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Acute Pancreatitis (AP)

Discuss AP?

Pancreatitis is classified as acute unless there are CT or ERCP findings of chronic pancreatitis. Gallstones and chronic alcohol abuse account for 75% of acute pancreatitis. However, in up to 10% of cases, the cause of AP remains unknown (idiopathic AP). Other causes are listed below

Discuss the aetiology of AP?

  • Post ERCP
  • Abdominal trauma
  • Drug Induced pancreatitis (mild and self limiting) Drugs strongly associated with AP include azathioprine, sulphonamides, sulindac, tetracycline, valproic acid, didanosine, methyldopa, estrogens, furosemide, 6-mercaptopurine, pentamidine, 5-aminosalicylic acid compounds, corticosteroids, and octreotide.
  • Infections- Viral infections (such as Epstein-Barr, Coxsackie virus, echovirus, varicella-zoster and measles) are the most common causes of infectious AP especially in children. Some bacteria and ascariasis may also cause AP.
  • Hereditary pancreatitis- Genetic analysis is recommended in the presence of family h/o acute pancreatitis or pancreatic cancer.
  • Hyperparathyroidism and hypercalcemia
  • Hypertriglyceridemia (11 mmol/l or more)
  • Developmental anomalies like pancreatic divisum, SOD dysfunction
  • Pancreatic ductal obstruction by tumours
  • Autoimmune pancreatitis

After a first episode of apparent idiopathic pancreatitis, most patients have no further episodes suggesting that extensive investigations are not required after the first episode. Hence a search for other causes of acute pancreatitis is not done. EUS to exclude pancreatic tumours should be considered in pts > 40 who presents with a first episode of unexplained pancreatitis.

Discuss the diagnosis of AP?

Abdominal pain together with elevation of plasma levels of pancreatic enzymes is the cornerstone of diagnosis.

  • Serum amylase- more than 3 times the upper limit of normal in the absence of renal failure. Other causes of raised amylase (usually < 3 times) – Pancreatic causes- pancreatic tumours. Abdominal causes- acute cholecystitis, CBD obstruction, bowel perforation, int. ischemia or obstruction, acute appendicitis, ruptured ectopic, acute salpingitis. Salivary glands- mumps, alcohol effects. Ovarian tumour, Ca lung etc.
  • Serum lipase- Elevation of lipase levels is somewhat more specific and is thus preferred. Elevations in amylase or lipase levels less than 3 times the upper limit of normal have low specificity for acute pancreatitis and hence are consistent with, but not diagnostic of, acute pancreatitis.
  • USS- universal use within 24 hrs to search for gallstones.
  • CT scan- Rapid-bolus contrast-enhanced CT should be performed after 72 hours of illness to assess the degree of pancreatic necrosis in patients with predicted severe disease (APACHE II score >8) and in those with evidence of organ failure during the initial 72 hours. CT should be used selectively based on clinical features in those patients not satisfying these criteria.
    An early CT (within 72 hours of illness onset) might underestimate the amount of pancreatic necrosis.
    CT or EUS should also be performed in those patients with unexplained pancreatitis who are at risk for underlying pancreatic malignancy (age older than 40 years).
  • ERCP- indications only 2- biliary sepsis or persistent obstructive jaundice.

Discuss the assessment of severity of AP?

  • The prediction of severe disease is best achieved by careful ongoing clinical assessment coupled with the use of a multiple factor scoring system and imaging studies.
  • The Acute Physiology and Chronic Health Evaluation (APACHE) II system is preferred, utilizing a cut off of more than 8. Those with predicted or actual severe disease, and those with other severe co morbid medical conditions, should be strongly considered for triage to an intensive care unit or intermediate medical care unit.
  • Ranson is another scoring system used in clinical practice.

Discuss the features that predict a severe AP?

