Pharmacogenomic study-A pilot study of the effect of pharmacogenomic phenotypes on the adequate dosing of verapamil for migraine prevention.

OBJECTIVE: To investigate factors affecting the efficacy and tolerability of verapamil for migraine prevention using individual pharmacogenomic phenotypes. BACKGROUND: Verapamil has a wide range of dosing in headache disorders without reliable tools to predict the optimal doses for an individual. METHODS: This is a retrospective chart review examining adults with existing pharmacogenomic reports at Mayo Clinic who had used verapamil for migraine. Effects of six cytochrome P450 phenotypes on the doses of verapamil for migraine prevention were assessed. RESULTS: Our final analysis included 33 migraine patients (82% with aura). The mean minimum effective and maximum tolerable doses of verapamil were 178.2(20-320) mg and 227.9(20-480) mg. A variety of CYP2C9, CYP2D6, and CYP3A5 phenotypes were found, without significant association with the verapamil doses after adjusting for age, sex, body mass index, and smoking status. CONCLUSIONS: We demonstrated a wide range of effective and tolerable verapamil doses used for migraine in a cohort with various pharmacogenomic phenotypes.

Persistent aura, visual snow, and other visual symptoms.

In neurology practice, it is common to encounter a variety of visual complaints. Historically, in the absence of known ocular pathology, epilepsy, or insult to the central nervous system, positive symptoms were assumed to be migrainous in origin. This assumption was sometimes made even in the absence of a history of migraine. In the past decade, there has been considerable effort to better delineate and study nonmigrainous visual phenomena, with the most extensive focus on a newly defined syndrome, visual snow syndrome (VSS). The heightened awareness of visual snow as a symptom and syndrome has greatly enhanced the understanding of this visual phenomenon; however, in the last few years, there has been an almost pendulous swing in clinic, with patients now being given the diagnosis of VSS for any dots or flickering they may have in their vision. To avoid clinical misdiagnosis, it is critical that we expand our understanding not just of VSS but also of underlying pathologies that may present similarly. This chapter will review classical migraine aura, persistent migraine aura, visual snow and a number of positive and negative visual complaints that are on the differential when seeing patients with suspected aura or visual snow. This is followed by an in-depth discussion on the current understanding of the presenting symptoms, pathophysiology, evaluation and management of VSS. We also outline secondary causes of visual snow.

Potential treatment targets for migraine: emerging options and future prospects.

Migraine is a leading cause of disability worldwide. Despite the recent approval of several calcitonin gene-related peptide-targeted therapies, many people with migraine do not achieve satisfactory headache improvement with currently available therapies and there continues to be an unmet need for effective and tolerable migraine-specific treatments. Exploring additional targets that have compelling evidence for their involvement in modulating migraine pathways is therefore imperative. Potential new therapies for migraine include pathways involved in nociception, regulation of homoeostasis, modulation of vasodilation, and reward circuits. Animal and human studies show that these targets are expressed in regions of the CNS and peripheral nervous system that are involved in pain processing, indicating that these targets might be regarded as promising for the discovery of new migraine therapies. Future studies will require assessment of whether targets are suitable for therapeutic modulation, including assessment of specificity, affinity, solubility, stability, efficacy, and safety.

Visual Snow: Updates and Narrative Review.

PURPOSE OF REVIEW: Visual snow (VS) involves visualization of innumerable dots throughout the visual field, sometimes resembling "TV static." Patients who experience this symptom may also have additional visual symptoms (e.g., photophobia, palinopsia, floaters, and nyctalopia) with a pattern now defined as visual snow syndrome (VSS). This manuscript describes both VS and VSS in detail and provides an updated review on the clinical features, pathophysiology, and optimal management strategies for these symptoms. RECENT FINDINGS: VS/VSS may be primary or secondary to a variety of etiologies, including ophthalmologic or brain disorders, systemic disease, and medication/hallucinogen exposure. Evaluation involves ruling out secondary causes and mimics of VS. Increasing evidence suggests that VSS is a widespread process extending beyond the visual system. Pathophysiology may involve cortical hyperexcitability or dysfunctional connectivity of thalamocortical or attention/salience networks. VSS is typically a benign, non-progressive syndrome and can be managed with non-medicine strategies. Though no medication provides complete relief, some may provide partial improvement in severity of VS.

The anatomy of head pain.

