What is acute pancreatitis and what are the problems?

The pancreas is an organ located behind the stomach. It secretes enzymes which are important for the digestion of food. It is also responsible for the secretion of important hormones such as insulin, the lack of which will result in diabetes mellitus.

Acute pancreatitis is a condition in which the pancreas becomes inflamed and swollen.
The  most common symptoms include severe upper abdominal pain, nausea, vomiting, diarrhoea and loss of appetite and even cardiopulmonary instability in severe cases. The most common causes of acute pancreatitis are gallstones and alcohol consumption. Other causes include certain medications, pancreatic tumours, ERCP (an endoscopic procedure used to treat bile duct and pancreatic duct disorders) and metabolic disorders such as high triglyceride levels and high calcium levels.

Most cases of acute pancreatitis are mild attacks. After a few days, the pain will subside and the patient will be able to resume normal food intake and normal activities. The subsequent issue will be to identify and treat the disposing factors. In 10 – 20% of cases, the acute attack is severe, and in this situation, the attack of acute pancreatits will run a more protracted and difficult clinical course. In the acute phase, patients may even go into multiple organ failure requiring acute supportive measures such as intubation with mechanical ventilation, dialysis and medications to support the cardiovascular system. In these severe cases, the death rates may reach greater than 20%, and even higher than 50% in certain cases. In the acute phase, the focus of the treatment is on fluid resuscitation and supporting organ functions. Empiric use of intravenous antibiotics may be required as well to either treat concomitant infections such as cholangitis or to prevent secondary bacterial infections. In the intermediate to late stage, at 3 – 4 weeks later, local complications develop. This is because during the process of severe inflammation, intraabdominal fluid collections form due to leakage from blood vessels and pancreatic cell death (necrosis) occurs. This will lead to local problems around the pancreas, such as pseudocysts (a walled off collection of fluid), abscess formation (a collection of pus) and infection of necrotic (dead) tissues. Walled off fluid collections can lead to problems such as mechanical obstruction of bile flow and obstruction of the normal passage of food from the stomach to the intestines; these fluid collections can also rupture and bleed, becoming a surgical emergency. The development of pancreatic abscesses and infected necrosis will affect the effectiveness of antibiotics.

What are the options for treating pancreatic abscesses and infected necrosis?

Open surgery has been considered the standard treatment for treatment of symptomatic pancreatic fluid collections. However, it requires general anaesthesia, and is relatively invasive, with considerable morbidity and mortality, depending on the type of fluid collection and the status of the patient. Surgery for abscesses and infected necrosis involves steps such as exploration, debridement, closed packing and external drainage.

Less invasive alternatives to open surgery include percutaneous drainage and endoscopic drainage. In the case of percutaneous drainage, under either ultrasound or computer tomography guidance, an external indwelling drainage catheter is inserted across the skin and abdominal wall into the cavity for drainage. This approach has limitations such as the occurrence of local complications like bleeding, accidental puncture of an adjacent organ, superimposed infection and the development of a fistulous tract from the cavity to the skin. In addition, due to the narrow diameter of these drainage tubes, it is not possible to remove necrotic debris with approach and salvage surgery may still be necessary.

Endoscopic drainage involves inserting a scope into either the stomach or duodenum (the first part of the small intestine), visualising the precise location of the abscess or necrotic collection through an ultrasound transducer at the tip of the scope (endoscopic ultrasound), puncturing across the gut wall into the cavity which is just adjacent to the gut lumen under real time ultrasound guidance and then inserting drainage tubes between the abscess or necrosis cavity and the gut lumen. Pus is then drained internally into the stomach cavity. When there is a lot of solid material within the cavity that cannot be drained out through the tubes, one can actually also perform endoscopic necrosectomy to remove all these solid debris and hence facilitate resolution and recovery. In the process of endoscopic necrosectomy, the opening from the stomach wall into the abscess cavity is dilated such that a scope can be inserted into the cavity. Under direct visual guidance, the necrotic solid material is then physically removed with the scope and endoscopic accessories.

Figure 3: After endoscopic necrosectomy, the inside of the necrotic collection appreared pink and healthy.

Case example

A 42 year old man was admitted for severe pancreatitis. In the early phase he had respiratory failure needing intubation and mechanical ventilation as well as renal failure needing dialysis. Subsequently he developed high fever that did not respond to antibiotics treatment. Computer tomography showed an infected necrotic collection at the pancreas. After discussion of the various treatment options, he opted for endoscopic treatment. He first
underwent endoscopic drainage, in which internal drainage tubes were inserted to drain the pus. This was
followed by endoscopic necrosectomy in which solid dead tissues were removed internally through a scope.
The procedures were successful and he recovered fully.