Pain due to a previous injury e.g. post amputation phantom limb pain.

Chronic abdominal pain e.g. constipation, intestinal infections, gastritis and lactulose intolerance.

Neuropathic pain. Pain that involves the neural tissues is classified as neuropathic pain and is less responsive to analgesics than pain that involves somatic and visceral tissues. Because young children are unable to describe the quality of pain, presence of neuropathic pain with cancer may be unrecognized and undetected(₆).

CRPS1 or reflex sympathetic dystrophy (RSD) is defined as “continuous pain in a portion of an extremity after trauma which may include fracture but does not involve major nerve lesions and is associated with sympathetic hyperactivity”. RSD is generally seen in children beyond the age of nine. RSD occurs particularly in girls, commonly overachievers who participate in competitive athletic programs. Pain often persists despite the absence of ongoing tissue injury or inflammation(₇).

Chronic headache. Investigated the incidence of headache in 9000 school-aged children in Sweden, the author estimated that by age of 6 years, 39% of children had suffered from headache. This figure dramatically increased to 70% by age 15 years. Other studies have reported similar trends with an incidence as high as 82%. Headache have a significant impact on the lives of children and adolescents, resulting in school absence and decreased extracurricular activities. The difficulty for the practitioner arises from the fact that the headache may be functional. The degree of headache is modulated by extracranial as well as intracranial structures(₈).

Chronic headache might be due to: chronic progressive headache e.g. organic brain disease and VP shunt malfunction, or chronic nonprogressive headache e.g. functional headache and mixed headache.

The patient's clinical status has to be very carefully evaluated in addition to computed tomography scans with the neurosurgeons. Once it has been confirmed by the neurosurgical service that the headache is not related to increased intracranial pressure, the patient is scheduled for an outpatient evaluation in the Chronic Pain Clinic(₈).

Chronic Pain in Sickle Cell Disease

When people think of sickle cell disease, they usually think of pain. The hallmark symptom of sickle cell disease is an excruciatingly painful episode known as a sickle cell crisis. As a result, people with sickle cell disease are often perceived as long-time sufferers, victims of uncontrollable pain crises that can strike without warning. An additional challenge is the fact that individuals with more severe forms of the disease can become physically dependent on the opioids prescribed to treat their chronic pain. Every sickle cell crisis is different, and each requires an approach that is attentive to the stated needs of the individual. Often, the patient and family should be well informed about the sickle cell specific disease pattern(₉).

Cancer pain in children:

One of the most challenging issues in pediatric pain management is the management of cancer pain, especially in the terminally ill patient. Pain in a cancer patient can result from tumor invasion, procedures like bone marrow aspiration, lumbar puncture, and venipuncture, etc. and therapy-related pain, which is related to the type of tumor, and the anticancer therapy that is being administered(₁₀).

Pain during terminal illness:

Treatment modalities for cancer and children have improved recently. Novel alternative methods for providing analgesia have been used like Nebulized opioids (the nebulization of opioids delivers medication directly into the airways and hence into the pulmonary circulation. Hepatic first-pass metabolism is avoided, and this route has been advocated as causing fewer adverse reactions) or the transdermal delivery systems in children (Transdermal delivery allows continuous systemic application of opioids through the intact skin. The time from application to minimal effective and maximum serum concentrations is 1.2 to 40 hours and 12 to 48 hours, respectively for fentanyl patch. It has fewer gastrointestinal adverse events than other routes of administration) to offset intractable pain. The adverse effects associated with long-term use of opioids include tolerance and withdrawal. Careful rotation of opioids, along with the judicious use of other agents including N-methyl-D-aspartate (NMDA)-receptor antagonists, should be considered in their care. Patient-controlled analgesia (PCA) has been used widely for home-bound patients with terminal cancer. Smaller, more user-friendly pumps (Fig 1) have been devised for easy programming and they require less frequent changing(₁₁).

