Interest of Pregabalin (Lyrica) on the Treatment of Reflex Earache in Head and Neck Cancer.

Overview

Referred otalgia is one of the symptoms of oropharynx and hypopharynx cancer. It can be primary (otodynia) or secondary (referred otalgia and projected pain). The mechanism of referred otalgia involves several non adjacent nerve territories as those of head, neck or ear. Referred otalgia is a projected pain due to injury (most of the time cancer) localized far from the ear but sharing the same innervation. In this contest, the otoscopy is normal. Four cranial nerves participate in the sensory innervation of the external ear: the trigeminal nerve (V) via the auriculo temporal nerve (V3), the facial nerve (VII) for the Ramsay-Hunt's zone with the conch, tragus, antitragus, a part of the anthelix, of the external auditory meatus and of the eardrum, the glossopharyngeal nerve (IX) via the Jacobson's nerve for the external ear canal and the C2 and C3 cervical plexus. However, there are important interindividual anatomical variations. The relationship between referred otalgia and probable nerve damage has been described. In he oropharynx and hypopharynx, the proximity of the sensory innervation of the ear can then explain the otalgia during the cancer progression. Then referred otalgia has a neuropathic component. In the literature, the curative treatment of referred otalgia is the cancer treatment. However, the high intensity of referred otalgia leads the patients to a large consumption of analgesics in particular of opioids. These latter are particularly adapted for pain resulting from excess of nociceptive stimulation. Pregabalin (Lyrica®) is an analogue of gamma aminobutyric acid. This molecule binds to alpha subunit 2 delta 1 calcium dependent voltage channels in the central nervous system. its effectiveness has been demonstrated for the treatment of neuropathic pain on diabetic neuropathy, post herpetic neuralgia, lesions in the bone marrow but also the postoperative pain when the molecule is administered after the surgery. The anti hyperalgesic activity of pregabalin is at a dosage of 150mg/day in two or three daily doses. The purpose of this study was to evaluate the activity of pregabalin administered orally for three weeks after the anesthesia consultation on the intensity of the pain of referred otalgia and on its neuropathic component.