Acute Pancreatitis

Symptoms, Diagnosis, Treatment

Acute abdomen

1. Causes
Although pancreatitis has numerous etiologies, alcohol exposure and biliary tract disease cause most cases. In 10-30% of cases, the cause is unknown,...
1.1 Most common causes
1.2 Less common causes
1.3 Causes by demographic
3. Diagnosis
3.1 Lab findings
3.2 Imaging Studies
3.3 Procedures

Acute pancreatitis is rapidly-onset inflammation of the pancreas. Depending on its severity, it can have severe complications and high mortality despite treatment. While mild cases are often successfully treated with conservative measures or laparoscopy, severe cases require invasive surgery (often more than one intervention) to contain the disease process.

1. Causes

Although pancreatitis has numerous etiologies, alcohol exposure and biliary tract disease cause most cases. In 10-30% of cases, the cause is unknown, although recent studies have suggested that up to 70% of cases of idiopathic pancreatitis are secondary to biliary microlithiasis.

Biliary tract disease (approximately 40%)
Alcohol (approximately 35%)
Post-ERCP (approximately 4%)
Trauma (approximately 1.5%)
Drugs (approximately 2%)
Infection (<1%)
Hereditary pancreatitis (<1%)
Hypercalcemia (<1%)
Developmental abnormalities of the pancreas (<1%)
Hypertriglyceridemia (<1%)
Tumor (<1%)
Toxins (<1%)
Postoperative (<1%)
Vascular abnormalities (<1%)
Autoimmune pancreatitis (<1%)
In up to 10% of cases, the cause of pancreatitis remains unknown (idiopathic).

1.1 Most common causes

A common mnemonic for the causes of pancreatitis spells "I get smashed", an allusion to heavy drinking which is one of the many causes:

I - idiopathic
G - gallstone. Gallstones that travel down the common bile duct and which subsequently get stuck in the Ampulla of Vater can cause obstruction in the outflow of pancreatic juices from the pancreas into theduodenum. The backflow of these digestive juices causes lysis (dissolving) of pancreatic cells and subsequent pancreatitis.
E - ethanol (alcohol)
T - trauma
S - steroids
M - mumps (paramyxovirus) and other viruses (Epstein-Barr virus, Cytomegalovirus)
A - autoimmune disease (Polyarteritis nodosa, Systemic lupus erythematosus)
S - scorpion sting - Tityus Trinitatis - Trinidad/ snake bite
H - hypercalcemia, hyperlipidemia/hypertriglyceridemia and hypothermia
E - ERCP (Endoscopic Retrograde Cholangio-Pancreatography - a procedure that combines endoscopy and fluoroscopy)
D -drugs (SAND - steroids & sulfonamides, azathioprine, NSAIDS, diuretics such as furosemide and thiazides, & didanosine) and duodenal ulcers

1.2 Less common causes

Pancreas divisum
Long common duct
Carcinoma of the head of pancreas, and other cancer
Ascaris blocking pancreatic outflow
Ischemia from bypass surgery
Fatty necrosis
Pregnancy
Infections other than mumps, including varicella zoster
Repeated marathon running.
Cystic fibrosis

1.3 Causes by demographic

The most common causes of pancreatitis are as follows:

Western countries - chronic alcoholism and gallstones accounting for more than 85% of all cases
Eastern countries - gallstones
Children - trauma
Adolescents and young adults – mumps

2. Symptoms

The most common symptom of acute pancreatitis is pain. Almost everybody with acute pancreatitis experiences pain.

The pain may come on suddenly or build up gradually. If the pain begins suddenly, it is typically very severe. If the pain builds up gradually, it starts out mild but may become severe.
The pain is usually centered in the upper middle or upper left part of the belly. The pain may feel as if it radiates through to the back.
The pain often begins or worsens after eating.
The pain typically lasts a few days.
The pain may feel worse when a person lies flat on his or her back.

People with acute pancreatitis usually feel very sick. Besides pain, people may have other symptoms.

Nausea (Some people do vomit, but vomiting does not relieve the symptoms.)
Fever, chills, or both
Swollen abdomen which is tender to the touch
Rapid heartbeat (A rapid heartbeat may be due to the pain and fever, or it may be a compensation if a person is bleeding internally.)

In very severe cases with infection or bleeding, a person may become dehydrated and have low blood pressure, in addition to the following symptoms:

Weakness or feeling tired (fatigue)
Feeling lightheaded or faint
Lethargy
Irritability
Confusion or difficulty concentrating
Headache

3. Diagnosis

3.1 Lab findings

Amylase and lipase

Serum amylase and lipase levels are typically elevated in persons with acute pancreatitis. Amylase or lipase levels at least 3 times above the reference range are generally considered diagnostic of acute pancreatitis.
The level of serum amylase or lipase does not indicate whether the disease is mild, moderate, or severe, and monitoring levels serially during the course of hospitalization does not offer insight into prognosis.

