Ruptured abdominal aortic aneurysms: clinical presentation in Auckland 1993-1997

Rupture of an abdominal aortic aneurysm (RAAA) carries a reported mortality rate in the range of 32-95%. Survival requires prompt diagnosis and surgical management. The presenting features, however, are varied, often insidious and potentially misleading with Osler noting nearly 100 years ago that a correct premortem diagnosis was achieved in only 33% of cases. The present study aims to review our present accuracy in diagnosing this condition and outline demographic and presenting features of patients with RAAA.

A review was undertaken of hospital and Coroner's files of all patients residing in the Auckland Coronial region who had RAAA between 1 January 1993 and 31 December 1997.

Three hundred and twenty-nine cases of RAAA were identified, and they occurred most commonly in the 8th decade. The male:female ratio was 3:1 and at least 73% of patients were Caucasian. The overall mortality was 71%. Nearly half underwent surgery and the hospital averaged mortality rate was 46%. No patient survived without surgery. Classic presenting features of RAAA were absent in many cases. Abdominal pain, back pain and a palpable mass occurred in only 49%, 36% and 18% of patients, respectively. Other common presenting symptoms included vomiting, general malaise and pelvic or hip pain. Forty-three patients (16%) were initially misdiagnosed.

Although our ability to correctly diagnose a RAAA has improved since Osler's time, the initial misdiagnosis rate of 16% leaves no room for complacency. Ruptured abdominal aortic aneurysms must be included in the differential diagnosis of any patient over the age of 55 years who presents with shock, even if the pain is non-specific or atypical.