A 76-year-old female with a 20-year history of type 2 diabetes mellitus (DM) was initially treated with Novolin 30R insulin. However, due to poor blood sugar control, she switched to insulin Lispro and added pioglitazone (15 mg daily) and acarbose (50 mg three times daily) to her treatment regimen one year ago. She also took olmesartan for hypertension and aspirin for a prior cerebral infarction. Recently, she experienced swelling and shortness of breath, prompting her to seek medical attention. Pioglitazone was discontinued, but her breathing difficulties persisted, along with noticeable edema. She did not report any night-time breathing problems. Upon examination, her vital signs were stable, and there were no signs of hypoxemia. A physical examination revealed pitting edema in her limbs (Fig. 1A) but no other classic symptoms of heart failure, such as extra heart sounds, jugular vein distension, or hepatojugular reflux. Lung sounds were diminished in the lower lung fields, but no crackling sounds (rales) were detected. Chest computed tomography (CT) showed moderate pleural effusion in both lungs, and abdominal CT revealed subcutaneous abdominal edema (Fig. 2A). Laboratory tests indicated an elevated erythrocyte sedimentation rate but normal levels of C-reactive protein, procalcitonin, albumin, complete blood count, electrolytes, liver and kidney function, and urine albumin creatinine ratio. Autoantibodies and antineutrophil cytoplasmic antibodies were negative, and there were no abdominal abnormalities except for gallstones on the CT scan. Echocardiography showed normal heart function with an ejection fraction of 65%.