Trigeminal autonomic cephalalgias (TACs) could be the only initial brainstem manifestation of neuromyelitis optica spectrum disorder (NMOSD), according to a new study published in the journal Multiple Sclerosis and Related Disorders.
“The activation of trigeminal-autonomic reflex and ephaptic coupling might be the underlying mechanism of symptomatic TACs in NMOSD,” the researchers wrote.
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They added that an underlying cause for short-lasting unilateral neuralgiform headache with conjunctival injection and tearing or short-lasting unilateral neuralgiform headache with autonomic symptoms should be considered, especially in case of limited response to anti-epileptic drugs.
Symptomatic TACs are rare in NMOSD. To better understand TACs and their possible association with NMOSD, a team from China reviewed research articles describing cases of NMOSD with TACs. They also presented 1 such case of their own.
The team identified 5 published reports of TACs in NMOSD apart from their case. Of these, 4 were cases of short-lasting unilateral neuralgiform headache with conjunctival injection, 1 was a case of short-lasting unilateral neuralgiform headache with autonomic symptoms, and 1 was paroxysmal hemicrania.
In 3 of these cases, headache was the only initial symptom.
Only 1 case responded well to routine TACs treatment.
All patients had lesions in the medulla oblongata and cervical cord.
TACs in 3 patients were side-locked. Of these, 2 had a lesion in the left dorsolateral medulla oblongata, which corresponded to the left side TACs.
In 3 cases, headaches occurred on either side, which the researchers said “could be explained by the activation of trigeminal-autonomic reflex and ephaptic coupling”.
TACs are a group of primary headaches characterized by pain on 1 side of the head, symptoms lasting a relatively short time, and cranial autonomic symptoms occurring on the same side such as lacrimation, Horner syndrome, and nasal congestion.
Reference
Liu J, Xiao S, Yang F, et al. Symptomatic trigeminal autonomic cephalalgias in neuromyelitis optica spectrum disorders. Mult Scler Relat Disord. Published online April 25, 2023. doi:10.1016/j.msard.2023.104722