Pain-sensitive structures in the head and neck, including the scalp, periosteum, meninges, and blood vessels, are innervated predominantly by the trigeminal and upper cervical nerves. The trigeminal nerve supplies most of the sensation to the head and face, with the ophthalmic division (V1) providing innervation to much of the supratentorial dura mater and vessels. This creates referral patterns for pain that may be misleading to clinicians and patients, as described by studies involving awake craniotomies and stimulation with electrical and mechanical stimuli. Most brain parenchyma and supratentorial vessels refer pain to the ipsilateral V1 territory, and less commonly the V2 or V3 region. The upper cervical nerves provide innervation to the posterior scalp, while the periauricular region and posterior fossa are territories with shared innervation. Afferent fibers that innervate the head and neck send nociceptive input to the trigeminocervical complex, which then projects to additional pain processing areas in the brainstem, thalamus, hypothalamus, and cortex. This chapter discusses the pain-sensitive structures in the head and neck, including pain referral patterns for many of these structures. It also provides an overview of peripheral and central nervous system structures responsible for transmitting and interpreting these nociceptive signals.

Novel Method of Dual-innervated Free Gracilis Muscle Transfer for Facial Reanimation: A Case Series.

Background: Dynamic facial reanimation is the gold standard treatment for a paralyzed face. The use of the cross-face nerve graft (CFNG) in combination with the masseteric nerve to innervate the free gracilis muscle has been reported to provide both spontaneity and strong neural input. We report a case series of dual innervation, using a novel method where the branch to masseter is coapted to the side of the CFNG. Methods: Eight patients received free gracilis muscle transfer using the new dual innervation method between September 2014 and December 2017. The CFNG, which was performed nine months prior, was sutured in an end-to-end fashion to the obturator nerve. A nerve graft was coapted to the ipsilateral masseteric nerve and then sutured in an end-to-side fashion to the CFNG proximal to its coaptation to the obturator nerve. Results: All patients recovered smile function with and without teeth clenching around the same time period. Smiles without teeth clenching appeared later in two of eight patients and earlier in one of eight patients, being noted at an average of 8.25 months of follow-up versus 7.6 months. The estimate of true attainment is limited by the spacing of follow-up dates. Average follow-up time was 36.07 months (range: 10-71.5). FACE-Gram software smile analysis with and without biting demonstrated similar excursion on average (7.64 mm versus 8.6 mm respectively, P = 0.93), both of which are significantly improved from preoperation. Conclusion: This novel method of a dual-innervated free gracilis muscle transfer offers a viable technique that achieves a symmetric, strong, and emotional smile.

Narrative review of migraine management in patients with renal or hepatic disease.

OBJECTIVES/BACKGROUND: Treatment of migraine in the setting of either renal or hepatic disease can be daunting for clinicians. Not only does the method of metabolism have to be considered, but also the method of elimination/excretion of the parent drug and any active or toxic metabolites. Furthermore, it is difficult to think about liver or kidney disease in isolation, as liver disease can sometimes contribute to impaired renal function and renal disease can sometimes impair hepatic metabolism, through the cytochrome P450 system. METHODS: A detailed search for terms related to liver disease, renal disease, and migraine management was performed in PubMed, Ovid Medline, Embase, and the Cochrane Library.For each medication, product labels were retrieved and reviewed using the US FDA website, with additional review of IBM Micromedex, LiverTox, and the Renal Drug Handbook. RESULTS: This manuscript provides an overview of migraine drug metabolism and how it can be affected by liver and renal impairment. It reviews the standard terminology recommended by the US Food and Drug Administration for the different stages of hepatic and renal failure. The available evidence regarding the use of abortive and preventative medicines in the setting of organ failure is discussed in detail, including more recent therapies such as lasmiditan, gepants, and calcitonin gene-related peptide antibodies. CONCLUSIONS: For acute therapy, the use of NSAIDS should be limited, as these carry risk for both severe hepatic and renal disease. Triptans can be selectively used, often with dose guideline adjustments. Ubrogepant may be used in severe hepatic disease with dose adjustment and lasmiditan can be used in end stage renal disease. Though non-medicine strategies may be the most reasonable initial approach, many preventative medications can be used in the setting of hepatic and renal disease, often with dose adjustment. This review provides tables of guidelines, including reduced dosing recommendations, for the use of abortive and preventative migraine medications in hepatic and renal failure.

