PMC9610571_01
Preoperative computed tomography (CT) scan of the brain. (a) Cerebral infarction was noted at bilateral anterior cerebral artery (ACA) territory which is more prominent on the right side (arrowheads). (b) Small intracerebral hemorrhage was noted in the right frontal region (arrowheads). CT angiography (CTA) (c) showing distal A2 segment aneurysm (white arrow). (d) Three-dimensional CTA showing left distal A2 segment aneurysm (white arrow). (e) Repeated CT scan of the brain showing expanded hematoma at the bilateral frontal region with intraventricular hemorrhage.
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F1
Brain computed tomography (CT) showed cerebral infarction in bilateral anterior cerebral artery (ACA) territory, which is more prominent on the right side, and intracerebral hemorrhage in the right frontal region without evidence of subarachnoid hemorrhage [Figures 1a and b]. CT angiography was performed on the same day to investigate the cause of the stroke, which showed an abnormal outpouching lesion at the left distal A2 segment of ACA [Figures 1c and d]. CT brain. CT brain showed expanded hematoma at the right frontal lobe with intraventricular hemorrhage, and left ACA territory infarction was more apparent [Figure 1e].
Intraoperative findings. (a) Pus and infected slough were noted along the bilateral frontal cortex, which is prominent on the right side (arrowheads). (b) Pus was identified in the right subdural space consistent with subdural empyema (arrow). After interhemispheric dissection, (c) thrombosis the in left distal ACA was noted at A2 to A3 segment (white arrowheads). (d) The left ACA was whitish in color and covered with slough (black arrowheads) in contrast to the right ACA (asterisk). (e) Flow was not detected in left distal ACA using intraoperative micro-Doppler ultrasound since it was thrombosed. (f) Aneurysm was identified at the left A2 segment (asterisk) with pus along proximal ACA wall (arrow). (g) Clips were applied at both proximal and distal to the aneurysm in an attempt to trap the aneurysm. (h) Pus was also noted in the left subdural space and Sylvian cistern (arrow).
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F2
Before interhemispheric dissection, the pus was noticed in the right side subdural space [Figures 2a and b] and collected for culture study. No flow was detected by intraoperative Doppler ultrasound, which led to the diagnosis of the left ACA thrombosis secondary to severe infection [Figures 2c-e]. The microsurgical dissection was continued until the aneurysm neck and proximal ACA were encountered [Figure 2f]. Therefore, the decision to perform an aneurysm trapping was made by the application of clips at both proximal and distal to the aneurysm [Figure 2g]. We also observed the pus in the left Sylvian cistern [Figure 2h].
Microscopic findings from brain pus and thrombus in an. (a) Gram stain showing Gram-positive branching filament with prominent polymorphonuclear leukocytes in the background (x1000). (b) Modified acid-fast staining of the same specimen showing a positive result (x1000). Macroscopic growth of the Nocardia from brain pus and thrombus in an aneurysm. (c) Chalky white colonies were identified in the Lowenstein-Jensen medium. (d) Colonies' growth was evident in chocolate media after 3 days.
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F3
The Gram stain and modified acid-fast stain of subdural pus and thrombus in an aneurysm also showed Gram positive with branching filament, which put suspicion on the Nocardia spp. [Figures 3a and b]. The aerobic bacterial cultures from pus, thrombus, and aneurysm wall grew chalky white colonies on chocolate media (Oxoid Limited, France), and macroscopic growth on the Lowenstein-Jensen medium was also noted [Figures 3c and d].
Postoperative CT scan of the brain. (a) New infarction was evident at the right internal capsule and right thalamus, including the left thalamus (arrowheads). (b) Infarction was also noted at the right midbrain (white arrow). (c) Sagittal view showing the applied clips at proximal and distal to an aneurysm (arrow).
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F4
The postoperative CT brain showed multiple infarctions at bilateral subcortical white matter and internal capsule, including the brainstem, which corresponded to an invasion of the bilateral internal carotid artery and basilar artery [Figures 4a-c].