‘Side Locked’ Migraine and Trigeminal Autonomic Cephalgias: Evidence for Clinical Overlap

Abstract

This paper will discuss evidence which supports a link between 'side locked' migraine (SLM) and the trigeminal autonomic cephalgias (TACs). Recent papers brought strictly unilateral primary headaches into focus, proposing new classification and discussing pathophysiological mechanisms. We reviewed those proposals and present evidence that SLM falls in between the well-defined TACs and side shifting migraine (SSM). It is difficult to differentiate SLM from the recently proposed headache subtype called hemicrania generis incerti (i.e. hemicrania continua unresponsive to indomethacin). We also present cases that may exemplify the considerations made in the paper.

Trigeminal Cephalgias and Facial Pain Syndromes Associated with Autonomic Dysfunction

“…Trigeminal autonomic dysfunction has been reported to occur in otherwise typical cases of migraine (2–4), perhaps representing a crossover between CH and migraine.…”

Cranial autonomic symptoms in migraine: characteristics and comparison with cluster headache

“…These symptoms are also common in patients with migraine but their reported prevalence varies widely from 27% to 73% based on the study settings 2 3 4. Moreover, up to 17% of patients with migraine have “side locked” headache,5 and those with CAS can mimic CH clinically 6 7…”

Persistent Idiopathic Facial Pain Responsive to Topiramate

“…Another disorder that should be ruled out is side‐locked migraine (SLM) (24, 25), although our patient does not fit all the migraine criteria (10). Primary trochlear headache was ruled out in our patient based on the absence of increasing pain during ocular movement or during palpation, and the pain improvement without steroid injection in the ipsilateral trochlear region (26).…”