Initial assessment

  • Clinical impression of severity
  • BMI>30
  • Pleural effusion on CXR
  • APACHE II score >8

24 h after admission

  • Clinical impression of severity
  • APACHE II score >8
  • Persisting organ failure, especially if multiple
  • CRP > 150 mg/l

48 h after admission

  • Clinical impression of severity
  • Persisting organ failure for 48 h
  • Multiple or progressive organ failure
  • CRP > 150 mg/l

You can calculate the Ranson’s score here

Discuss the treatment of AP?
Treatment is mainly supportive

  • NPO- initiate oral feeding when abdominal pain and tenderness subside, if there are no complications and serum amylase is nearly normal. Begin oral feeding by giving clear fluids for first 24 hrs. If tolerated, advice feedings gradually over 3-4 days to soft and finally solid foods. Severe pancreatitis may need nutritional support- enteral feeding preferred using endoscopically placed NJ tube. There is some evidence that nasogastric feeding may be feasible in up to 80% of cases.
  • IV fluids-vigorous fluid resuscitation. NG tube not used as it is not beneficial. It is only used to treat gastric or intestinal ileus or intractable n & v.
  • Pain relief- opiods are normally used including morphine and pethidine
  • Role of prophylactic antibiotics- Antibiotic prophylaxis, if used, should be restricted to patients with substantial pancreatic necrosis (>30% of the gland necrotic by CT criteria) and should continue for no more than 14 days. Imipenem or cefuroxime may be used.

Discuss gallstone pancreatitis?

In patients with no history of alcohol consumption, an increased level of serum alanine aminotransferase up to 3 times its normal value is indicative of gallstone pancreatitis.

Discuss the role of ERCP in AP?

  • Urgent ERCP (within 24 hours) should be performed in patients with gallstone pancreatitis who have concomitant cholangitis.
  • Early ERCP (within 72 hours) should be performed in those with a high suspicion of a persistent common bile duct stone (visible common bile duct stone on non-invasive imaging, persistently dilated common bile duct, and jaundice).
  • BSG in addition recommends urgent ERCP in those with predicted or actual severe gallstone pancreatitis in the absence of cholangitis or a high suspicion of a persistent common bile duct. This practice is however controversial.

British Society of Gastroenterology recommends endoscopic sphincterotomy in all patients undergoing early ERCP whether or not stones are found in the bile duct. However data supporting this practice are lacking. In those unfit for surgery, ERCP and sphincterotomy alone provides adequate long-term therapy. In all others with gallbladder in situ, definitive surgical management (cholecystectomy) should be performed in the same hospital admission if possible and, otherwise, no later than 2–4 weeks after discharge. Failure to perform cholecystectomy is associated with 25% risk of recurrent acute pancreatitis, cholecystitis or cholangitis within 6 weeks. A cholangiogram and clearing the CBD of stones during surgery or by ERCP are mandatory to prevent recurrent pancreatitis after cholecystectomy.

Discuss the Management of necrosis?

The development of infected necrosis is suspected in those patients with pre-existing sterile pancreatic necrosis who have persistent or worsening symptoms or symptoms and signs of infection, typically after 7–10 days of illness.
The infection may be diagnosed either by the presence of gas within the pancreatic collection or by fine needle aspiration.
There is agreement that all patients with infected necrosis require intervention by radiological or surgical drainage. There is controversy over the roles of radiological drainage and surgical necrosectomy in the management of infected pancreatic and peripancreatic necrosis. Standard surgical practice is that all patients with infected necrosis should undergo necrosectomy. This has been challenged by retrospective studies from referral centres describing good outcome in patients managed by percutaneous drains.

Discuss Ranson’s 11 criteria?
AP is severe if 3 or more present;
At admission-
Age>55, WCC>16,000, Glucose >11, LDH>350, AST>250
During initial 48 hrs-
Haematocrit decrease of >10mg/dl
BUN increase of more than 5mg/dl
Calcium <8mg/dl
PaO2 <60mm Base deficit > 4
Fluid sequestration >6L

Ref

  1. British Society of Gastroenterology guidelines for the management of acute pancreatitis


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