Biomarkers of Migraine and Cluster Headache: Differences and Similarities.

OBJECTIVE: This study was undertaken to identify magnetic resonance imaging (MRI) biomarkers that differentiate migraine from cluster headache patients and imaging features that are shared. METHODS: Clinical, functional, and structural MRI data were obtained from 20 migraineurs, 20 cluster headache patients, and 15 healthy controls. Support vector machine algorithms and a stepwise removal process were used to discriminate headache patients from controls, and subgroups of patients. Regional between-group differences and association between imaging features and patients' clinical characteristics were also investigated. RESULTS: The accuracy for classifying headache patients from controls was 80%. The classification accuracy for discrimination between migraine and controls was 89%, and for cluster headache and controls it was 98%. For distinguishing cluster headache from migraine patients, the MRI classifier yielded an accuracy of 78%, whereas MRI-clinical combined classification model achieved an accuracy of 99%. Bilateral hypothalamic and periaqueductal gray (PAG) functional networks were the most important MRI features in classifying migraine and cluster headache patients from controls. The left thalamic network was the most discriminative MRI feature in classifying migraine from cluster headache patients. Compared to migraine, cluster headache patients showed decreased functional interaction between the left thalamus and cortical areas mediating interoception and sensory integration. The presence of restlessness was the most important clinical feature in discriminating the two groups of patients. INTERPRETATION: Functional biomarkers, including the hypothalamic and PAG networks, are shared by migraine and cluster headache patients. The thalamocortical pathway may be the neural substrate that differentiates migraine from cluster headache attacks with their distinct clinical features. ANN NEUROL 2023;93:729-742.

Recent Advances and Updates in Trigeminal Autonomic Cephalalgias.

Trigeminal autonomic cephalalgias (TACs) are discrete primary headache disorders, characterized by severe unilateral head pain, typically trigeminal distribution, with ipsilateral cranial autonomic symptoms. The conditions within this group are hemicrania continua, cluster headache, paroxysmal hemicrania, and short-lasting unilateral neuralgiform headache with conjunctival injection and tearing and short-lasting unilateral neuralgiform headache with autonomic symptoms. Several advances have been made in understanding the pathogenesis and evolving treatment options in TACs. This review will outline the advances and updates in each TAC.

Guidelines of the International Headache Society for Controlled Clinical Trials in Cluster Headache.

In 1995, a committee of the International Headache Society developed and published the first edition of the Guidelines for Controlled Trials of Drugs in Cluster Headache. These have not been revised. With the emergence of new medications, neuromodulation devices and trial designs, an updated version of the International Headache Society Guidelines for Controlled Clinical Trials in Cluster Headache is warranted. Given the scarcity of evidence-based data for cluster headache therapies, the update is largely consensus-based, but takes into account lessons learned from recent trials and demands by patients. It is intended to apply to both drug and neuromodulation treatments, with specific proposals for the latter when needed. The primary objective is to propose a template for designing high quality, state-of-the-art, controlled clinical trials of acute and preventive treatments in episodic and chronic cluster headache. The recommendations should not be regarded as dogma and alternative solutions to particular methodological problems should be explored in the future and scientifically validated.

Comparison and predictors of chronic migraine vs. new daily persistent headache presenting with a chronic migraine phenotype.

OBJECTIVE: To compare the clinical phenotype of patients with chronic migraine (CM) to patients with new daily persistent headache of the chronic migraine subtype (NDPH-CM). METHODS: A study was conducted of CM (n = 257) and NDPH-CM (n = 76) from a tertiary headache center in the UK, and in the US of patients with daily CM (n = 60) and NDPH-CM (n = 22). RESULTS: From the UK cohort, the age of first headache onset was lower in CM (mean ± SD: 16 ± 12 years) than in NDPH-CM (mean ± SD: 23 ± 14 years; p < 0.001). There was a greater number of associated migrainous symptoms in CM compared to NDPH-CM (median and interquartile range: 6, 5-8 vs. 5, 4-7; p < 0.001). A family history of headache was more common in CM compared to NDPH-CM (82%, 202/248, vs. 53%, 31/59; p < 0.001). In the US cohort there were no differences. Osmophobia (B = -1.08; p = 0.002) and older age at presentation to the clinic (B = -0.06; p = 0.001) were negative predictors of NDPH-CM. CONCLUSION: NDPH-CM is relatively less migrainous than CM in the UK cohort. Family history of headache is less common in NDPH-CM, with negative predictors for NDPH-CM including osmophobia and older age of presentation to the clinic. More work is required to understand the chronic migraine phenotype of new daily persistent headache.

