CSF physiology, the blood-brain barrier and intracranial pressure
How CSF is made, circulates and is absorbed, what the blood-brain barrier lets through and where it is absent, the Monro-Kellie doctrine and compliance curve, cerebral perfusion pressure, the types of cerebral oedema, and how these explain raised ICP, hydrocephalus, IIH, osmotherapy, osmotic demyelination and drug entry into the brain.
Tier 2Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- CSF is secreted mainly by the choroid plexus at about 500 mL/day and absorbed through arachnoid granulations into the dural venous sinuses.
- The blood-brain barrier is endothelial tight junctions plus efflux pumps. Small lipid-soluble molecules cross; polar ones need transporters.
- The skull is a fixed box (Monro-Kellie). Once compensation runs out, small volume increases raise ICP steeply.
Loading the rest of the note…
Finished reading?
Sources
- Robertson CS, Valadka AB, Hannay HJ et al. Prevention of secondary ischemic insults after severe head injury. Crit Care Med 1999;27:2086-95Critical Care Medicine, 1999
- Hawryluk GWJ, Aguilera S, Buki A et al. A management algorithm for patients with intracranial pressure monitoring: the Seattle International Severe Traumatic Brain Injury Consensus Conference (SIBICC). Intensive Care Med 2019;45:1783-94Intensive Care Medicine, 2019
- Principles of Neural Science (6th ed.)McGraw Hill (Kandel, Koester, Mack and Siegelbaum, 2021), 2021
- Carney N et al. Guidelines for the Management of Severe Traumatic Brain Injury, Fourth Edition. Neurosurgery 2017;80:6-15Brain Trauma Foundation, 2017
- Guyton and Hall Textbook of Medical Physiology (14th ed.)Elsevier (Hall and Hall, 2021), 2021
- Friedman DI, Liu GT, Digre KB. Revised diagnostic criteria for the pseudotumor cerebri syndrome in adults and children. Neurology 2013;81:1159-65Neurology, 2013
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Turnstile bot check on sign-in and signed-out feedback