Delayed diagnosis of intracranial aneurysms: confounding factors in clinical presentation and the influence of misdiagnosis on outcome.

The initial presentation of intracranial aneurysm can be missed in routine clinical practice. An underlying aneurysm may have a subtle presentation that warrants definitive diagnostic procedures. A retrospective review of 270 patients with aneurysms at our institution revealed 40 patients (14.8%) with a significant delay in diagnosis before definitive treatment. The delay due to missed diagnosis varied from 2 days to a few months. In retrospect, 58% had a Hunt and Hess grade I clinical presentation at readmission. Clinical status was rated as grade 0-I in the majority of patients (65%), grade II in 20%, and grade III in 12.5%. One patient had grade IV status. These grades are significantly different from the initial grade at which each of the patients first sought medical attention. The second admission significantly affected the outcome. A delay in diagnosis of aneurysmal subarachnoid hemorrhage resulting in poor clinical grade influenced neurologic outcome significantly.