Q J Med 2014; 107:855–856 doi:10.1093/qjmed/hcu061 Advance Access Publication 19 March 2014
Clinical picture Isolated third cranial nerve palsy from non-aneurysmal internal carotid artery compression has been reported in literature only once by a posterior-communicating artery compression. In our case, there was an anomalous S-shaped artery but no evidence of aneurysm and in addition a complete occlusion of the contralateral ICA which along with the hypertension caused a hyperdynamic circulation through the left ICA acting as a possible contributing factors for the nerve compression. Our patient was not a candidate for any endovascular procedure or surgery due to her renal impairment and was managed with secondary prevention. This case of CN3 palsy and pupillary involvement is highly suggestive of external compression to the nerve and this is because the pupillary fibers occupy the peripheral of the nerve. On the other hand, ischemia is less likely to cause pupillary involvement due to the rich vascularization of the pupillary fibers. So patients with vascular risk factors such as diabetics are more likely to have sparing of the pupil when they present with oculomotor palsy.
Figure 1. (a) MRA showing absence of the right ICA (white arrow) and branches of right external CA (black arrow). (b) MRA showing a tortuous S-shaped ICA within the left cavernous sinus.
! The Author 2014. Published by Oxford University Press on behalf of the Association of Physicians. All rights reserved. For Permissions, please email: [email protected]
Downloaded from by guest on November 14, 2015
An 86 year-old-female, presented with a 6-day history of sudden onset of left-sided retro-orbital pain, ptosis and diplopia. On examination, her blood pressure was 190/90 and had a normal heart rate and temperature. Neurological examination revealed only complete left side oculomotor nerve—CN3 palsy with complete ptosis, mydriasis and with the eye looking down and out and unable to adduct the orbit. The pupillary reaction was sluggish. Her medical history included hypertension and chronic kidney failure but was not on dialysis. Initial non-contrast CT was done to rule out intracranial bleeding and that was normal as was her lumbar puncture. Her MRI was normal but MRA (Figure 1a and b) revealed a complete occlusion of the right internal carotid artery (ICA) and a tortuous atheromatous S-shaped left ICA within the cavernous sinus, which was the cause of the nerve compression. There were no aneurysms. Compression of CN3 from a non-aneurysmal arterial compression
856
Clinical picture
Clinicians should be aware that CN3 palsy with pupillary involvement is due to external pressure to the nerve until proven otherwise and that it warrants urgent investigation with Magnetic Resonance Angiography scan-MRA and Magnetic Resonance Imaging scan-MRI to rule out an aneurysm as this can be one stage prior to rupture.1 Photographs and text from: Department of Emergency Middlesex University Hospital, UK; D. Bell, Department of
G.A. Demetriou, Medicine, North London N18 1QX, Radiology, North
Middlesex University Hospital, London N18 1QX, UK. email: [email protected] Conflict of interest: None declared.
Reference 1. American Academy of Ophthalmology. Basic and Clinical Science Course: Neuro-Ophthalmology. The Academy, 2002–2003, 238–45. http://www.aao.org (1 March 2014, date last accessed).
Downloaded from by guest on November 14, 2015
Clinical picture Isolated third cranial nerve palsy from non-aneurysmal internal carotid artery compression has been reported in literature only once by a posterior-communicating artery compression. In our case, there was an anomalous S-shaped artery but no evidence of aneurysm and in addition a complete occlusion of the contralateral ICA which along with the hypertension caused a hyperdynamic circulation through the left ICA acting as a possible contributing factors for the nerve compression. Our patient was not a candidate for any endovascular procedure or surgery due to her renal impairment and was managed with secondary prevention. This case of CN3 palsy and pupillary involvement is highly suggestive of external compression to the nerve and this is because the pupillary fibers occupy the peripheral of the nerve. On the other hand, ischemia is less likely to cause pupillary involvement due to the rich vascularization of the pupillary fibers. So patients with vascular risk factors such as diabetics are more likely to have sparing of the pupil when they present with oculomotor palsy.
Figure 1. (a) MRA showing absence of the right ICA (white arrow) and branches of right external CA (black arrow). (b) MRA showing a tortuous S-shaped ICA within the left cavernous sinus.
! The Author 2014. Published by Oxford University Press on behalf of the Association of Physicians. All rights reserved. For Permissions, please email: [email protected]
Downloaded from by guest on November 14, 2015
An 86 year-old-female, presented with a 6-day history of sudden onset of left-sided retro-orbital pain, ptosis and diplopia. On examination, her blood pressure was 190/90 and had a normal heart rate and temperature. Neurological examination revealed only complete left side oculomotor nerve—CN3 palsy with complete ptosis, mydriasis and with the eye looking down and out and unable to adduct the orbit. The pupillary reaction was sluggish. Her medical history included hypertension and chronic kidney failure but was not on dialysis. Initial non-contrast CT was done to rule out intracranial bleeding and that was normal as was her lumbar puncture. Her MRI was normal but MRA (Figure 1a and b) revealed a complete occlusion of the right internal carotid artery (ICA) and a tortuous atheromatous S-shaped left ICA within the cavernous sinus, which was the cause of the nerve compression. There were no aneurysms. Compression of CN3 from a non-aneurysmal arterial compression
856
Clinical picture
Clinicians should be aware that CN3 palsy with pupillary involvement is due to external pressure to the nerve until proven otherwise and that it warrants urgent investigation with Magnetic Resonance Angiography scan-MRA and Magnetic Resonance Imaging scan-MRI to rule out an aneurysm as this can be one stage prior to rupture.1 Photographs and text from: Department of Emergency Middlesex University Hospital, UK; D. Bell, Department of
G.A. Demetriou, Medicine, North London N18 1QX, Radiology, North
Middlesex University Hospital, London N18 1QX, UK. email: [email protected] Conflict of interest: None declared.
Reference 1. American Academy of Ophthalmology. Basic and Clinical Science Course: Neuro-Ophthalmology. The Academy, 2002–2003, 238–45. http://www.aao.org (1 March 2014, date last accessed).
Downloaded from by guest on November 14, 2015
