Acute Peritonitis Is Not Always a Surgical Fix: A Rare Case of Mixed Connective Tissue Disease Presenting as Polyserositis

Abstract

Mixed connective tissue disease (MCTD) is a complex rheumatologic condition whose diagnosis often presents a challenge to even specialists in the field. Many cases are therefore underrecognized or misdiagnosed due to the heterogeneity of the presentation and manifestations. This report highlights the intricacies of diagnosing a case of MCTD when the presenting symptom is atypical. Herein, we present a case of a young girl who had severe abdominal pain, initially concerning for acute peritonitis from cholecystitis, and was found to have polyserositis affecting the pleural space, pericardium, peritoneum and pelvis secondary to mixed connective tissue disease and adrenal insufficiency.

Keywords: acute abdomen; autoimmune disease; mixed-connective-tissue-disease; peritonitis; polyserositis; rheumatological disease; serositis.

Figure 1. A computerized tomography of the abdomen and pelvis demonstrating pleural effusions and intra-abdominal fluid.

(A) Sagittal views of a CT demonstrating a small right basilar pleural effusion, as denoted by the yellow arrow, as well as a pericardial effusion, which is also denoted by another yellow arrow. (B) Sagittal views of a CT demonstrating a small amount of perihepatic fluid, as denoted by the yellow arrow.

Figure 2. A computerized tomography of the abdomen and pelvis demonstrating interval increase in ascites and pleural effusions.

(A) Sagittal views of a CT demonstrating moderate bilateral pleural effusions, right more than left, significantly increased from the prior examination. The pleural effusions are indicated by the arrows. (B) Moderate volume ascites noted in the abdomen and pelvis increased in volume since the prior exam, as indicated by the yellow arrows.