Introduction: The percentage of patients with an aneurysmal subarachnoid hemorrhage (SAH) misdiagnosed at initial medical presentation, the reasons for misdiagnosis, and clinical outcome as a result of this misdiagnosis is unknown.
Methods: We reviewed medical records of consecutive patients managed by our institution in the recent five years. Clinical symptoms and hospital course and reasons for misdiagnosis were analyzed.
Results: From January 2006 to December 2010, 598 patients were treated due to an aneurysmal SAH in our institution. Thirty one patients (31/598, 5.2%) were misdiagnosed at initial medical contact. Among patients who were misdiagnosed, no appropriate diagnostic imaging test (computed tomography (CT) scan) was performed in 23 patients (23/31, 74.2%) at initial medical contact. Image interpretation errors occurred in six patients (6/31, 19.4%). When a diagnostic image showed a clinically suspected negative finding, no further examination (lumbar puncture, further MR image etc.) was performed in two patients (2/31, 6.5%). Misdiagnosis of 26 patients (26/31, 83.9%) occurred in non-teaching hospitals and five patients (5/31, 16.1%) received a misdiagnosis in teaching hospitals. Clinical deterioration occurred in 14 patients (14/31, 45.2%). Four patients (4/31, 12.9%) suffered fatal rebleeding and ten patients (10/31, 32.3%) showed neurological deterioration (Hunt-Hess grade=3) before receiving a correct diagnosis and definitive management.
Conclusions: In this study, misdiagnosis of an aneurysmal SAH occurred in 5.2% (31/598) of patients. An unfavorable outcome (Glasgow outcome scale, 1 to 3) occurred in 29.0% (9/31) of patients. More detailed examination and a low threshold for diagnostic imaging tests, such as CT scan of patients with mild symptoms suggestive of aneurysmal SAH may reduce the frequency of misdiagnosis.
Learning Objectives: Knowing the cause of misdiagnosis of aneurysmal SAH is essential factor for reduce the misdiagnosis and improving the clinical outcome.