Narrative review of peripheral nerve blocks for the management of headache.

OBJECTIVE: To provide an overview of the current available literature on peripheral nerve blocks for the management of migraine and other headache disorders in adults. BACKGROUND: Peripheral nerve blocks have been commonly performed in the headache practice for migraine, cluster headache, occipital neuralgia, and other headache disorders, despite a paucity of evidence supporting their use historically. In the past decade, there has been an effort to explore the efficacy and safety of peripheral nerve blocks for the management of headache, with the greatest interest centered around greater occipital blocks. DESIGN: We performed a search in PubMed using key words including "occipital nerve blocks," "peripheral nerve blocks," "occipital nerve," "migraine," "cluster headache," and "neuralgia." We reviewed the randomized controlled trials (RCTs), observational studies, and case series, and summarized the anatomy, techniques, and the evidence for the use of peripheral nerve blocks in different headache disorders, with particular focus on available RCTs. Case reports were included for a detail review of adverse events. RESULTS: Of 12 RCTs examining the use of greater occipital nerve blocks for migraine, all but one demonstrate efficacy with reduction in headache frequency, intensity, and/or duration compared to placebo. Studies have not demonstrated a difference in clinical outcomes with the use of corticosteroids for nerve blocks compared to blocks with local anesthetic in the treatment of migraine. There are two RCTs supporting the use of greater occipital blockade for cluster headache, both showing benefit of suboccipitally injected corticosteroid. One RCT suggests benefit of greater occipital nerve blocks for cervicogenic headache. Observational studies and case series/reports show that greater occipital nerve block may be effective in prolonged migraine aura, status migrainosus, post-dural puncture headache, and occipital neuralgia. Overall, peripheral nerve blocks are well tolerated. Serious side effects are rare but have been reported, including acute cerebellar syndrome and infection. CONCLUSIONS: Peripheral nerve blocks, especially occipital nerve blocks, are a viable treatment option for migraine and may be helpful in cluster headache as a transitional therapy or rescue therapy. Additional prospective studies are needed to investigate the efficacy and safety of occipital nerve blocks for long-term migraine prevention, as well as for other headache disorders, such as occipital neuralgia.

Real-World Patient Experience of CGRP-Targeting Therapy for Migraine: a Narrative Review.

PURPOSE OF REVIEW: To summarize available calcitonin gene-related peptide (CGRP)-targeting therapies for migraine and discuss their use in real-world populations. BACKGROUND: CGRP has long been a topic of interest in migraine pathophysiology, with new therapies targeting CGRP since 2018 for both the preventive and acute treatment of migraine. METHODS: We searched PubMed using keywords including "migraine," "CGRP," "real-world," "erenumab," "galcanezumab," "fremanezumab," "eptinezumab," "ubrogepant," "rimegepant," and "atogepant." We reviewed all pertinent studies and summarized main findings. We also compiled detailed patient characteristics (e.g., migraine diagnoses, medication overuse, prior treatment failures) and treatment outcome measures, such as 50% responder rates, reduction in migraine days, and adverse event rates in several tables. Overall, studies reporting real-world patient experiences of CGRP-targeting therapies suggested meaningful effectiveness for migraine treatment with response rates comparable to the numbers reported in clinical trials. Furthermore, studies suggested benefit in patients with multiple prior unsuccessful treatment trials, medication overuse, and complex medical comorbidities. In some studies, adverse event rates have been notably higher than reported in clinical trials. Additional long-term data is needed to further evaluate sustained efficacy, predictors of treatment response, and adverse events.

Pearls & Oy-sters: Postpipeline Headache Phenomenon: Nummular Headache Presenting After Intracranial Aneurysm Stenting.

We report on a 31-year-old right-handed woman with a medical history of presyncopal episodes and migraine headaches who presented to the outpatient clinic with a nummular headache after intracerebral stenting, which was different than her previous migraines. This represents postpipeline embolization headache phenomenon, which is a relatively new term to describe a new or different headache in individuals who recently underwent intracranial vascular stenting as a treatment for cerebral aneurysms.

Current Understanding of the Pathophysiology and Approach to Tension-Type Headache.

