Abstract Patients presenting to the emergency department with right upper quadrant pain are usually placed on a list of critical, yet limited differential diagnoses. Of these diagnoses, cholecystitis is fairly common. Although most cases of cholecystitis are relatively straight-forward, there are numerous extracholecystic conditions which have been known to cause acute acalculous cholecystitis. Examples include systemic infections, acute and chronic renal failure, systemic lupus erythematosus, and congestive heart failure. These conditions lead may lead to diffuse gallbladder wall thickening through a number of hypothesized mechanisms, including an increase in portal venous pressure, and a decrease in plasma oncotic pressure. The right upper quadrant pain caused by this gallbladder wall thickening however, is usually a late complaint, after the primary etiology has made itself clear. We report the case of a 6 year old female who presented to the emergency department with acute right upper quadrant pain and vomiting. Apart from the gastrointestinal system, examination of all other systems (including cardiovascular) was negative. An ultrasound was done and the diagnosis of acute acalculous cholecystitis was made. The patient did not respond to treatment, and after additional investigations, evidence of congestive heart failure with bilateral pulmonary effusions was seen. It was concluded that the patient's heart failure, although not apparent on initial examinations, was the etiology behind her initial gallbladder thickening and abdominal pain. This case reports an important etiology to be aware of in patients presenting with right upper quadrant pain which is unresponsive to treatment methods. Multiple extracholecystic disease entities such as congestive heart failure, must be placed in the list of differential diagnoses by the caring physician.