Olfactory hallucinations caused by an unruptured posterior communicating artery aneurysm improved by clipping: A case report with literature review
- Department of Neurosurgery, Japanese Red Cross Kumamoto Hospital, Kumamoto City, Japan
- Department of Neurosurgery, Kumamoto University Hospital, Kumamoto City, Japan.
Shimpei Tsuboki, Department of Neurosurgery, Japanese Red Cross Kumamoto Hospital, Kumamoto City, Japan.
DOI:10.25259/SNI_173_2023Copyright: © 2023 Surgical Neurology International This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, transform, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
How to cite this article: Shimpei Tsuboki1, Tatemi Todaka1, Shu Hasegawa1, Yasuyuki Kaku2, Yuki Ohmori2, Akitake Mukasa2. Olfactory hallucinations caused by an unruptured posterior communicating artery aneurysm improved by clipping: A case report with literature review. 28-Apr-2023;14:152
How to cite this URL: Shimpei Tsuboki1, Tatemi Todaka1, Shu Hasegawa1, Yasuyuki Kaku2, Yuki Ohmori2, Akitake Mukasa2. Olfactory hallucinations caused by an unruptured posterior communicating artery aneurysm improved by clipping: A case report with literature review. 28-Apr-2023;14:152. Available from: https://surgicalneurologyint.com/?post_type=surgicalint_articles&p=12299
Background: Unruptured cerebral aneurysms that lead to epilepsy are rare and olfactory hallucinations caused by such an aneurysm are extremely rare. Various treatments have been proposed, including wrapping, clipping with or without cortical resection, and coil embolization, but there is no consensus on the best approach.
Case Description: We present a case of a 69-year-old female who experienced olfactory hallucinations caused by a posterior communicating artery aneurysm and was treated with clipping without cortical resection, with a positive outcome.
Conclusion: According to our knowledge, there has been only one report of a posterior communicating artery aneurysm presenting with olfactory hallucinations has been reported, where clipping and cortical resection were performed. This is the first report of a posterior communicating artery aneurysm with olfactory hallucinations that was effectively treated with clipping alone. There have been a few similar reports of large middle cerebral artery aneurysms, most of which are believed to be caused by entorhinal cortex compression. Although a definitive treatment protocol for this condition remains elusive, we suggest that elimination of the pulsatile compressive stress exerted on the cerebral cortex through surgical clipping or coil embolization is crucial for achieving efficacious seizure management.
Keywords: Clipping, Epilepsy, IC PC aneurysm, Olfactory hallucination, Unraptured aneurysm
Olfactory hallucinations is a symptom of medial temporal lobe epilepsy and is mainly seen in brain tumors of the temporal lobe and hippocampal sclerosis, but is very rare when caused by a unruptured cerebral aneurysm. It is believed that are associated with entorhinal cortex, amygdala, rostral insula, and even with olfactory bulb.[
History and imaging
A 69-year-old female patient with no significant prior medical history presented at a local clinic complaining of a persistent olfactory disturbance, characterized as a smell resembling burnt dust, which had persisted for 1 month before her visit. A magnetic resonance imaging (MRI) scan revealed the presence of an aneurysm at the bifurcation of the right internal carotid artery (ICA) and posterior communicating artery. Subsequently, the patient was referred to our clinic for further management. The MRI scan revealed a substantial aneurysm at the bifurcation of the right posterior communicating artery, and the aneurysm was situated within the amygdala, showing high intensity on the fluid attenuated inversion recovery image in the cerebral parenchyma surrounding the aneurysm [
(a) The preoperative state fluid attenuated inversion recovery image in magnetic resonance imaging detected a substantial aneurysm located in the right posterior communicating artery, displaying high intensity in the brain parenchyma surrounding the aneurysm (arrow). (b) The fluid attenuated inversion recovery image of the magnetic resonance imaging scan taken 1 year postsurgery showed resolution of aneurysm-induced pressure drainage at the medial temporal lobe, and the high intensity surrounding the aneurysm had also disappeared.
Surgery and outcome
Under general anesthesia, the ICA was exposed at the level of the neck. A frontotemporal craniotomy was then performed, and the aneurysm was visualized utilizing a trans-sylvian approach. Because the aneurysm was large, neck clipping of the aneurysm was carried out without viewing the entire aneurysm following temporary occlusion of the cervical segment of the ICA [
Intraoperative findings of surgical clipping (a) We attained access to the aneurysm (asterisk) with trans-sylvian approach. The aneurysm was found to be in proximity to the temporal lobe (black arrowheads). The black and white arrows indicate the proximal and distal neck of the aneurysm, respectively. (b) Following temporary occlusion of the cervical segment of the internal carotid artery (ICA), neck clipping of the aneurysm was performed with a straight clip. The posterior communicating artery (white arrowheads) was confirmed between the optic nerve and the ICA and preserved.
The previous reports have described Olfactory hallucinations are rarely seen, with a reported prevalence of 0.9–16% in particular epileptic patient groups and have been shown to be associated with entorhinal cortex, amygdala, rostral insula, and even with olfactory bulb.[
In this study, we present a case of an unruptured posterior communicating artery aneurysm that was accompanied by olfactory hallucinations and was effectively treated through surgical clipping. Although a definitive treatment protocol for this condition remains elusive, we posit that elimination of the pulsatile compressive stress exerted on cerebral cortex through surgical clipping or coil embolization is critical for attaining efficacious seizure management.
The authors certify that they have obtained all appropriate patient consent.
There are no conflicts of interest.
The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Journal or its management. The information contained in this article should not be considered to be medical advice; patients should consult their own physicians for advice as to their specific medical needs.
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