In sickle cell disease ( SCD ), pain is considered chronic if it lasts more than 3 months. People with sickle cell disease experience both nociceptive and neuropathic pain. Nociceptive pain is a hallmark of acute pain. Chronic pain, including that described in people without SCD, is often associated with neuropathic pain.
The pathology of the transformation from chronic nociceptive pain to neuropathic pain is not well understood.
The Pain in Sickle Cell Epidemiology Study ( PiSCES ) showed that adults reported chronic SCD pain at home during about 55% of the 31,017 days surveyed. Similarly, children reported SCD pain at home on about 9% of the 1,515 days surveyed.
In the Multicenter Study of Hydroxyurea in Sickle Cell Anemia ( MSH ), at-home analgesics were used for SCD pain on 40% of diary days and during 80% of 2-week follow-up periods, with Oxycodone and Codeine being used most frequently.
The major types of sickle cell disease-associated chronic pain include the following:
Chronic pain often of unclear etiology. This type of chronic sickle cell pain may be an extension of recurrent acute painful episodes. Therefore, early and aggressive intervention in treating acute sickle cell pain may reduce the development of chronic pain;
Chronic pain in a specific tissue or organ, such as avascular necrosis ( AVN ) of the hips, or leg ulcers. Chronic SCD pain is usually described as constant and deep, nagging, and achy in nature. It can occur in the chest, back, abdomen, extremities, neck, or head and is difficult to treat;
Chronic neuropathic pain. This is usually described as burning, numb, tingling, lancinating, shooting, or paroxysmal in nature and is associated with a sensation of pins and needles. Its severity is also enhanced by exposure to either cold or heat. This pain can be secondary to either peripheral or central nerve injury or nerve dysfunction. Sickle cell disease -related neuropathic pain has two etiologies. The first is tissue damage secondary to occlusion of blood vessels that supply the nerves as can be found in mental nerve neuropathy and spinal cord infarction. The second seems to be chronic pain. Persistent chronic pain, the resulting inflammation, and/or pain management seem to lead to neuropathic pain.
Breakthrough pain is another type of pain often identified by health care professionals who treat patients with sickle cell disease. This term literally means the act of breaking through pain relief. Originally used to describe patients with cancer pain who were maintained on a stable dose of analgesics, breakthrough pain was defined as a flair-up of sudden pain unresponsive to usual therapy. Such a flare-up is usually sudden and incidental, and can last from a few seconds to a few hours. There are currently no data that clearly describe or can be used to define breakthrough pain in sickle cell disease.
The pathophysiology, management, and goals of treating chronic pain differ from those related to acute pain. Whereas the aim of acute pain treatment is to heal the acute process, the aim of chronic pain management is to restore function and improve the quality of life. With the onset of chronic pain of unknown etiology, there seems to be a process of rewiring in the brain, where the threshold for pain perception is lowered so that ambient environmental stimuli that are normally painless or mildly painful induce the perception of severe pain.
Chronic pain is often associated with other conditions that enhance its chronicity. These include psychosocial factors such as depression, anxiety, feelings of despair, insomnia, loneliness, helplessness, posttraumatic stress disorder ( PTSD ), and dependence on pain medications.
Management of chronic pain in people with sickle cell disease is a major challenge for health care professionals. The goals of providing adequate pain relief to improve functionality and quality of life must be balanced by the need to minimize the risk of abuse, misuse, or diversion of opioids ( medications which are a mainstay in managing chronic pain in people with SCD ). Believing the patient’s report of pain is critical to optimizing therapeutic outcomes and achieving adequate pain relief and maintaining or improving functionality and the person’s quality of life.
Medications used to treat sickle cell disease -related pain should be tailored to the individual. Medications include nonsteroidal anti-inflammatory drugs ( NSAIDs ), opioids, antidepressants, and anticonvulsant medications. Management of all types of chronic pain associated with sickle cell disease may be enhanced by adding nonpharmacologic approaches. These may include psychological intervention, occupational therapy, behavioral and cognitive interventions, acupuncture, mild to moderate exercise if tolerable, and aqua therapy. ( Xagena )
NIH - Evidence-Based Management of Sickle Cell Disease - Expert Panel Report, 2014