Acute Pancreatitis - Causes, Presentation, Diagnosis, and Management

Introduction:

Acute pancreatitis is a common gastrointestinal emergency for hospitalization. The most common cause of acute pancreatitis is gallstones, followed by the intake of alcohol. Acute pancreatitis can be a mild form or a severe form which can be life-threatening. The diagnostic criteria for acute pancreatitis include pain in the abdomen, increased levels of serum amylase or lipase, and positive abdominal imaging. The treatment includes management of pain, intravenous hydration, which should be done aggressively, and appropriate nutrition.

What Is Acute Pancreatitis?

Acute pancreatitis (AP) is the inflammation of the pancreas with short onset of time. Pancreas is the organ present behind the abdomen whose main function is to help with digestion and regulate the blood sugar level by secreting insulin. This inflammation can be associated with the impairment of functions of other organs called systemic inflammatory response syndrome (SIRS).

What Are the Causes of Acute Pancreatitis?

The causes of acute pancreatitis are:

• Gallstone Pancreatitis: It is the common cause, and about 28 % to 38 % of cases are due to this. Gallstone is formed due to obstruction in the duct, increased duct pressure, and stimulation of pancreatic enzymes.

• Alcoholic Pancreatitis: It is the second most common cause, and about 19 % to 41 % of cases are due to this.

• Hypertriglyceridemia: It is one of the rare causes of acute pancreatitis. There are increased levels of triglycerides (a type of fat) in the body.

• Changes in Genetics: Specific cystic fibrosis gene (CFTR) genotypes are associated with acute pancreatitis. Hereditary pancreatitis is caused due to mutation in the cationic trypsinogen (PRSS1) gene and usually causes chronic pancreatitis. In the case of young patients with no definite cause, changes in genes should be considered.

• Drug-Induced Acute Pancreatitis: It is a rare cause. Drugs such as Sulfonamides, Pentamidine, Diuretics, 6-mercaptopurine, Azathioprine, Steroids, and Estrogen can cause acute pancreatitis.

• Infection-Induced Acute Pancreatitis: Mumps, hepatitis B virus, varicella-zoster virus, mycoplasma, herpes simplex virus, toxoplasma, salmonella, cytomegalovirus, and cryptosporidium are associated with acute pancreatitis.

• Trauma-Induced Acute Pancreatitis: A blunt trauma can also cause acute pancreatitis.

• Post-Endoscopic Retrograde Cholangiopancreatography (ERCP): ERCP is done to treat pancreatic and bile ducts. After an ERCP, there are increased levels of serum amylase causing acute pancreatitis.

• Hypercalcemia: Increased calcium levels can induce AP.

• Pancreatic Anatomical Abnormalities: Pancreatic ductal stricture and annular pancreas can cause AP.

• Vascular: Rheumatic diseases (immune system affecting the joints, organs, and muscles), shock, and atheromatous embolization (a complication of atherosclerosis which is a build-up of plaque in the arteries) are also associated with AP.

• Pregnancy: It is a rare cause.

• Malignancies: Intra-ductal papillary mucinous neoplasms (IPMNs, benign pancreatic cysts) are associated with AP.

• Autoimmune Pancreatitis (AIP): This is caused due to defect in the immune system.

• Idiopathic: Unidentifiable causes are usually due to microlithiasis (small deposits of calcium).

How Are Acute Pancreatitis Presented and Diagnosed?

In the beginning, the patient presents with symptoms such as epigastric abdominal pain, which occurs below the ribs, and above the abdomen that lasts for many hours; sometimes, the pain radiates to the back, vomiting and nausea. When a patient with acute pancreatitis is presented in the hospital, serum amylase or lipase levels, liver chemistries such as bilirubin, alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase levels, and an ultrasound of the abdomen for the evaluation of gallstones in the gallbladder or in the common bile duct called cholelithiasis and choledocholithiasis respectively should be evaluated. Invasive evaluations should not be performed. The diagnosis includes:

• The diagnosis should focus on the symptoms and should evaluate any presence of previous gallstones, history of alcohol intake, history of hypertriglyceridemia (increased levels of triglycerides in the body), presence of autoimmune disorder, family history of pancreatic diseases, and drug history.

• On physical examination, there is tenderness on palpation around the abdomen area, and there are no bowel sounds. Rarely Cullen's and Turner's signs (discoloration around the umbilical area and left flank) are seen, which suggests a risk of mortality and is associated with hemorrhage.

• Laboratory tests show increased pancreatic enzymes and trypsin levels.

• A contrast CT (computed tomography) scan and MRI (magnetic resonance imaging) are used to scan the pancreatic area. The characteristic feature is the presence of a focal or diffuse area in the pancreas.

• A contrast-enhanced CT scan can help in assessing the severity of the inflammation.

• MRI is indicated in the case of high levels of LFTs (liver function tests).

• The diagnostic criteria are the presence of any two of the criteria, which are abdominal pain, increased serum amylase or lipase levels to three folds, and positive findings of AP in the abdominal scanning.

How Is Acute Pancreatitis Managed?

Before the management, the severity should be assessed to select the proper treatment plan. The management of AP includes:

• Initial Assessment: This is an important step. A patient with severe inflammatory response syndrome (SIRS) should be directly admitted into the ICU (intensive care unit). In case of three or more BISAP (bedside Index of Severity in Acute Pancreatitis) scores, the patient should also be admitted to ICU.

• Fluid Resuscitation: This involves aggressive early fluid resuscitation, which can decrease mortality in case of severe sepsis (extreme infection). This should be evaluated after six to 24 hours because extreme fluids can have worse outcomes. The rate of fluids should be modified according to the urine output, mean arterial pressure, and BUN (blood urea nitrogen) values. The fluids which are used in this are normal saline and Ringer's Lactate solution.

• Nutrition: Oral feedings should be initiated early, within 24 hours, in case of mild AP, which helps in preventing bacterial translocation and protecting the gut-mucosal barrier. In case of patients have difficulty in feeding, they should undergo enteral feeding through nasojejunal or nasogastric routes.

• Management of Pain: Opioids are used in the case of uncontrolled pain

• Antibiotics: These are given to reduce the inflammation of the pancreas and are given as early as possible. Antibiotics such as Quinolones, Carbapenems, and Metronidazole are used, which can penetrate the pancreas.

• Endoscopy: This is indicated in case of gallbladder stones or obstruction in the bile duct. In the case of cholangitis (bile duct infection), the patient should undergo ERCP, which can reduce morbidity.

• Surgery: It is indicated in the case of gallstones, and in the case of necrosis, necrosectomy (removal of dead tissue) is performed. In the case of mild AP, cholecystectomy (removal of the gallbladder) is performed on the same day of admission.

• Alcoholic Cessation: Patients should undergo counseling to stop the intake of alcohol. Positive effects can stop the recurrence for at least two years.

Conclusion:

Acute pancreatitis is one of the major causes of emergency treatment and mostly occurs due to gallstones and alcohol. It can either be a mild or severe life-threatening situation. Management of complications necrosis, inflammation around the pancreas, formation of pseudocysts, and hemorrhage should be taken care of.