Misdiagnosis of ruptured abdominal aortic aneurysms.

Ruptured abdominal aortic aneurysm is a surgical emergency with a high mortality rate even when diagnosed and repaired immediately. We retrospectively reviewed 152 cases of ruptured abdominal aneurysms to identify the incidence of misdiagnosis leading to a delay in treatment, the most frequent misdiagnoses, and the outcome in this group of patients. Forty-six (30%) were initially misdiagnosed. The most common misdiagnoses were renal colic, diverticulitis, and gastrointestinal hemorrhage. The most common initial physical findings in misdiagnosed patients were abdominal pain (70%), shock (57%), and back pain (50%). A pulsatile abdominal mass was found in only 26% of misdiagnosed patients versus 72% of patients correctly diagnosed (p less than 0.005). Misdiagnosed ruptured abdominal aneurysm had a 44% mortality rate, which was not significantly different from patients correctly diagnosed (58%, p = 0.34). The lack of difference in mortality rates is most likely due to preselection of those misdiagnosed patients who were able to withstand the delay in diagnosis and survive to surgical treatment. The 30% incidence of misdiagnosis in this series suggests that it is frequently a difficult diagnosis to make and must be considered in elderly patients, especially men, who are admitted with abdominal pain and/or back pain.