Figure 1

Figure 1: Ambit ® PCA infusion pump()

NSAIDs and steroids are particularly useful in the management of bone pain from metastasis. Carbamazepine, gabapentin and tricyclic antidepressants (TCAs) are useful for the management of neuropathic pain. Hypnosis, biofeedback and distraction techniques can be used very effectively in children who are not heavily sedated. A home care coordinator should be available for the management of any adverse conditions. The combination of various techniques for the management of cancer pain should enhance the child's motivation to lead as normal a life as the disease state allows.

To effectively treat chronic pain, the APS's statement stresses that physical and psychological manifestations must be viewed together and separating them could lead to inappropriate investigations, procedures, and interventions(₅).

The APS recommends that an evaluation of pediatric chronic pain should include:

A history of the present problem, including a detailed description of the pain detailing onset, development, intensity, duration, location, exacerbating and alleviating factors, and impact on daily life (such as sleeping, eating, school and social interactions).

Assessment of the child and family's perception of the pain's cause and their response to it.

A review of past pain problems in the family and current treatments for the child's pain, including home remedies and alternative treatments.

Observation of the child's general appearance, posture, gait, emotional and cognitive state.

Assessment of muscle spasms, trigger points, and areas sensitive to light touch; and a complete neurological examination.

The objectives of pain assessment are to:

• Detect the presence of pain.

• Estimate the potential impact of pain on the individual.

• Quantify the success of intervention.

• In older children, tools for the assessment of pain involve the patient in self- reporting pain(13). There are several self-report measures that can be followed objectively for a prolonged period of time (Table 1).

Figure 2

Table 1: Self-Report Measures of Pain in Children

The visual analog score and faces pain scale (Fig 2) are the measures commonly used in the pain clinic. Self-report measures are very useful in determining precipitating and aggravating factors that cause pain in the older child. These also allow us to assess patients for compliance and the viability of treatment regimens. Using these measures, physicians will be able to predict patient pain tolerance and ability to cope with pain(₁₄).

Figure 3

Figure 2: Representative samples of pain intensity rating scales

Treatment strategies should be based on the findings of the assessment and should address the inciting and contributing factors. A multimodal approach often is more effective than a single sequential treatment approach.

The World Health Organization (WHO) has suggested an analgesic stepladder protocol for the management of pain in cancer patients(₁₅):

Step 1 Non-opioids & adjuvants

Step 2 Weak opioids; Non-opioids & adjuvants

Step 3 Potent opioids and adjuvants

• Oral or intravenous administration of pain medication is the Most preferred methods. Avoid intramuscular injections.

• Base the initial choice of analgesic on the severity and type of pain: intravenous opioids Morphine can be safely titrated to effect in the pediatric setting.

• Use Meperidine with caution. Meperidine should not be used in patients with decreased renal function.

• PCA or nurse controlled analgesia (NCA) are acceptable methods of administering pain medications. Patients and families should be educated on PCA delivered medication. Parents should be instructed never to push the PCA button when the child is asleep(16).

Figure 4

Treatment techniques include education about the pain experience and the pain problem, cognitive-behavioral (e.g., self-regulatory behaviors such as hypnosis or biofeedback) strategies, family interventions, physical interventions (e.g., massage, acupuncture, TENS, physical therapy). Exercise is prescribed to correct impairment, improve musculoskeletal function, and maintain a state of well-being (₁₇).

Pain is both a physical and psychological experience. Therefore, psychologists, especially those who specialize in treating pain problems, can provide a number of important services to the child with pain:

Self-management techniques for pain: These include relaxation strategies such as deep breathing exercises, muscle relaxation.

Evaluation and treatment for pain-related disability: The psychologist can work with school personnel to find ways of helping a child with pain function in the school environment.

Evaluation and treatment for pain-related emotional difficulties.

Important notes about narcotic treatment in children:

Addiction to narcotics is rare (less than 1% of patients) and usually occurs in patients with a prior history of substance abuse.

Pseudoaddiciton must be differentiated from true addiction. Patients experiencing continued pain will exhibit anxiety and drug-seeking behavior. These behaviors typically disappear once the pain is relieved. This pseudoaddictive behavior is extinguished by adequate pain relief, unlike the continued drug-seeking behavior of true addiction(₁₈).