Differential diagnosis between amoebic liver abscess and acute cholecystitis

The Research Committee of the World Organization of Gastroenterology has gather information regarding the etiology of acute abdominal pain. Seven diseases cover 96% of the causes of this syndrome in many countries of the world, but some geographical variations have been observed. One example of these variations is amoebic liver abscess, present in 5 to 10% of Mexico City patients. Right upper quadrant pain is often present in amoebic liver abscess and acute cholecystitis. Thus, differential diagnosis of these two entities is difficult. Using discriminant analysis and "stepwise" procedures in 100 cases with cholecystitis and a similar number of patients with amoebic liver abscess, we found six variables (symptoms and signs with a significant chi square to distinguish between these two diseases. The symptoms and signs chosen were hepatomegaly, Murphy's sign, duration of pain greater than or equal to 48 hours, previous history of abdominal pain, dysentery, and facial pallor. These variables proved to be better than laboratory test results. With five of these variables it was possible to obtain an accuracy of 92%. Using six variables, if cases of tie (three variables present and three absent) were excluded, accuracy rose to 96%.