An introduction to controlling pain in children

Pain is an unpleasant physical and psychological experience which if not managed appropriately in children can lead to distress, clinical deterioration and severe functional limitations. Pain can be associated with numerous paediatric diseases and conditions and is an important consideration in children undergoing procedures and surgery. Cancers in children in particular are associated with ongoing pain that requires treatment. Control of Pain in Children (Paediatric Pain Management) can be quite difficult as it hard to determine the exact level of pain present. In addition, many of the medications used to treat pain have not been appropriately tested in children so doctors may not be entirely sure of their effects and be reluctant to use them. Failure to recognise the extent of pain in children and inadequate treatment can have large impacts on the patient’s quality of life. However, paediatric pain management has made several advances in recent decades through improved understanding of effects of ongoing pain, greater insight into the benefits and risks of aggressive management, and greater knowledge of the clinical aspects of the analgesic (pain reducing) drugs in children. Pain management now focuses on a combination of pharmacological agents (drugs) including simple analgesics and opioids, along with proven non-pharmacological techniques such as hypnosis and Cognitive-Behavioural Therapy .


What is pain?

Pain is described as an unpleasant and unique physical and psychological experience. In general terms it can be divided into acute pain, which is often a natural response and acts to protect the body, and chronic pain which lasts for several months. Pain in children has several unique features which make appropriate management challenging. In the past, pain has been poorly managed in paediatric patients due to the false belief that neonates and children do not experience pain or require pain relief, as commonly as adults. It was thought that neonates did not experience or remember pain due to their immature nervous systems. Subsequent studies showed these responses develop much earlier than expected. Furthermore, several studies have highlighted that many health professionals underestimate the level of pain experienced by young children. More recent studies have confirmed the benefits of appropriate pain relief in young patients and that neonates, infants, and children can receive analgesia and anesthesia safely if the necessary dosing and administration adjustments are made. Inadequate management of pain, particularly chronic forms can have substantial impacts on children. A recent study proved that chronic pain in children and adolescents can cause considerable functional limitations, particularly school absenteeism, sleep disturbance and inability to perform sporting activities. Ongoing absences from school due to pain can lead to poor school performance and long-term complications. Pain in the acute setting can lead to deterioration in the patient’s clinical condition.


How is pain expressed?

All children experience pain differently and it can be quite difficult as a parent to guess that behavioral changes and other signs may be due to pain. Some children in severe pain may become quiet and withdrawn whilst others may display aggressive tendencies. In young children especially, it can be hard to tell as they simply can’t verbalise that something is painful or sore. On the contrary, adolescents tend to minimse or deny pain in the presence of their peers thus they require specific and private questioning about their pain. The varying outward expressions of pain also make it hard for medical staff to diagnose and manage pain in children. As an overview, pain may present in various forms including changes in:

  • Behaviour
  • Appearance
  • Activity level
  • Vital signs- These include heart rate, respiratory rate, blood pressure and other signs which are often monitored in hospital.

This is by no means an exhaustive list of the possible manifestations of pain.


How is pain assessed?

Perhaps the greatest challenge of pain management in children, is gaining an objective assessment of the level of pain. Infants and young children cannot verbalise their pain levels so rely on adult’s and health professional’s interpretations of external manifestations of the pain. Older children may still be unable to conceptualise and communicate their pain. Difficulties assessing pain have lead to the development of numerous pain assessment scales that health professionals use to grade patient’s pain. These look at behaviour pattern and what the child reports as their level of pain. There are different tools for different age groups. With a reliable tool for assessing pain, management becomes far easier. Children older than eight years of age can usually describe their pain similar to adults by rating it according to the intensity of pain on a horizontal ruler. For younger children, doctors use series of faces and pictures (progressively becoming more distressed) which the child can point to identify their pain level. Neonates, infants and children under four years are assessed based on observation of behaviour and physiologic changes such as facial expressions, motor expressions, verbal responses and vital signs (such as pulse, blood pressure etc). The assessment tools are not entirely reliable but usually give the medical staff a sufficient idea of whether pain is present and how severe so they can treat it appropriately.


