Neuropathic pain: a personal case reflection on a critical incident.

Neuropathic pain is a distressing symptom for the patient and a difficult symptom for the physician to treat. There is lack of evidence-based clinical guidelines for the management of malignant neuropathic pain. The case reflection is a personal account of what has been learnt from a critical incident in a particular patient in the management of neuropathic pain. Psychological issues are known to increase pain percetion and affect the quality of life. The case reflection explores problem areas, defines lacunae in knowledge, and demonstrates active learning of the management of neuropathic pain through reflective practice.

INTRODUCTION

This reflection follows the “What? So what? Now what?” model of reflective practice proposed by Rolfe et al.[1]

CASE HISTORY: WHAT?

The incident is that of Mrs Kamble (name changed), female, aged 45, a patient with recurrent unresectable, metastatic (lung), chondrosarcoma of the right thigh which was infiltrating the muscles. As no active oncological intervention was planned, she was referred to the palliative care service to formulate a care plan for her. She was however offered palliative radiation to the right thigh for pain relief which she completed a week after presenting to the Palliative Care Service. At presentation, she had pain 3/10 on a numeric rating scale (NRS) as part of edmonton symptom assessment scale (ESAS)[2] and a fixed flexion deformity of 20° at the knee, with a performance status of ECOG 1 (Eastern Cooperative Oncology Group).[3] Her pain was controlled with Tab. Ibuprofen (brufen) 400 + Paracetamol (crocin) 500 mg q 8 hourly.

The critical incident occurred when after a month of referral to palliative care she developed paresthesia and shooting pain at the back side of the right thigh and leg. Her pain score was 8/10. The pain caused her a lot of anguish, discomfort, disturbed her sleep, and overall she felt worse. According to the WHO cancer pain ladder,[4] she was started on oral morphine (regular) (vermor) 10 mg q 4 hourly, Tab. Ibuprofen (brufen) 400mg + Paracetamol (crocin) 500 mg q 8 hourly, Tab. Amitriptyline (tryptomer) 25 mg at night and Tab. Dexamethasone (decmax) 4 mg q 8 hourly to be tapered over 7 days and maintained at 4 mg once every day. Adequate laxatives and antacids were prescribed. Mrs. Kamble had some relief in 10 days of treatment but the numbness below her knee was more than before and she continued to suffer from episodic lancinating pain down the back of her thigh and leg down to her fourth and fifth digits. She continued to be anxious and had difficulty falling asleep.

SO WHAT?

Mrs. Kamble had advanced cancer which was infiltrating the sciatic nerve leading to Neuropathic pain. Neuropathic pain due to advanced cancer is difficult to manage. It occurs in 70% of patients with advanced cancer.[5-7] Though there has been an increase in the understanding of neuropathic pain, the pathophysiology of neuropathic pain and neuropathic pain in cancer is not fully understood.

Drug therapy for neuropathic pain is not well defined and is limited by systemic adverse effects at effective doses, especially in the elderly.[8-10] Mrs. Kamble did not have any comorbidities and was expected to tolerate the medications for neuropathic pain well.

Available evidence-based guidelines for the treatment of neuropathic pain in advanced cancer is few and heterogeneous. However, few such as the European Federation of Neurological Societies (EFNS) have tried to frame guidelines for the management of neuropathic pain.[11]

The following were considered as possible options for management.

Opioid analgesic: oral morphine →trans dermal fentanyl.

+/- Steroids/nonsteroidal antiinflammatory drugs.

+/- Tricyclic antidepressants/anti-epileptics/serotonin + dopamine uptake inhibitors/selective serotonin reuptake inhibitors (SSRI).

Combination of adjuvants: tricyclic antidepressants + gabapentin/pregabalin +/- steroids.

Interventions.

Because patients with neuropathic pain take a longer time to achieve adequate, stable pain control and require higher final doses of opioids and adjuvant therapies compared to those with no neuropathic pain,[12] it could be weeks before Mrs. Kamble gets satisfactory relief from her recent onset neuropathic pain. It was a concern that in spite of adequate treatment Mrs. Kamble's pain could be as those of a considerable few who never achieve a pain-free state.[12]

It is known that neuropathic pain reduces the health-related quality of life (HR-QOL) and increases the overall cost of analgesic treatment.[1314] Mrs. Kamble hails from a middle-class family and her illness was fast depleting her resources. She has financial constraints and that could have a bearing on compliance to my advice.

Because patients with psychological distress take longer time to achieve adequate neuropathic pain control,[1215-18] it was a matter of concern that Mrs. Kamble's anxiety about her two unmarried daughters who have been out of work to take care of her and the fact that she was not fully aware of her prognosis (collusion) and outcome, could lead to suboptimal pain control.

Interventions like nerve blocks could be considered for patients who do not achieve adequate pain relief with medical therapy. But this has largely been successful for celiac plexus block in pancreatic cancer and in pelvic pain. The results for peripheral neuropathic pain have not been encouraging. Mrs. Kamble was clearly not a candidate for intervention.[1920]

NOW WHAT?

It was decided to start Mrs. Kamble on tab. Morphine (vermor) 10 mg q 4 hourly. There is evidence for the efficacy of morphine in the treatment of moderate to severe neuropathic pain.[2122] Though there is some evidence for the use of tramadol for neuropathic pain, based on its property of serotonin and nonadrenalin reuptake inhibition, there are no head to head trials to state that tramadol is superior to morphine.[2324] Tramadol is also three times costlier than morphine at our Centre.

