The middle meningial artery during a migraine attack: 3T magnetic resonance angiography study

Is calcitonin gene-related peptide (CGRP) the missing link in food histamine-induced migraine? A review of functional gut-to-trigeminovascular system connections

Calcitonin gene-related peptide (CGRP) and histamine plasma concentrations increase during migraine attacks. Both mediators are potent vasodilators, and they have been shown to reciprocally contribute to the release of each other in the trigeminovascular system, possibly driving migraine development. A high-histamine-content diet triggers migraine in patients who have histamine degradation deficiency owing to diaminooxidase (DAO) gene mutations. Therefore, studying functional links between exogenous histamine and CGRP seems promising for the understanding of diet-induced migraine generation. Notably, there is a lack of knowledge about the interplay of the enteric nervous system and the spinal/trigeminal somatosensory system with regard to CGRP and histamine. Based on background evidence, we propose that a functional interconnection between exogenous histamine and CGRP contributes to migraine development.

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.

Course of Preexisting Migraine Following Spontaneous Subarachnoid Hemorrhage

Background

Our objective was to observe the course of preexisting migraine following subarachnoid hemorrhage (SAH) in patients with and without craniotomy.

Methods

We designed an exploratory analysis and hypothesis-generating study of prospectively collected data starting by recruiting patients suffering from SAH with the Hunt and Hess scale score of ≤ 4. Out of 994 cases, we identified 46 patients with preexisting active migraine defined by at least four attacks in the year before SAH. According to the treatment, we subdivided the patients into two groups: the first group included patients with surgical aneurysm clipping with transection of the middle meningeal artery (MMA) and accompanying trigeminal nerve branches and the second group included patients with endovascular aneurysm coiling or without any interventional treatment. During the follow-up, we recorded the course of migraine frequency, duration, intensity, and character.

Results

For both groups (craniotomy n = 31, without craniotomy n = 15), a significant improvement regarding the preexisting migraine during a mean follow-up of 46 months (min. 12 months, max. 114 months) was seen regarding complete remission or at least >50% reduction in migraine attacks (p < 0.001 and p = 0.01). On comparing the groups, this effect was significantly more pronounced in patients with craniotomy (for no recurrence of migraine: p = 0.049). After craniotomy, 77.4% of the patients had no further attacks of migraine headache and 19.4% showed a reduction of >50% while only 2.2% did not report any relevant change. In the non-surgical group, 46.7% had no further migraine attacks, 20% had a reduction of >50%, while no change was noted in 33.3%.

Conclusions

Our study provides evidence that the dura mater might be related to migraine headaches and that transection of the MMA and accompanying trigeminal dural nerve branches might disrupt the pathway leading to a reduction of migraine attacks. However, coiling alone ameliorated migraine complaints.

Parenchymal neuroinflammatory signaling and dural neurogenic inflammation in migraine

Background

Pain is generally concomitant with an inflammatory reaction at the site where the nociceptive fibers are activated. Rodent studies suggest that a sterile meningeal inflammatory signaling cascade may play a role in migraine headache as well. Experimental studies also suggest that a parenchymal inflammatory signaling cascade may report the non-homeostatic conditions in brain to the meninges to induce headache. However, how these signaling mechanisms function in patients is unclear and debated. Our aim is to discuss the role of inflammatory signaling in migraine pathophysiology in light of recent developments.

Body

Rodent studies suggest that a sterile meningeal inflammatory reaction can be initiated by release of peptides from active trigeminocervical C-fibers and stimulation of resident macrophages and dendritic/mast cells. This inflammatory reaction might be needed for sustained stimulation and sensitization of meningeal nociceptors after initial activation along with ganglionic and central mechanisms. Most migraines likely have cerebral origin as suggested by prodromal neurologic symptoms. Based on rodent studies, a parenchymal inflammatory signaling cascade has been proposed as a potential mechanism linking cortical spreading depolarization (CSD) to meningeal nociception. A recent PET/MRI study using a sensitive inflammation marker showed the presence of meningeal inflammatory activity in migraine with aura patients over the occipital cortex generating the visual aura. These studies also suggest the presence of a parenchymal inflammatory activity, supporting the experimental findings. In rodents, parenchymal inflammatory signaling has also been shown to be activated by migraine triggers such as sleep deprivation without requiring a CSD because of the resultant transcriptional changes, predisposing to inadequate synaptic energy supply during intense excitatory transmission. Thus, it may be hypothesized that neuronal stress created by either CSD or synaptic activity-energy mismatch could both initiate a parenchymal inflammatory signaling cascade, propagating to the meninges, where it is converted to a lasting headache with or without aura.

Conclusion

Experimental studies in animals and emerging imaging findings from patients warrant further research to gain deeper insight to the complex role of inflammatory signaling in headache generation in migraine.