Pain and pharmacological considerations

It is important to remember that children are not just small adults. They are actively growing and many of their systems are not yet fully developed. Thus, drugs affect children differently to adults and often the children’s body absorbs, transports, distributes and excretes drugs slightly differently to an adult’s body. Your doctor therefore has to carefully consider your child’s age and stage of development before prescribing drugs. For example, recently born babies have not yet developed efficient means of excreting drugs from the body using the kidney and liver, so drugs must be given at lower doses per body weight compared to adults to avoid toxicity. It is also important for medical staff to closely monitor children taking pain medication because as fore mentioned the exact effects on young children are not always known due to the lack of research in this field. Your child may have to be closely watched or have blood test to check the drug is at the right level and having an appropriate response.


Drugs and techniques used to control pain in children

There are numerous options available for paediatric pain management outlined below. In general, a multidisciplinary approach (that is using several different agents such as drugs and other techniques in combination) has been proven to be the most beneficial.


Acetaminophen, aspirin and NSAIDs

These are mild analgesics and are usually considered first in treating mild to moderate pain. Acetaminophen (paracetamol) is probably the most commonly used analgesic as it is very safe. Aspirin is an effective analgesic but it has some nasty side effects such as Reye’s hepatic encephalopathy which damages the brain and liver. Non-steroidal anti-inflammat
ory drugs
(such as ibuprofen and naproxen) are also used in children but they have limited uses in childhood cancer and other conditions due to their inhibition of platelet function (platelets normally help the blood clots when there is a cut). In general, these agents are given orally which is the preferred route of administration for most patients.


Opioids

Opioids are stronger drugs used for more severe pain such as that associated with surgery or chronic cancer. Morphine, fentanyl, codeine and merperidine (pethidine) may be administered by various routes. In some cases the drug can be given intravenously (into the veins and bloodstream) and may be connected to a special pump. The patient can press a button to get a dose of medication as required. This is called ‘patient controlled analgesia’ and is a good method of administering pain medications due to the highly varied doses needed to get appropriate pain relief. It has been used in children as young as six years. The machine has special cut off values so the patient is unable to overdose by pressing the button too much. In other cases the nurse or parent may control the doses. It should be recognized that infants less than 3 months old and neonates and infants with lung disease are at particular risk of respiratory depression from some of these drugs. This is because accumulation of the drug causes inhibition of the breathing centers in the brain. Caution must always be taken giving these types of drugs to young patients.


Local anaesthetics

Local anaesthetics such as lidocaine and bupivacaine, are widely used in children undergoing procedures. They have a narrow dose for which they are effective without causing side effects. Maximum doses of both drugs should not be exceeded or toxic side effects will occur. Administering epinephrine with the drug allows a slightly higher dose to be used. Epinephrine constricts surrounding blood vessels to keep the agent local so it cannot spread throughout the body and cause side-effects. Other analgesic techniques include blocking particular nerves to stop the pain signal.


Others

Tricyclic antidepressants and anti-epileptic medications can be used in the management of neuropathic pain (pain originating from damage or irritation to a nerve pathway). Numerous sedative drugs are also used in children undergoing surgery and other procedures. However, these drugs are more to treat anxiety than pain per se but they are worth a mention. Chloral hydrate, benzodiazepines (especially midazolam), ketamine, barbiturates and nitrous oxide are the main sedative agents used in pediatrics. The safety of sedation in children has greatly increased over the years particularly when agents were developed that could reverse some of the respiratory depressive actions of the above drugs.


Non-pharmacological

Non-pharmacological agents are often used in combination with the drug classes already mentioned in the management of chronic pain. Examples are listed below:

  • Hypnosis has been proven beneficial in clinical studies.
  • Cognitive Behavioral therapy- There is also good evidence for this treatment.
  • Deep breathing and relaxation exercises.
  • Distraction techniques- Focusing a child’s attention away from something negative to something more positive such as music, toys or bubbles.
  • Play therapy.
  • Friendly hospital environment- This can reduce anxiety and fear in young patients which has been shown to exacerbate pain.
  • Transcutaneous nerve electrical stimulation (TENS) refers to sending small electric currents through the skin. It is a possible treatment for neuropathic pain (in combination with opioids) but is not always effective. It has few side-effects so is often trialed initially in patients with moderate pain.
  • Behaviour- Pain in neonates can be helped by breast feeding, sugars, pacifiers and multisensory stimulation of your baby (e.g. massage, voice, eye contact).
  • Education- If your child is adequately described the details and nature of a procedure (including being shown equipment and being allowed to ask questions) it can reduce their fear and help reduce pain. Only necessary procedures should be performed on your child.
  • Parent training programs- It can help your child if you are taught ways to identify and cope with pain so you are able to offer positive support.

References

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