Introduction
Chronic pancreatitis describes a syndrome of chronic inflammation of the pancreas. Treatment of chronic pancreatitis involves supplementation for malnutrition and pancreatic enzyme deficiencies, and treatment for chronic pain that develops. Chronic pancreatitis is estimated to cost the healthcare system approximately 150 million dollars in the United States. Managing the pain of pancreatitis adequately could help reduce morbidity and reduce this cost burden. In this chapter, we will review chronic pancreatitis followed by the various pain treatments available for this chronic condition.
Etiology, Pathogenesis, and Clinical Features
There are several different known etiologies including alcohol, smoking, genetic causes, anatomic abnormalities, and ductal obstruction. Smoking, in particular, is associated with chronic pancreatitis even when adjusting for alcohol intake. It is a progressive, ongoing inflammatory syndrome involving mononuclear cell infiltration and activation of pancreatic stellate cells. This leads to fibrosis and loss of acinar and islet cells. , An initial insult with alcohol or tobacco occurs and this incites the first episode of acute pancreatitis. At this time, inflammatory cells are recruited. Repeated insults incite further episodes of acute pancreatitis that activates stellate cells and begins the process of fibrogenesis. Pancreatitis can also have idiopathic or autoimmune causes. In these cases, it is unknown what provokes the initial episode of pancreatitis. Complications of pancreatitis include but are not limited to biliary obstruction, duodenal obstruction, portal vein thrombosis, vascular aneurysms, pseudocysts, and bleeding.
Diagnosis
The standard for diagnosis had been the triad of diabetes mellitus, steatorrhea, and pancreatic calcifications visible on abdominal radiographs. It is now known that this will only be seen in end-stage disease. Measuring of pancreatic enzymes and endoscopic ultrasound, magnetic resonance imaging (MRI), or computed tomography (CT) can help diagnose pancreatitis earlier in the course of disease. On MRI and CT, one could see pancreatic atrophy and/or calcifications with irregularities in the pancreatic duct. Clinically, epigastric pain is typically seen and can be debilitating; this pain is thought to be due to “increased pressure in the ductal system and/or neuroplastic changes.” Managing pain can become the single most prominent component of disease management in chronic pancreatitis.
Physical Exam Findings
Chronic pancreatitis pain typically presents as epigastric pain radiating toward the back. A thorough history should be taken to assess the intensity of pain, if the pain is constant or intermittent, exacerbating factors, mitigating factors, and impact of pain on activities of daily living and quality of life. Physical exam should include a full, thorough abdominal exam but should also include a general physical examination of other systems (cardiovascular, pulmonary, etc.). A full neurological exam should be performed as well. On exam, one could find tenderness to palpation in the epigastric region. It is important to remember that earlier in the course of the disease, an abdominal exam could potentially be normal with no tenderness to palpation elicited. This highlights the importance of ordering pancreatic enzyme labs and imaging if one has a high clinical suspicion for pancreatitis. As mentioned previously, imaging options include endoscopic ultrasound, CT, or MRI for the diagnosis of pancreatitis.
Treatment
Lifestyle modifications and conservative therapies: Treating pain often becomes the focal point of chronic pancreatitis management. Lifestyle modifications are imperative to discuss. Tobacco and alcohol cessation are an important component of reducing the likelihood of disease progression, which, in turn, has an impact on pain . Pancreatic enzyme replacement therapy has been shown in being effective in pain reduction as well and patients should be referred to a gastroenterologist for evaluation.
To manage the pain, conservative management with oral medications should be attempted first. Initially, over the counter analgesics can be attempted if there are no contraindications. This includes acetaminophen and antiinflammatories. If pain is not adequately managed by over the counter analgesics, then prescription-strength medications are to be attempted. All nonopioid options should be exhausted before trialing opioids. This includes gabapentinoids and tricyclic antidepressants. In a randomized, double-blinded, placebo-controlled trial, it was found that pregabalin is associated with reduced central sensitization in pain related to chronic pancreatitis. Tricyclic antidepressants (TCAs) such as nortriptyline or amitriptyline can be trialed as well.
If gabapentinoids or TCAs prove ineffective, then tramadol, a weak opioid, can be trialed next. A discussion including risks of tolerance, dependence, and addiction should be done with the patient regarding chronic opioid therapy. If tramadol proves ineffective, oral opioids, such as hydrocodone or oxycodone, can be considered with caution paying careful attention to dose. The lowest possible dose to achieve pain relief is recommended.
Referral to a pain psychologist for coping strategies is another conservative management option that should be utilized. Cognitive behavioral therapy has been utilized for managing chronic pain. It teaches coping mechanisms and alters thoughts and perception for patients to approach their pain. Understanding how to cope and manage pain flares is crucial in positive long-term outcomes.
Interventional procedures: In addition to oral medications for pain management, there are several interventional therapies available.
Celiac plexus block may be considered in patients with chronic upper abdominal pain secondary to chronic pancreatitis. Typically, this procedure is done for patients with pancreatic cancer or upper abdominal malignancies, but it is reasonable to consider this procedure in patients with chronic pancreatitis who are refractory to oral medications.
Please refer to Chapter 13 for technique and different approaches to the celiac plexus block. For chronic pancreatitis, local anesthetic (8–10 mL of 2% lidocaine or 0.25% bupivacaine) with corticosteroid can be administered. A study found that patients with chronic pancreatitis who experienced pain relief had 2 months of relief with a subset of patients receiving minimal to no pain relief. Expectations should be discussed with patients before proceeding with celiac plexus block for chronic pancreatitis. If patients do have adequate relief but short term, then neurolysis with alcohol or phenol can be considered.
Neuromodulation: If the above interventions are not effective, surgical pain management techniques can be considered. Spinal cord stimulation (SCS) for abdominal visceral pain has been performed with significant pain relief, although research into this specific area is limited (see Figs. 14.1 and 14.2 ). Khan et al. reported five cases of chronic nonalcoholic pancreatitis that were treated with SCS. Leads were placed midline along the dorsal column, with the electrode tips at the T5–T6 vertebral bodies. In one instance, the leads were placed at the T5–T8 levels. All five patients experienced at least 50% pain relief and significantly reduced their opioid usage.
