Enlarged Optic Nerve Sheath in Aneurysmal Subarachnoid Hemorrhage despite Normal Intracranial Pressure.
BACKGROUND
This study investigates the diagnostic value of optic nerve sheath diameter (ONSD) assessed by transorbital sonography for estimation of intracranial pressure (ICP) in patients with aneurysmal subarachnoid hemorrhage (SAH).


METHODS
Simultaneous measurements of the ONSD and ICP in 27 patients suffering from SAH and acute hydrocephalus after placement of an extraventricular drain.


RESULTS
Despite normal mean ICP values ONSD was significantly higher in patients with SAH compared with healthy volunteers and no relevant decline of ONSD over time could be identified. In addition, no correlation between ONSD and ICP was observed.


CONCLUSIONS
In patients with SAH and acute hydrocephalus after aneurysm rupture, the ONSD remains expanded after normalization of ICP. This is most likely due to an impaired retraction capability of the optic nerve sheath. This finding should be considered when using transorbital sonography in the neuromonitoring of aneurysmal SAH.
Department of Neurology, University Medical Center Freiburg, Germany.
Jochen
J
Bäuerle
Department of Neurology, University Medical Center Freiburg, Germany.
Wolf-Dirk
WD
Niesen
Department of Neuroradiology, University Medical Center Freiburg, Germany.
Karl
K
Egger
Department of Neurosurgery, University Medical Center Freiburg, Germany.
Klaus-Jürgen
KJ
Buttler
Department of Neurology, University Medical Center Freiburg, Germany.
Matthias
M
Reinhard
D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D007427:Intracranial Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009900:Optic Nerve / Q000000981:diagnostic imaging* / Q000473:pathology; D009929:Organ Size / Q000502:physiology; D011446:Prospective Studies; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D014463:Ultrasonography
Aneurysmal SAH; optic nerve sheath diameter; raised intracranial pressure; transorbital sonography