MULTIPLE SCLEROSIS (MS)
It is common to find adults with MS-related pain. Of those with MS, approximately 5% will have their first symptoms prior to the age of 16 (25). There are multiple types of pain children with MS may experience including neuropathic pain. They, as their adult counterparts, may suffer from trigeminal neuralgia.
POSTHERPETIC NEURALGIA (PHN)
Although the herpes zoster infection or "shingles" is mostly known in adults, children too can experience PHN. While the incidence of herpes zoster in children does not reach that of adults, immunocompromised children can develop this infection and may go on to develop PHN. The incidence of herpes zoster is particularly prevalent in children undergoing treatment for acute lymphoblastic leukemia (25).
Although seen less frequently in children than the adult population, children can present with radicular pain secondary to herniated discs. Children with vertebral anomalies such as pars defect, transitional or sixth vertebrae can be prone to further injury just as the adult population. In addition, children can suffer traumatic fracture of vertebrae or traumatic spondylolysis, which we have seen in contact sport injuries.
TREATMENT OF NEUROPATHIC PAIN IN CHILDREN
As in adults, neuropathic pain in children can be difficult to treat. Tricyclic antidepressants, gabapentin, and pregabalin have the most frequent use in children. There are also reports of use of intravenous (IV) and intrathecal ketamine as well as topical treatments including lidocaine and capsaicin cream. In addition to common pharmacologic management, it is also important to remember that sometimes treatment of the underlying disease can lead to improved neuropathic pain. As is discussed in the following, pediatric pain is best treated within the context of the biopsychosocial model with the best responses seen with a multimodal approach to pain.
COMPLEX REGIONAL PAIN SYNDROME (CRPS)
CRPS, formerly known as reflex sympathetic dystrophy, is well described in pediatric literature. Diagnostic criteria for CRPS can be defined by methods typically used to assess adult patients utilizing either The Budapest Criteria or the IASP Criteria most frequently. There are two defined types of CRPS: CRPS-1, where there is no defined nerve injury, and CRPS-2, which can be traced to a direct nerve injury (28). The disease can be debilitating, commonly characterized by allodynia, hyperalgesia, and burning pain (29). Children with CRPS are prone to significant emotional distress, school absenteeism, and decreased social interaction. There are some notable differences seen in children compared to the disease in adults. The first is a large gender gap with a female-to-male ratio between 3:1 and 6:1 (30). Also found in children is a large preference of the disease for the lower extremity (31). In addition, the long-term prognosis for children with CRPS is more favorable in comparison to their adult counterparts. Specifically, greater than 90% of children can achieve remission of the disease and this is almost always accomplished with physical therapy (PT), desensitization, mirror visual feedback, and cognitive behavioral therapy (CBT) alone (26,32,33).
It is now better understood that CRPS is not only a peripheral problem but strongly involves the neocortex, hence the role of multidisciplinary treatment (34). Children with CRPS respond best to noninvasive interdisciplinary programs with a focus on PT. Children tend to do well without any intervention apart from those used to facilitate PT in the early rehabilitation period. Desensitization therapy with continued use and mobilization of the limb is the mainstay of PT. Psychological therapy is also a cornerstone in the treatment of CRPS in children. Multiple models exist for accomplishing aggressive PT and behavioral therapy including inpatient models, day hospital treatment programs, and outpatient programs (35). Mainstay medication therapy used in children with CRPS mirrors those used in adults, which includes antidepressants, antiepileptic drugs (AEDs), as well as nonsteroidal anti-inflammatory drugs (NSAIDs) and tramadol. Opioids are of limited benefit and are best avoided.
Although the basis of treatment is nonintervention, a small percentage of children will fail noninvasive therapy or will at some point in their treatment undergo interventional pain management. Various types of intervention such as peripheral nerve blockade, lumbar sympathetic nerve blockage, epidural infusion, and spinal cord stimulation are reported in children (32,36). However, the majority of children will recover without such interventions and mainstream therapy remains focused on PT and CBT with positive outcomes.