Palliative medicine

Pain

Pain management:

• Is an essential component of palliative care.

• Requires assessment, communication, planning and a sound knowledge of pharmacology and physiology.

• Is often under-recognized in children with disability.

• Can dramatically improve quality of life for child and family if done well.

According to the International Association for the Study of Pain, pain is ‘an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.’ It is:

• Subjective (whatever the child says it is)

• Influenced by past pain experiences and concerns about personal well-being or that of others

• Influenced by context (different situations).

All children, including the extremely preterm, are able to feel pain. Pain in palliative care is usually neither wholly acute nor entirely chronic. It has elements of both, and may be complicated by the existential context of deterioration towards death.

Management of pain

Consider and treat specific reversible causes

• Constipation

• Gastro-oesophageal reflux

• Orthopaedic, especially hip dislocation

Consider non-pharmacological measures

• Attention to reversible sources of fear and anxiety

• Counterirritants (hot or cold packs, acupuncture or TENS), distraction techniques

• Behavioural techniques (cognitive behavioural therapy, relaxation, visualization or art therapy)

Pharmacological approach: the pain ladder

Key point

The WHO pain ladder ( Fig. 34.1 ) is the basis for rational management of palliative pain. It expresses the concept that increases in the intensity of pain should be matched by changes both in the type of analgesic, and the manner in which they are prescribed.

There are three steps on the WHO pain ladder. As pain intensity increases and the effect of prescribing on one step becomes inadequate, the prescriber should move to the next step. Each step is characterized by:

• A specific class of analgesic

• A specific approach to dosing (regular versus ‘as needed’)

• The need to consider adjuvants ( Box 34.3 ) appropriate to the nature of pain

  Box 34.3

  Adjuvants to analgesics

  These depend on characteristics of pain:

  • Bone pain – NSAID, radiotherapy (if metastatic cause), bisphosphonates (especially in presence of osteopenia), steroids (if metastatic cause)

  • Nerve pain – Anticonvulsants, antidepressants, NMDA antagonists (ketamine, methadone), baclofen, steroids (if cause is pressure, e.g. from tumour oedema)

  • Muscle spasm – Baclofen, benzodiazepines, botulinum toxin

  • Cerebral irritation – Phenobarbital, benzodiazepines

  • Neurolytic and other interventions – Regional nerve blocks and spinal blocks

Key point

An adjuvant is a medication or other intervention that is not an analgesic but, used alongside analgesics, its actions can reduce pain in certain specific situations.

For prescription of major opioids ( Box 34.4 ), there are three phases, namely: initiation, titration and maintenance. The opioids can be given as immediate release (e.g. oramorph, buccal diamorphine), continuous release (e.g. MST, transcutaneous patch, syringe driver). There should always be both regular (background) and ‘as needed’ doses. This is a specialist skill and should be undertaken in discussion with the local or regional palliative care team.

Box 34.4

Common fears and myths about morphine

• ‘It is the ‘death drug’.’ Explanation with family to increase understanding about benefits and side-effects.

• ‘It will stop my child breathing.’ Respiratory depression is extremely rare when opioids are used for pain. It is avoided by careful titration of dose.

• ‘ It has all kinds of side effects.’ There are adverse effects, but fear of them is often disproportionate to the reality:

  • Drowsiness: The child is likely to be drowsy for 3–5 days when first starting strong opioids or when doses are increased.

  • Nausea and vomiting: This can occur when first starting, is less common than in adults and wears off.

  • Constipation: Laxatives are necessary and can be titrated according to need.

  • Other side effects should be monitored but are rare (e.g. pruritus, urinary retention, nightmares)

• ‘ It is addictive . ’ Explain to the family about issues relating to addiction and dependence. Physical dependence is not usually a primary concern in the palliative care setting, but opioids should always be weaned slowly if the pain resolves to avoid withdrawal.

