PALLIATIVE CARE: Neuropathic pain underrecognized

Among types of pain associated with advanced or chronic illnesses in children, said Stefan J. Friedrichsdorf, MD, FAAP, pediatric neuropathic pain remains particularly underrecognized and undertreated. Its prevalence in children is unclear, but a meta-analysis showed that the proportion of children with cancer who suffer from neuropathic pain ranges from 19% to 39%.¹

In his presentation “Pediatric Pain and Suffering: Managing Common Problems in Children With Advanced or Chronic Illness,” Friedrichsdorf suggested a sequential "non–evidence-based" approach to manage neuropathic pain in pediatric palliative care:

• Treat the underlying disease process if possible and appropriate.

• Incorporate integrative nonpharmaceutical therapies such as massage and biofeedback to manage comorbidities such as anxiety and sleep disturbances.

• Consider first-line medications: amitriptyline, gabapentin, and perhaps opioids. Regarding assumptions about opioid use in children, he emphasized, tolerance does not equal addiction, and fears of oversedation are largely overblown. Nevertheless, opioids are not indicated for chronic pain or long-term use.

• Apply World Health Organization (WHO) principles for acute pain. These include dosing at regular intervals (to ensure steady blood levels, minimizing the peaks and valleys of as-needed dosing) and employing a 2-step strategy: milder analgesics such as ibuprofen and/or acetaminophen for mild pain, versus morphine or other narcotics (fentanyl, hydromorphone, oxycodone, methadone) for moderate to severe pain. Whichever strategy is required, the WHO also recommends regular pain assessment using multidimensional rating scores, often with a dose of creativity. Ask a stuffed toy, for instance, if the patient is in pain.

• Low-dose ketamine may provide potent adjuvant analgesia for neuropathic and nociceptive pain. Ketamine may reverse opioid-induced hyperalgesia and opioid tolerance, explained Friedrichsdorf, increasing opioids' efficacy and reducing their adverse effects.

• Consider regional anesthesia. Although evidence is limited to case reports and series, approaches such as central neuraxial infusions and implanted intrathecal medication ports and pumps show promise.

Stefan J. Friedrichsdorf, MD, FAAP, is medical director, Department of Pain Medicine, Palliative Care, and Integrative Medicine, Children's Hospitals and Clinics of Minnesota, Minneapolis/St. Paul, and associate professor of pediatrics, University of Minnesota Medical School.

REFERENCE

1. Bennett MI, Rayment C, Hjermstad M, Aass N, Caraceni A, Kaasa S. Prevalence and aetiology of neuropathic pain in cancer patients: a systematic review. Pain. 2012;153(2):359-365.

Neuropathic pain is one of the most commonly misdiagnosed sources of pain. There is a tendency not to recognize pain as neuropathic in nature, and a tendency to diagnose pain as neuropathic when it's not.

Every headache in the community may look like a migraine, but there are at least 6 different types of migraine, and unless you're familiar with these, often you'll misdiagnose and mistreat. The same goes for neuropathic pain. If you have not been trained and exposed to it, you can misdiagnose and consequently mismanage the patient.

There are many venues to learn how to recognize and manage neuropathic pain or pain in general in children. In California, to renew your license, you need 12 CME hours dedicated specifically to pain.

Additionally, the Society for Pediatric Anesthesia just created a chapter, the Society for Pediatric Pain Medicine (SPPM; www.pedspainmedicine.org/). Every year, we have a full-day session discussing pain in children (SPPM 2nd Annual Meeting; March 12, 2015; Phoenix, Arizona). There's also a lot of literature available on neuropathic pain in children.

I'm not sure the way people are currently exposed to pain in the training process is the right way.

I practice at a children's hospital, and it's very hard to carve out time from trainees' schedules because the American Council on Graduate Medical Education mandates what they should learn. Unfortunately, pain doesn't fit their agenda.

However, pain should be addressed in medical school, especially for those in pediatrics, although it's not. A lot of evidence shows that 60% to 70% of kids eventually will experience pain, and a great proportion of them will have chronic pain, including neuropathic pain.

Additionally, it's very hard to find specific treatment guidelines for neuropathic pain. There is a tendency of prescribing opioids, but there is no indication in my mind or in many people's minds for opioids in neuropathic pain. Usually, they don't work.

Regarding low-dose ketamine, it's difficult in the community to send patients home with ketamine, and it's not our approach to neuropathic pain. We have been using medications such mexiletine. It's much easier to titrate than ketamine, with far fewer adverse effects.

In cases of chronic pain in which the baseline disease cannot be managed, we have been using spinal-cord stimulators. At times, we use regional anesthesia and it works fairly well, but it is effective only in specific types of neuropathic pain (ie, complex regional pain syndrome), and it is, by definition, time limited. In our experience, spinal-cord stimulators are more effective and easier to manage than intrathecal pumps for the delivery of spinal morphine.

Giovanni Cucchiaro, MD, MPP, is director, pain management and palliative care, Children’s Hospital Los Angeles, California.

Mr Jesitus is a medical writer based in Colorado. He has nothing to disclose in regard to affiliations with or financial interests in any organizations that may have an interest in any part of this article.