Liver-associated enzymes

Determine alkaline phosphatase, total bilirubin, aspartate aminotransferase, and alanine aminotransferase levels to search for evidence of gallstone pancreatitis.
An alanine aminotransferase level greater than 150 U/L suggests gallstone pancreatitis and a more fulminant disease course.

Calcium, magnesium, cholesterol, and triglycerides: Determine these levels to search for an etiology of pancreatitis (hypercalcemia or hyperlipidemia) or complications of pancreatitis (hypocalcemia resulting from saponification of fats in the retroperitoneum). However, be wary of the fact that baseline serum triglyceride levels can be falsely lowered during an episode of acute pancreatitis.
Serum electrolytes, BUN, creatinine, and glucose: Measure these to look for electrolyte imbalances, renal insufficiency, and pancreatic endocrine dysfunction.
CBC count

Hemoconcentration at admission (an admission hematocrit value greater than 47%) has been proposed as a sensitive measure of more severe disease.
Leukocytosis may represent inflammation or infection.

C-reactive protein

A C-reactive protein (CRP) value can be obtained 24-48 hours after presentation to provide some indication of prognosis. Higher levels have been shown to correlate with a propensity toward organ failure.
A CRP value in double figures (ie, >10 mg/dL) strongly indicates severe pancreatitis. CRP is an acute-phase reactant that is not specific for pancreatitis.

Arterial blood gases

Measure ABGs if a patient is dyspneic.
Whether tachypnea is due to acute respiratory distress syndrome or diaphragmatic irritation must be determined.

3.2 Imaging Studies

Although unnecessary in most cases of pancreatitis, visualization of inflammatory changes within the pancreas provides morphologic confirmation of the diagnosis. Obtain imaging tests when the diagnosis is in doubt, when severe pancreatitis is present, or when a given imaging study might provide specific information needed to answer a clinical question.
Abdominal radiography

These radiographs are primarily used to detect free air in the abdomen, indicating a perforated viscus, as would be the case in a penetrating, perforated duodenal ulcer.

Abdominal ultrasonography

This is the most useful initial test in determining the etiology of pancreatitis and is the technique of choice for detecting gallstones.

Abdominal CT scanning
Magnetic resonance cholangiopancreatography

Magnetic resonance cholangiopancreatography (MRCP) has an emerging role in the diagnosis of suspected biliary and pancreatic duct obstruction in the setting of pancreatitis.

Endoscopic ultrasonography

3.3 Procedures

Endoscopic retrograde cholangiopancreatography
CT-guided needle aspiration
EUS-guided needle aspiration
EUS-guided fluid collection drainage

4. Treatment

In acute pancreatitis, the choice of treatment is based on the severity of the attack. If no complications are present, care usually focuses on relieving symptoms and supporting body functions so that the pancreas can recover.

Most people who are having an attack of acute pancreatitis are admitted to the hospital.
Those people who are having trouble breathing are given oxygen.
An IV line is started, usually in the arm. The IV line is used to give medications and fluids. The fluids replace water lost from vomiting or from inability to take in fluids, helping the person to feel better.
If needed, medications for pain and nausea are prescribed.
Antibiotics are given if the health care provider suspects an infection may be present.
No food or liquid should be taken by mouth for a few days. This is called bowel rest. By refraining from food or liquid intake, the intestinal tract and pancreas are given a chance to start healing.
Some people may need a nasogastric (NG) tube. The thin, flexible plastic tube is inserted through the nose and down into the stomach to suck out the stomach juices. This suction of the stomach juices rests the intestine further, helping the pancreas to recover.
If the attack lasts longer than a few days, nutritional supplements are administered through an IV line.
If the pancreatitis is caused by gallstones, an operation to have the gallbladder and gallstones removed (cholecystectomy) is likely.

If certain complications (for example, enlargement or severe injury of the pancreas, bleeding, pseudocysts, or abscess) develop, surgery may be needed to drain, repair, or remove the affected tissues.

5. References

[1] Cope's Early Diagnosis of the acute abdomen. chapter 9 Acute pancreatitis.

[2] Acute pancreatitis, Wikipedia. (http://www.answers.com/topic/acute-pancreatitis)

[3] Pancreatitis, acute, eMedicine. (http://www.emedicine.com/MED/topic1720.htm)

[4] Pancreatitis, eMedcineHealth. (http://www.emedicinehealth.com/pancreatitis/article_em.htm)

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