Postoperative hyperalgesia-A clinically applicable narrative review

Postoperative hyperalgesia (POH) is a condition characterized by signs and symptoms of pain despite the provision of conventional analgesia. In most cases, anesthesiologists are called upon soon after surgery, but occasionally it may occur as a late event. Persistent uncontrolled pain may transform into chronic or neuropathic pain. Correct diagnosis of POH is essential since similar phenomenon may exacerbate if misdiagnosed, while proper treatment is frequently achievable by pharmacological remedies. This review will describe the causes for POH and its bio-neuro-pharmacological basis, and clinical symptoms and signs directing the physician towards correct diagnosis of this paradoxical condition of pain, as well as modes capable of preventing POH from occurring. The pharmacological approach upon suspecting or diagnosing POH will focus on the use of anesthetic and non-anesthetic drugs that attenuate nociceptive- and opioid-induced paradoxical pain, and non-opioid adjuvant drugs, among which are ketamine or gabapentinoids, the two notably compounds that antagonize abnormal central sensitization that is at the basis of POH.