Areas of cerebral blood flow changes on arterial spin labelling with the use of symmetric template during nitroglycerin triggered cluster headache attacks.

BACKGROUND: Cluster headache is a rare, strictly unilateral, severe episodic primary headache disorder. Due to the unpredictable and episodic nature of the attacks, nitroglycerin has been used to trigger attacks for research purposes to further our understanding of cluster headache pathophysiology. OBJECTIVES: We aimed to identify regions of significant cerebral blood flow (CBF) changes during nitroglycerin triggered cluster headache attacks, using MRI with arterial spin labelling (ASL). METHODS: Thirty-three subjects aged 18-60 years with episodic and chronic cluster headache were recruited and attended an open clinical screening visit without scanning to receive an intravenous nitroglycerin infusion (0.5 µg/kg/min over 20 min). Those for whom nitroglycerin successfully triggered a cluster headache attack, were invited to attend two subsequent scanning visits. They received either single-blinded intravenous nitroglycerin (0.5 µg/kg/min) or an equivalent volume of single-blinded intravenous 0.9% sodium chloride over a 20-minute infusion. Whole-brain CBF maps were acquired using a 3 Tesla MRI scanner pre-infusion and post-infusion. As cluster headache is a rare condition and purely unilateral disorder, an analysis strategy to ensure all the image data corresponded to symptomatology in the same hemisphere, without losing coherence across the group, was adopted. This consisted of spatially normalising all CBF maps to a standard symmetric reference template before flipping the images about the anterior-posterior axis for those CBF maps of subjects who experienced their headache in the right hemisphere. This procedure has been employed in previous studies and generated a group data set with expected features on the left hemisphere only. RESULTS: Twenty-two subjects successfully responded to the nitroglycerin infusion and experienced triggered cluster headache attacks. A total of 20 subjects completed the placebo scanning visit, 20 completed the nitroglycerin scanning visit, and 18 subjects had completed both the nitroglycerin and placebo scanning visits. In a whole-brain analysis, we identified regions of significantly elevated CBF in the medial frontal gyrus, superior frontal gyrus, inferior frontal gyrus and cingulate gyrus, ipsilateral to attack side, in CBF maps acquired during cluster headache attack; compared with data from the placebo session. We also identified significantly reduced CBF in the precuneus, cuneus, superior parietal lobe and occipital lobe contralateral to the attack side. Of particular interest to this field of investigation, both the hypothalamus and ipsilateral ventral pons showed higher CBF in a separate region of interest analysis. CONCLUSION: Our data demonstrate that severe cluster headache leads to significant increases in regional cerebral perfusion, likely to reflect changes in neuronal activity in several regions of the brain, including the hypothalamus and the ventral pons. These data contribute to our understanding of cluster headache pathophysiology; and suggest that non-invasive ASL technology may be valuable in future mechanistic studies of this debilitating condition.

Cluster headache pathophysiology - insights from current and emerging treatments.

