Pancreatitis




(1)
Division of Pulmonary and Critical Care Medicine, Eastern Virginia Medical School, Norfolk, VA, USA

 



Diagnosis

Risk Stratification

Complications

Management

References


Keywords
PancreatitisAlcoholGall stonesEnteral nutritionFluid resuscitationAmylaseLipasePancreatic abscessPseudocyst


Acute pancreatitis is a common disease that causes significant morbidity and mortality. Pancreatitis is the most common principle gastrointestinal discharge diagnosis in the United States [1]. More than 250,000 patients are admitted per year for pancreatitis and about 3,000 die from this disease per year in the US [1, 2]. Furthermore, the hospitalization rate for acute pancreatitis in the US is rising [2]. About 15 % of all patients with acute pancreatitis develop necrotizing pancreatitis. Mortality ranges from 3 % for patients with interstitial edematous pancreatitis to 15 % for patients who develop necrosis [3, 4]. In developed countries, obstruction of the common bile duct by stones (38 %) and alcohol abuse (36 %) are the most frequent causes of acute pancreatitis. Gallstone-induced pancreatitis is caused by duct obstruction of gallstone migration. Obstruction is localized in the bile duct, the pancreatic duct, or both. Other well established causes of acute pancreatitis include:



  • Hypertriglyceridemia


  • Post–ERCP


  • Drug induced


  • Autoimmune


  • Genetic


  • Abdominal trauma


  • Postoperative


  • Ischemia


  • Infections


  • Hypercalcemia and hyperparathyroidism


  • Posterior penetrating ulcer


  • Scorpion venom

Abdominal pain is the cardinal symptom. It occurs in about 95 % of cases. Typically it is generalized to the upper abdomen, but it may be more localized to the right upper quadrant, epigastric area, or, occasionally, left upper quadrant. The pain typically occurs acutely, without a prodrome, and rapidly reaches maximum intensity. It tends to be moderate to severe in intensity and tends to last for several days. The pain typically is boring and deep because of the retroperitoneal location of the pancreas. About 90 % of patients have nausea and vomiting, which can be severe and unremitting. The severity of the physical findings depends on the severity of the attack. Mild disease presents with only mild abdominal tenderness. Severe disease presents with severe abdominal tenderness and guarding, generally localized to the upper abdomen. Rebound tenderness is unusual.


Diagnosis






  • Leukocytosis is common because of a systemic inflammatory response.


  • Mild hyperglycemia is common because of decreased insulin secretion and increased glucagon levels.


  • The serum lipase level is the primary diagnostic marker for acute pancreatitis because of its high sensitivity and specificity. Serum lipase is more than 90 % sensitive for acute pancreatitis [5]. The serum lipase level rises early in pancreatitis and remains elevated for several days.


  • Serum amylase concentrations exceeding three times the normal upper limit supports the diagnosis of acute pancreatitis. However, the serum amylase is within the normal range on admission in up to 20 % of the patients.


  • In a meta-analysis, a serum ALT level higher than 150 IU/L had a positive predictive value of 95 % in diagnosing acute gallstone pancreatitis [6].


  • Any patient who has unexplained, severe abdominal pain should undergo supine and upright chest and abdominal radiographs. Abdominal radiographs are performed mainly to exclude alternative abdominal diseases, such as gastrointestinal perforation.


  • Abdominal ultrasonography is the primary imaging study for abdominal pain associated with jaundice and for excluding gallstones as the cause of acute pancreatitis. It has the advantages of low cost, ready availability, and easy portability for bedside application in very sick patients. It is ubiquitous in the evaluation of pancreatitis. When adequately visualized, an inflamed pancreas is recognized as hypoechoic and enlarged because of parenchymal edema. The pancreas is visualized inadequately in 30 % of cases.


  • Patients who present with severe pancreatitis or who present initially with mild to moderate pancreatitis that does not improve after 5–7 days of supportive therapy should undergo abdominal CT imaging [7]. CT scan with contrast is the standard approach for the diagnosis and work-up of severe pancreatitis. Except in cases of initial diagnostic uncertainty, it is advisable to wait 5–7 days to obtain the initial scan. A contrast enhanced CT scan obtained within the first few days cannot be used to determine whether a patient has necrotizing or severe interstitial pancreatitis. Patients should receive both intravenous and oral contrast. Areas of necrosis with diminished or no enhancement upon contrast bolus are detected with an accuracy of 87 % (see CT Grading system below). Renal insufficiency is a relative contraindication to the use of intravenous contrast agent.


