An 84-year-old man is brought to the emergency department due to severe left-sided flank pain and nausea over the last hour. He has also had syncope but no chest pain, bowel symptoms, or bladder symptoms. Other medical conditions include hypertension, dyslipidemia, sigmoid diverticulosis, and a transient ischemic attack 5 years ago. He has a 50-pack-year smoking history. Temperature is 37.1C (98.8 F), blood pressure is 90/60 mm Hg, and pulse is 112/min and regular. Pulse oximetry shows 94% on room air. The patient appears anxious, pale, and diaphoretic. Diffuse abdominal tenderness to deep palpation and left costovertebral angle tenderness is present. Bowel sounds are present. There is no rigidity or guarding. Peripheral pulses are decreased. Which of the following is the most likely diagnosis?
Abdominal aortic aneurysm | |
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CTD = connective tissue disease; HD = hemodynamically. | |
This patient's acute onset of severe flank pain, syncope, and hemodynamic instability is concerning for a ruptured abdominal aortic aneurysm (AAA). AAA typically occurs in patients age >60 and is more common in smokers, men, and those with a history of atherosclerosis or connective tissue disease. Patients typically have few symptoms until the AAA markedly expands or ruptures, precipitating abdominal or flank pain. Less common presentations include distal ischemia, due to embolization of the thrombus or of atherosclerotic debris from the aneurysm; and high-output heart failure, resulting from erosion of the AAA into the vena cava (ie, aortocaval fistula).
AAA rupture usually occurs posteriorly into the retroperitoneum, which can delay the onset of hemodynamic instability (eg, 1 h of symptoms in this patient); however, rupture may occur anteriorly with direct leakage into the peritoneum and rapid onset of hemodynamic instability and shock. Physical examination may reveal a pulsatile abdominal mass at the umbilicus as well as flank or umbilical hematomas. However, findings are sometimes subtle or nonspecific. Delayed or missed diagnosis is common because ruptured AAA often mimics other abdominal pathologies (eg, renal colic, acute pancreatitis) and approximately 75% of presenting patients have no known history of AAA.
(Choice B) Acute pyelonephritis commonly presents with flank pain, and hemodynamic instability may occur due to sepsis; however, this patient's lack of fever or dysuria makes this diagnosis less likely.
(Choice C) Acute renal infarction presents with abdominal or flank pain. However, it is accompanied by hypertension (rather than hypotension) due to increased renin secretion; fever is also common.
(Choice D) Nephrolithiasis with obstruction would not account for this patient's hemodynamic instability and reduced peripheral pulses. Of note, AAA complicated by an aortocaval fistula can cause venous congestion of the bladder, sometimes leading to hematuria that is misdiagnosed as nephrolithiasis.
(Choice E) Left lower quadrant pain, nausea, and vomiting are commonly present in acute diverticulitis. When perforation occurs, patients usually have signs of peritonitis (eg, rebound, guarding).
Educational objective:
Ruptured abdominal aortic aneurysm presents with the acute onset of severe abdominal or flank pain, sometimes accompanied by syncope, a pulsatile abdominal mass, and/or flank or umbilical hematomas. The onset of hemodynamic instability can be abrupt or delayed.