A 24-year-old African American man complains of abdominal pain while vacationing in the mountains with his parents. They arrived after 2 days of driving. Thirty-six hours after arrival, the patient experienced upper abdominal pain and nausea. The pain has increased and is localized to the left side of his abdomen. It is sharp, constant, and increased by deep inspiration. He also feels pain on the top of his left shoulder. He vomited a small amount of clear material once. The patient has no history of similar episodes. He considers himself to be in good health with no known medical problems. He does not use tobacco or illicit drugs but drinks 1-2 beers on weekends.
On examination, he looks mildly uncomfortable. His temperature is 37.8 C (100.5 F), pulse is 90/min, and respirations are 24/min. Pulse oximetry is 96% on ambient air. He appears to be splinting his left chest. No rales or rhonchi are heard. He has pain on palpation in the left upper quadrant without rebound tenderness. There is no lower-extremity swelling or tenderness. There are no skin rashes.
Laboratory results are as follows:

Chest x-ray reveals blunting of the left costophrenic angle.
Which of the following studies would best reveal the underlying cause of this patient's condition?

Question

A 24-year-old African American man complains of abdominal pain while vacationing in the mountains with his parents.  They arrived after 2 days of driving.  Thirty-six hours after arrival, the patient experienced upper abdominal pain and nausea.  The pain has increased and is localized to the left side of his abdomen.  It is sharp, constant, and increased by deep inspiration.  He also feels pain on the top of his left shoulder.  He vomited a small amount of clear material once.  The patient has no history of similar episodes.  He considers himself to be in good health with no known medical problems.  He does not use tobacco or illicit drugs but drinks 1-2 beers on weekends.
On examination, he looks mildly uncomfortable.  His temperature is 37.8 C (100.5 F), pulse is 90/min, and respirations are 24/min.  Pulse oximetry is 96% on ambient air.  He appears to be splinting his left chest.  No rales or rhonchi are heard.  He has pain on palpation in the left upper quadrant without rebound tenderness.  There is no lower-extremity swelling or tenderness.  There are no skin rashes.
Laboratory results are as follows:

Chest x-ray reveals blunting of the left costophrenic angle.
Which of the following studies would best reveal the underlying cause of this patient's condition?

Quizplus · Accepted Answer

11ec193a_96cd_3083_853d_eb4c18bc0c9f_MD0002_00 This patient's presentation is suggestive of splenic infarction due to sickle cell trait (Hb AS). The best next step to confirm the diagnosis is hemoglobin electrophoresis. Patients with sickle cell trait are usually asymptomatic and do not have complications of sickle cell disease such as vaso-occlusive crisis and hemolysis. However, some patients may experience renal complications such as hematuria from infarction of renal medullary blood vessels. Splenic infarction can also occur with strenuous exercise or exposure to hypoxic conditions. If the infarction occurs in the portion of the spleen adjacent to the diaphragm, a small sympathetic pleural effusion may be seen and the pain can be felt on top of the shoulder. Treatment involves supportive care and analgesia. (Choice A) Deep-vein thrombosis or pulmonary embolus is unlikely to cause splenic infarction, and Doppler ultrasound is not needed. (Choices C & E) Both antiphospholipid syndrome and cardiac source of embolism can cause splenic infarction. However, given that this patient is African American and his episode occurred under hypoxic conditions, sickle cell trait is much more likely. (Choice D) Abdominal pain (usually epigastric with band-like radiation to the back), nausea, vomiting, and a small left pleural effusion are also seen in patients with acute pancreatitis. However, this patient has no risk factors for pancreatitis (history of gallstones or substantial alcohol use) and serum lipase is unlikely to be of help. Educational objective: Acute onset of left upper-quadrant pain raises the possibility of splenic infarction in patients with sickle cell trait (Hb AS); diagnosis is through hemoglobin electrophoresis. Treatment of splenic infarction is supportive. __________ References: Splenic infarction: an update on William Osler's observations. (http://www.ncbi.nlm.nih.gov/pubmed/20928991) Splenic syndrome in sickle trait. Four case presentations and review of the literature (http://www.ncbi.nlm.nih.gov/pubmed/10091500)

A 24-Year-Old African American Man Complains of Abdominal Pain While