  • Magnetic resonance cholangiopancreatography (MRCP) has become a useful procedure for identifying retained common bile duct stones [7]. Selective use of MRCP can reduce the need for endoscopic retrograde cholangiopancreatography (ERCP) for patients with suspected gallstone pancreatitis.


Risk Stratification


Most episodes of acute pancreatitis are mild and self-limiting, needing only brief hospitalization. However, 20 % of patients develop severe disease with local and extrapancreatic complications characterized by early development and persistence of hypovolemia and multiple organ dysfunction. Risk stratification plays a key role in the management of patients with acute pancreatitis. Although amylase and lipase remain the standard for diagnosis, they are poor predictors of severity. A number of scoring systems have been developed to assess the severity of pancreatitis. The Ranson Criteria was the first scoring system to be developed and remains commonly employed today [8]. More recently, the APACHE II Scoring System and the Imrie Score have been used to predict severity. The Balthazar computed tomography grading system is widely used in patients who have undergone CT scanning. Severe Acute Pancreatitis as defined by the Atlanta Symposium include a Ranson Score ≥ 3, APACHE-II score ≥8, organ failure and/or local complications (necrosis, abscess or pseudocyst) [9]. The Bedside Index of Severity in Acute Pancreatitis is a 5-factor scoring system that can be performed during the first 24 h of admission [10]. The Bedside Index of Severity in Acute Pancreatitis score >2 within 24 h is associated with a sevenfold increase in the risk of organ failure and a tenfold increase in the risk of mortality [11, 12].

(a)

Ranson’s Criteria



  • At presentation



    • Age older than 55 years


    • Blood glucose level greater than 200 mg/dL


    • White blood cell count greater than 16,000/mm3


    • Lactate dehydrogenase level greater than 350 IU/L


    • Alanine aminotransferase level greater than 250 IU/L


  • 48 h after presentation



    • Hematocritd 10 % decrease


    • Serum calcium less than 8 mg/dL


    • Base deficit greater than 4 mEq/L


    • Blood urea nitrogen increase greater than 5 mg/dL


    • Fluid sequestration greater than 6 L


    • PaO2 less than 60 mmHg

 

(b)

Glasgow (Imrie) Severity Scoring System



  • Age >55 years


  • White cell count >15 × 109/L


  • PaO2 < 60 mmHg Serum lactate dehydrogenase >600 units/L


  • Serum aspartate aminotransferase >200 units/L*


  • Serum albumin <3.2 g/dL


  • Serum calcium <2 mmol/L (8 mg/dL)


  • Serum glucose >10 mmol/L (180 mg/dL)


  • Serum urea >16 mmol/L (44.8 mg/dL)

 

(c)

Balthazar CT Grading System



  • A: Normal


  • B: Gland enlargement, small intrapancreatic fluid collections


  • C: Peripancreatic inflammation, >30 % pancreatic necrosis


  • D: Single extrahepatic fluid collection, 30–50 % pancreatic necrosis


  • E: Extensive extrapancreatic fluid collections, >50 % pancreatic necrosis

 

(d)

The Bedside Index of Severity in Acute Pancreatitis (one point each)



  • Bun > 25 mg/dL


  • Altered mental state


  • Systemic inflammatory response syndrome (SIRS)


  • Age ≥ 60 years


  • Pleural effusion

 

(e)

The Revised Atlanta Classification recognizes 3° of severity [13].



  • Mild disease is defined as acute pancreatitis not associated with organ failure, local complications or systemic complications.


  • Moderately severe acute pancreatitis is defined by the presence of transient organ failure, local complications or systemic complications. Transient organ failure is define by organ failure that is present for <48 h.


  • Severe acute pancreatitis is defined by the presence of persistent organ failure (>48 h). Most patients with severe pancreatitis have pancreatic necrosis and a reported mortality of about 30 % [14].

 


Complications




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Oct 12, 2016 | Posted by in CRITICAL CARE | Comments Off on Pancreatitis

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