Mechanisms of migraine as a chronic evolutive condition

Understanding the mechanisms of migraine remains challenging as migraine is not a static disorder, and even in its episodic form migraine remains an "evolutive" chronic condition. Considerable progress has been made in elucidating the pathophysiological mechanisms of migraine, associated genetic factors that may influence susceptibility to the disease, and functional and anatomical changes during the progression of a migraine attack or the transformation of episodic to chronic migraine. Migraine is a life span neurological disorder that follows an evolutive age-dependent change in its prevalence and even clinical presentations. As a disorder, migraine involves recurrent intense head pain and associated unpleasant symptoms. Migraine attacks evolve over different phases with specific neural mechanisms and symptoms being involved during each phase. In some patients, migraine can be transformed into a chronic form with daily or almost daily headaches. The mechanisms behind this evolutive process remain unknown, but genetic and epigenetic factors, inflammatory processes and central sensitization may play an important role.

Non-invasive methods for measuring vascular changes in neurovascular headaches

Vascular changes during spontaneous headache attacks have been studied over the last 30 years. The interest in cerebral vessels in headache research was initially due to the hypothesis of cerebral vessels as the pain source. Here, we review the knowledge gained by measuring the cerebral vasculature during spontaneous primary headache attacks with the use of single photon emission tomography (SPECT), positron emission tomography (PET), magnetic resonance imaging (MRA) and transcranial Doppler (TCD). Furthermore, the use of near-infrared spectroscopy in headache research is reviewed. Existing TCD studies of migraine and other headache disorders do not provide solid evidence for cerebral blood flow velocity changes during spontaneous attacks of migraine headache. SPECT studies have clearly shown cortical vascular changes following migraine aura and the differences between migraine with aura compared to migraine without aura. PET studies have shown focal activation in brain structures related to headache, but whether the changes are specific to different primary headaches have yet to be demonstrated. MR angiography has shown precise changes in large cerebral vessels during spontaneous migraine without aura attacks. Future development in more precise imaging methods may further elucidate the pathophysiological mechanisms in primary headaches.

Cerebral Hemodynamic Changes During Migraine Attacks and After Triptan Treatments

Introduction

Migraine has been known for many years, but its mechanism remains unclear. Different cerebral hemodynamic changes have been observed at different stages of a migraine attack. Published results on cerebral hemodynamics are contradictory. For this reason, we aimed to investigate cerebral hemodynamic changes during attacks as well as the effects of frovatriptan and rizatriptan.

Methods

Forty migraine patients with aura using rizatriptan (n=20) and frovatriptan (n=20) and 20 healthy individuals were included in our study. Cerebral blood flow velocities and breath-holding indices were recorded bilaterally from middle and posterior cerebral arteries. All procedures were repeated one hour after treatments and one week after attacks.

Results

We observed similar values of cerebral blood flow velocities and breath holding indices in all patients with migraine during the attack-free period compared to the control group. All cerebral vascular structures in migraine patients had significantly lower cerebral blood flow velocities and higher values in breath-holding indices during attacks. After taking rizatriptan and frovatriptan for an attack, the changes in hemodynamics disappeared.

Conclusion

During attacks of migraineurs with aura, vasodilatation develops. In addition, higher vasomotor reactivity during attacks supports hypersensitivity in migraine pathophysiology. Triptans, acting as vasoconstrictor agents, were able to stop over-vasodilatation during attacks. In other words, it is possible that triptans show their effects by eliminating vascular hypersensitivity during acute attacks.

Enlargement of the middle meningeal artery on MR angiography in chronic subdural hematoma

OBJECT

The middle meningeal artery (MMA) is suspected to play an important role in the development of chronic subdural hematoma (CSDH). The aim of this study was to clarify whether the MMA was enlarged in patients with CSDHs.

METHODS

The authors retrospectively assessed 55 patients in whom CSDH was diagnosed between 2010 and 2014 and who underwent MR angiography (MRA) after the onset of CSDH. The authors compared MMA diameters between hemispheres with and without CSDHs on MR angiograms. A case-control study was also performed with 55 sex- and age-matched patients with incidental unruptured aneurysms as controls.

RESULTS

In 55 patients with CSDHs, the diameters of the 79 MMAs on the CSDH side were significantly larger than the diameters of the 31 MMAs on the non-CSDH side (p < 0.05). In 24 patients with bilateral CSDHs, no significant difference was found between the MMA diameters on the larger hematoma side and those on the smaller hematoma side. In 13 patients who underwent MRA before the onset of the CSDH, the MMAs on MR angiograms acquired after onset of the CSDH were significantly larger than those on MR angiograms acquired before the CSDH onset (p < 0.05). The diameters of the MMAs in 55 patients with CSDHs were significantly larger than those of the MMAs in the 55 control patients (p < 0.05).

CONCLUSIONS

The MMA is enlarged with development of a CSDH. Information about the MMA observed on MRA in patients with CSDHs may be useful in developing a strategy for future treatment of CSDHs.

