Acute Acalculous Cholecystitis in the Setting of Negative Ultrasound and Computed Tomography Scan of the Abdomen

Acute acalculous cholecystitis (AAC) is most commonly seen after surgery in critically ill patients. Early diagnosis and treatment is the key in the management of AAC. Ultrasound is the commonly used first modality for right upper quadrant (RUQ) pain with sensitivity equal to or greater than 80% for AAC. Computed tomography (CT) scan is reported to have a sensitivity close to 90% and if both the ultrasound and CT scan are combined, it further increases the sensitivity for the diagnosis of AAC. It is unlikely for AAC to be present in the setting of both negative ultrasound and CT scan of the abdomen. Our case report presents a similar clinical scenario where the patient was found to have both negative ultrasound and CT scan abdomen but was positive on hepatobiliary iminodiacetic acid (HIDA) scan for AAC as stated below. A 32-year-old male presented to the emergency room with complaints of RUQ pain for two days which was associated with one episode of non-bilious and non-bloody vomiting as well as subjective fever and chills. On presentation, the patient's blood pressure was 87/54 mmHg. Other vitals were unremarkable. The patient had both CT scan abdomen and ultrasound of the RUQ done which reported non-specific findings but were grossly negative for AAC. On the first night of admission, the patient's blood pressure dropped to 84/32 mmHg. The patient was transferred to the intensive care unit (ICU) given the concern for sepsis and was started on intravenous (IV) vancomycin, IV metronidazole and IV levofloxacin (patient was allergic to penicillin). Given the high clinical suspicion, a HIDA scan performed which was positive for AAC. The patient then had a cholecystostomy tube placed by the interventional radiology team. The patient improved rapidly and was eventually discharged with a 14-day course of Bactrim DS (Roche Pharmaceuticals, Nutley, NJ) and metronidazole, and four weeks of outpatient follow up with general surgery. The patient underwent outpatient cholecystectomy in the eighth week from discharge. This leads to the conclusion that even if both the ultrasound and CT scan of the abdomen are negative and clinical suspicion is still high for AAC, the patient should undergo a HIDA scan as delay in treatment is associated with greater than 50% mortality in patients with AAC.