The usefulness of Trans-dermal Fentanyl was considered as it maintains a more constant plasma concentration than morphine and this is believed to increase the likelihood of better pain control.[2526] Though this was available, Mrs. Kamble was happy with the current medication and did not want to spend more on the patch.

Neuropathic pain due to tumour infiltration responds to antiinflammatory agents as they reduce the peri-tumour oedema. Nonsteroidal antiinflammatory drugs are also believed to have some opioid sparing effect.[2728] It was not sure if there was a reason to start both steroids and nonsteroidal anti-inflammatory drugs together and the literature is also not very clear on this. Ibuprofen 400 mg+ Paracetamol 500 mg q 8 hourly was continued as the patient was already on it and was needed for adequate pain control. I was more inclined to start high-dose steroids for a short time and taper it to a lower dose along with nonsteroidal antiinflammatory drugs because of its (steroid's) widespread use to reduce neural oedema in spinal cord compression and space-occupying lesions in the brain.[29-33] Starting high-dose steroids and tapering off to a low continuous dose is standard practice in our cancer centre. Dexamethasone is preferred over prednisolone for its lower mineralocorticoid action.

Mrs. Kumble was started on Amitriptyline (tryptomer), the tricyclic antidepressants with the longest track record of being used for neuropathic pain. Though there is no robust evidence for the use of tricyclic antidepressants in neuropathic pain in cancer, Amitriptyline being the most cost effective, has widely been used for neuropathic pain in cancer and noncancer conditions with moderate success as an adjuvant along with opioids and antiinflammatory agents.[34-36] The dose recommended and practiced in our centre is 25 mg at night increased slowly up to 75 mg over 2 weeks. There is evidence that dual uptake inhibitors (serotonin and noradrenalin) are more potent as analgesics than selective serotonin reuptake inhibitors.[3738] Though there is evidence that antiepileptics are useful in neuropathic pain,[39] there is nothing to suggest that they are better than tricyclic antidepressants.

When Mrs. Kamble's lancinating pain persisted during the weeks following the initiation of treatment, it was decided to discuss the patient's management plan in the departmental meeting. The team seemed to be confident based on clinical experience with the use of Tab Pregabalin (lyrica) 75 mg at night or Cap Gabapentin (gabata) 300 mg at night +/- Amitriptyline 25 mg at night. We could gather evidence that Gabapentin and Pregabalin inhibit the release of excitatory neurotransmitters by blocking the calcium channel and could be more useful in lancinating pain and allodynia.[4041] We decided to start Mrs. Kamble on Cap Gabapentin 300 mg along with Amitriptyline 25 mg at night based on reports[4243] that combination of calcium channel alfa-2-delta blockers and antidepressants was safe and effective in controlling the neuropathic pain. Patient could not afford Pregabalin and there was no evidence to suggest that it was superior to Gabapentin.

Having learnt that psychological distress and anxiety could contribute to suboptimal neuropathic pain control[1215-18] and that the preexisting collusion could increase patient anxiety, her consultation with the psychologist was arranged. In the discussion that followed, it became evident that the patient was not informed about her prognosis at the insistence of her husband, as is the case with many patients in India.[4445] The recent onset neuropathic pain had heightened her suspicion that there is something “serious” with her condition and she was anxious to know how severe the condition is. She was also anxious thinking about the future of her two unmarried daughters who were both out of work. Financial constraints were also a matter of concern.

When we referred to the initial whole-patient assessment notes, it was evident that the collusion existed right from the time she was diagnosed to have lung metastasis. Though after the initial consultation, the husband agreed to have an open discussion with the patient, he had not yet had one and was not ready yet to have one.

We decided to wait till Mrs. Kamble gets some pain relief before handling the collusion. We allowed ourselves 10 days after the start of therapy when, the pain reduced partially and the husband agreed for us to have a discussion with the patient and her daughters in his presence. We were able to discuss the prognosis and outcomes with the patient and agreed to arrange for a meeting of her daughters with the social worker for support and employment. She was started her on Tab. Lorazepam (larpose) 2 mg at night for her insomnia and anxiety.[46]

Mrs. Kamble felt much better; she could voice her concerns, have her concerns addressed, was less anxious, slept well and had achieved satisfactory pain relief through active team work.

On reflection, we believe that handling collusion early on when the patient is controlled of the symptoms could be less stressful for the patient, caregiver, and the physician. There was a symptom-free period of 1 month when this could have been done.

We discussed this with the team of counsellors and senior colleagues who agreed that precious time was lost partly because nobody followed up with the patient or her husband to see if collusion was handled.

We realise that the treatment of neuropathic pain in cancer is difficult and the evidence is not direct. Most of the recommendations are extrapolations of years of experience in noncancer neuropathic pain. It would be worthwhile to design and conduct a randomized control trial to compare tricyclic antidepressants and anti-epileptics with or without opioids and NSAIDs and also investigate the role of steroids.

We are convinced that reflective practice is a good way of learning and the knowledge acquired can be easily shared with the team.

CHANGE IN PRACTICE

After the reflective learning, a check list of problems in patients was introduced and attached to the front of the whole-patient assessment sheet in order that these problems are nots—overlooked in the future during follow-up visits