Clinical importance of the middle meningeal artery: A review of the literature

The middle meningeal artery (MMA) is a very important artery in neurosurgery. Many diseases, including dural arteriovenous fistula (DAVF), pseudoaneurysm, true aneurysm, traumatic arteriovenous fistula (AVF), moyamoya disease (MMD), recurrent chronic subdural hematoma (CSDH), migraine and meningioma, can involve the MMA. In these diseases, the lesions occur in either the MMA itself and treatment is necessary, or the MMA is used as the pathway to treat the lesions; therefore, the MMA is very important to the development and treatment of a variety of neurosurgical diseases. However, no systematic review describing the importance of MMA has been published. In this study, we used the PUBMED database to perform a review of the literature on the MMA to increase our understanding of its role in neurosurgery. After performing this review, we found that the MMA was commonly used to access DAVFs and meningiomas. Pseudoaneurysms and true aneurysms in the MMA can be effectively treated via endovascular or surgical removal. In MMD, the MMA plays a very important role in the development of collateral circulation and indirect revascularization. For recurrent CDSHs, after burr hole irrigation and drainage have failed, MMA embolization may be attempted. The MMA can also contribute to the occurrence and treatment of migraines. Because the ophthalmic artery can ectopically originate from the MMA, caution must be taken to avoid causing damage to the MMA during operations.

The qualitative problem of major quotation errors, as illustrated by 10 different examples in the headache literature

There are two types of errors when references are used in the scientific literature: citation errors and quotation errors, and these errors have in reviews mainly been evaluated quantitatively. Quotation errors are the major problem, and 1 review reported 6% major quotation errors. The objective of this listing of quotation errors is to illustrate by qualitative analysis of different types of 10 major quotation errors how and possibly why authors misquote references. The author selected for review the first 10 different consecutive major quotation errors encountered from his reading of the headache literature. The characteristics of the 10 quotation errors ranged considerably. Thus, in a review of migraine therapy in a very prestigious medical journal, the superiority of a new treatment (sumatriptan) vs an old treatment (aspirin plus metoclopramide) was claimed despite no significant difference for the primary efficacy measure in the trial. One author, in a scientific debate, referred to the lack of dilation of the middle meningeal artery in spontaneous migraine despite the fact that only 1 migraine attack was studied. The possibility for creative major quotation errors in the medical literature is most likely infinite. Qualitative evaluations, as the present, of major quotation errors will hopefully result in more general awareness of quotation problems in the medical literature. Even if the final responsibility for correct use of quotations is with the authors, the referees, the experts with the knowledge needed to spot quotation errors, should be more involved in ensuring correct and fair use of references. Finally, this paper suggests that major misleading quotations, if pointed out by readers of the journal, should, as a rule, be corrected by way of an erratum statement.

The evolution of a migraine attack - a review of recent evidence

A migraine attack is an extraordinarily complex brain event that takes place over hours to days. This review focuses on recent human studies that shed light on the evolution of a migraine attack. It begins with a constellation of premonitory symptoms that are associated with activation of the hypothalamus and may involve the neurotransmitter dopamine. Even in the premonitory phase, patients experience sensitivity to sensory stimuli, indicating that central sensitization is a primary phenomenon. The migraine attack progresses to a phase that in some patients includes aura, which involves changes in cortical function, blood flow, and neurovascular coupling. The aura phase overlaps with the headache phase, which is associated with further changes in blood flow and function of the brainstem, thalamus, hypothalamus, and cortex. Serotonin receptors, nitric oxide, calcitonin gene-related peptide, pituitary adenylate cyclase-activating polypeptide, and prostanoids are demonstrated specific chemical mediators of migraine based on therapeutic and triggered migraine studies. A number of migraine symptoms persist beyond resolution of headache into a postdromal phase, accompanied by persistent blood flow changes in several brain regions. Although these phases of migraine have substantial temporal, neurochemical, and anatomical overlap, each represents an important window onto the pathophysiology of migraine as well as a target for therapeutic intervention. A comprehensive approach to migraine requires an understanding of the entire range of mechanisms and resultant symptoms that occur throughout the evolution of an attack.

The role of the neurovascular scalp structures in migraine

AIM

To review reports suggesting a role for neurovascular scalp structures in migraine.

MAIN DATA REPORTED

(A) Scalp periarterial nervous fibres contain all the main peptides and receptors involved in pain. (B) It is possible to interrupt or alleviate migraine pain with a prolonged compression of the main scalp arteries, which decreases blood flow through the pain-sensitized vessels and probably induces a temporary conduction block of periarterial nociceptive fibres. (C) Painful points are present on the scalp arteries of a considerable percentage of migraine sufferers. (D) It is possible to stop or alleviate pain by intervening on nociceptive periarterial fibres, as for example with the injection of lidocaine or 3-5 ml saline, and with percutaneous application of a capsaicin cream.

CONCLUSION

The data reported suggest a role for neurovascular scalp structures in at least some patients with migraine. It would be of interest to find a clinical distinction between patients according to the prevalence of an intracranial or extracranial peripheral pain mechanism. This could lead to more efficacious treatments.

The biological basis of headache

This article covers the remarkable recent decades as clinicians and scientists have grappled with understanding headache. It is a challenge to understand how a 'normal' brain can become dysfunctional, incapacitating an individual, and then become 'normal' again. Does the answer lie in the anatomy, electrical pathways, the chemistry or a combination? How do the pieces fit together? The components are analyzed in this article. Animal models have provided potential answers. However, these processes have never been proven in man. The dynamic imaging of pain and headache is rapidly evolving and providing new insights and directions of research.