Severe Acute Pancreatitis

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Severe Acute Pancreatitis

Key points

Severe acute pancreatitis means organ failure lasting more than 48 hours (revised Atlanta). Mortality is about 20 to 40%.
Deaths come in two waves: early from SIRS and organ failure (first 1 to 2 weeks), late from infected necrosis and sepsis.
Moderate goal-directed fluids, early enteral feeding, and no prophylactic antibiotics.
Watch bladder pressure for abdominal compartment syndrome.
Infected necrosis is treated with antibiotics and a delayed, minimally invasive step-up approach, ideally after 4 weeks.

1. Recognize it early

Organ failure is defined by the modified Marshall score of 2 or more in any of: respiratory (PaO2/FiO2 300 or less), renal (creatinine 1.9 mg/dL or more), cardiovascular (systolic BP under 90 not responsive to fluids).
Early warning signs: persistent SIRS beyond 48 hours, BUN above 20 mg/dL or rising, hematocrit rising, BISAP 3 or more, age over 60, obesity, pleural effusion.
Admit to ICU or step-down for organ failure, persistent SIRS or rising risk markers.
Contrast CT after 72 hours (or sooner if diagnosis unclear) to look for necrosis.

2. ICU management

Issue	What to do
Fluids	Lactated Ringer’s, moderate and goal-directed; stop escalating once perfusion targets are met. Over-resuscitation worsens lung injury and compartment syndrome.
Nutrition	Enteral within 24 to 72 hours; nasogastric is as safe as nasojejunal. Parenteral only if enteral fails.
Antibiotics	No prophylaxis. Treat proven or strongly suspected infection.
Pain	Opioids or epidural analgesia; multimodal approach.
Abdominal pressure	Measure bladder pressure every 4 to 6 hours in the sickest patients (see below).
Thrombosis	Pharmacologic DVT prophylaxis; splanchnic vein thrombosis is common.
Cause	ERCP within 24 hours only for cholangitis; insulin infusion for high triglycerides.

Abdominal compartment syndrome

Intra-abdominal hypertension: bladder pressure 12 mmHg or more. Compartment syndrome: above 20 mmHg with new organ failure.
First steps: limit fluids, nasogastric and rectal decompression, sedation and neuromuscular blockade if ventilated, drain ascites percutaneously.
Surgical decompression if pressure and organ failure persist despite these.

3. Necrosis and infection

FIGURE: THE STEP-UP APPROACH TO INFECTED NECROSIS

Suspected infected necrosis: gas on CT, or new sepsis after week 1 with no other source

Step 1: antibiotics that penetrate necrosis (carbapenem, fluoroquinolone with metronidazole)

Step 2: drainage when walled-off (about 4 weeks): endoscopic transmural (preferred) or percutaneous

Step 3: necrosectomy (endoscopic or minimally invasive surgical) if no improvement

Original diagram based on the AGA 2020 necrosis update and the ACG 2024 guideline.

Sterile necrosis rarely needs drainage unless it causes obstruction, persistent pain or failure to thrive.
Fine-needle aspiration of necrosis is rarely needed; treat on clinical and CT grounds.
Early open necrosectomy carries high mortality and has been replaced by the step-up approach.
If a stable patient with infection can wait, postponing intervention until encapsulation lowers complications.

4. Other complications to watch for

Pseudoaneurysm (often splenic or gastroduodenal artery): sudden bleeding or a falling hemoglobin; CT angiography and embolization.
Disconnected pancreatic duct: recurrent collections; long-term transmural plastic stents help.
Splanchnic vein thrombosis: splenic, portal or mesenteric; anticoagulate if it extends or causes symptoms.
Gastric outlet or biliary obstruction from large collections.
Long term: diabetes and exocrine insufficiency develop in many survivors; screen at follow-up.

Self-check questions

What separates severe from moderately severe acute pancreatitis?
Day 3, 40% necrosis, no fever. Should antibiotics be started?
Day 25, gas in a necrotic collection, stable patient. What now?
Bladder pressure is 24 mmHg with rising creatinine. What is this, and what are first steps?

Answers: (1) Organ failure persisting more than 48 hours. (2) No; there is no role for prophylaxis. (3) Antibiotics, then drainage once the collection is walled off (endoscopic preferred). (4) Abdominal compartment syndrome; limit fluids, decompress the gut, drain ascites, consider sedation or paralysis, then surgery if it persists.

References

Tenner S, Vege SS, Sheth SG, et al. American College of Gastroenterology Guidelines: Management of Acute Pancreatitis. Am J Gastroenterol. 2024;119(3):419-437.
Baron TH, DiMaio CJ, Wang AY, Morgan KA. American Gastroenterological Association Clinical Practice Update: Management of Pancreatic Necrosis. Gastroenterology. 2020;158(1):67-75.
van Santvoort HC, Besselink MG, Bakker OJ, et al. A step-up approach or open necrosectomy for necrotizing pancreatitis (PANTER). N Engl J Med. 2010;362(16):1491-1502.
Banks PA, Bollen TL, Dervenis C, et al. Classification of acute pancreatitis 2012: revision of the Atlanta classification. Gut. 2013;62(1):102-111.
Kirkpatrick AW, Roberts DJ, De Waele J, et al. Intra-abdominal hypertension and the abdominal compartment syndrome: updated consensus definitions and clinical practice guidelines. Intensive Care Med. 2013;39(7):1190-1206.

For educational purposes only. This note does not replace clinical judgment or local protocols. Check doses against current labeling and institutional guidance.