PURPOSE OF REVIEW: Description of headache dates back thousands of years, and to date, tension-type headache (TTH) remains the most common form of headache. We will review the history and current understanding of the pathophysiology of TTH and discuss the recommended clinical evaluation and management for this syndrome. RECENT FINDINGS: Despite being the most prevalent headache disorder, TTH pathophysiology remains poorly understood. Patients with TTH tend to have muscles that are harder, more tender to palpation, and may have more frequent trigger points of tenderness than patients without headache. However, cause and effect of these muscular findings are unclear. Studies support both peripheral and central mechanisms contributing to the pain of TTH. Diagnosis is based on clinical presentation, while the focus of evaluation is to rule out possible secondary causes of headache. Treatment options have remained similar over the course of the past decade, with some additional studies supportive of both pharmacological and non-pharmacological options. An approach to TTH has been outlined including historical context, evolution over time, and the best evidence regarding our current understanding of the complex pathophysiology and treatment of this disease.

Genetic variants related to successful migraine prophylaxis with verapamil.

BACKGROUND: Currently, there is no biologically based rationale for drug selection in migraine prophylactic treatment. METHODS: To investigate the genetic variation underlying treatment response to verapamil prophylaxis, we selected 225 patients from a longitudinally established, deeply phenotyped migraine database (N = 5983), and collected uninterrupted quantitated verapamil treatment response data and DNA for these 225 cases. We recorded the number of headache days in the four weeks preceding treatment with verapamil and for four weeks, following completion of a treatment period with verapamil lasting at least five weeks. Whole-exome sequencing (WES) was applied to a discovery cohort consisting of 21 definitive responders and 14 definitive non-responders, and the identified single nucleotide polymorphisms (SNPs) showing significant association were genotyped in a separate confirmation cohort (185 verapamil treated patients). Statistical analysis of the WES data from the discovery cohort identified 524 SNPs associated with verapamil responsiveness (p < 0.01); among them, 39 SNPs were validated in the confirmatory cohort (n = 185) which included the full range of response to verapamil from highly responsive to not responsive. RESULTS: Fourteen SNPs were confirmed by both percentage and arithmetic statistical approaches. Pathway and protein network analysis implicated myo-inositol biosynthetic and phospholipase-C second messenger pathways in verapamil responsiveness, emphasizing the earlier pathogenic understanding of migraine. No association was found between genetic variation in verapamil metabolic enzymes and treatment response. CONCLUSION: Our findings demonstrate that genetic analysis in well-characterized subpopulations can yield important pharmacogenetic information pertaining to the mechanism of anti-migraine prophylactic medications.

First Bite Syndrome: What Neurologists Need to Know.

PURPOSE OF REVIEW: Though first bite syndrome is well known in surgical settings, it is not commonly included in the differential for sharp paroxysmal facial pain in the neurology literature. This paper will highlight the clinical features and relevant anatomy of first bite syndrome, with the goal of helping clinicians differentiate this from other similar facial pain disorders. RECENT FINDINGS: First bite syndrome is severe sharp or cramping pain in the parotid region occurring with the first bite of each meal and improving with subsequent bites. Pathophysiology has been attributed to imbalanced sympathetic/parasympathetic innervation of the parotid gland. This is seen most typically in the post-surgical setting following surgery in the parotid or parapharyngeal region, but neoplastic etiologies have also been reported. It is common for patients to present with concurrent great auricular neuropathy and/or Horner's syndrome. Evidence regarding treatment is limited to case reports/series, however, botulinum toxin injections and neuropathic medicines have been helpful in select cases. It is critical for clinicians to be able to differentiate first bite syndrome from other paroxysmal facial pain. To help with this, we have proposed diagnostic criteria for clinical assessment. Patients often improve gradually over time, but symptomatic treatment with botulinum toxin or neuropathic medicine may be required.

Two hundred and forty-eight cases of visual snow: A review of potential inciting events and contributing comorbidities.

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.

COVID-19 and Headache Medicine: A Narrative Review of Non-Steroidal Anti-Inflammatory Drug (NSAID) and Corticosteroid Use.

