Mehta, Dev

Objective To review characteristics and outcomes of all cases of visual snow seen at our institution, with attention to possible triggering events or comorbidities. Methods This is a retrospective case series of patients seen at our tertiary care center from January 1994 to January 2020. Charts were reviewed if they contained the term “visual snow”. Results Of the 449 charts reviewed, 248 patients described seeing visual snow in part or all of their vision. Thirty-eight reported transient visual snow as their typical migraine aura. Of the remaining 210 patients, 89 were reported to have either an inciting event or contributing comorbidity for their visual snow symptoms, including: Post-concussion (n = 15), dramatic change in migraine or aura (n = 14), post-infection (n = 13), hallucinogen persisting perception disorder (n = 10), ocular abnormalities (n = 7), idiopathic intracranial hypertension (n = 4), neoplastic (n = 1), and posterior cortical atrophy (n = 1). Some patients had partial improvement with benzodiazepines (n = 6), lamotrigine (n = 5), topiramate (n = 3) and acetazolamide (n = 3). Presenting characteristics were similar, but patients with visual snow attributed to an inciting event or contributing comorbidity were more likely to have some improvement in their symptoms by last follow-up compared to spontaneous visual snow ( p < .001). Conclusions Though most cases of visual snow are spontaneous, potential secondary causes should be recognized by clinicians. Patients who develop visual snow after an inciting event or related to an underlying comorbidity may have a better prognosis than those in whom it develops spontaneously. In select cases, treatment of the suspected underlying cause may significantly alleviate the otherwise typical intractable visual disturbances associated with visual snow.

Introduction Cervicogenic headache (CH) is a chronic headache that is referred to the head from the cervical spine that typically starts or worsens with neck movement. The pain typically presents posteriorly with anterior radiation. Nociceptive input from structures innervated by the upper three cervical spinal nerves can theoretically exacerbate primary headache disorders like migraine. We present three cases of CH related to C1-C2 joint arthropathy that significantly improved after treatment with calcitonin gene-related peptide (CGRP) antibodies initiated for chronic comorbid migraine. Case Descriptions We describe a case series of 3 patients with co-morbid CH and migraine that were treated with CGRP antibodies. All three patients had significant improvement in their migraines with C1-C2 joint injections and subsequently CGRP antibodies provided a greater than 50% benefit in each patient preventing the need for repeat injections. Conclusions The diagnosis of CH in patients is confirmed when treatment of the cervical spine lesion alleviates pain significantly. While CH itself has not been shown to be associated with elevated serum CGRP as has been demonstrated in migraine, animal models of osteoarthritis have shown reduction of hyperalgesia with galcanezumab. An upregulation in CGRP related to nociceptive input from degenerative changes in the cervical spine could lead to potentiation and sensitization which could potentially respond to systemic administration of CGRP antibodies. As a result, the presence of features suggestive of CH in patients with migraine may be a predictor of a positive response to CGRP antibodies. For patients with comorbid migraine and CH, CGRP antibodies could prevent the need for invasive injection treatments.