Pancreatitis is the inflammation of the pancreas. It occurs when the enzymes that digest food are activated in the pancreas instead of the small intestine. Pancreatitis may be acute or chronic. Acute pancreatitis is very sudden and lasts for a few days while chronic pancreatitis occurs over many years. Chronic pancreatitis has multiple causes, painful symptoms, and many simple ways to be cured.
Severe upper abdominal pain, with radiation through to the back, is the hallmark of pancreatitis. Nausea and vomiting (emesis) are prominent symptoms. Findings on the physical exam will vary according to the severity of the pancreatitis and whether or not it is associated with significant internal bleeding. The blood pressure may be high (when pain is prominent) or low (if internal bleeding or dehydration has occurred). Typically, both the heart and respiratory rates are elevated. Abdominal tenderness is usually found but may be less severe than expected given the patient's degree of abdominal pain. Bowel sounds may be reduced as a reflection of the reflex bowel paralysis (i.e., ileus) that may accompany any abdominal catastrophe. Many symptoms of pancreatitis are extremely painful and/or uncomfortable. Symptoms include pain in the upper abdomen which can spread to the upper back, nausea, vomiting, fever, and jaundice. In some serious cases, chronic pancreatitis can cause diabetes. Unexplained weight loss may also occur because the body does not have enough pancreatic enzymes to digest food, so nutrients are not absorbed normally.
Causes
Some of the causes of acute pancreatitis can be remembered by the mnemonic "I GET SMASHED"::
- Idiopathic;
- Gallstones;
- Ethanol;
- Trauma;
- Steroids;
- Mumps;
- Autoimmune;
- Scorpion sting;
- Hypercalcaemia, hypertriglyceridaemia, hypothermia;
- ERCP (endoscopic retrograde cholangiopancreatography);
- Drugs (e.g., azathioprine, diuretics);
Most common causes: gallstones and alcohol
The most common cause of acute pancreatitis is the presence of gallstones—small, pebble-like substances made of hardened bile—that cause inflammation in the pancreas as they pass through the common bile duct.
Excessive alcohol use is the most common cause of chronic pancreatitis, and can also be a contributing factor in acute pancreatitis. There are many causes of chronic pancreatitis. The most common cause is overconsumption of alcohol. Chronic pancreatitis can form from just one attack of acute pancreatitis. Chronic pancreatitis can result if certain medications continue to be taken, alcohol intake continues to be high, and eating habits do not change.
Other causes
Less common causes include,
- Pancreatic cancer
- Vasculitis (i.e., inflammation of the small blood vessels within the pancreas), and
- Autoimmune pancreatitis
- Pancreas divisum, a common congenital malformation of the pancreas may underlie some cases of recurrent pancreatitis
- Porphyrias (particularly acute intermittent porphyria and erythropoietic protoporphyria)
Pregnancy can also cause pancreatitis, but in some cases the development of pancreatitis is probably just a reflection of the hypertriglyceridemia which often occurs in pregnant women. Pancreatitis is less common in paediatric population.
Rarely, calculi can form or become lodged in the pancreas or its ducts forming pancreatic duct stones. Treatment varies but is of course aimed at removal of the offending stone or stones. This can be accomplished endoscopically, surgically, or even by the use of ESWL.
Type 2 diabetes subjects have 2.8-fold higher risk for pancreatitis compared to nondiabetic subjects. People with diabetes should promptly seek medical care if they experience unexplained severe abdominal pain with or without nausea and vomiting.
Medications
Many medications have been reported to cause pancreatitis. Some of the more common ones include the AIDS drugs DDI and pentamidine, diuretics such as furosemide and hydrochlorothiazide, the anticonvulsants divalproex sodium and valproic acid, the chemotherapeutic agents L-asparaginase and azathioprine, and estrogen. As is the case with pregnancy-associated pancreatitis, estrogen may lead to the disorder because of its effect of raising blood triglyceride levels.
Pancreatitis caused by statins first started appearing in the medical literature as early as 1990. All statins currently in use reportedly can cause pancreatitis, a not surprising observation when one considers that all statins are reductase inhibitors and can be expected to have similar side effect profiles. Both chronic and acute pancreatitis are curable. Fasting is often needed for a few days or sometimes even weeks to heal the pancreas. Intravenous (IV) fluids are used to maintain nutrition while fasting. Sometimes a surgery to drain the abdomen is needed. People with chronic pancreatitis often take pills with enzymes to help them digest their food. The change of daily living habits is also necessary to avoid immediate danger. Pancreatitis can be either acute or chronic. Pancreatitis' most common cause is high alcohol intake. It has many unpleasant symptoms, and it can be cured in multiple ways. Acute and chronic pancreatitis have similar symptoms.
Genetics
Hereditary pancreatitis may be due to a genetic abnormality that renders trypsinogen active within the pancreas, which in turn leads to digestion of the pancreas from the inside.
