Introduction: In a large series of surgically treated unruptured aneurysms, we encountered a subset of patients with clear evidence of hemosiderin deposition around the aneurysm indicating a previous bleed.
Methods: Medical records of 421 unruptured cerebral aneurysm patients treated surgically between January 2003 and September 2010 were retrospectively reviewed. Nine patients were excluded due to prior subarachnoid hemorrhage and craniotomy. Records were reviewed for intra-operative descriptions of hemosiderin or fresh subarachnoid clot around the aneurysm structures as well as history of headaches, time to presentation, co-morbidities, aneurysm characteristics, procedures, and radiologic imaging.
Results: Intra-operative hemosiderin deposition was identified in eight patients within a single surgeons’ experience during the study period. Each patient had a history of remote atypical headache more than six months prior to presentation. Five of these patients (62.5%) had aneurysms classified as thin-walled. Though it is difficult to discern a pattern due to small sample size, aneurysm location varied amongst patients with three aneurysms located in the ICA (37.5%), two in each the MCA (25.0%) and ACoA (25.0%) complex and one in the ACA (12.5%). Co-morbidities found in this group of patients included four patients with a history of smoking (50%), and two patients with hypertension (25.0%). Dyslipidemia, hypercholesterolemia, family history and alcohol abuse were each present in one patient (12.5%).
Conclusions: We suggest that this group of patients had suffered mild bleeding in the distant past resulting in local hemosiderin deposition next to the aneurysm. The origins and clinical implications of such microbleeds are unknown and warrant further investigation.
Patient Care: The presence of hemosiderin deposition in relation to an aneurysm structures may indicate the possibility of lesion growth and future rupture. Understanding the pathophysiology of such condition might be the difference between a true unruptured aneurysm, and a lesion possibly progressing into a warning leak or frank subarachnoid hemorrhage.
Learning Objectives: • Recognize microbleed as a subclinical form of subarachnoid hemorrhage
• Recognize sign and symptoms associated with this condition
• Indentify best imaging technique for possible diagnosis