Cluster headache is a debilitating primary headache disorder that affects approximately 0.1% of the population worldwide. Cluster headache attacks involve severe unilateral pain in the trigeminal distribution together with ipsilateral cranial autonomic features and a sense of agitation. Acute treatments are available and are effective in just over half of the patients. Until recently, preventive medications were borrowed from non-headache indications, so management of cluster headache is challenging. However, as our understanding of cluster headache pathophysiology has evolved on the basis of key bench and neuroimaging studies, crucial neuropeptides and brain structures have been identified as emerging treatment targets. In this Review, we provide an overview of what is known about the pathophysiology of cluster headache and discuss the existing treatment options and their mechanisms of action. Existing acute treatments include triptans and high-flow oxygen, interim treatment options include corticosteroids in oral form or for greater occipital nerve block, and preventive treatments include verapamil, lithium, melatonin and topiramate. We also consider emerging treatment options, including calcitonin gene-related peptide antibodies, non-invasive vagus nerve stimulation, sphenopalatine ganglion stimulation and somatostatin receptor agonists, discuss how evidence from trials of these emerging treatments provides insights into the pathophysiology of cluster headache and highlight areas for future research.

Comprehensive clinical phenotyping of nitroglycerin infusion induced cluster headache attacks.

BACKGROUND: Nitroglycerin administration allows the study of cluster headache attacks in their entirety in a standardised way. METHODS: A single-blind, placebo-controlled, cross-over study using weight-calculated intravenous nitroglycerin administration at 0.5 µg/kg/min over 20 minutes to study cluster headache attacks, including accompanying non-headache symptoms and cranial autonomic symptoms. RESULTS: Thirty-three subjects with cluster headache were included in the study; 24 completed all three study visits. Nitroglycerin-induced attacks developed in 26 out of 33 subjects (79%) receiving unblinded nitroglycerin infusion, and in 19 out of 25 subjects (76%) receiving single-blinded nitroglycerin infusion, compared with one out of 24 subjects (4%) receiving single-blinded placebo infusion. Episodic cluster headache subjects had a shorter latency period to a nitroglycerin-induced attack compared to the chronic cluster headache (CCH) subjects (U = 15, z = -2.399, p = 0.016). Sixteen of nineteen episodic cluster headache (mean, 84%; 95% confidence interval, 66-100%) and 11 of 14 chronic cluster headache subjects developed a nitroglycerin-induced attack (79%, 54-100%) following the unblinded nitroglycerin infusion. Following the single-blinded nitroglycerin infusion, eight out of 13 episodic cluster headache (62%, 31-92%) and 11 out of 12 chronic cluster headache (92%, 73-100%) subjects developed nitroglycerin-induced attacks. Nitroglycerin induced non-headache symptoms in the majority of subjects receiving it: 91% in the open unblinded nitroglycerin visit and 84% in the single-blinded nitroglycerin visits, compared with 33% in the single-blinded placebo visit. Cranial autonomic symptoms were induced by nitroglycerin infusion, 94% in the open unblinded nitroglycerin visit and 84% in the single-blinded nitroglycerin visit, compared with 17% in the single-blinded placebo visit. CONCLUSION: Intravenous weight-adjusted nitroglycerin administration in both episodic cluster headache in bout and chronic cluster headache is effective and reliable in inducing cluster headache attacks, cranial autonomic symptoms and non-headache symptoms.

Biochemical Modulation and Pathophysiology of Migraine.

BACKGROUND: Migraine is a common disabling neurological disorder where attacks have been recognized to consist of more than headache. The premonitory, headache, and postdromal phases are the various phases of the migraine cycle, where aura can occur before, during, or after the onset of pain. Migraine is also associated with photosensitivity and cranial autonomic symptoms, which includes lacrimation, conjunctival injection, periorbital edema, ptosis, nasal congestion, and rhinorrhoea. This review will present the current understanding of migraine pathophysiology and the relationship to the observed symptoms. EVIDENCE ACQUISITION: The literature was reviewed with specific focus on clinical, neurophysiological, functional imaging, and preclinical studies in migraine including the studies on the role of calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase activating polypeptide (PACAP). RESULTS: The phases of the migraine cycle have been delineated by several studies. The observations of clinical symptoms help develop hypotheses of the key structures involved and the biochemical and neuronal pathways through which the effects are mediated. Preclinical studies and functional imaging studies have provided evidence for the role of multiple cortical areas, the diencephalon, especially the hypothalamus, and certain brainstem nuclei in the modulation of nociceptive processing, symptoms of the premonitory phase, aura, and photophobia. CGRP and PACAP have been found to be involved in nociceptive modulation and through exploration of CGRP mechanisms, new successful treatments have been developed. CONCLUSIONS: Migraine is a complex neural disorder and is important to understand when seeing patients who present to neuro-ophthalmology, especially with the successful translation from preclinical and clinical research leading to successful advances in migraine management.

