An ultrasound of the abdomen is the standard test for detecting gallstones, and in that regard is much more likely to pick these up than a CT scan. However, an ultrasound of abdomen is operator-dependent and if it is negative in the presence of a strong clinical suspicion of gallstones, consideration should be given to a repeat ultrasound of abdomen. Rarely stones may not be detected on an ordinary ultrasound and can only be shown on an endoscopic ultrasound (EUS) which involves the use of special camera with a scanner at the tip of it that is then passed through the mouth into the stomach under sedation and comes very close to the gallbladder inside the abdomen to detect finer stones. MRCP also can be utilized to assess biliary tree (common bile duct) and the gallbladder.

Complications of gallstones are not uncommon. The most common complications may include:

1. Acute cholecystitis: This is the most common complication of gallstones and represents an acute inflammation of the gallbladder that is often caused by a stone obstructing the gallbladder. This is characterised by a rather constant, and often severe, pain in the right upper abdomen, fever, nausea and vomiting. Current guidelines state that if no contraindications exist patients should be operated on (laparoscopic cholecystectomy) within 7 days of the onset of symptoms. Alternatively patients could be managed with antibiotics, and possibly an ultrasound-guided drainage of the gallbladder, until the inflammation settles down and then arrange a laparoscopic cholecystectomy 6-8 weeks later. Failure to treat acute cholecystitis promptly and adequately could result in sepsis and peritonitis, which are serious and potentially life threatening complications.
2. Obstructive Jaundice: This refers to a yellowish discolouration of the skin and the whites of the eyes. It is often caused by at least one or multiple stones passing from the gallbladder into the main bile duct (common bile duct) and causing obstruction to the flow of bile. Bowel motions often become rather pale and clay-coloured, the urine becomes dark and tea-coloured and the skin becomes itchy. This is often associated with abdominal pain. The presence of a bile duct stone can be confirmed on a scan (called MRCP) but these are occasionally seen on a simple ultrasound scan of the abdomen. The stone might pass spontaneously, but most likely these will need to be removed either by a camera procedure that is passed into the stomach under sedation (called ERCP), or during surgery to explore the bile duct and remove also the gallbladder.
3. Acute pancreatitis: This is acute inflammation of the pancreas gland that sits behind the stomach and produces insulin, to help regulate the levels of our blood sugar, and enzymes to facilitate digestion. The duct of the pancreas joins the main bile duct at the same point into the intestine, just beyond the stomach, and drains its digestive juices into the intestine. A gallstone passing down the bile duct may temporarily block the pancreatic duct resulting in acute pancreatitis; this is more likely to be caused by smaller than larger stones. Acute pancreatitis is an infrequent complication of gallstones and is characterised by a constant central abdominal pain radiating to the back that is often severe and associated with fever, nausea and vomiting. Although it is commonly mild and resolves within few days, acute pancreatitis can be quite severe in 3-out of-10 patients (30%) who then end up with further complications and prolonged hospitalisation.
4. Mucocele of the gallbladder: This is caused usually by a large gallstone that blocks the gallbladder and prevents its content from draining down the bile duct into the intestine. The gallbladder fills up and distends with mucus causing a constant dull ache under the right lower ribcage. Unlike acute cholecystitis, there is no infection here and no symptoms of fever or sepsis.