Sickle cell pain: a critical reappraisal.

Sickle cell pain includes 3 types: acute recurrent painful crises, chronic pain syndromes, and neuropathic pain. The acute painful crisis is the hallmark of the disease and the most common cause of hospitalization and treatment in the emergency department. It evolves through 4 phases: prodromal, initial, established, and resolving. Each acute painful episode is associated with inflammation that worsens with recurrent episodes, often culminating in serious complications and organ damage, such as acute chest syndrome, multiorgan failure, and sudden death. Three pathophysiologic events operate in unison during the prodromal phase of the crisis: vaso-occlusion, inflammation, and nociception. Aborting the acute painful episode at the prodromal phase could potentially prevent or minimize tissue damage. Our hypothesis is that managing these events with hydration, anti-inflammatory drugs, aggressive analgesia, and possibly vasodilators could abort the crisis and prevent or minimize further damage. Chronic pain syndromes are associated with or accompany avascular necrosis and leg ulcers. Neuropathic pain is not well studied in patients with sickle cell disease but has been modeled in the transgenic sickle mouse. Management of sickle cell pain should be based on its own pathophysiologic mechanisms rather than borrowing guidelines from other nonsickle pain syndromes.