Effect of Ultrasound Guided Bilateral Greater Occipital Nerve Block on Serum Calcitonin Gene Related Peptide (CGRP) in Chronic Migraine

Abstract

igraine is a common, multifactorial, neurovascular disorder with major individual and societal effects. Migraine affects roughly 15% of people and is typically characterised by disabling episodes of severe headache accompanied by nausea, vomiting, and hypersensitivity to light, sound, and smell for up to 3 days (migraine without aura). In a third of patients, attacks might be associated with transient focal neurological aura symptoms (migraine with aura); it has been suggested that migraine with and without aura are distinct disorders. Once a migraine attack has started, the mechanisms underlying migraine aura and headache are reasonably well understood. Aura is most likely caused by cortical spreading depression, and headache by activation of the trigeminovascular system and associated release of CGRP. Migraine headache is caused by activation of the trigeminovascular system the trigeminovascular system consists of nociceptive trigeminal sensory afferents surrounding cranial blood vessels. Upon activation of these perivascular trigeminal afferents, the signal travels through the trigeminal ganglion to neurons in the trigeminocervical complex, using CGRP as the main neurotransmitter. The signals are then relayed to the thalamus; because all nociceptive inputs are