Acute Pancreatitis (AP) is caused due to a major insult to the pancreatic tissue from various factors. This leads to release of activated pancreatic enzymes which cause autodigestion and necrosis of the Pancreas itself as well as activate an inflammatory cascade which affects distal organs like intestines, kidneys and lungs.
What are the causes of Acute Pancreatitis?
Most common causes of Acute Pancreatitis include Alcohol intake and Gall stones. One in every two patients with AP is very likely to have either these two risk factors. Other causes of AP are enlisted in table 1.
Table 1 : Causes of Acute Pancreatitis
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What are the symptoms of Acute Pancreatitis?
The characteristic symptom of AP is abdominal pain which is present in nearly all patients with the disease. Onset of pain is rapid, and it reaches to maximal intensity in 10 to 20 minutes beyond which it tends to be constant. Pain is moderate to severe and usually localised to upper abdomen with occasional radiation to back (50% of patients). Most patients resort to use of analgesics due to severe pain which is seldom useful.
Nausea and vomiting are other common symptoms of AP and seen in around 90% of the patients. Patients usually cannot tolerate food orally during the initial days of severe AP and complain of pain and vomiting post feeds.
Also based on severity and other organ involvement, symptoms might include a feeling of breathlessness, severe constipation, decreased urine output and altered mentation.
What is the outcome after Acute Pancreatitis?
AP occurs in varying spectrums of severity. Contrary to popular belief, most cases of AP are mild and go unnoticed.
Based on the potential to cause mortality(death) and mortality(complications or disabling symptoms), AP is often classified into three types.
Figure : Classification of Acute Pancreatitis according to severity (Modified Atlanta Classification)
Mild Acute Pancreatitis
Most cases of mild AP go unnoticed. Those patients who have symptoms (usually self-limiting abdominal pain) can usually be managed on outpatient basis. There are usually no complications or sequelae. The cause of AP however has to be identified and treated judiciously to avoid repeat attacks of AP in future.
Moderately Severe Acute Pancreatitis
Patients with moderately severe AP need admission and appropriate treatment (Treatment modalities of AP discussed in Chapter ). A small proportion of patients with moderately severe AP may have other organ compromise like respiratory distress, hypotension or decreased urine output.
Such patients may need admission and treatment in Intensive Care Unit. However, in moderately severe AP other organ dysfunction is short lasting and usually gets resolved within 48 hours.
More commonly, several of these patients have Pancreas related local complications like development of fluid collections. Fluid collections occur due to catalytic action of pancreatic enzymes on surround tissues causing necrosis. In the initial stages of disease, this fluid/necrotic material is scattered but this tends to coalesce and localise over a period of time (usually 3-4 weeks).
These fluid collections tend to cause abdominal discomfort like pain, fullness, vomiting or fever. Management of AP related local complications are discussed later.
Morbidity (complications impairing the overall quality of life) is common in moderately severe AP. Mortality(death) may also occur in few cases with moderately severe AP.
Severe Acute Pancreatitis
Severe AP is a medical emergency and needs immediate admission and aggressive management in Intensive Care Unit. The hallmark of severe AP is presence of prolonged organ failure ( > 48 hours). Organ failure means severe compromise of one or more organ systems. Most commonly encountered organ failures in severe AP are
- Respiratory : characterised by significant difficulty in breathing and inability to maintain oxygen saturation without external support. Non-invasive or invasive ventilatory support is often needed.
- Renal : characterised by decreasing urine output and associated complications of kidney dysfunction like electrolyte (sodium, potassium, magnesium etc.) imbalance.
- Circulatory : characterised by decreasing blood pressure (shock) and needed aggressive intravenous fluids of vasopressor support ( medicines to increase falling blood pressure)
Severe AP is associated with high mortality (15-30%) and morbidity rates. Prolonged hospitalisation and care is usually needed (discussed later).