A 25-year-old woman comes to the emergency department due to 2 days of progressive pain in the left upper quadrant. The pain is constant and deep. Medical history is significant for several years of joint pain. The patient does not use tobacco, alcohol, or illicit drugs. Temperature is 37.1 C (98.8 F), blood pressure is 128/82 mm Hg, pulse is 86/min, and respirations are 16/min. BMI is 25 kg/m². The lungs are clear to auscultation. Cardiac examination reveals an nondisplaced point of maximum impulse and a 2/6 holosystolic murmur at the apex. Abdominal examination shows tenderness in the left upper quadrant with no rigidity or rebound guarding. Bowel sounds are present. The remainder of the examination shows no abnormalities. Laboratory results are as follows: CT scan of the abdomen is shown in the exhibit. Which of the following is the best next step in management of this patient?

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Explanation: 11ec25c8_d405_5972_bc81_d97085f4e665_MD0003_00 This patient's acute left upper quadrant pain and CT evidence of a wedge-shaped splenic deficit indicate splenic infarction. Most cases arise due to an acute interruption in arterial blood flow through the splenic artery or its subbranches in the setting of 1 of the following: Thrombosis due to a hypercoagulable state (eg, cancer, systemic lupus erythematosus [SLE], antiphospholipid antibody syndrome [APLAS]) Embolism due to atrial fibrillation, endocarditis, or atheroma Hemoglobinopathy (eg, sickle cell disease) This patient's young age, long-standing joint pain, and thrombocytopenia raise suspicion for possible SLE. In patients with SLE, possible etiologies of splenic infarction include splenic artery thrombosis or embolism from nonbacterial thrombotic endocarditis. Therefore, in addition to antinuclear antibody testing (as part of the workup for SLE), this patient should also undergo antiphospholipid antibody testing (to evaluate for APLAS) as well as echocardiography (to examine the heart valves for vegetations). Her mitral regurgitation murmur (holosystolic radiating to apex) may indicate that nonbacterial thrombotic endocarditis is the cause of her infarction. Most patients with splenic infarction have acute pain and tenderness in the left upper quadrant; fever, nausea, splenomegaly, and leukocytosis also frequently occur. The diagnosis is typically made with abdominal CT scan. (Choice B) Factor V Leiden mutation makes factor V insensitive to the anticoagulant activity of activated protein C. This can lead to venous thromboembolism, often in unusual locations (eg, cerebral vein); however, there is minimal association between factor V Leiden and arterial thrombosis. In addition, chronic joint pains, significant thrombocytopenia, and cardiac murmur are not common with Factor V Leiden mutation. (Choice C) Sickle cell disease (SCD) is diagnosed with hemoglobin electrophoresis. Although sickle cell crises can be associated with vasoocclusion and subsequent tissue infarction, this patient's normal hemoglobin makes SCD unlikely. In addition, SCD would not explain the presence of a mitral regurgitation murmur. (Choice D) Infectious mononucleosis is diagnosed using the Monospot test. Although this infection often causes significant splenomegaly, infarction is less common. Furthermore, almost all patients have pharyngitis, generalized lymphadenopathy, and other systemic symptoms; cardiac murmur is atypical. (Choice E) Parvovirus can cause acute arthralgia (not chronic) in adults but is not linked to splenic infarction or cardiac murmur. Because the virus destroys erythrocyte progenitor cells, transient anemia can occur; thrombocytopenia is less common. Educational objective: Splenic infarction usually presents with acute pain and tenderness in the left upper quadrant. Most cases arise in those with hypercoagulable states (eg, systemic lupus erythematosus, malignancy), embolic disease, or hemoglobinopathy.

A 25-Year-Old Woman Comes to the Emergency Department Due to 2