• ‘ Once you start morphine, there’s nothing to turn to later when the pain becomes really bad.’ Tolerance probably occurs if opioids are used for long periods. The remedy is to increase the dose of opioids. Families may find it beneficial to understand the principle of tolerance rather than assuming that escalating doses of analgesia imply disease progression.

• ‘People will break in and steal it.’ Discuss safe storage, particularly in the home setting.

Nausea and vomiting

• Nausea and vomiting are distressing symptoms that may cause more upset than pain.

• Full control of nausea and vomiting is more difficult than that of pain – negotiating acceptable goals with the family may be necessary.

• In children with cognitive impairment, feeds are a common cause – liaise with dietitians to manipulate volumes/rates/type of feed.

• Constipation is another common cause.

Nausea and vomiting due to:

• Gastrointestinal tract damage (chemotherapy, radiotherapy) is often mediated through 5-HT ₃ receptors and blocked by 5-HT ₃ antagonists (ondansetron, granisetron)

• Liver swelling/damage or toxins (infection, metabolic, uraemia, drugs) are often mediated through dopamine receptors and blocked by dopamine blockers (domperidone, metoclopramide, haloperidol). Because metoclopramide blocks dopamine receptors in the CNS as well as peripherally, it is both more effective than domperidone and more likely to cause adverse neurological effects.

• Vestibular problems (travel sickness, vertigo) and raised intracranial pressure is largely mediated through acetylcholine and histamine (H ₁ ) and is blocked by anticholinergics, anti-H ₁ (cyclizine acts at both receptors) medications.

Additional factors to consider are:

• Levomepromazine (phenothiazine) blocks most receptors and is good second-line treatment, or first-line if cause is multifactorial/not known

• Functional delay – can use prokinetics (dopamine antagonists, erythromycin)

• Efferent (motor) pathway is through vagus nerve (acetylcholine) so anticholinergics are often partially effective irrespective of cause

• Steroids can be valuable by reducing:

  • –

    Oedema (e.g. in raised intracranial pressure)

  • –

    Tissue damage

  • –

    Release of emetogenic mediators

  but adverse (Cushingoid, etc.) effects after prolonged administration of steroids can limit their usefulness.

In bowel obstruction, consider:

• Anticholinergic to relieve spasm (hyoscine butylbromide (buscopan))

• Analgesic to relieve pain (strong opioid parenterally)

• Anti-secretory to reduce hypersecretion (octreotide)

Gastro-oesophageal reflux (GOR) is common but does not always cause discomfort. The risk is increased by prone position, decreased activity, medication and liquid feeds (all more likely among debilitated patients). A presumptive diagnosis and treatment of GOR may be appropriate in pain and discomfort related to feeding without an obvious cause. In reflux, consider:

• Antacid to relieve pain (ranitidine, proton blockers)

• Prokinetic to improve gastric emptying (domperidone, metoclopramide)

• Dopamine blocker to reduce reflux (domperidone, metoclopramide)

Dyspnoea

The profound and multidimensional significance of difficulty breathing is illustrated by the dual meanings of words like ‘inspire’ and ‘expire’. In paediatric palliative care, respiratory arrest is the most common mode of death and altered pattern of breathing is one of the critical signs that death is approaching. Dyspnoea is a common and distressing symptom.

Regarding dyspoea:

• Different factors contribute to the symptom, including physical, psychosocial and existential/spiritual factors.

• Fear and anxiety play a significant part in its pathophysiology (they can be both cause and effect of dyspnea, causing a vicious cycle).

• Breathing can be abnormal (e.g. tachypnoea) without being uncomfortable and vice versa.

Causes of dyspnoea in children with life-limiting conditions ( Fig. 34.2 ) can be:

• Reversible (e.g. chest infection, fluid overload, pressure from metastatic tumour)

• Inevitable (e.g. muscle weakness in Duchenne muscular dystrophy)

• Irreversible but amenable to palliation (e.g. secretions pooling in the hypopharynx in the last hours/days of life, causing ‘death rattle’).