Pharmacotherapies for Migraine and Translating Evidence From Bench to Bedside

Migraine is a ubiquitous neurologic disorder that afflicts more than 1 billion people worldwide. Recommended therapeutic strategies include the use of acute and, if needed, preventive medications. During the past 2 decades, tremendous progress has been made in better understanding the molecular mechanisms underlying migraine pathogenesis, which in turn has resulted in the advent of novel medications targeting signaling molecule calcitonin gene-related peptide or its receptor. Here, we provide an update on the rational use of pharmacotherapies for migraine to facilitate more informed clinical decision-making. We then discuss the scientific discoveries that led to the advent of new medications targeting calcitonin gene-related peptide signaling. Last, we conclude with recent advances that are being made to identify novel drug targets for migraine.

OnabotulinumtoxinA affects cortical recovery period but not occurrence or propagation of cortical spreading depression in rats with compromised blood-brain barrier

ABSTRACT

OnabotulinumtoxinA (BoNT-A) is an Food and Drug Administration-approved, peripherally acting preventive migraine drug capable of inhibiting meningeal nociceptors. Expanding our view of how else this neurotoxin attenuates the activation of the meningeal nociceptors, we reasoned that if the stimulus that triggers the activation of the nociceptor is lessened, the magnitude and/or duration of the nociceptors' activation could diminish as well. In the current study, we further examine this possibility using electrocorticogram recording techniques, immunohistochemistry, and 2-photon microscopy. We report (1) that scalp (head) but not lumbar (back) injections of BoNT-A shorten the period of profound depression of spontaneous cortical activity that follows a pinprick-induced cortical spreading depression (CSD); (2) that neither scalp nor lumbar injections prevent the induction, occurrence, propagation, or spreading velocity of a single wave of CSD; (3) that cleaved SNAP25-one of the most convincing tools to determine the anatomical targeting of BoNT-A treatment-could easily be detected in pericranial muscles at the injection sites and in nerve fibers of the intracranial dura, but not within any cortical area affected by the CSD; (4) that the absence of cleaved SNAP25 within the cortex and pia is unrelated to whether the blood-brain barrier is intact or compromised; and (5) that BoNT-A does not alter vascular responses to CSD. To the best of our knowledge, this is the first report of peripherally applied BoNT-A's ability to alter a neuronal function along a central nervous system pathway involved in the pathophysiology of migraine.

Unusual Brain MRI Findings in Patients Imaged for Headache: a Case Series

PURPOSE OF REVIEW

We describe a series of cases with unusual brain MRI findings in patients who present with headache disorders.

RECENT FINDINGS

Incidental findings in patients imaged for headache include the following: aneurysm, arachnoid cyst, cerebral vascular malformations, Arnold-Chiari malformations, empty sella turcica, gray matter heterotopias, mastoiditis, mega cisterna magna, meningioma, normal variants of cerebral circulation, paranasal sinus disease, pineal cyst, pituitary tumor, Rathke's cleft cyst, skull hyperostosis, and vestibular schwannoma. The most common abnormal MRI findings encountered in migraine are nonspecific white matter lesions. The current 2019 guidelines from the American College of Radiology and American Headache Society recommend against ordering neuroimaging in patients with a high probability of a primary headache disorder not typically associated with diagnostic imaging findings and who have normal neurologic exam in addition to no red flags in history. Often, unnecessary neuroimaging yields incidental findings, and this typically results in patient anxiety and further unnecessary testing. Detailed below are a series of cases in which unusual findings were found in patients presenting to our clinic for further evaluation of headache disorders. Imaging may have been done prior to presentation to us or by us due to concern for secondary causes.

Updated Evaluation of IV Dihydroergotamine (DHE) for Refractory Migraine: Patient Selection and Special Considerations

Dihydroergotamine (DHE) is an ergot alkaloid derivative of substances produced by rye fungus. Ergotamine was first used in the field of gynecology and obstetrics, then used for migraine treatment a few years later. DHE was developed as a derivative of ergotamine. DHE, when compared to ergotamine, demonstrates greater alpha-adrenergic antagonist activity, lower arterial vasoconstriction, less dopaminergic agonism, and lower emetic potential. DHE can be delivered via several routes including intravenous (IV), intramuscular (IM), subcutaneous (SC), intranasal (IN), oral, and orally inhaled (although the latter two are not available in the USA and the last remains experimental only). DHE can be used in an outpatient basis in infusion centers, emergency departments, and urgent care centers, as well as inpatient treatment for admitted patients. There are protocols for adults as well as pediatric migraine treatment. DHE and other ergot alkaloids are considered contraindicated in pregnant women as they decrease uterine blood flow and increase uterine muscle contractility predisposing to spontaneous abortion. DHE during lactation is also not recommended as it can lead to gastrointestinal distress and weakness in infants; it can also suppress milk production. Caution should be taken before administering DHE in patients with cardiovascular risk factors. DHE is an older drug with an interesting history, yet it is still clinically useful today for patients with migraine attacks not responsive to triptans, who have a greater burden from migraine, and in refractory migraine.