Case Report: A Lupus Patient with Abdominal Pain

Diagnosis

At this point our differential diagnoses included mesenteric/portal vein thrombosis, inflammatory bowel disease, small bowel ischemia, lupus/autoimmune enteritis, vasculitis or malignancy. 

A gastroenterologist was consulted, and an abdominal ultrasound with duplex was recommended to look for Budd-Chiari syndrome, an angiogram to evaluate the mesenteric vasculature and a push entero­scopy with biopsies of the stomach and small bowel.

Paracentesis revealed a total WBC count of 498 cells/µl: 81% monocytes, 12% lympho­cytes, 6% neutrophils and 1% eosinophils. The red blood cell count was 454 cells/µl, glucose 42 mg/dL, lactate dehydrogenase 169 U/L and serum-ascites albumin gradient was <1.1 g/dL. Cultures for bacteria, acid fast bacilli and fungus were negative. Cytology revealed reactive mesothelial cells and chronic inflam­mation, with no malignancy. 

An abdominal ultrasound with duplex revealed a patent main portal vein and middle hepatic vein, with appropriate direction of flow and a moderate volume of abdominopelvic ascites. A right pleural effusion was partially visualized. The trace, right hydroureteronephrosis had improved from the prior exam. 

Stool studies were negative. Her anti-dsDNA antibodies were 594 IU/mL (reference range: 0–99 IU/mL), C3 was 35 mg/dL (lower limit of normal: 88 mg/dL) and C4 was 7 mg/dL (lower limit of normal: 16 mg/dL). 

A diagnosis of lupus enteritis was made, and our patient was treated with 1,000 mg of intravenous, pulse-dose methyl­prednisolone per day for presumed lupus enteritis and then intravenous methyl­prednisolone taper. With this therapy she improved clinically. She was then initiated on mycophenolate mofetil with a slow up-titration plan at discharge and a plan to start hydroxy­chloroquine in the outpatient setting.

Abdominal Pain in SLE

The incidence of abdominal pain in patients with SLE ranges from 8–40%.¹ Common triggers are infections and medication side effects. Symptoms are often masked by treatment with glucocorticoids and/or immunosuppressive medications, which can lead to a delay in diagnosis. 

Autopsy studies have shown peri­tonitis in 60–70% of patients with SLE, but clinically, it is described in only 10% of cases.² 

Mortality among SLE patients with acute abdominal pain is 11%.² 

When evaluating patients, considerations must be given to SLE-related causes, side effects related to medications (e.g., NSAIDs, steroids, hydroxychloroquine, azathioprine) and non-SLE-related causes (e.g., if ascites is present, rule out infection with paracentesis). Table 1 lists the most common causes of acute abdom­inal pain in SLE patients. Table 2, from a review article by Brewer and Kamen, shows the anatomic dis­tribution of GI involvement among patients with SLE.²

Table 1: Leading Causes of Acute Abdominal Pain in SLE Patients³