A previously healthy 19-year-old man comes to the emergency department (ED) due to persistent abdominal discomfort. The patient previously came to the ED 3 days ago after he fell while mountain biking. He did not lose consciousness and recalls hitting the handlebars prior to flipping and landing on his back. His trauma workup-which included CT scan of the chest, abdomen, and pelvis-was negative, and he was discharged. Since then, the patient has had persistent upper abdominal discomfort and nausea, along with an episode of nonbilious emesis. Temperature is 38.1 C (100.6 F), blood pressure is 104/62 mm Hg, and pulse is 108/min. The lungs are clear to auscultation, and heart sounds are normal. Ecchymosis is present across the upper abdomen, which is tender to palpation with voluntary guarding. Bowel sounds are decreased. Bedside ultrasonography reveals a large amount of free fluid in the upper abdomen. Which of the following is the most likely cause of this patient's condition?

Question

A previously healthy 19-year-old man comes to the emergency department (ED) due to persistent abdominal discomfort.  The patient previously came to the ED 3 days ago after he fell while mountain biking.  He did not lose consciousness and recalls hitting the handlebars prior to flipping and landing on his back.  His trauma workup-which included CT scan of the chest, abdomen, and pelvis-was negative, and he was discharged.  Since then, the patient has had persistent upper abdominal discomfort and nausea, along with an episode of nonbilious emesis.  Temperature is 38.1 C (100.6 F), blood pressure is 104/62 mm Hg, and pulse is 108/min.  The lungs are clear to auscultation, and heart sounds are normal.  Ecchymosis is present across the upper abdomen, which is tender to palpation with voluntary guarding.  Bowel sounds are decreased.  Bedside ultrasonography reveals a large amount of free fluid in the upper abdomen.  Which of the following is the most likely cause of this patient's condition?

Quizplus · Accepted Answer

Explanation: This patient with a negative abdominal CT scan following blunt abdominal trauma (BAT) (eg, handlebar impact) now has persistent upper abdominal discomfort and nausea accompanied by a low-grade fever and a large upper abdominal fluid collection. This presentation is most concerning for pancreatic duct injury, with resulting leakage of inflammatory pancreatic juice leading to accumulation of peripancreatic fluid. Pancreatic injuries may result from BAT that rapidly compresses the fixed, retroperitoneal pancreas against the vertebral column. Pancreatic injury is often difficult to diagnose immediately following trauma because physical examination is nonspecific, initial serum amylase and lipase levels are unreliable markers, and abdominal CT scan has variable (~50%-80%) sensitivity. Therefore, the development of the following symptoms and signs in patients with recent BAT should raise suspicion for undiagnosed pancreatic injury: Persistent abdominal discomfort/tenderness Persistent nausea/emesis Increasing amylase over serial measurements Peripancreatic fluid collection (due to pancreatic duct injury) Ductal injury may require cholangiopancreatography for diagnosis. Some (eg, low-grade) pancreatic injuries can be managed nonoperatively, but most ductal injuries require surgical intervention. (Choice A) Abdominal aortic injuries due to BAT are rare (<1%). Many patients with traumatic aortic injury die from exsanguination before reaching the hospital. Those who survive (because bleeding has been initially contained within the retroperitoneum) would be extremely unlikely to have a large amount of free fluid on FAST without accompanying significant hemodynamic instability (eg, systolic blood pressure <90 mm Hg). (Choice B) Diaphragmatic rupture, which can occur after BAT due to a sudden increase in intraabdominal pressure, may result in herniation of abdominal organs into the thoracic cavity. This may trap the stomach or small bowel and cause obstructive symptoms (eg, nausea, emesis). However, it does not typically cause significant intraabdominal free fluid and is unlikely to cause a low-grade fever. (Choices C and D) The liver and spleen are the most commonly injured solid organs in blunt abdominal trauma. Although both hepatic laceration and splenic rupture can generate intraabdominal free fluid (ie, blood), injuries severe enough to cause a large amount of intraabdominal bleeding (eg, large amount of free fluid) are nearly always detected on initial abdominal CT scan. Educational objective: Blunt trauma that rapidly compresses the upper abdomen against the vertebral column can injure the pancreas. Pancreatic injury can be difficult to diagnose immediately following trauma; persistent abdominal discomfort or nausea, increasing amylase, or peripancreatic fluid collection should raise suspicion for an undiagnosed injury. References: Pancreatic trauma: a concise review. (http://www.ncbi.nlm.nih.gov/pubmed/24379625) Blunt pancreatic trauma: a persistent diagnostic conundrum? (http://www.ncbi.nlm.nih.gov/pubmed/26981225) Clinical update on management of pancreatic trauma. (http://www.ncbi.nlm.nih.gov/pubmed/30005994)

A Previously Healthy 19-Year-Old Man Comes to the Emergency Department