Today’s USMLE® Step 1 question of the day features a 26-year-old man in the ER after a car accident who reports dizziness, nausea, and pain on his left side. What’s the most likely diagnosis? Do you know the answer? Let’s find out!
A 26-year-old man is brought to the emergency department by local paramedics after a motor vehicle collision. He was wearing a seat belt while driving, and his car was hit by a truck from the left side. The patient reports severe abdominal pain radiating to the left shoulder, nausea, and dizziness. Temperature is 36.7°C (98°F), pulse is 110/min, respirations are 20/min and blood pressure is 85/50 mmHg. Physical examination shows an area of ecchymosis over the left lower chest wall, diffuse abdominal tenderness, and dullness to percussion over the left upper quadrant. Lungs are clear to auscultation bilaterally. Focused assessment with sonography for trauma (FAST) reveals intraperitoneal free fluid. CT scan with contrast of the abdomen and pelvis is performed, as shown below.
Which of the following is the most likely cause of this patient’s presentation?
A. Duodenal hematoma
B. Abdominal aortic rupture
C. Liver laceration
D. Diaphragmatic injury
E. Splenic laceration
Scroll down for the correct answer!
The correct answer to today’s USMLE® Step 1 Question is…
E. Splenic laceration
Correct: See Main Explanation.
Incorrect Answer Explanations
A. Duodenal hematoma
Incorrect: Rapid compression of the abdomen against the vertebral column can crush the duodenum, potentially causing duodenal hematoma. It does not cause free intraperitoneal fluid as the bleeding remains confined to the duodenal wall. Moreover, this patient suffered trauma from the left side of his vehicle.
B. Abdominal aortic rupture
Incorrect: Abdominal aortic rupture is frequently fatal due to the profuse bleeding that results from the rupture, and many patients die before reaching the hospital. The minority of the patients who survive is most likely due to the containment of the blood in the retroperitoneal space. Moreover, a blunt trauma from the left side is less likely to cause aortic rupture.
C. Liver laceration
Incorrect: Blunt force mechanisms such as motor vehicle accidents are a common cause of liver laceration, and FAST may show free intraperitoneal fluid. Tenderness, however, is located over the right upper quadrant (rather than LUQ as seen in this patient).
D. Diaphragmatic injury
Incorrect: Diaphragmatic injury can occur after blunt trauma due to a sudden increase in intra abdominal pressure. Chest auscultation may reveal bowel sounds. Free intraperitoneal fluid on FAST in this patient is suggestive of splenic laceration.
Main Explanation
This patient suffered a blunt abdominal trauma (BAT) during a motor vehicle accident, has diffuse abdominal tenderness, left shoulder pain (Kehr’s sign), and signs of shock (hypotension, tachycardia). This together with free intraperitoneal fluid on Focused assessment with Sonography for Trauma (FAST), left lower chest ecchymosis, and left upper quadrant dullness to percussion is consistent with splenic laceration.
The spleen lies within the intraperitoneal cavity in close proximity to the stomach (intraperitoneal), colon (transverse: intraperitoneal, descending: retroperitoneal), left kidney, and pancreas (both retroperitoneal). It is one of the most commonly injured intra-abdominal organs following blunt trauma. In most adults, the spleen does not extend inferiorly past the rib cage, unless it is otherwise enlarged. The spectrum of its injury can range from contusion or subcapsular hematoma to laceration and intraperitoneal bleeding (due to high vascularity).
Patients can present with abdominal pain, tenderness in the epigastrium, pain in the left flank, and sharp left shoulder pain in cases of minor injury. Whereas, a ruptured spleen may result in massive intra-abdominal bleeding and should therefore be treated as a medical emergency.
Major Takeaway
The spleen is an intraperitoneal organ and lies in close proximity to other major organs of the abdomen. The most common cause of a ruptured spleen is blunt abdominal trauma, such as in traffic collisions. The clinical features include abdominal pain, radiating pain to the left shoulder (Kehr’s sign), nausea, lightheadedness and abdominal guarding. A ruptured spleen may result in massive intra-abdominal bleeding and should be treated as a medical emergency.
Want to learn more about this topic?
Watch this Osmosis video: Ruptured Spleen
References
- Bjerke HS, Geibel J. Splenic rupture. In: Splenic rupture. New York, NY: WebMD. http://emedicine.medscape.com/article/432823-overview#a6. Updated November 24, 2014. Accessed December 5, 2016.
- Söyüncü, S., Bektaş, F., & Cete, Y. (2012). Traditional Kehr’s sign: Left shoulder pain related to splenic abscess. Ulusal travma ve acil cerrahi dergisi= Turkish journal of trauma & emergency surgery: TJTEConcannon L.G., & Bhatti O.M., & Fry A.L., & Harrast M.A. (2019). Emergency assessment and care of the athlete. Mitra R(Ed.), Principles of Rehabilitation Medicine. McGraw-HillS, 18(1), 87-88.
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