Cholecystitis is divided into acute cholecystitis and chronic cholecystitis. The symptoms of acute cholecystitis manifest as sudden severe pain in the upper right abdomen, which can also radiate to the right shoulder and back, and is the most typical symptom of acute cholecystitis. These symptoms generally occur after consuming a large amount of fat, at night, or after a full meal. It may also be accompanied by moderate fever, severe chills, nausea, vomiting, loss of appetite, and other gastrointestinal symptoms. Chronic cholecystitis generally has atypical symptoms; it often causes pain in the upper right abdomen after a full meal or consuming greasy foods. The intensity of pain varies among individuals, and it can sometimes radiate to the right shoulder and back. Fever and chills are rarely present in chronic cholecystitis.