Managing cluster headache.

Cluster headache is a neurological disorder that presents with unilateral severe headache associated with ipsilateral cranial autonomic symptoms. Cluster headache attacks often occur more than once a day, and typically manifesting in bouts. It has a point prevalence of 1 in 1000 and is the most common trigeminal autonomic cephalalgia. This article aims to guide general neurologists to an accurate diagnosis and practical management options for cluster headache patients.

Therapeutic Approaches for the Management of Trigeminal Autonomic Cephalalgias.

Trigeminal autonomic cephalalgia (TAC) encompasses 4 unique primary headache types: cluster headache, paroxysmal hemicrania, hemicrania continua, and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms. They are grouped on the basis of their shared clinical features of unilateral headache of varying durations and ipsilateral cranial autonomic symptoms. The shared clinical features reflect the underlying activation of the trigeminal-autonomic reflex. The treatment for TACs has been limited and not specific to the underlying pathogenesis. There is a proportion of patients who are refractory or intolerant to the current standard medical treatment. From instrumental bench work research and neuroimaging studies, there are new therapeutic targets identified in TACs. Treatment has become more targeted and aimed towards the pathogenesis of the conditions. The therapeutic targets range from the macroscopic and structural level down to the molecular and receptor level. The structural targets for surgical and noninvasive neuromodulation include central neuromodulation targets: posterior hypothalamus and, high cervical nerves, and peripheral neuromodulation targets: occipital nerves, sphenopalatine ganglion, and vagus nerve. In this review, we will also discuss the neuropeptide and molecular targets, in particular, calcitonin gene-related peptide, somatostatin, transient receptor potential vanilloid-1 receptor, nitric oxide, melatonin, orexin, pituitary adenylate cyclase-activating polypeptide, and glutamate.

Case Report of the Safety Assessment of Transcranial Magnetic Stimulation Use in a Patient With Cardiac Pacemaker: To Pulse or Not to Pulse?

BACKGROUND: Single-pulse transcranial magnetic stimulation (sTMS) is an emerging neuromodulation method reported to be useful in migraine. Despite a low propensity for side effects, some concern with its use in patients with cardiac pacemakers has been expressed. CASE: We present a patient with chronic migraine with a cardiac pacemaker, who had tried unsuccessfully several migraine preventives with either poor efficacy or tolerability. With involvement of the cardiology team, we tested the effect of sTMS on her pacemaker and found it to be a safe and effective option for her. CONCLUSION: Having regard to the risk/benefit ratio of sTMS, its use in patients with disabling migraine in the presence of a cardiac pacemaker can be carefully evaluated and may represent a useful therapeutic option.

Undiagnosed neurological disease as a potential cause of male lower urinary tract symptoms.

