1 / 75

Physiology of the Cerebrospinal Fluid and Intracranial Pressure

Physiology of the Cerebrospinal Fluid and Intracranial Pressure. Chapter 10 Presentation: S. Bahram Seif, Resident of Neurosurgery Isfahan University of Medical Sciences. Protective and Homeostatic Systems of the CNS. Skull Bones ( physical protection )

marceleneg
Download Presentation

Physiology of the Cerebrospinal Fluid and Intracranial Pressure

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Physiology of theCerebrospinal FluidandIntracranial Pressure Chapter 10 Presentation: S. Bahram Seif, Resident of Neurosurgery Isfahan University of Medical Sciences

  2. Protective and Homeostatic Systems of the CNS • Skull Bones (physical protection) • CSF(hydraulic shock absorption) • Continuous Turnover of Extracellular Fluid (substrate supply and cellular homeostasis) • BBB

  3. Protective Systems can Become Detrimental

  4. Elevated ICP • Congenital lesions • Neoplasms • Metabolic syndromes • Infectious syndromes • Infarction • Hemorrhage • Trauma

  5. HISTORICAL CONSIDERATIONS • Galen • Hippocrates • Early Egyptian physicians Removing Pieces Of Skull

  6. 19th Century • Alexander Monro • George Kellie Monro-Kellie Doctrine

  7. Lumbar Puncture • 1911 • Quincke • 1951 continuously ICP monitoring • Lundberg

  8. NORMAL INTRACRANIAL PRESSURE • Upper limit of normal ICP: 15 mmHg • Usual range is 5 to 10 mmHg • Coughing or Sneezing: 30 to 50 mmHg

  9. mmHg x 1.36 = cmH2O

  10. ICP Evaluation • Intraventricular • Intraparenchymal • Subdural • Epidural

  11. CSF Pulsatility • Associated with Cardiac andRespiratoryactivity • Changes in these pulsatile components can be one of the earliest signs

  12. Cardiac Component • Left ventricular contraction • Peripheral arterial pulse • Choroid plexus and pial arteries • High-compliance venous blood vessels

  13. Respiratory Component • Generated by pressure changes in the thoracic and abdominal cavities

  14. Percussion wave (WI), the most constant, Pulsations in large intracranial arteries. • Tidal wave (W2), brain elastance. • Dicrotic wave (W3), dicrotic notch in the arterial.

  15. ICP is synonymous with CSF Pressure

  16. Atmospheric pressure • Hydrostatic pressure • Filling pressure

  17. As volume is added there are two principal routes for compensation

  18. Distention of the spinal dura mater • Displacement of CSF and blood

  19. ICP depends on the total volume inside the skull

  20. Intracranial Space: 1500-mL • 87%: the Brain • 9%: CSF (ventricles, cisterns, and subarachnoid space) • 4%: blood

  21. CSF • Compartmental • Extracellular space 164.5 mL

  22. CSF Production • Choroid plexuses • Ventricular ependyma

  23. Choroid Plexuses • Invaginations of the pia mater into the ventricular cavities Roofs of the third and fourth ventricles Walls of the lateral ventricles

  24. Energy-dependent secretion and reabsorption processes • 0.35 to 0.37 mL/min

  25. Higher sodium, chloride, and magnesium • Lower potassium, calcium, urea, and glucose • Similar osmolality

  26. Peak Production Rates Late evening Early morning

  27. CSF Drainage • Dural Venous System Even in CSF pressures of less than 5 mm Hg

  28. NPH • Ventricular enlargement • Absence of elevated ICP

  29. Gait disturbance • Dementia • Incontinence

  30. Lumbar Pressures: 6 to 24 cm H2O.

  31. Symptoms and Signs of ElevatedIntracranial Pressure • Depends greatly on the nature and anatomic location of the underlying pathologic condition • Headache, vomiting and papilledema.

  32. Cranial nerve palsies may arise as a result of pressure on brainstem nuclei (particularly abducens palsies)

  33. Papilledema • Reliable • Objective • Good specificity • Sensitivity: observer dependent

  34. Vital Sign Changes • Cushing response: Arterial Hypertensionand Bradycardia

  35. CPP = MAP - ICP

  36. Abnormal Respiration • Cheyne-Stokes: diencephalic region • Sustained hyperventilation: midbrain and upper pons • Slow respiration: Midpontine • Ataxic respirations: pontomedullary lesions • Rapid shallow breathing: upper medullary lesions

  37. Herniation Syndromes • Most serious complication of raised lCP

  38. Central Syndrome • Progressive dysfunction of structures in a rostral to caudal direction • 1st Diencephalic Structures: Change in behavior or even loss of consciousness, Cheyne-Stokes respiration • Pupils :small, with a poor reactivity • Contralateral hemiparesis • Pupils fall into a midline fixed position

  39. Uncal Syndrome • Unilaterally dilated and poorly reactive pupil • External oculomotor ophthalmoplegia • Ipsilateral hemiparesis: pressure on the contralateral cerebral peduncle on the edge of the tentorium cerebelli

More Related