Pain in Persons with Disorders of Consciousness

Abstract

Pain and suffering in persons with disorders of consciousness (DoC) remain poorly understood, frequently unaddressed or inadequately addressed, and controversial on numerous levels. This narrative literature review will address a number of critical issues germane to pain and suffering in this challenging group of patients, providing an introductory overview of the topic, perspectives on current knowledge regarding pain pathoanatomy and pathophysiology, and a review of common pain generators and factors that can lead to the chronifcation of pain. Caveats on bedside pain assessment challenges, as well as electrophysiologic and neuroimaging findings in these patients, will also be explored. Pain management techniques, including non-pharmacological and pharmacological, will be reviewed. Ethical considerations in the context of pain and suffering in persons with disorders of consciousness will round out the review prior to our concluding comments.

Keywords: assessment; disorders of consciousness; ethics; management; pain; pathophysiology; severe brain injury; suffering.

Figure 1

Legend: Schematic diagram of the pain neuromatrix involving cortical and subcortical structures. ACC, anterior cingulate cortex; DH, dorsal horn; IC, insular cortex; PAG, periaqueductal gray; PFC, prefrontal cortex; RVM, rostral ventral medulla; SI, primary somatosensory cortex; SII, secondary somatosensory cortex.