PURPOSE OF REVIEW: In the central nervous system there are many regulatory processes controlling the lower urinary tract. This review considers the possibility that urinary dysfunction may precede diagnosis of neurological disease. RECENT FINDINGS: Lower urinary tract symptoms (LUTS) occur early in multiple system atrophy, Parkinson's disease and normal pressure hydrocephalus, and may present before neurological diagnosis. Some people present with LUTS and subsequently are diagnosed with multiple sclerosis or a spinal condition. In male LUTS, the symptoms could reflect early stages of a neurological disease, which has not yet been diagnosed ('occult neurology'). Key symptoms include erectile dysfunction, retrograde ejaculation, enuresis, loss of filling sensation or unexplained stress urinary incontinence. Directed questioning should enquire about visual symptoms, back pain, anosmia, bowel dysfunction and incontinence, or memory loss. Examination features can include resting tremor, 'croaky' speech, abnormal gait, orthostatic hypotension, ataxia, or altered perineal sensation. Imaging, such as MRI scan, should only be requested after expert neurological examination, to ensure the correct parts of the central nervous system are scanned with appropriate radiological protocols. SUMMARY: Urologists should consider an undiagnosed neurological condition can be present in a few cases. Any finding should be further evaluated by colleagues with relevant expertise.

Reversible hypertensive encephalomyelopathy - the spinal variant of the posterior reversible encephalopathy syndrome.

Posterior reversible encephalopathy syndrome (PRES) is characterised clinically by encephalopathy, headache, visual disturbance and/or focal neurological symptoms. Bilateral cerebral oedema on T2 MRI sequences within the posterior cerebral white matter is the radiological hallmark, although involvement of the frontal lobe, basal ganglia and brainstem can occur. PRES with spinal cord involvement has been rarely reported and is under-recognised due to lack of myelopathic features in nearly half of the reported cases. We report a patient with PRES with spinal cord involvement and review the literature.

Reversible cerebral vasoconstriction in Guillain-Barré syndrome.

We present a 51-year-old woman with clinical and neurophysiological evidence of Guillain-Barré syndrome (GBS) who developed a generalised headache and autonomic dysfunction with sinus tachycardia, hypertension, gastrointestinal motility symptoms and urinary retention. MRI/MRA demonstrated cerebral vasoconstriction and a small convexity subarachnoid haemorrhage which resolved after 3 months. Reversible cerebral vasoconstriction syndrome (RCVS) is characterised by headache, focal neurological deficits or seizures, and reversible cerebral vasoconstriction. To our knowledge, this is the first reported case of RCVS complicating autonomic dysfunction in GBS. This case depicts a rare complication of a common condition and also sheds light on the potential mechanism of RCVS. Neurologists should be aware that autonomic dysfunction can lead to RCVS in GBS.

Asymmetric oro-facial angioedema following alteplase for acute ischaemic stroke.

We present a patient with asymmetric oro-facial angioedema following thrombolysis for acute ischaemic stroke with serial photographs of this phenomenon. We discuss the mechanism for the development of asymmetric oro-facial oedema following thrombolysis and suggest a management plan.

The use of injectable forms of fibrin and fibronectin to support axonal ingrowth after spinal cord injury.

Many studies have described biomaterial devices (conduits and scaffolds) that can be implanted into experimental lesions and which support axonal growth. However, a disadvantage of such pre-formed devices is that tissue needs to be excised to allow their insertion. In this study we have therefore examined four biomaterials that can be injected into an injury site and which gel in situ; namely collagen, viscous fibronectin, fibrin, and fibrin + fibronectin (FB/FN). The materials were tested in an experimental knife-cut cavity in the rat spinal cord, and evaluated at 1 week and 4 weeks survival for their biocompatibility, neuroprotective efficacy, and permissiveness for axonal growth. At one week, all four materials showed good integration with the host spinal cord and supported some degree of axonal ingrowth, which was associated with infiltration of Schwann cells and deposition of laminin. However axon growth in the collagen implants was uneven because implants contained dense inclusions which were not penetrated by axons. At 4 weeks, axon growth was greatest in the fibronectin and FB/FN implants, however the fibronectin implants had large cavities at the interface between the implant and host spinal cord. The fibronectin implants also had fewer surviving neurons in the intact spinal cord adjoining the implant site. The FB/FN mixture thus had the best combination of properties in that it was easy to handle, integrated with the host spinal cord tissue, and supported robust growth of axons. It therefore has promise as an injectable biomaterial for filling cavities at spinal cord injury sites.