The pancreas is a 6 to 10-inch organ located in upper part of abdomen behind the stomach. It produces enzymes needed to digest food and hormones such as insulin and glucagon.
Pancreatitis is swelling (inflammation) of the pancreas can occur due to a wide variety of reasons. When this occurs quickly it is addresses as acute pancreatitis. If acute pancreatitis fails to resolve or gets worse or if there are repeated attacks, it can lead to permanent damage or continuing inflammation. This is addressed as chronic pancreatitis and is seen more commonly in men, especially those between the ages of 30 to 40 years.
Chronic pancreatitis is a multifaceted long-term illness with impact of all aspects of one’s life including social, financial, employment and relationships. Pain in pancreatitis can be continuous, severe with associated mood and sleep disturbances. It is often the main reason behind seeking hospital admission and is known to be responsible for reduced quality of life, disability. For those with uncontrolled pain hospital environment becomes a safe haven and hence long-term control of this pain is important not only for preventing repeated hospital admissions but also for improving the quality of life.
Common presenting features of chronic pancreatitis include:
- Upper abdominal pain – this may be present constantly or may come and go
- Described as dull aching, penetrating or boring pain. Some of the other words used by patents to describe the pancreatitis pain include burning, ripping, bursting, stabbing, crushing, and electric shock like
- Pain is generally diffuse and poorly localised
- Can radiate to back, chest and occasionally the left shoulder
- It can increase in severity after eating, drinking alcohol
- Often relieved by leaning forwards
- Loss of appetite with weight
- Diarrhoea, nausea and vomiting
- Foul-smelling fatty, oily or pale coloured stools which are difficult to flush
There are many factors behind the development of pancreatitis and of these, alcohol is an important preventable trigger. The common causes of chronic pancreatitis include:
- Blockade of ducts draining the pancreatic enzymes such as with gallstones and pancreatic duct strictures
- High levels of a fat called triglycerides in the body (hyperlipidaemia)
- Abdominal/ pancreatic trauma
- Autoimmune conditions where one’s immune system attacks the body
- Hereditary/ genetic conditions where it is passes down the families
- Chronic renal failure
- Increased calcium levels (Hypercalcaemia)
- Medicines such as sulfonamides, thiazides, and azathioprine
Research evidence suggests that smokers have a 2.8 times higher risk of development of chronic pancreatitis compared with non-smokers. Smoking accelerates alcohol related chronic pancreatitis and pancreatic calcification (calcium deposition in pancreas)
Many theories have been proposed to explain the pain in chronic pancreatitis and these include:
- Plumbing theory where there is Increased pressure within the pancreas from blockage of the ducts and reduced blood flow as a result. This is not the only mechanism responsible for pain in pancreatitis as relief of obstruction does not correlate well with improvement in pain.
- Wiring or the neuronal theory- Pancreas have pain sensing nerve fibres and these become more sensitive (peripheral sensitisation) with persistent or repeat attacks of inflammation during acute pancreatitis. These in turn communicate with the spinal cord and brain and lead to changes in wiring and sensitisation of these structures as well (central sensitisation).
In about 30% of patients there is persisting pain despite removal of the pancreas and this implies that not all pain originates from the pancreas and new bouts of pain do not always imply new injury as there are other pain contributing mechanisms independent of the pancreas.
It can be challenging to diagnose chronic pancreatitis in early stages. Generally imaging modalities are used more commonly as the routine laboratory tests such as amylase, lipase, and inflammatory parameters can be completely normal or only slightly elevated in chronic pancreatitis. Histological evidence of loss of issue and fibrosis is perhaps the most definitive diagnostic method but is not always available.
Imaging tests include
- CT scan of the abdomen
- MRI with MRCP (Magnetic resonance cholangiopancreatography)
- Endoscopic ultrasound (EUS)
- Endoscopic retrograde cholangiopancreatography (ERCP)- this involves visualising the bile and pancreatic ducts using an endoscope. It provides good images of the pancreatic ducts but is not used so often for the diagnosis.
- Ultrasound of the abdomen
Other tests include
- Faecal elastase – helps to assess pancreatic function although is not very accurate
- Serum trypsin
- Serum amylase, lipase and trypsinogen
- Serum IgG4 (for diagnosing autoimmune pancreatitis)
- Gene testing, in presence of family history
Optimal management of these patients requires a multidisciplinary team that includes gastroenterologists, pain specialists, surgeons, interventional radiologists, endocrinologists and dieticians. Identifying the disease etiology and any complications can have implication on the treatments selected such as steroids for patients with autoimmune pancreatitis and relief of duct obstructions for patients with obstruction.