OBJECTIVE: To summarize the current literature on non-steroidal anti-inflammatory drug and corticosteroid use during the coronavirus disease 2019 (COVID-19) pandemic, recognizing that these are commonly used treatments in the field of headache medicine. BACKGROUND: The use of non-steroidal anti-inflammatory drugs and corticosteroids in patients during the COVID-19 pandemic has been a controversial topic within the medical community and international and national health organizations. Lay press and social media outlets have circulated opinions on this topic despite the fact that the evidence for or against the use of these medications is sparse. In the field of headache medicine, these medications are used commonly and both patients and clinicians may have questions or hesitations pertaining to their use during the COVID-19 pandemic. METHODS: A detailed search of the scientific and popular literature was performed. RESULTS: There is limited literature pertaining to the safety of non-steroidal anti-inflammatory drugs and corticosteroids during the COVID-19 pandemic. To date, there are no clear scientific data that preclude the use of non-steroidal anti-inflammatory drugs in the general population who may acquire COVID-19 or in those acutely infected with the virus. Several health organizations have concluded that treatment with corticosteroids during active infection should be avoided due to concerns of prolonged viral shedding in the respiratory tract and the lack of survival benefit based on the data from past coronaviruses and influenza virus; specific exceptions exist including treatment for underlying asthma or chronic obstructive pulmonary disease, septic shock, and acute respiratory distress syndrome. CONCLUSION: Scientific information regarding the COVID-19 pandemic is constantly evolving, and limited or contradictory information can lead to confusion for both patients and clinicians. It is recommended that prior to prescribing non-steroidal anti-inflammatory drugs and steroids for the treatment of headache, clinicians have open discussions with their patients about the potential risks and benefits of using these medications during the COVID-19 pandemic. This manuscript summarizes the currently available evidence and understanding about these risks and benefits to help clinicians navigate such discussions.

Dual innervation of free gracilis muscle for facial reanimation: What we know so far.

BACKGROUND: In the last decade, some institutions have begun combining the CFNG and masseteric nerve to provide dual innervation to the gracilis muscle for dynamic facial reanimation in facial paralysis patients. We reviewed the various ways that these two nerves have been coapted to provide dual innervation, and summarized the functional outcome for these methods. METHODS: A search of the Ovid EMBASE, MEDLINE, Cochrane, and Scopus databases was performed from 1946 to May 2019 for dual innervation of gracilis muscle using CFNG plus masseteric nerve for facial reanimation. RESULTS: A total of 184 articles were identified in the initial search, of which seven met our inclusion criteria. Three additional abstracts with 43 patients were identified but the level of details was not sufficient to include the results in the analysis. A total of 57 patients were reviewed (mean age of 42.1 years (6-79 years)). The majority of dual innervation procedures were performed using the ipsilateral masseteric nerve sutured end-to-end to the obturator nerve, and an additional CFNG connected end-to-side to the obturator nerve. In the 26 patients with Terzis scores available, there were no differences between masseteric nerve coapted end-to-end and CFNG as end-to-side to the obturator, or the reverse coaptation. All but two patients achieved function of the gracilis activated by the masseteric nerve within 2-5 months. CONCLUSIONS: This review shows that dual innervation of the gracilis is safe; and in some cases, does appear to provide early onset gracilis activation as well as an eventual spontaneous smile.

Sphenopalatine ganglion block in primary headaches: An American Headache Society member survey.

BACKGROUND: The sphenopalatine ganglion (SPG), in the pterygopalatine fossa, is a known current and historical target for therapeutic intervention in headache disorders because of its role in cranial autonomics and vasodilation. There remains an overall lack of well-established SPG treatment protocols, particularly with the advent of newer commercial devices. METHODS: A 22 multiple-choice question survey was created to evaluate clinical practice patterns with SPG block and sent to members of the American Headache Society (AHS). Questions focused on determining indications, preferred applicators, medications applied, perceived efficacy, tolerability, and reimbursement. RESULTS: One hundred seventy-two of 1,346 (12.8%) AHS members participated. Ninety-three respondents (56.3%) had performed SPG blocks on 50 or fewer patients. The SphenoCath (42.4%) and the Tx360 (41.8%) were the most common methods of application. Ease of use was the top reason for provider preference in applicator type. SPG blocks were mostly used as an as-needed one-time procedure. When a scheduled protocol was used, twice weekly for 6 weeks was most common. Chronic migraine was the most commonly treated headache disorder and rated the most likely to respond to SPG block. Experienced clinicians found SPG more helpful as a stand-alone treatment and tended to report that acute relief was not predictive of enduring response. CONCLUSIONS: The variety of responses strongly suggests that clinicians would benefit from formalized protocols for SPG blocks. More experienced clinicians may have developed individualized protocols that they feel are more effective. The lack of evidence-based protocols contribute to clinicians not performing SPG blocks more frequently.