IM Board Review

A 41-year-old man with abdominal pain

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A 41-year-old man presented with pain in  the left upper quadrant for 4 days. The pain was constant, was worse on inspiration, and did not radiate. He denied fevers, night sweats, nausea, vomiting, diarrhea, and urinary symptoms. He had been diagnosed with multiple sclerosis a few years earlier, and he had undergone aortofemoral bypass surgery on the left side 2 years ago. He denied smoking or using illicit drugs and described himself as a social drinker.

In the emergency room, he appeared comfortable. He was afebrile, blood pressure 136/69 mm Hg, pulse rate 98 per minute, and respiratory rate 16. All pulses were palpable and equal, the jugular venous pressure was not elevated, and no cardiac murmurs were heard. The abdomen was tender in the left upper quadrant, with no guarding or rigidity. Examination of the nervous, musculoskeletal, and respiratory systems was unremarkable. Skin examination revealed only scars from previous surgery.


  • White blood cell count 7.2 × 109/L (reference range 4.0–10.0) with a normal differential
  • Hemoglobin 134 g/dL (140–180)
  • Platelet count 167 × 109/L (150–400)
  • Renal and liver panels were normal
  • Erythrocyte sedimentation rate 30 mm/hour
  • C-reactive protein level 14.3 mg/L
  • D-dimer level 2,670 ng/mL (< 500)
  • International normalized ratio (INR) 1.0 (0.9–1.3)
  • Activated partial thromboplastin time (aPTT) 44 seconds (25–38)
  • Fibrinogen level 3.0 g/L (1.8–3.5)
  • Urinalysis negative for leukocytes and casts.
Figure 1. Abdominal computed tomography revealed a wedge-shaped, hypodense area (arrow) along the inferolateral aspect of the spleen measuring 6 × 3.8 cm, consistent with a recent infarct.

Computed tomography of the abdomen showed a wedge-shaped area of hypodensity along the inferolateral aspect of the spleen measuring 6 × 3.8 cm, consistent with a recent infarct (Figure 1). There was also evidence of a previous infarct in the posterolateral aspect of the spleen. Splenic, celiac, superior mesenteric, and inferior mesenteric arteries were patent.

1. Given these findings, which of the following diagnoses should be considered?

  • Subacute infective endocarditis
  • Inherited thrombophilia
  • Antiphospholipid syndrome

All three diagnoses should be considered in this case.


Embolism from a source in the heart caused by subacute bacterial endocarditis is more common than the other two conditions listed here and must be excluded.

Our patient lacks key features of this condition: he has no predisposing factors (artificial valve, cyanotic congenital heart disease, previous endocarditis, intravenous drug abuse); no constitutional symptoms of fever, night sweats, and weight loss; no findings on examination of skin and cardiovascular systems; and a normal white blood cell count. Nevertheless, even though the absence of these features makes bacterial endocarditis unlikely, it does not exclude it. Blood cultures and transesophageal echocardiography are indicated to rule out bacterial endocarditis.

We obtained serial blood cultures, which were negative, and transesophageal echocardiography showed normal valves and no evidence of thrombus or vegetation, thus excluding a cardiac source of emboli.


Our patient has a history of recurrent thromboembolic episodes, and this warrants testing to rule out an inherited thrombophilia. A family history of thromboembolic disease should also be sought.1

When antiphospholipid syndrome occurs with systemic lupus erythematosus, it is termed ‘secondary’

In our patient, tests for prothrombotic activity including protein C chromogen, activated protein C ratio, free protein S, functional protein S, antithrombin factor V Leiden, and the prothrombin 20210G>A mutation were either negative or within the reference range. A negative family history of thromboembolic disease and the negative laboratory tests make inherited thrombophilia unlikely in our patient.

Sickle cell disease, polycythemia vera, and essential thrombocythemia may also cause splenic infarction but can be ruled out in this patient on the basis of history and initial blood tests.

Antiphospholipid syndrome

A history of vascular disease (aortofemoral bypass surgery), a recent splenic infarct, and an elevated aPTT makes antiphospholipid syndrome the likeliest diagnosis in this patient.

Appropriate tests are for lupus anticoagulant, immunoglobulin G (IgG) or IgM cardiolipin antibody, and beta-2 glycoprotein 1 (beta-2 GP1) antibody, as well as the dilute Russell viper venom time (dRVVT) and the dRVVT ratio. The IgG and IgM cardiolipin antibody and beta-2 GP1 antibody tests have the same diagnostic value, and only medium to high titers should be considered positive.

Our patient’s IgG cardiolipin antibody level was in the normal range at 15 IgG phospholipid units (reference range 0–22); his IgM cardiolipin antibody level was high at 41 IgM phospholipid units (0–10). The dRVVT was 57 seconds (24–42), and the dRVVT ratio was 2.0 (0.0–1.3).

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