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Hydrocephalus is a topic covered in the 5-Minute Emergency Consult.

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  • Increased volume of CSF in cranial cavity
  • Cerebral atrophy also leads to increased CSF in the cranial vault but CSF pressure is not increased
  • Obstructive hydrocephalus is the most common form:
    • Obstruction is within ventricular system or in subarachnoid space
  • Acute obstructive hydrocephalus may cause rapid rise in intracranial pressure (ICP), rapidly leading to death or permanent cerebral damage
  • Nonobstructive hydrocephalus causes subacute symptoms and is a potentially treatable form of dementia
  • Also described as “communicating” and “noncommunicating”:
    • Communicating hydrocephalus: Flow of CSF is blocked after it exits the ventricles (ventricles still “communicate”)
    • Noncommunicating hydrocephalus: Flow of CSF blocked along 1 or more of the passages connecting the ventricles (ventricles do not “communicate”)


  • Obstructive hydrocephalus:
    • Obstruction of:
      • Aqueduct of Sylvius (most common, both lateral ventricles and 3rd ventricle dilated, 4th ventricle is spared)
    • Aqueductal stenosis can be congenital or acquired (tumor, subarachnoid hemorrhage, post meningitis, idiopathic)
      • Foramen of Monro (lateral ventricles dilated, usually both but may be unilateral)
      • Foramina of Luschka and Magendie (4th ventricle blocked followed by 3rd and lateral ventricles)
      • Subarachnoid space around brainstem (postinfectious or postsubarachnoid hemorrhage [post-SAH] entire system dilated)
    • Acute presentations usually secondary to CSF shunt blockage, SAH, or severe head trauma
  • Nonobstructive hydrocephalus:
    • Normal pressure hydrocephalus:
      • Increased intracranial volume of CSF without intracranial hypertension
      • Increased ventricular size on CT (without volume loss as in atrophy)
      • Sometimes called “chronic hydrocephalus”
      • Usually occurs due to inadequate CNS absorption
  • Pediatric hydrocephalus:
    • Congenital hydrocephalus owing to neonatal hemorrhage, congenital malformations, or acquired post meningitis secondary to subarachnoid scarring around brainstem

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Rosen, Peter, et al., editors. "Hydrocephalus." 5-Minute Emergency Consult, 5th ed., Lippincott Williams & Wilkins, 2016. Emergency Central, emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307018/all/Hydrocephalus.
Hydrocephalus. In: Rosen P, Shayne P, Barkin AZ, et al, eds. 5-Minute Emergency Consult. 5th ed. Lippincott Williams & Wilkins; 2016. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307018/all/Hydrocephalus. Accessed April 24, 2019.
Hydrocephalus. (2016). In Rosen, P., Shayne, P., Barkin, A. Z., Wolfe, R. E., Hayden, S. R., Barkin, R. M., & Schaider, J. J. (Eds.), 5-Minute Emergency Consult. Available from https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307018/all/Hydrocephalus
Hydrocephalus [Internet]. In: Rosen P, Shayne P, Barkin AZ, Wolfe RE, Hayden SR, Barkin RM, Schaider JJ, editors. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2016. [cited 2019 April 24]. Available from: https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307018/all/Hydrocephalus.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Hydrocephalus ID - 307018 ED - Rosen,Peter, ED - Shayne,Philip, ED - Barkin,Adam Z, ED - Wolfe,Richard E, ED - Hayden,Stephen R, ED - Barkin,Roger M, ED - Schaider,Jeffrey J, BT - 5-Minute Emergency Consult UR - https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307018/all/Hydrocephalus PB - Lippincott Williams & Wilkins ET - 5 DB - Emergency Central DP - Unbound Medicine ER -