Page 11 - Acute Pancreatitis (Viêm tụy cấp)

902 PART VII Pancreas

to adjacent organs, surgery or endoscopic therapy may be neces- BOX 58 .5 Factors That Increase the Risk of Post-ERCP

sary to treat a pancreatic ductal injury.
The diagnosis of traumatic pancreatitis is difficult and requires Pancreatitis
a high degree of suspicion. Trauma can range from a mild con-
tusion to a severe crush injury or transection of the gland; the PATIENT-RELATED
latter usually occurs at the point where the gland crosses over Young age, female gender, suspected SOD, history of recurrent
the spine. Transection injury can cause acute duct rupture and pancreatitis, history of post-ERCP pancreatitis, normal serum
pancreatic ascites. It is impossible to determine on the basis of the bilirubin level
characteristics of the abdominal pain and tenderness whether the PROCEDURE-RELATED
pancreas has been injured as opposed to adjacent intra-abdominal
structures. Serum amylase or lipase activity may be increased in Pancreatic duct injection, difficult cannulation, pancreatic sphinc-
patients with abdominal trauma whether or not the pancreas has terotomy, precut access, balloon dilation
been injured. OPERATOR OR TECHNIQUE-RELATED
Diagnosis of pancreatic trauma is highly dependent on CT, Trainee (fellow) participation, nonuse of a guidewire for cannulation,
MRI, or MRCP, which may show enlargement of a portion of failure to use a pancreatic duct stent in a high-risk procedure
the gland caused by a contusion or subcapsular hematoma, pan-
creatic inflammatory changes, or fluid within the anterior parare-
nal space if there is ductal disruption. CT may be normal during cases in which ERCP should be avoided if possible, or in which
the first 2 days despite significant pancreatic trauma. If there is protective endoscopic or pharmacologic interventions should be
a strong clinical suspicion of pancreatic injury, or if the CT or considered.
MRCP scan shows an abnormality, ERCP is required to define In general, the more likely a patient is to have an abnormal
whether there is PD injury. If the PD is intact and there are no bile duct or PD, the less likely the patient will develop PEP. 138
other significant intra-abdominal injuries, surgery is not required. Cheng created a 160-variable database that prospectively evalu-
However, if ERCP reveals duct transection with extravasation of ated more than 1000 patients from 15 centers in the midwest-
pancreatic fluid and there are no other intra-abdominal injuries, ern USA. 134 Their study emphasized the role of patient factors
stenting of the PD across the leak if possible may be curative. 130 including age, SOD, prior history of PEP pancreatitis, and tech-
Serious injuries to the pancreas can be treated with appropriate nical factors, including number of PD injections, performance
debridement. Associated injuries to the duodenum or bile duct of a sphincterotomy of the minor papilla, and operator experi-
can be treated by biliary diversion, gastrojejunostomy, and feed- ence. The patient most at risk of developing PEP was a woman
ing jejunostomy. External pancreatic fistulas occur in approxi- with suspected choledocholithiasis and normal serum bilirubin,
mately one third of patients after surgery for pancreatic trauma. who underwent a sphincterotomy and no stone was found. In
Octreotide may be beneficial after pancreatic injury to decrease this patient population, 27% developed PEP. MRCP and EUS,
pancreatic secretion. 131 which do not cause pancreatitis, can provide useful information
The prognosis in patients with pancreatic trauma is favorable (perhaps as accurate as ERCP) in many of these cases and are
if there is no serious injury to other structures (regional blood preferred modalities in the initial evaluation of such patients. In
vessels, liver, spleen, kidney, duodenum, and colon). However, a study of 2715 therapeutic ERCPs, it was found that the endos-
duct injuries can scar and cause a stricture of the main PD, result- copist’s experience reduces patient- and procedure-related risk
ing in obstructive chronic pancreatitis. factors for post-ERCP complications. 138
Early recognition of PEP may be possible by evaluating
Post-ERCP serum amylase or lipase after the procedure. 139,140 In a study
that involved 231 patients, the 2-hour serum amylase and lipase
AP is the most common and feared complication of ERCP, asso- were more accurate than a clinical assessment in distinguishing
ciated with substantial morbidity and occasional mortality (see nonpancreatitis abdominal pain from post-ERCP AP. Serum
Chapter 42). Asymptomatic hyperamylasemia occurs after 35% amylase values above 276 IU/L (reference range, 30 to 70 IU/L)
to 70% of ERCPs. 133 Clinical AP occurs in 5% of diagnostic and lipase above 1000 IU/L (reference range, 45 to 110 IU/L) 2
ERCPs, 7% of therapeutic ERCPs, and up to 25% in those with hours after completing the procedure had almost a 100% positive
suspected SOD or in those with a history of post-ERCP pancre- predictive value (PPV) for PEP. 141 More recently, Ito and col-
atitis (PEP). 133 leagues found that if the serum amylase was normal after 3 hours,
A recent systematic review of 108 randomized controlled tri- only 1% of patients developed PEP, compared with 39% if the
als (RCTs) with 13,296 patients in the placebo or no-stent arms amylase was greater than 5 times the upper limit of normal. 142
reported an overall incidence of PEP of 9.7%, and the mortality A serum amylase or lipase alone should not guide a decision of
rate was 0.7%. Severity of PEP was reported for 8857 patients: whether a patient has PEP, because the disease may unfold over
5.7%, 2.6%, and 0.5% of patients had mild, moderate, and severe the next 24 hours. However, in the presence of abdominal pain, a
AP, respectively. The incidence of PEP in 2345 high-risk patients normal serum amylase and or lipase rules out AP at that moment.
was 14.7% (mild, moderate, and severe in 8.6%, 3.9%, and 0.8%, Although there has been an interest in developing medications
respectively, with a 0.2% mortality rate). The incidence of PEP that can prevent PEP, few studies have identified a medication
was 13% in North American RCTs, compared with 8.4% in worthy of widespread use. A number of drugs have not shown
European and 9.9% in Asian RCTs. ERCPs conducted before any benefit including nitroglycerin, nifedipine, sprayed lidocaine,
and after 2000 had a PEP incidence of 7.7% and 10%, respec- and injected botulinum toxin. The protease inhibitor gabex-
tively. 134 ate showed some benefit in small trials but is very expensive. 144
The mechanisms that lead to PEP are complex and not fully Inhibiting exocrine pancreatic secretion by somatostatin was not
understood. Rather than a single pathogenesis, PEP is believed beneficial in many studies, and its analog octreotide reduces only
to be multifactorial, involving a combination of chemical, hydro- hyperamylasemia.
static, enzymatic, mechanical, and thermal factors. Although The 3 major modalities shown to reduce the risk are post-
there is some uncertainty in predicting which patients will develop ERCP pancreatitis include prophylactic pancreatic stents, pre-
PEP, a number of risk factors acting independently or in concert procedural intravenous fluids, and rectal administration of
have been proposed as predictors of PEP (Box 58.5). 135,136 Iden- NSAIDs. Pancreatic stent placement clearly decreases the risk of
tification of these risk factors for PEP is essential to recognize PEP in high-risk patients. 144 Placement of PD stents has become