TAC-Tic syndromes: a case series on the complex overlap between trigeminal autonomic cephalalgias and trigeminal...

Trigeminal autonomic cephalalgias (TACs) and trigeminal neuralgia (TN) are classified as distinct disorders, although overlap syndromes are increasingly recognized.

We retrospectively describe five women with TAC-tic overlap: two with SUNCT-tic, two with cluster-tic, and one with paroxysmal hemicrania-tic syndrome. Each had distinguishable neuralgic and autonomic pain phenotypes, appearing either simultaneously or sequentially. In both SUNCT-tic cases, repeat imaging disclosed neurovascular compression after an initially negative study; microvascular decompression produced complete remission of both phenotypes. Cluster-tic presentations were controlled with peripheral nerve blocks, carbamazepine, and verapamil. In the paroxysmal hemicrania-tic case, the autonomic component responded to indomethacin whereas the neuralgic component required neuromodulator adjustment.

The opposite order of phenotype emergence in the SUNCT-tic cases, together with shifts in the dominant phenotype during treatment, supports bidirectional temporal plasticity. Convergence of trigeminal and upper cervical afferents in the trigeminocervical complex offers a plausible link between peripheral input, the trigeminal-autonomic reflex, and the observed response to occipital nerve blocks.

TAC-tic syndromes are rare and probably underrecognized. Repeated phenotyping, imaging tailored to the trigeminal root when clinically indicated, and treatment directed at each component may improve clinical control.