Pancreatic diseases are notoriously complex disorders resulting from the interaction of multiple genetic, environmental, and metabolic factors.
Three candidates for genetic testing are currently under investigation:
- Trypsinogen mutations (Trypsin 1)
- Cystic Fibrosis Transmembrane Conductance Regulator Gene (CFTR) mutations
- SPINK1 which codes for PSTI - a specific trypsin inhibitor.
The diagnostic criteria for pancreatitis are "two of the following three features: 1) abdominal pain characteristic of acute pancreatitis, 2) serum amylase and/or lipase ≥3 times the upper limit of normal, and 3) characteristic findings of acute pancreatitis on CT scan."
Most frequently, measurement is made of amylase and/or lipase, and often one or both, are elevated in cases of pancreatitis. Two practice guidelines state:
It is usually not necessary to measure both serum amylase and lipase. Serum lipase may be preferable because it remains normal in some nonpancreatic conditions that increase serum amylase including macroamylasemia, parotitis, and some carcinomas. In general, serum lipase is thought to be more sensitive and specific than serum amylase in the diagnosis of acute pancreatitis".
Although amylase is widely available and provides acceptable accuracy of diagnosis, where lipase is available it is preferred for the diagnosis of acute pancreatitis (recommendation grade A)".
Most, but not all individual studies support the superiority of the lipase. In one large study, no patients with pancreatitis who had an elevated amylase with a normal lipase were found. Another study found that the amylase could add diagnostic value to the lipase but only if the results of the two tests were combined with a discriminant function equation. Previously, the Phadebas Amylase Test was the dominating test method but it is no longer registered as an IVD.
Conditions other than pancreatitis may lead to increases in these enzymes, and those conditions may also cause pain that resembles that of pancreatitis. These conditions include cholecystitis, perforated ulcer, bowel infarction (i.e., dead bowel as a result of poor blood supply), and even diabetic ketoacidosis).
The treatment of pancreatitis is supportive. It will depend on the severity of the pancreatitis itself. Still, general principles apply and include:
1. Provision of pain relief. The preferred analgesic is morphine for acute pancreatitis. In the past, pain relief was provided preferentially with meperidine (Demerol), but it is now not thought to be superior to any narcotic analgesic. Indeed, given meperidine's generally poor analgesic charactersitics and its high potential for toxicity, it should not be used for the treatment of the pain of pancreatitis.
2. Provision of adequate replacement fluids and salts (intravenously).
3. Limitation of oral intake (with dietary fat restriction the most important point). Though NG tube feeding was once the preferred method to avoid pancreatic stimulation and possible infection complications caused by bowel flora, recent studies have suggested quicker recovery with fewer complications if oral feeding is resumed as soon as possible.
4. Monitoring and assessment for, and treatment of, the various complications listed above.
5. ERCP in the case of gallstone pancreatitis.
When necrotizing pancreatitis ensues, and the patient shows signs of infection, it is imperative to start antibiotics such as Imipenem and other drugs that have ability to penetrate the pancreas. Fluoroquinolone with metronidazole is another treatment option.
Acute (early) complications of pancreatitis include:
- shock
- Hypocalcemia (low blood calcium)
- High blood glucose
- Dehydration, and kidney failure (resulting from inadequate blood volume which, in turn, may result from a combination of fluid loss from vomiting, internal bleeding, or oozing of fluid from the circulation into the abdominal cavity in response to the pancreas inflammation, a phenomenon known as third spacing).
- Respiratory complications are frequent and are major contributors to the mortality of pancreatitis. Some degree of pleural effusion is almost ubiquitous in pancreatitis. Some or all of the lungs may collapse (atelectasis) as a result of the shallow breathing which occurs because of the abdominal pain. Pneumonitis may occur as a result of pancreatic enzymes directly damaging the lung or simply as a final common pathway response to any major insult to the body (i.e., ARDS or acute respiratory distress syndrome).
- Infection of the inflamed pancreatic bed can occur at any time during the course of the disease. In fact, in cases of severe hemorrhagic pancreatitis, antibiotics should be given prophylactically.
- pancreatic acitis due to necrotised pancreatic ducts leak,or through necrotic tissue.
Pancreatic abscess is a late complication of acute necrotizing pancreatitis, occurring more than four weeks after the initial attack. A pancreatic abscess is a collection of pus resulting from tissue necrosis, liquefaction, and infection. It is estimated that approximately 3% of the patients suffering from acute pancreatitis will develop an abscess.
According to the Balthazar and Ranson's radiographic staging criteria, patients with a normal pancreas, an enlargement that is focal or diffuse, mild peripancreatic inflammations or a single collection of fluid (pseudocyst) have less than a 2% chance of developing an abscess. However, the probability of developing an abscess increases to nearly 60% in patients with more than two pseudocysts and gas within the pancreas.