Outline the diagnostic features, complications and treatment of critically ill patients with pancreatitis.

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College Answer

This is a complex field with a large amount of literature to collate. Pancreatitis is usually presents with persistent upper abdominal pain, associated with nausea and vomiting, which can be associated with signs of local tenderness through to peritonism, and/or signs of a systemic inflammatory response  (e.g.  fever,  tachycardia) or  signs  of  associated  disorders  (e.g.  jaundice  with  biliary obstruction) or rarely signs of complications (e.g. ecchymotic discoloration in flank [Grey-Turner’s sign] or peri-umbilical [Cullen’s sign] regions). These signs may be difficult to elicit or masked in critically ill patients. Investigations that assist in the diagnosis include: serum amylase (usually > 3 times normal) (serum lipase does not improve diagnostic accuracy); liver function tests (looking for evidence of obstructive pattern with gall stone induced pancreatitis); plain abdominal radiograph (excludes other aetiologies, and may show localised ileus [“sentinel loop”]; abdominal ultrasound (enlarged hypo-echoic pancreas, and looking for gall stones); and abdominal CT scan with contrast (confirm diagnois and looking for areas of necrosis or pseudocysts). Ranson’s criteria (or more recently Glasgow criteria or Imrie score) are used to assess severity and predict outcome, and they include white cell count (>16,000/mm3), glucose (>11 mmol/L), AST > 250 IU/L, Ca < 2mmol/L, hypoxaemia (<8kPa), and a decrease in haematocrit (>10%) and an increase in urea (>1.8 mmol/L).

Complications include: those associated with a systemic inflammatory response (e.g. myocardial depression/shock,  ARDS,  renal  failure,  death);  respiratory  (including  pleural  effucsion  and atelectasis);  metabolic  (including  hypocalcaemia,  glucose  disturbances);  and   intrabdominal problems (including ileus, necrosis, pseudo-cysts, abscess formation, etc).

Treatment should include: aggressive fluid resuscitation to stabilise the haemodynamic state, treatment of underlying cause (e.g. ERCP if gall stones present, withdrawal of offending drug), treatment of pain (morphine controversial), surgical treatment of complications (e.g. aspiration/drainage of infected collections) and general support of the critically ill patient. More contentious issues that should be considered include: early prophylactic broad spectrum antibiotics (evidence that decrease complications), prophylactic anti-fungal therapy, jejunal feeding (safe, feasible, cheaper than TPN, possibly of benefit), the use of somatostatin, octreotide or protease inhibitors (none have sufficient evidence base to use routinely), and the timing and nature of surgical interventions.

Discussion

This question dates back to a time when there was a whole massive period during which one had plenty of thinking room, planning, and then the process of written communication could take place at a civilised pace, without rush. Now, of course, a question like this has the candidate trying to fit the last 30 years of pancreatitis literature into a ten minute answer.

One patently cannot do this.

The suggested answer below is one which could easily be produced over the course of ten minutes.

Diagnostic features

  • Presentation with severe abdominal pain, nausea and vomiting on presentation
  • Metabolic acidosis and shock; hypocalcemia
  • Elevated pancreatic enzyme levels, of which lipase is the more pancreas-specific
  • An abdominal CT may reveal that a widened common bile duct is present, potentially with an impacted stone in the bile duct.

Complications

  • SIRS and hemodynamic compromise
  • renal failure
  • infection of pancreatic necrosis
  • hepatic failure
  • abdominal comaprtment syndrome
  • ARDS
  • hypocalcemia
  • metabolic acidosis
  • myocardial contractility depression
  • ileus

Treatment

  • Airway:
    • intubation may be required; aspiration may be a major risk
  • Breathing:
    • mechanical ventilation with PEEP titrated to permit recruitment of collapsed lung bases
    • As ARDS develops, tidal volumes may nee to be reduced and lung-protective ventilation may need to be adopted, with permissive hypercapnea
  • Circulation:
    • Initial stages of resuscitation will likely consist of fluids only
    • The SIRS response may lead to cardiovascular collapse; given that metabolic acidosis and SIRS-associated cardiomyopathy may also be present, inotropes as well as vasopressors will likely be required
  • Pain control:
    • this will be vitally important in the non-intubated patient, in order to maintain VQ matching by continuing deep breathing
  • Electrolytes- particularly calcium - must be carefully monitored
  • Fluid balance management neesd to be careful, and dialysis may be required
  • Feeds via the NG tube may be commenced; there does not appear to be any evidence that "pancreatic rest" is in any way beneficial. The necrotic pancreas is not going to be responsive to the normal secretory stimuli, and the
  • Coagulation factors need to be corrected, and careful surveillance of the abdominal vessels must occur, as the splenic artery has a tendency to form aneurysms and bleed everywhere
  • Antibiotics are probably not indicated
  • ERCP to manage the cause of CBD obstruction should take place at the earliest opportunity, as indicated. if there is no ERCP-amenable cause, surgical drainage of the necrotic pseudocyst may take place as soonas the pseudocyst has formed a sufficiently distinct "wall".
  • An alternative to surgical cyst drainage is endoscopic ultrasound-guided drainage, which may be a better option for the frail patient.

References

References

Wilmer, Alexander. "ICU management of severe acute pancreatitis." European journal of internal medicine 15.5 (2004): 274-280.