- Department of Neurosurgery, School of Medicine and Biomedical Sciences, Buffalo, New York, USA
- Department of Radiology, School of Medicine and Biomedical Sciences, Buffalo, New York, USA
- Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, New York, USA
- Department of Neurosurgery, Gates Vascular Institute, Kaleida Health, Buffalo, New York, USA
Correspondence Address:
Adnan H. Siddiqui
Department of Neurosurgery, School of Medicine and Biomedical Sciences, Buffalo, New York, USA
Department of Radiology, School of Medicine and Biomedical Sciences, Buffalo, New York, USA
Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, New York, USA
Department of Neurosurgery, Gates Vascular Institute, Kaleida Health, Buffalo, New York, USA
DOI:10.4103/2152-7806.121109
Copyright: © 2013 Sorkin GC. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.How to cite this article: Sorkin GC, Jaleel N, Mokin M, Dumont TM, Eller JL, Siddiqui AH. Ruptured mycotic cerebral aneurysm development from pseudoocclusion due to septic embolism. Surg Neurol Int 08-Nov-2013;4:144
How to cite this URL: Sorkin GC, Jaleel N, Mokin M, Dumont TM, Eller JL, Siddiqui AH. Ruptured mycotic cerebral aneurysm development from pseudoocclusion due to septic embolism. Surg Neurol Int 08-Nov-2013;4:144. Available from: http://sni.wpengine.com/surgicalint_articles/ruptured-mycotic-cerebral-aneurysm-development-from-pseudoocclusion-due-to-septic-embolism/
Abstract
Background:Cerebral mycotic aneurysms are rare sequelae of systemic infections that can cause profound morbidity and mortality with rupture. Direct bacterial extension and vessel integrity compromise from septic emboli have been implicated as mechanisms for formation of these lesions. We report the 5-day development of a ruptured mycotic aneurysm arising from a septic embolism that caused a focal M1 pseudoocclusion.
Case Description:A 14-year-old girl developed acute left-sided hemiparesis while hospitalized for subacute bacterial endocarditis that was found after she presented with a 2-week history of fever, myalgia, shortness of breath, and lethargy. Mitral valve vegetations were confirmed in the setting of hemophilus bacteremia. Brain magnetic resonance (MR) imaging and angiography confirmed middle cerebral artery infarct with focal pseudoocclusion of the distal M1 segment. Given that further middle cerebral artery territory was at risk, a trial of heparin was attempted for revascularization but required discontinuation owing to hemorrhagic conversion. Decline of the patient's mental status necessitated craniectomy for decompression. Postoperatively, her mental status improved with residual left hemiparesis. On the third postoperative day (5 days after MR angiography), the patient's neurologic condition acutely declined, with development of right-sided mydriasis. Computed tomography (CT) angiography revealed a ruptured 19 × 16 mm pseudoaneurysm arising from the M1 site of the previous occlusion. Emergent coiling of aneurysm and parent vessel followed by hematoma evacuation ensued. At discharge, the patient had residual left hemiparesis but intact speech and cognition.
Conclusion:Focal occlusions due to septic emboli should be considered high-risk for mycotic aneurysm formation, prompting aggressive monitoring with neuroimaging and treatment when indicated.
Keywords: Cerebral aneurysm, infective endocarditis, mycotic aneurysm, septic emboli
INTRODUCTION
Cerebral mycotic aneurysms are rare sequelae of systemic infections that can cause profound morbidity and mortality with rupture. Direct bacterial extension and vessel integrity compromise from septic emboli have been implicated as mechanisms for formation of these lesions. We report the 5-day development of a ruptured mycotic aneurysm arising from a septic embolism that caused a focal M1 pseudoocclusion.
CASE REPORT
A 14-year-old girl with no major past medical history was sent to the emergency department for evaluation after her primary care doctor found a new heart murmur on physical examination in the setting of a 2-week history of fevers, myalgias, fatigue, and shortness of breath. She was admitted to the hospital for treatment of subacute endocarditis and was found to have blood cultures positive for nontypeable Hemophilus influenzae. Mitral valve vegetations were confirmed on transesophageal echocardiography. The patient's history was remarkable for a recent orthodontic appliance adjustment 1 month prior to admission.
Neurosurgical involvement began after the patient was found to have a right middle cerebral artery (MCA) territory infarct on computed tomographic (CT) imaging with symptoms starting 1 day earlier consisting of a left-sided hemiparesis and facial asymmetry. After removal of the patient's orthodontic appliance, magnetic resonance (MR) imaging and MR angiography of the brain confirmed completed infarction of approximately one-half of the right MCA territory due to a focal pseudoocclusion (high-grade stenosis causing near occlusion) in the distal M1 at the MCA bifurcation [ MR angiogram of the head reveals focal pseudoocclusion of the right M1 Diffusion-weighted magnetic resonance image (a) and noncontrast computed tomographic scan of the head (b) show completed infarct Noncontrast CT scan of head shows hemorrhagic conversion of right MCA territory infarct Noncontrast CT scan of head after decompressive craniectomy showing improvement of midline shift
On postoperative day 3 after the decompressive craniectomy, 5 days after original presentation and MR angiography documenting the M1 pseudoocclusion, the patient became acutely comatose with right-sided mydriasis. CT angiography of the head revealed a ruptured 19 × 16 mm mycotic aneurysm arising from the M1 occlusion site, associated with a large intracerebral hemorrhage and midline shift [Figures Noncontrast CT scan of head shows increased intracerebral hemorrhage with midline shift associated with the ruptured mycotic aneurysm CT angiogram of head, thin-cut axial image, reveals right M1 ruptured mycotic aneurysm CT angiogram of head, coronal reconstruction, reveals right M1 ruptured mycotic aneurysm CT angiogram of head, sagittal reconstruction, reveals right M1 ruptured mycotic aneurysm Cerebral angiogram – early arterial phase, anteroposterior (AP) internal carotid artery injection – reveals right M1 mycotic aneurysm with occlusion of distal branches Cerebral angiogram – mid-arterial phase; AP internal carotid artery injection – reveals right M1 mycotic aneurysm with occlusion of distal branches Cerebral angiogram – early arterial phase, AP internal carotid injection – reveals coiled M1 mycotic aneurysm and parent vessel Noncontrast CT scan of head status post hematoma evacuation showing improvement of mass effect
DISCUSSION
Mycotic aneurysms account for 1.2-5.4% of all known cerebral aneurysms.[
The majority of these pseudoaneurysms are formed after development of a septic embolism from infective endocarditis.[
These mechanisms of mycotic aneurysm pathogenesis are relevant to the patient described above. Her imaging studies demonstrated a focal septic embolism from which a mycotic aneurysm developed, and subsequently ruptured within 5 days. This implies a hostile local milieu that compromised vessel integrity as described by the mechanisms above. Furthermore, one must ask if there is predictive value in identifying focal occlusions as a risk factor for local mycotic aneurysm formation. Because the development of a mycotic aneurysm is such a rare occurrence, this question will be difficult to answer. We believe, given the profound morbidity and mortality associated with rupture of these lesions, focal occlusions due to septic emboli should be considered high risk for mycotic aneurysm formation, and as such, close surveillance and aggressive treatment are warranted.
ACKNOWLEDGMENTS
The authors thank Paul H. Dressel BFA for assistance with preparation of the illustrations and Debra J Zimmer for editorial assistance.
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