Table 1.

Chronicity and type of pain

Chronicity of pain
 Acute pain• Typically persists for <3 mo.
• Associated with tissue damage.
• Usually episodic with periods without pain.
• Tends to last a predictable period, have no progressive pattern and subsides as healing occurs.
• Tends to respond well to pharmacologic therapy: titrating analgesics against pain intensity usually works well.
 Chronic pain• Often defined as any painful condition that persists for >3 mo (8).
• Usually initiated by tissue injury but is perpetuated by neurophysiologic changes, which take place within the peripheral and central nervous system leading to continuation of pain once healing has occurred.
• Severity is often out of proportion with the extent of the originating injury.
• More likely to result in functional impairment and disability, psychologic distress, sleep deprivation, and poor QOL than acute pain.
• The pain experience may be affected substantially by mood, stress, and social circumstances.
• May not respond well to analgesics, including opioids, except early in the course of treatment.
 Recurrent pain• Acute pain from tissue injury, which may occur over long periods of time (e.g., pain from needling fistulas, intradialytic steal syndrome, intradialytic headaches, and cramps).
• Patient will also be free from pain for long periods.
• More intrusive on everyday life than “acute pain.”
Type of pain
 Nociceptive pain• Results from tissue damage in the skin, muscle, and other tissues, causing stimulation of sensory receptors.
• May be described as sharp or like a knife and often felt at the site of damage (e.g., joint pain from dialysis-related arthropathy).
• With stimulation of visceral nociceptors, may be experienced as dull, aching, and poorly localized (e.g., gut ischemia).
• Tends to respond to analgesics.
 Neuropathic pain• Results from damage to the nervous system resulting in either dysfunction or pathologic change.
• May be felt at a site distant from its cause (e.g., in the distribution of a nerve).
• Common descriptors include burning, shooting, and electrical.
• May be associated with episodes of spontaneous pain, hyperalgesia, and allodynia; the presence of allodynia is pathognomonic.
• Examples include peripheral neuropathy. Severe pain associated with limb ischemia and calciphylaxis tend to have substantial neuropathic components.
• Responds poorly to analgesics and typically requires adjuvant therapy such as anticonvulsants (gabapentinoids or carbamazepine) and tricyclic antidepressants.
  • QOL, quality of life.