Zebra sign
Zebra sign refers to a pattern, comparable to zebra skin, of hyperdensity indicative of blood and hypodensity indicative of normal cerebellar parenchyma in a curvilinear, stripe-like fashion along the cerebellar folia.
Hemorrhage is often characterized by a typical, streaky bleeding pattern due to blood spreading in the cerebellar sulci. Three different cases featuring this bleeding pattern following spinal, supratentorial, and thoracic surgery are presented. Possible pathomechanisms leading to RCH are discussed. Based on data from the underlying cases and the reviewed literature, the authors concluded that this zebra-pattern hemorrhage seems to be typical in a postoperative loss of CSF, which should always be considered on presentation of this bleeding pattern 1).
Zebra sign was found in 64% of cases in a systematic review of RCH after supratentorial procedures 2)
2: Taieb MAH, Maamri K, Trifa A, Elkahla G, Hadhri MM, Darmoul M. Remote cerebellar hemorrhage after the evacuation of a subdural hematoma: a case report. Pan Afr Med J. 2022 Jan 11;41:24. doi: 10.11604/pamj.2022.41.24.32799. PMID: 35291356; PMCID: PMC8895559.
3: Kumar S, Kale HA. Remote cerebellar haemorrhage: A case report. Indian J Radiol Imaging. 2020 Oct-Dec;30(4):521-523. doi: 10.4103/ijri.IJRI_123_20. Epub 2021 Jan 13. PMID: 33737786; PMCID: PMC7954161.
4: Lee IH, Choi JΙ. Remote cerebellar hemorrhage following surgical clipping of an unruptured cerebral aneurysm of the middle cerebral artery. J Cerebrovasc Endovasc Neurosurg. 2021 Mar;23(1):49-53. doi: 10.7461/jcen.2020.E2020.08.006. Epub 2020 Oct 14. PMID: 33050685; PMCID: PMC8041513.
5: Lim CHS, Salkade PR, Peter AC. Remote cerebellar hemorrhage as a complication of lumbar spine surgery. J Radiol Case Rep. 2020 Feb 29;14(2):1-11. doi: 10.3941/jrcr.v14i2.3844. PMID: 32184932; PMCID: PMC7060016.
6: Omer A, Engelman E, Bath K, Krauthamer AV, Pisinski L. Remote cerebellar hemorrhage: A case report. Radiol Case Rep. 2019 Jan 3;14(3):385-389. doi: 10.1016/j.radcr.2018.12.006. PMID: 30766645; PMCID: PMC6360913.
8: Sturiale CL, Rossetto M, Ermani M, Baro V, Volpin F, Milanese L, Denaro L, d'Avella D. Remote cerebellar hemorrhage after spinal procedures (part 2): a systematic review. Neurosurg Rev. 2016 Jul;39(3):369-76. doi: 10.1007/s10143-015-0673-8. Epub 2015 Dec 2. PMID: 26627110.
9: Nagendran A, Patel B, Khan U. The zebra sign: an unknown known. Pract Neurol. 2016 Feb;16(1):48-9. doi: 10.1136/practneurol-2015-001180. Epub 2015 Aug 13. Erratum in: Pract Neurol. 2016 Apr;16(2):165. PMID: 26271264.
10: Moser M, Hildebrandt G. Remote Cerebellar Hemorrhage after Supratentorial Burr-Hole Trepanation for Unilateral Chronic Subdural Hematoma: Case Report. NMC Case Rep J. 2015 Jun 26;2(3):114-117. doi: 10.2176/nmccrj.2014-0377. PMID: 28663979; PMCID: PMC5364896.
11: Dincer A, Özcan Ü, Kaya D, Usseli MI, Erzen C, Pamir MN. Asymptomatic remote cerebellar hemorrhage: CT and MRI findings. Cerebellum. 2012 Dec;11(4):880-6. doi: 10.1007/s12311-011-0351-5. PMID: 22249914.
12: Kobayashi S, Mutoh T, Ishikawa T, Moroi J, Tamagawa N, Yoshioka S, Hikichi K, Suzuki A. [Remote cerebellar hemorrhage after single burr hole drainage of chronic subdural hematoma of the elderly]. No Shinkei Geka. 2011 Aug;39(8):755-61. Japanese. PMID: 21799225.
13: Figueiredo EG, de Amorim RL, Teixeira MJ. Remote cerebellar hemorrhage (zebra sign) in vascular neurosurgery: pathophysiological insights. Neurol Med Chir (Tokyo). 2009 Jun;49(6):229-33; discussion 233-4. doi: 10.2176/nmc.49.229. PMID: 19556730.