This is a dangerous complication of acute pancreatitis (13.9). A collection of pus, necrotic tissue, and clot fills the patient's lesser sac; it enlarges behind his peritoneum, it expands anteriorly to obliterate his lesser sac, and it pushes his stomach and transverse colon forwards.
If his abscess develops during the course of an attack of pancreatitis, the diagnosis is usually obvious, but it may be difficult otherwise. So if ever a severely sick patient has an ill-defined deep-seated epigastric mass, remember that he might perhaps have a pancreatic abscess.
PANCREATIC ABSCESS SPECIAL TESTS. The patient's urinary and serum amylase are high. A plain erect film may show a large cavity with a fluid level, or gas. A barium meal may show a deformity in the outline of his stomach, caused by a mass behind it pushing it forwards. See also Section 13.10.
DRAINAGE. Under general anaesthesia and with adequate relaxation, prepare and drape his upper abdomen. Then feel for the mass again.
Make an upper midline incision from his xiphisternum to his umbilicus. Open his peritoneal cavity with care, because the mass, or his stomach or colon, may have stuck to his abdominal wall.
You may find it difficult to know what you are seeing. Dissection is difficult and dangerous, because his tissues are so vascular and oedematous. Lift and free his abdominal wall from the organs under it, and insert a self-retaining retractor.
Feel for the upper border of the abdominal mass. Try to find a place where you can incise it without injuring anything. This will usually be through his gastrocolic omentuum, or his lesser omentum.
When you have decided where to drain, seal the area from the rest of his peritoneum with large moist packs. Using a syringe and a large needle, aspirate the place where there seems to be the thinnest layer of tissue between the abscess and your finger. Take pus for culture.
If you find pus under pressure, decompress the abscess with a trocar and cannula, to which suction is attached. Enlarge the abscess so that you can insert two fingers, but don't try to dissect further. Wash out floating solid matter.
CAUTION ! At the same time, don't disturb the necrotic pancreatic tissue at the bottom of his abscess[md]it will bleed!
Place two Malecot catheters in the abscess cavity, and bring them out through stab wounds. Bring one out anteriorly, and the other as far back as possible, in the most ''dependent' position. Use these to irrigate the abscess cavity continuously with saline (about 2 l in 24 hours). Make a feeding jejunostomy (9.7), because he will not be able to eat for 3 weeks, and you will probably be unable to feed him parenterally. Feeding him through a jejunostomy results in less secretion of gastric juice than feeding him through a gastrostomy.
Close his abdomen securely as a single layer (9.8). Leave his skin open, and lay a hypochlorite or saline pack on it.
Continue nasogastric suction, fluids, and antibiotics until his temperature is normal. Don't be in a hurry to remove the drains, even if leaving them in does seem to increase the risk of a fistula. Allowing pus to collect again is a greater risk. If the wound is looking fairly clean, close it by secondary suture in 7 to 10 days.
CAUTION ! A pancreatic abscess carries a 30 to 50% mortality, and often reforms, even with adequate drainage. If so, be prepared to reoperate 3 or 4 times if necessary.