walls of small arterioles become thickened to prevent transmission of high blood pressure to capillaries 27 Contd…..
- 28. CSF PROTECTIVE MECHANISMS OF BRAIN 3. Blood flow in case of low blood pressure and metabolic disorders Autoregulation Roll of CO2, H+ and O2 4. Edema Tight capillary junctions 5. Protection of brain from endogenous and exogenous toxins Blood-CSF and Blood- Brain Barriers 28
- 29. CSF DISEASES RELATED TO CSF AND CEREBRAL BLOOD FLOW Cerebral stroke Brain injury Brain edema ↑CSF Pressure 29
- 30. CSF DISEASES RELATED TO CSF AND CEREBRAL BLOOD FLOW (CEREBRAL STROKE) Blockage of cerebral arteries Rupture of cerebral arteries 30 Contd……..
- 31. CSF DISEASES RELATED TO CSF AND CEREBRAL BLOOD FLOW (CEREBRAL STROKE) BLOCKAGE OF CEREBRAL ARTERIES Old age Arteriosclerotic plaques Activation of clotting mechanism 31 Contd……..
- 32. CSF DISEASES RELATED TO CSF AND CEREBRAL BLOOD FLOW (CEREBRAL STROKE) RUPTURE OF CEREBRAL ARTERIES Rupture of cerebral arteries High blood pressure Middle cerebral artery Loss of function in Wernich’s speech comprehension area Dementia Loss of function in Broca’s area Unable to speak Posterior cerebral artery Infarction in occipital lobe Loss of vision on both sides in the half of retina on the same side of stroke lesion Damage to blood supply of midbrain Blockage of nerve conduction in major pathways between brain and spinal cord Sensory and motor abnormalities 32
- 33. CSF DISEASES RELATED TO CSF AND CEREBRAL BLOOD FLOW (BRAIN EDEMA) When systems for protecting against transudation of fluid into the brain break down e.g. Brain concussion Blow to head High blood pressure Mechanism ↑Capillary Pressure ↑ Damage to capillary walls Coma and death 33
- 34. CSF TREATMENT OF BRAIN EDEMA Emergency Osmotic diuretics Mannitol Ventricular needle puncture 34
- 35. CSF DISEASES RELATED TO CSF AND CEREBRAL BLOOD FLOW (BRAIN INJURY) Coupe Damage/injury to the brain on the same side of trauma Countercoup Damage/injury to the brain on the opposite side of trauma 37
- 36. CSF DISEASES RELATED TO CSF AND CEREBRAL BLOOD FLOW (↑CSF PRESSURE) Causes ↑ formation (rare) ↑ number of blood cells or plasma proteins Hemorrhage Infection Blockage of reabsorption ↓reabsorption (Obstruction to outflow) Fibrosis of villi Brain tumors Congenital Hydrocephalus 38
- 37. CSF EFFECTS OF ↑CSF PRESSURE 1. Papilledema 2. Hydrocephalus 39
- 38. CSF FECTS OF ↑CSF PRESSURE Papilledema : Edema of the Optic Disc (& Retinal edema) Significance of Papilledema Clinical diagnosis of ↑CSF Pressure by ophthalmoscope Effects of Papilledema Blindness/ blurred vision 40
- 39. CSF EFFECTS OF ↑CSF PRESSURE Hydrocephalus Excess water in cranial vault Types Communicating Non-Communicating Swelling of head in children Brain damage 41
- 40. CSF MEASUREMENT OF CSF PRESSURE Person lying horizontally on his/ her side so that pressure in spinal canal = pressure in cranial vault Spinal needle is inserted in lumber spinal canal Same procedure for composition of CSF 42
- 41. CSF BLOOD-CSF AND BLOOD- BRAIN BARRIERS Blood- Brain Barrier Tight junctions between adjacent Endothelial cells Blood-CSF Barrier Tight junctions between adjacent Choroid Epithelial cells Many large molecular weight substances hardly pass into CSF or interstitial fluids of brain These barriers are similar, therefore Blood-CSF and Blood- Brain Barriers= Blood- Brain Barrier 43
- 42. CSF FUNCTIONS OF BLOOD- BRAIN BARRIER 1. Maintain constant environment of neurons • Brain neurons highly sensitive to changes in ionic concentration 2. Protection of brain from endogenous and exogenous toxins 3. Prevention of escape of neurotransmitters into general circulation 44
- 43. CSF CLINICAL IMPLICATIONS OF BLOOD- BRAIN BARRIER 1. Immature at birth → Kernicterus (Entry of free bilirubin in brain) 2. Some amines (e.g. dopamine and serotonin do not penetrate brain tissue, so their precursors are given, i.e. L-Dopa and 5-Hydroxytryptophane) 3. Breakdown of Blood- Brain Barrier in infection or injury 45
- 44. CSF BRAIN METABOLISM Brain weight= 2% of body weight Brain metabolism= 15% of body metabolism (resting, awake) 46
- 45. CSF SPECIAL REQUIREMENTS OF BRAIN FOR OXYGEN LACK OF SIGNIFICANT ANAEROBIC METABOLISM Most tissues of body can live without Oxygen for many minutes Anaerobic metabolism Excessive amounts of glucose and glycogen are used Brain is not capable of significant anaerobic metabolism Reason:- High metabolic rate of neurons Sudden cessation of brain blood flow/ or total lack of oxygen:- Unconsciousness within 5-10 minutes 47
- 46. CSF BRAIN UTILIZES GLUCOSE AS ENERGY Brain needs continuous supply of Glucose Only about 2 minute supply of glucose normally stored in brain as Glycogen Almost all energy is derived from glucose derived from blood Glucose delivery to brain not dependent on insulin Advantage: preventing loss of function in Diabetes (↓Insulin) Disadvantage: over-treatment with insulin→ unconsciousness 48
- 47. CSF SUMMARY Physiological Anatomy Location Composition Functions Formation Circulation Reabsorption CSF Pressure Diseases Cerebral blood flow Perivascular Space Lymphatic system Cerebral Vascular Resistance Cerebral Microcirculation Protective mechanisms of brain Blood-CSF and Blood- Brain Barriers Brain metabolism 49
Editor's Notes
- #2: Dr. Rashid Mahmood