For pain management an individualised approach using combination of lifestyle changes, medications, interventions and if required surgery is used.
Alcohol - Abstinence from alcohol is essential as it has been shown to slow the disease progression and reduces the likelihood of complications such as cancer.
Smoking - Smoking is an independent risk as it is associated with progression, with smokers showing onset of chronic pancreatitis at least 5 years earlier compared to non-smokers. It also has a synergistic effect with alcohol usage.
Diet - Detailed dietary advice forms an essential component of treatment with malabsorption, reduced appetite and weight loss being seen commonly in these patients. Generally small sized meals, low-fat diets with vitamin supplements and antioxidant therapies are recommended for these patients. Intake of meat and non-vegetarian food should be reduced and refined food such as bread, pastas and sugar should be avoided. Pancreatic enzymes are used with meals to help digest food better, gain weight and reduce diarrhoea. A dietician can help in creating a diet plan.
This includes medications to relieve symptoms and suppress pancreatic secretion such as
- Simple painkillers
- Opioids (Morphine like medicines)
- Nerve type of pain killers (Neuropathic agents) such as anticonvulsants & antidepressants
- Pancreatic enzymes
- Medications to relieve acidity such as PPIs and H2-blockers
- Vitamin and antioxidant therapy to reduce oxidative stress
- Modify transmission of pain signals such as Coeliac plexus block and splanchnic neve blocks, radiofrequency or surgical resection of splanchnic nerves
- Relieve any obstruction such as ERCP (sphincterotomy), stents, removal of stones
Analgesics: A combination of different classes of pain killers is used depending on the severity of pain, patient comorbidities and the stage of disease and the expected outcomes. Commonly used analgesics include paracetamol, anti-inflammatory drugs, morphine like painkillers and patches (opioids), nerve type of pain killers (neuropathics) etc.
Opioids (Morphine like pain killers) – approximately half of all patients with chronic pancreatitis require treatment with opioids. There is no strong evidence favouring one opioid over another. The choices have to be made cautiously, especially in those with addiction issues or previous history of alcohol abuse. Long acting preparations of these drugs are generally preferred over short acting ones.
Pancreatic enzymes: non-enteric coated preparations are used along with meals and anti-acid medications to avoid degradation of these by acid in the stomach. There is some evidence to indicate that the response is better in young women with idiopathic chronic pancreatitis.
Antioxidants: A review on role of antioxidants (Cochrane review, 2014) concluded that can they might reduce pain slightly in patients with chronic pancreatitis, but further studies are needed to define the patient population most likely to respond. Generally, a mixture of selenium, methionine, vitamins E and C, and b-carotene is used.
NERVE BLOC, NEUROLYSIS AND RADIOFREQUENCY TREATMENT
In patients where above measures fail to achieve satisfactory relief options such as nerve blocks, neurolysis and radiofrequency treatment can be considered. Pain signals from the pancreas pass through a network of nerves located in upper part of abdomen called the Coeliac plexus. It lies deep in the abdomen, in front of spine and around a big blood vessel called aorta. One of the main nerves in this network are the Splanchnic nerves. This network of nerves plays an important role in sending messages from the upper abdominal organs to the brain where pain is perceived. Interruption of these signals leads to reduced pain.
These procedures can be classified as
- Diagnostic blocks– Blocking the coeliac plexus of the splanchnic nerves involves injecting local anaesthetic with or without steroids around these nerves to interrupt the pain signals being sent to the brain. This can reduce the pain one perceives and help in predicting if procedures such as neurolysis will work.
- Neurolytic blocks– this involves use of chemicals such as alcohol / phenol to achieve prolonged interruption of pain signals being transmitted by nerves. This option is utilised more for those with pancreatic cancer.
- Radiofrequency ablation of splanchnic nerves– these procedures utilise radiofrequency energy to heat the needle tip which in turn reduces the pain signals being transmitted to the brain. The nerves can also be sectioned surgically but this is a much more invasive procedure compared to radiofrequency.
For all these procedures image guidance is used to accurately place the needles close to the target nerves. The modalities used include - X Ray (Fluoroscopy), ultrasound, CT, Endoscopic guidance or a combination of the above.