Pain is a complex and subjective experience that involves sensory, emotional, and cognitive components. It is a signal that alerts us to potential or actual tissue damage and motivates us to take actions to relieve it. However, sometimes pain persists even after the cause of pain has been treated or removed. This is called chronic or unrelieved pain, and it can have serious consequences for our health and well-being.
The Physiology of Pain
To understand the physiologic effects of unrelieved pain, we need to first understand how pain works in our body. Pain is produced by specialized nerve endings called nociceptors, which detect harmful stimuli such as heat, cold, pressure, or chemicals. When nociceptors are activated, they send electrical signals to the spinal cord, where they are processed by secondary neurons that relay the information to the brain.
The brain then interprets the signals and produces the sensation of pain, as well as emotional and behavioral responses. The brain can also modulate the pain signals by sending feedback signals to the spinal cord, which can either enhance or inhibit the transmission of pain. This is called the descending pain pathway, and it involves various neurotransmitters and hormones that can affect the perception of pain.
The Physiologic Effects of Unrelieved Pain
Unrelieved pain can disrupt the normal functioning of the descending pain pathway, leading to increased sensitivity and reduced inhibition of pain signals. This can result in hyperalgesia (increased pain response to a normally painful stimulus) and allodynia (pain response to a normally non-painful stimulus). Unrelieved pain can also activate the stress response system, which involves the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS).
The HPA axis releases hormones such as cortisol and adrenocorticotropic hormone (ACTH), which have various effects on metabolism, immunity, inflammation, and mood. The SNS releases neurotransmitters such as norepinephrine and epinephrine, which increase heart rate, blood pressure, respiration, and blood glucose levels. These changes are adaptive in acute situations, but when they persist for a long time, they can cause harmful effects on multiple organs and systems.
Some of the physiologic effects of unrelieved pain are:
- Cardiovascular system: Unrelieved pain can increase the risk of hypertension, arrhythmias, myocardial ischemia, and heart failure.
- Respiratory system: Unrelieved pain can impair ventilation, oxygenation, and cough reflex, leading to atelectasis, pneumonia, and respiratory failure.
- Gastrointestinal system: Unrelieved pain can reduce gastric motility and secretion, causing nausea, vomiting, constipation, ileus, and ulceration.
- Renal system: Unrelieved pain can reduce renal blood flow and glomerular filtration rate, causing oliguria, anuria, and renal failure.
- Musculoskeletal system: Unrelieved pain can cause muscle spasm, tension, weakness, atrophy, contractures, and joint stiffness.
- Immune system: Unrelieved pain can suppress immune function and increase susceptibility to infection and inflammation.
- Endocrine system: Unrelieved pain can alter glucose metabolism and insulin sensitivity, causing hyperglycemia and diabetes mellitus.
- Nervous system: Unrelieved pain can cause neuroplasticity changes in the spinal cord and brain, resulting in chronic neuropathic pain syndromes.
- Psychological system: Unrelieved pain can affect mood, cognition, memory, attention, sleep quality, and quality of life. It can also increase the risk of depression, anxiety, post-traumatic stress disorder (PTSD), substance abuse disorder (SUD), and suicide.
The Management of Unrelieved Pain
Unrelieved pain is a serious health problem that requires comprehensive assessment and treatment. The management of unrelieved pain should be individualized according to the patient’s needs and preferences. It should also involve a multidisciplinary approach that includes pharmacological and non-pharmacological interventions.
Pharmacological interventions include analgesics such as opioids (morphine), nonsteroidal anti-inflammatory drugs (NSAIDs) (ibuprofen), acetaminophen (paracetamol), antidepressants (amitriptyline), anticonvulsants (gabapentin), local anesthetics (lidocaine), and adjuvant drugs (ketamine). These drugs should be prescribed according to the principles of analgesic ladder, which recommends starting with mild analgesics and escalating to stronger ones as needed.
Non-pharmacological interventions include physical modalities such as heat or cold therapy, massage, acupuncture, transcutaneous electrical nerve stimulation (TENS), and spinal cord stimulation (SCS). These modalities can reduce pain by stimulating the descending pain pathway and blocking the ascending pain signals. They can also improve blood circulation, muscle relaxation, and tissue healing.
Other non-pharmacological interventions include psychological therapies such as cognitive-behavioral therapy (CBT), mindfulness-based stress reduction (MBSR), hypnosis, and biofeedback. These therapies can help patients cope with pain by changing their thoughts, emotions, and behaviors related to pain. They can also enhance self-efficacy, resilience, and well-being.
Additionally, non-pharmacological interventions include social and spiritual support such as family, friends, peers, counselors, and religious leaders. These sources of support can provide emotional, informational, and practical assistance to patients with unrelieved pain. They can also help patients find meaning, purpose, and hope in their lives.
Unrelieved pain is a complex and multifaceted phenomenon that can have detrimental effects on various physiological systems. It can impair the normal functioning of the body and the mind, causing physical, psychological, and social problems. Therefore, it is important to recognize and treat unrelieved pain as soon as possible, using a holistic and multidisciplinary approach that combines pharmacological and non-pharmacological interventions. By doing so, we can improve the quality of life of patients with unrelieved pain and prevent further complications.