Clinical Images - A Quarterly Column: Actively Rupturing Intracranial Aneurysm

DISCUSSION

Our case is unusual because this patient's aneurysm was imaged during the time of active hemorrhage. This phenomenon is rarely seen during CT angiography and is associated with poor prognosis, with an estimated mortality of 80%.¹ The active hemorrhage in this patient was consistent with rebleeding in the ED and ultimately led to her death. Standard practice at Ochsner, as at other institutions, involves CTA of the brain immediately after the initial noncontrast CT to help choose the method of treatment and guide the need for general anesthesia prior to conventional angiography.²

If a patient survives the initial hemorrhage from a ruptured aneurysm, active bleeding has typically subsided well before the patient reaches the hospital. If a patient has continuous intracranial arterial bleeding for longer time periods, the resulting increased intracranial pressure will likely lead to brain death. An estimated 12%-15% of patients with aneurysm hemorrhage expire before reaching the hospital.³

In patients who survive the initial bleed, an estimated 50% of their aneurysms will rerupture within 6 months.⁴ Hyperacute rehemorrhage (within 6 hours) is estimated to occur in 49% of patients with rerupture, and the mortality rate for this group is approximately 60%.⁵ Factors associated with aneurysm rerupture include longer time to treatment, worse neurological status on admission, initial loss of consciousness, previous sentinel headache, larger aneurysms, and systolic blood pressure >160 mmHg.² Rebleeding within the first 48 hours is the most common cause of death in patients with aneurysms who reach the hospital alive.⁶ Current evidence suggests early treatment can reduce the risk of rebleeding.⁶ Consequently, ruptured aneurysms should be treated within 48 hours of presentation via either endovascular or surgical techniques if possible.²

The treatment of unruptured, asymptomatic aneurysms is controversial. The estimated rate of rupture for aneurysms must be weighed against the likelihood of rupture during the patient's lifetime, knowing that all aneurysms are not the same and each carries an individual risk. Risk factors for aneurysm rupture include size, geometry, location, and patient history of hypertension, smoking, and family medical history.⁷ Currently, studies investigating computational flow dynamics using hemodynamic parameters such as wall shear stress (WSS), WSS gradient, inflow jet, impingement zone, and aneurysm inflow-angle are ongoing in an attempt to improve predictive models of aneurysm rupture risk.⁸ Such research may eventually help stratify which unruptured aneurysms should be treated.