Wednesday, August 18, 2010

Acute pancreatitis---another review

There have been several reviews of acute pancreatitis lately, all varying slightly in their focus. The latest is from The Journal of Hospital Medicine.

Points of interest:

Although the 20% or so of patients who do not have gallstones or a history of ethanol abuse are considered idiopathic they aren't really idiopathic. If a gallbladder is in tact a diagnosis of microlithiasis or sludge can be invoked, and that is supported by evidence. If the gallbladder has been removed Sphincter of Oddi dysfunction is plausible and evidence supported. Of the remainder of these 20% of patients drugs, hypercalcemia, hypertriglyceridemia, familial cause, anatomic abnormalities or autoimmune pancreatitis (which can also cause chronic pancreatitis or mimic pancreatic carcinoma) are known causes. The patient really has idiopathic pancreatitis if none of these are present.

CT is a useful imaging modality but not mandatory in all cases. CT scanning on day 1 is used principally to exclude other causes of abdominal pain if the diagnosis is not clear on clinical and laboratory grounds. CT scanning on day 2, 3 or 4 is more useful for assessment of complications or severity.

MRCP has the highest sensitivity for diagnosing common bile duct stones and can provide information on ductal anatomy that may clarify the cause of the pancreatitis, as well as select patients for ERCP.

Severity assessment
This is critical as it impacts management in several ways. Several scoring systems are presented.

Initial management
This consists mainly of general symptomatic and supportive care. Fluid resuscitation is believed to be critical but the optimal volume is controversial. High level data are lacking. Expert opinion and pathophysiologic rationale have led to recommendations for 250-300 ml/hr for the first 48 hrs if the patient's cardiopulmonary status permits.

In mild cases the patient can be started on clear liquids with advancement as tolerated, as soon as pain is markedly improved. In severe cases artificial support is indicated. Enteral is favored over TPN. Jejunal feeding has been favored over NG feeding in the past although recent data challenge that tradition. NG feeding is acceptable in many cases.

Antibiotics are not indicated for pancreatitis per se although there are specific indications. Prophylactic antibiotics, to prevent infected pancreatic necrosis or other pancreatic infections, have been traditionally recommended for patients who are assessed as having severe pancreatitis or who have pancreatic necrosis. This is controversial, however, and current guidelines do not recommend them. A septic picture or other signs/symptoms of infection justify antibiotics as well as suspected cholangitis. Antibiotics are generally recommended for cholecystitis although the evidence is unclear. When antibiotics are used, “pancreatic coverage” generally consists of either a pemen or a quinolone combined with metronidazole.

ERCP has a role in gallstone pancreatitis. Timing depends on clinical circumstances and is urgent in cholangitis.

This is indicated in documented gallstone pancreatitis, that same admission if possible, but at least no later than 4 weeks, absent surgical contraindications, given the high rate of relapse of gallstone pancreatitis if not done.

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