British Journal of Neurosurgery, April 2008; 22(2): 295 – 297 SHORT REPORT Br J Neurosurg Downloaded from informahealthcare.com by SUNY State University of New York at Stony Brook on 10/30/14 For personal use only. Post-traumatic pericallosal artery aneurysm presenting with subdural haematoma without subarachnoid haemorrhage S. SUHARA, A. S. H. WONG & J. O. L. WONG Department of Neurosurgery, Sarawak General Hospital, Kuching, Malaysia Abstract A 27-year-old patient presented with severe headache and seizures about a month after the initial head trauma. Computed tomography (CT) brain scan revealed acute subdural bleed continuous into the interhemispheric region, with no subarachnoid haemorrhage. This was due to rupture of a traumatic pericallosal artery aneurysm. This represents a rare case of traumatic pericallosal artery aneurysm presenting with subdural haematoma without subarachnoid haemorrhage. Key words: Subdural haematoma without subarachnoid bleed, traumatic pericallosal artery aneurysm. Introduction Traumatic intracranial aneurysms are rare, comprising less than 1% of all intracranial aneurysms. This can be caused by a closed or a penetrating head injury. We report on a case of a traumatic left-sided pericallosal artery aneurysm, which presented with an acute subdural haematoma (SDH) without subarachnoid haemorrhage. This was treated successfully with surgery. Case report A 27-year-old female was involved in a road traffic accident in early November 2002. She was a helmeted pillion rider on a motorcycle. She sustained loss of consciousness and fracture of the right leg (compound open fracture of right tibia, fibula and mid-shaft fracture of right femur).The day after, she was transferred to another hospital where a CT brain scan was done, which showed no abnormality. The fracture in her right leg was treated with fixation and she was discharged well 2 weeks later. One month later, on the 1st December 2002, she developed a sudden onset of severe headache, followed by generalized seizures. She was warded overnight for observation in the hospital and discharged the following day. Subsequently, she had another episode of severe headache followed by fits on the 8th December 2002. Glasgow Coma Scale (GCS) on admission was 8. The CT brain showed an acute right-sided subdural haemorrhage and a falcine bleed. (This is shown in Fig. 1). A right-sided fronto-temporoparietal craniectomy was done for evacuation of the bleed. Recovery was uneventful, she was discharged a week later with full GCS. She returned to her home state and a follow-up CT brain was done in March 2003, which showed a hyperdense lesion in the anterior interhemispheric region. This was performed in preparation for a cranioplasty. The absence of subdural haemorrhage on the initial admission, delayed intracranial haemorrhage 1 month after the accident and sudden onset of headache underscored a possible traumatic aneurysm. This suspicion was supported by the interhemispheric bleed in preoperative scan (performed on the 8th December 2002) and hyperdense lesion at the falx in the postoperative scan (March 2003). Cerebral angiogram showed a saccular aneurysm measuring about 7 mm in diameter arising from the proximal end of the pericallosal artery on the left side (shown in Fig. 2). Surgical clipping of the aneurysm was performed 5 days later. Intraoperatively, the aneurysm was thrombosed and stuck to the falx. Histological examination of the aneurysm showed absence of vessel wall components with fibrosis and organizing thrombus, indicating a pseudo-aneurysm (shown by the arrow in Fig. 3). Postoperative recovery was uneventful. She was discharged well with no neurological deficit. Correspondence: S. Suhara, Department of Neurosurgery, Sarawak General Hospital, Kuching, 93586, Malaysia. E-mail: ssuhara@yahoo.co.uk Received for publication 23 March 2007. Accepted 6 August 2007. ISSN 0268-8697 print/ISSN 1360-046X online Ó The Neurosurgical Foundation DOI: 10.1080/02688690701687678 Br J Neurosurg Downloaded from informahealthcare.com by SUNY State University of New York at Stony Brook on 10/30/14 For personal use only. 296 S. Suhara et al. FIG. 1. CT brain 1 month after the accident showed acute right sided subdural and falcine bleed. FIG. 2. Preoperative cerebral angiogram showing aneurysm arising from the proximal end of left pericallosal artery. Discussion Traumatic intracranial aneurysm was first reported in the