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Abdominal Pain Approach to Pain Management in the Palliative Care setting Dr Pam Cupples RHSC, Glasgow APPM November 2012 Slide 2 Slide 3 Case Study 1 12 year old girl diagnosed with type 1 Neurofibromatosis Complex retroperitoneal neurofibroma arising early in childhood, which was not fully resectable Age 11 the mass became symptomatic Significant abdominal pain & distension Protracted vomiting & weight loss Rx chemotherapy and radiotherapy and further surgery to partially resect the tumour pathology showed localised malignant transformation With tumour progression and metastases Slide 4 Case Study 1 5 months after surgery she presented with intractable vomiting & colicky abdominal pain due to malignant bowel obstruction Child averse to NG placement So not passed until day 4 > 1L of bilious gastric content Vomiting 15 times / day How would you manage the patients symtoms? Coronal view of CT abdomen and pelvis revealing large left-sided retroperitoneal round tumor causing obstruction, with marked dilatation of proximal first portion of duodedum and stomach. Slide 5 Management Plan Symptom control Analgesia in the hospital setting & at home Antiemetics Decompression of bowel Any alternative Rx to consider Slide 6 Octreotide Synthetic analogue of somatostatin GH releasing inhibiting factor Inhibition of endocrine & exocrine secretions Inhibits gastrin, secretin, VIP, insulin, glucagon, cholecystokinin, pancreatic peptide Decreases splanchnic flow Inhibits secretion of Cl into the jejunum, which increase water reabsorption Decreased secretion of water and electrolytes, inhibits pancreatic secretions, increased absorption of of water and electrolytes Slide 7 Slide 8 Case Study 2 3 year old boy with diagnosis of left sided Wilms Tumour Presents with palpable mass and constant abdominal pain Following Rx and surgical resection Complaining of sharp stabbing pain in scar and generalised upper abdominal pain, which has been present for > 3 months Not responsive to standard analgesics How would you manage this patient particularly with regards to his non opioid responsive abdominal pain Computed tomography scan of a large left Wilms' tumor with a small rim of functioning renal parenchym Slide 9 Classification of Abdominal Pain Somatic Abdominal Pain Stimulation of the parietal peritoneum Accurate localisation sharp Visceral Pain Diffuse nature experienced of large area of the abdomen Associated with nausea and autonomic symptoms Few pain receptors Receptors in the walls of hollow viscera are very sensitive to distension Colicky type pain Perceived site of visceral pain relates to the embryological origin Slide 10 Chronic Visceral Pain Heightened perception of GI sensation visceral hyperalgesia Noxious stimuli peripheral release of inflammatory mediators Activation and peripheral sensitisation of nociceptive afferents Reduced firing thresholds Expression & recruitment of previously silent nociceptors Transient receptor potential vallinoid 1 TRPV1 Protease activated receptors PAR Opioid agonists limited by central action and side effects Voltage Gated Sodium Channels VGSC Nav 1.3-1.9 Central sensitisation NMDA & PGE2 New Rx in the future NMDA & PGE2 antagonists, serine protease inhibitors, TRPV1 antagonists Slide 11 Rx Options to be considered TSE or TENS Oral Neuropathic medication Gabapentin Lamotrigine Regional techniques Epidural with ketamine Slide 12 TENs Frequency dependent analgesia A (50-200Hz) A (2- 4Hz) Tingling sensation may be a problem TSE Slide 13 Transcutaneous Spinal Electroanalgesia - TSE 1991 Biphasic waveform Ultrashort duration 4 sec Slide 14 Chronic Neuropathic Pain Somatic Pain Gabapentin Blocks the voltage gated Ca > 50kg - max. dose up to 2400mg / 24hrs 35-50kg max. dose up to 1600mg / 24hrs 25-35kg max. dose up to 1200mg / 24hrs < 25kg not recommended Visceral Pain Lamotrigine Blocks the Na channels > 50kg start 10mg twice daily up to max. of 40mg b.d. 30-50kg 5mg b.d up to max of 25mg Parental Opioids Infusions Preterm 5mcg/kh/h Term up to 8mcg/kg/hr 1-3months up to 10mcg/hr >3 months up to 20mcg/hr PCA 1mg/kg in 50mls of 0.9% saline bolus = 1ml = 20mcg/kg with a max of 1mg 5min lockout +/- background of 4mcg/kg/hour Slide 33 Parental Opioids Infusions Preterm 5mcg/kh/h Term up to 8mcg/kg/hr 1-3months up to 10mcg/hr >3 months up to 20mcg/hr PCA 1mg/kg in 50mls of 0.9% saline bolus = 1ml = 20mcg/kg with a max of 1mg 5min lockout +/- background of 4mcg/kg/hour Slide 34 OPIOIDS MORPHINE Oral Morphine200- 400mcg/kg 4 hourly Convert to single/ twice daily sustained release MST continus Single daily dose of MXL Morphine not tolerated consider oxycodone DIAMORPHINE More potent, more soluble Subcutaneous Infusion 20-100mcg/kg/hour Converting from oral morphine total daily dose of morphine /3 Slide 35 OPIOIDS OXYCODONE Opioid Naive 0.2mg/kg 4 hourly Previous exposure to opioids Conversion ratio for morphine to oxycodone 2:1 Ie half the daily morpine dose FENTANYL Less sedation & constipation 25mcg, 50mcg, 75mcg & 100mcg patches Continue morphine for up to 12 hours after starting patch Remember breakthrough oral morphine Therapeutic levels 6-12 hrs Takes 24-48 hours to assess results Slide 36 NCA - Nurse Controlled Analgesia Age < 1month self ventilating Bolus of 5mcg/kg lockout of 30min No background Age 1-3months Bolus of 10mcg/kg lockout of 30mins no background Age >3months Bolus of 20mcg with max of 1mg Lockout of 20min Background of 20mcg/kg/hr