What types of pain are addressed by palliative care in patients with chronic, severe, or life-limiting illnesses?

Types of Pain Addressed by Palliative Care

Palliative care addresses multiple distinct pain types including nociceptive pain (both somatic and visceral), neuropathic pain, cardiac ischemic pain, musculoskeletal pain, and procedure-related pain, with treatment selection based on the underlying pathophysiological mechanism rather than a one-size-fits-all approach. 1

Primary Pain Categories in Palliative Care

Nociceptive Pain

• Cancer-related pain is the most extensively studied, affecting 60-90% of cancer patients and requiring assessment of both intensity and mechanism 2, 3
• Bone pain from metastases is specifically addressed with bisphosphonates in breast cancer and myeloma patients, alongside NSAIDs and opioids 1, 4
• Visceral pain from organ involvement, tense ascites, or dyspepsia requires mechanism-based treatment 1
• Somatic pain from musculoskeletal sources, oedematous legs, or peripheral vascular disease 1

Neuropathic Pain

• Requires distinct pharmacological approaches using antidepressants (tricyclic antidepressants) and anticonvulsants as first-line agents 2, 3
• Opioids serve as second-line therapy for neuropathic pain, though they remain effective across all pain types 2, 3

Cardiac Ischemic Pain

• Chronic refractory angina despite optimal cardiologic treatment may require spinal cord stimulation 1
• Acute coronary syndrome pain is managed with intravenous strong opioids like morphine 1
• This pain type is particularly relevant in heart failure patients, where pain prevalence reaches 89% in NYHA Class IV 1

Procedure-Related Pain

• Turning is the most painful procedure for ICU adults 1
• Endotracheal suctioning causes moderate to severe pain in over 30% of cancer patients and post-cardiac/abdominal surgery patients 1
• Invasive procedures including chest tube removal, central line insertion, femoral sheath removal, arterial catheter insertion, and wound care all generate significant pain requiring proactive management 1

Pain Assessment Framework

For Communicative Patients

• Use a 0-10 Numeric Rating Scale (NRS) as the primary tool, validated as the most feasible in ICU settings 1
• Patients can respond verbally or by pointing to numbers 1
• Assessment must occur regularly and periodically for all patients with serious illness 1, 5

For Non-Communicative Patients

• Rely on behavioral pain indicators and physical signs, though this population remains less well understood 1

Pain Management by Mechanism

Nociceptive Pain Management

• Non-opioid analgesics are ideal first-line agents for nociceptive pain 2
• Paracetamol is safe in heart failure patients 1
• NSAIDs must be avoided in heart failure due to fluid retention risk and increased renal strain, particularly with concurrent loop diuretics and ACE inhibitors 1
• Topical NSAIDs may be tried but lack safety data in heart failure 1

Neuropathic Pain Management

• Antidepressants and anticonvulsants reduce neuropathic pain intensity as first-line therapy 2
• Opioids remain effective but are restricted to second-line choice 2

Opioid Selection Considerations

• Morphine is essential for quality end-of-life care for both pain and dyspnea 4, 5
• Avoid morphine in significant renal impairment (GFR <30 mL/min) due to active metabolites with renal excretion; switch to alternative opioids 1
• Tilidine and Tramadol are prodrugs requiring hepatic activation and are vulnerable to drug-drug interactions that block conversion 2
• Rapid-release opioids should be used for breakthrough cancer pain 2
• Transdermal opioid applications are recommended for swallowing disorders but not for initiating pain control 2

Special Population Considerations

Heart Failure Patients

• Pain prevalence increases with age and functional class, reaching 89% in NYHA Class IV 1
• At least moderate pain affects 61% of hospitalized heart failure patients 1
• 40% experience pain at multiple sites 1
• Inadequately treated chronic pain correlates with fatigue, depression, and more frequent hospital admissions 1
• Palliative care service involvement improves pain burden in both inpatient and outpatient settings 1

Critical Care Patients

• 70-77% recall pain during ICU treatment, with 63-64% rating it as moderate or severe 1
• Pain, dyspnea, and thirst are the most prevalent and distressing physical symptoms 1

Critical Pitfalls to Avoid

• Undertreatment of pain occurs more frequently in heart failure patients compared to cancer patients 1
• Women and minority groups have cancer pain undertreated more frequently 6
• Chronic non-cancer pain requires non-pharmacologic and non-opioid pharmacologic therapy as preferred approaches, with careful risk-benefit analysis for long-term opioid use 1
• Opioid-induced delayed gastric emptying can delay absorption of oral antiplatelet agents; use crushed tablets, prokinetic drugs, or parenteral loading to overcome this effect 1
• Inadequate pain assessment remains a fundamental barrier, as more than 80% of cancer pain patients can achieve adequate relief through simple pharmacological methods 6

Refractory Pain Management

When pain cannot be adequately controlled despite aggressive efforts, the symptom is designated as refractory if further interventions are incapable of providing relief, associated with excessive morbidity, or unlikely to provide relief within a tolerable timeframe 1

Palliative sedation is indicated as a last resort for refractory symptoms including pain, using supervised administration of sedative medications to induce decreased or absent awareness 1, 4, 5