Question Of The Day #33

This elderly male patient presents to the emergency department with abdominal pain. Compared to younger patients, abdominal pain in an elderly patient has a higher likelihood of being due to a surgical emergency or from a diagnosis that carries a higher mortality. Elderly patients may have more nonspecific associated symptoms that may make it difficult to confirm a dangerous diagnosis without advanced imaging. Additionally, elderly patients do not always have a fever or elevated white blood cells during an abdominal infection. The differential diagnosis of abdominal pain in an elderly patient should be broad and encompass conditions related to many body systems.

The syncopal event and signs of shock should raise concern for a more serious etiology of the patient’s symptoms. The CT image provided shows a dilated aorta filled with contrast dye and a large surrounding intra-luminal thrombus. An infrarenal abdominal aorta measuring over 3cm is considered aneurysmal. This patient’s abdominal aorta measures approximately 7cm from outer wall to outer wall using the scale provided on the right-hand side of the image. The green measurement line in the image below shows the size of the aorta from outer wall to outer wall (includes thrombus).

The diagnosis for this patient is a ruptured abdominal aortic aneurysm (AAA). This condition carries a high mortality and is often lethal without prompt surgical intervention (Choice A). Administration of blood products is helpful if there are signs of hemorrhagic shock as in this patient. Antibiotics, like IV Vancomycin and Piperacillin-Tazobactam (Choice B), are not helpful in the management of this diagnosis. Endotracheal intubation (Choice C) is needed prior to operative intervention, but Emergency department management should focus on volume resuscitation and close communication with the surgical team for operative repair. IV Heparin (Choice D) may be beneficial in acute mesenteric ischemia from an embolic etiology (i.e. Atrial fibrillation), but anticoagulation would worsen this patient’s hemorrhagic shock.

AAAs can present to the Emergency department without any symptoms and be discovered incidentally on imaging or on physical exam as a pulsatile abdominal mass. Other presentations include severe back pain (the abdominal aorta is retroperitoneal) and circulatory shock. Rupture of a AAA can be large and result in rapid decompensation and death, or bleeding can be contained in the retroperitoneal space with transiently stable vital signs. Risk factors for AAA formation are male sex, tobacco use, hypertension, increased patient age, Marfans syndrome, or Ehlers-Danlos syndrome. The diagnosis of AAA is clinical and includes the use of bedside aortic ultrasound or CT aortic angiogram imaging. Treatment for AAA depends on aortic size and patient symptoms. Operative repair is indicated for any AAA over 5.5cm diameter in men, over 5.0cm diameter in women, or any size if there are signs of shock or concern for AAA rupture.