early 19th century. It is associated with penetrating injury (27%), skull base and anterior cranial fossa fracture. Other causes are non-penetrating and iatrogenic injury. Non-penetrating trauma accounted for 62% of these and it usually involves the distal anterior cerebral artery.1 Traumatic aneurysm of the pericallosal artery arises when there is a shearing force between the inferior margin of the falx cerebri FIG. 3. Histology slide of the aneurysm wall showing fibrosis and thrombus (indicated by arrow). and the distal anterior cerebral artery. Traumatic intracranial aneurysm can be classified as occurring more than 4 weeks post-trauma (late onset) or within 4 weeks of trauma (early onset). It affects only a small percentage of trauma patients, which ruptures on an average of 3 weeks after the said head injury, resulting in sudden neurological deterioration. This is echoed by Ventureyra who cautioned a high index of suspicion in patients who develop delayed neurological deterioration.2 Our case ruptured 4 weeks after the initial trauma. In all patients with delayed neurological deficit and delayed haemorrhage after a head injury, traumatic intracranial aneurysm should be suspected. This can be a minor head injury. The diagnosis is often not picked up on the initial CT scan because the lesion is obscured by other more obvious intracranial injury, such as brain contusion, in this case the subdural bleed. This patient had at least two ruptures indicated by the two episodes of sudden severe headaches. Delayed diagnosis leads to increased morbidity and mortality, especially if a rupture has occurred. Magnetic resonance angiogram/imaging (MRA/MRI) and angiogram remain valuable diagnostic techniques in suspected cases of traumatic intracranial aneurysm. The management after diagnosis is aimed at preventing further rupture. Treatment options include surgical clipping or endovascular coiling. Pure acute SDH can be seen as a result of rupture of spontaneous distal anterior distal artery (ACA) aneurysm. The characteristic CT brain appearance is that of a convexity SDH continuous with a wedgeshaped interhemispheric SDH, with no subarachnoid bleed seen. However, pure subdural haemorrhage without subarachnoid haemorrhage from a traumatic Br J Neurosurg Downloaded from informahealthcare.com by SUNY State University of New York at Stony Brook on 10/30/14 For personal use only. Post-traumatic pericallosal aneurysm pericallosal aneurysm is rarely reported. To our knowledge, to date, only two articles reported on six cases of pure acute subdural haemorrhage from a pericallosal/distal ACA aneurysmal rupture.3,4 This report highlights the need for a high index of suspicion of traumatic aneurysmal rupture when there is delayed neurological deterioration posttrauma. It also stresses on the importance of detailed history taking, of reviewing scans in detail, and not to dismiss any headache lightly, especially one without an obvious cause. The interval between the injury and the diagnosis of traumatic aneurysm in this case is longer than reported. A CT brain done 4 months after the accident revealed the falcine calcification, which supports that the aneurysmal sac was formed after the trauma. The angiogram supported the diagnosis subsequently and the histology findings confirmed the diagnosis. It is imperative to pay attention to detail in taking history. In the acute phase, the angiographic findings may be normal initially and a repeat study is necessary, so as not to miss out on this entity. 297 Conclusion This is a rare case of a traumatic pericallosal aneurysm that presented with acute subdural haematoma without subarachnoid haemorrhage. Traumatic subdural haematoma should not be confused with a traumatic aneurysm haemorrhage leading to subdural haematoma particularly in the falcine location. References 1 Martin EM, Hummelgard AB. Traumatic aneurysm. J Neurosci Nurs 1986;18(2):89 – 94. 2 Ventureyra EC, Higgins MJ. Traumatic ICA in childhood and adolescence, case reports and review of literature. Childs Nerv Syst 1994;10:361 – 79. 3 Yokota H, Tazaki T, Murayama K. Traumatic cerebral aneurysm: 94 cases from the literature and 5 cases observed by the authors. No Shiaki Geka (Tokyo) 1983;11:521 – 9. 4 Katsuno M, Murai Y, Teramoto A. Acute subdural hematoma without subarachnoid hemorrhage following rupture of a distal anterior cerebral artery aneurysm: a case report. No To Shinkei 2003;55:435 – 8.