The pathophysiology of the trigeminal autonomic cephalalgias, with clinical implications

Harlequin syndrome in a patient with probable hemicrania continua and exertional headache - is there a link? a case report

BACKGROUND

The harlequin syndrome is a rare disorder of the autonomic nervous system characterized by unilateral diminished flushing and sweating of the face following exposure to heat or physical activity. It results from sympathetic dysfunction and most commonly occurs idiopathically. A secondary development due to an underlying pathology (e.g., carotid artery dissection, tumors) must be excluded at first appearance. There is evidence that the cranial autonomic system is involved in the pathophysiology of trigeminal autonomic headaches like hemicrania continua. Therefore, an overlap in the pathophysiology of harlequin syndrome and trigeminal autonomic headache disorders seems plausible. However, the association of a harlequin syndrome with hemicrania continua was never reported.

CASE PRESENTATION

This work describes the case of a 42-year-old female patient presenting to our headache unit. The patient reported persisting unilateral headache of the right side of dragging or squeezing character accompanied by trigeminal autonomic symptoms, including lacrimation, nasal congestion, conjunctival injection and Horner's syndrome, and was responsive to treatment with 75mg/d indomethacin. Five months after the initial consultation, the patient noted that the upper right quadrant of her face was pale after jogging. A harlequin syndrome was diagnosed. Further, she developed a short-lasting, bilateral headache of pulsatile character during strenuous exercise consistent with exertional headache. Comprehensive diagnostic evaluations, encompassing cranial and cervical MRI scans, laboratory tests, and biopsies, culminated in the diagnosis of Sjögren's syndrome. This finding suggests that the trigemino-autonomic dysfunction may either be idiopathic or a direct manifestation of Sjögren's syndrome.

CONCLUSIONS

This report documents the case of a rare combination of a headache resembling probable hemicrania continua and the harlequin syndrome (and even exertional headache). It illustrates the underlying anatomy of the autonomic nervous system in a clinical context and emphasizes the hypothesis of a pathophysiological link between abnormal sympathetic activity and trigeminal autonomic headaches.

Symptomatic trigeminal autonomic cephalalgias in neuromyelitis optica spectrum disorders

BACKGROUND

The pathophysiology of trigeminal autonomic cephalalgias (TACs) is poorly understood at present. Symptomatic TACs are rarely reported in neuromyelitis optica spectrum disorders (NMOSD). To better clarify this distinct clinical manifestation in NMOSD and to investigate its possible pathophysiology, we reviewed articles describing such cases including our own case.

METHODS

We performed a search of all clinical studies of TACs in NMOSD published up to September 1st, 2022. We put no restrictions on the year of English publication in our search. The following keywords were searched: trigeminal autonomic cephalalgias, cluster headache, short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), short-lasting unilateral neuralgiform headache with autonomic symptoms (SUNA), hemicrania continua, paroxysmal hemicrania, neuromyelitis optica, neuromyelitis optica spectrum disorder, Devic's disease.

RESULT

We reviewed six cases (five published reports and our own case study) that fulfilled the diagnosis of NMOSD and TACs. Four of them were SUNCT, one was SUNA, and one was paroxysmal hemicrania. In three of these cases, headache was the initial sole manifestation. Only one case had a good response to routine TACs' treatment. All these patients had lesions in the medulla oblongata and cervical cord. Three cases' TACs were side-locked, and two of them had a left dorsolateral medulla oblongata lesion that corresponded with the left side TACs, while three cases' headaches happened on either side of the head. The phenomenon could be explained by the activation of trigeminal-autonomic reflex and ephaptic coupling.

CONCLUSION

TACs could be the initial sole brainstem manifestation of NMOSD. An underlying cause for SUNCT/SUNA should be considered, especially if there is a limited response to anti-epileptic medication. The activation of trigeminal-autonomic reflex and ephaptic coupling might be the underlying mechanism of symptomatic TACs in NMOSD.

Recent advances in the diagnosis and management of cluster headache

Cluster headache, a primary headache disorder, consists of short (15-180 minutes), frequent (up to eight a day), unilateral attacks of facial pain with associated ipsilateral autonomic features and restlessness. The attacks are suspected to be one of the most painful human experiences, and the disorder is associated with a high rate of suicidal ideation. Proper diagnosis is key, as some of the most effective treatments, such as high flow oxygen gas, are rarely used in other headache disorders. Yet diagnostic delay is typically years for this disorder, as it is often confused with migraine and trigeminal neuralgia, and secondary causes may be overlooked. This review covers the clinical, pathophysiologic, and therapeutic features of cluster headache. Recent updates in diagnosis include the redefinition of chronic cluster headache (remission periods lasting less than three months instead of the previous one month), and recent advances in management include new treatments for episodic cluster headache (galcanezumab and non-invasive vagus nerve stimulation).

Temporary resolution of hemicrania continua following ipsilateral ear piercing

Background

Hemicrania continua is an uncommon subtype of trigeminal autonomic cephalgia that exhibits dramatic therapeutic response to indomethacin. Unfortunately, indomethacin is associated with a range of adverse effects, including neuropsychiatric complications, which limits its use in many patients. Although no other effective pharmacologic agents exist, there is emerging evidence for interventional treatments such as occipital nerve and vagus nerve stimulation, which may act by modulating neural activity within the trigeminovascular system.

Case

We present a 30-year-old woman with long-standing refractory hemicrania continua who suffered adverse effects to indomethacin. She experienced temporary, but near-complete, symptom resolution following piercing of the crus of the ear helix ipsilateral to her headache, whereas contralateral piercing produced no benefit.

Conclusions

To our knowledge, this case is the first to describe a therapeutic benefit following ear piercing in a patient with trigeminal autonomic cephalgia. We argue that symptom relief was obtained through a similar mechanism to occipital or vagus nerve stimulation.

SUNCT/SUNA in Pediatric Age: A Review of Pathophysiology and Therapeutic Options

The International Classification of Headache Disorders, 3rd edition (ICHD3) defines Short-lasting Unilateral Neuralgiform Headache Attacks (SUNHA) as attacks of moderate or severe, strictly unilateral head pain lasting from seconds to minutes, occurring at least once a day and usually associated with prominent lacrimation and redness of the ipsilateral eye. Two subtypes of SUNHA are identified: Short-lasting Unilateral Neuralgiform headache attacks with Conjunctival injection and Tearing (SUNCT) and Short-lasting Unilateral Neuralgiform headache attacks with cranial Autonomic symptoms (SUNA). These pathologies are infrequent in children and difficult to diagnose. The authors reviewed the existing literature on SUNCT and SUNA, especially in the developmental age, which describes the pathophysiology in detail and focuses on the therapeutic options available to date. SUNHA-type headaches must be considered on the one hand, for the possibility of the onset of forms secondary to underlying pathologies even of a neoplastic nature, and on the other hand, for the negative impact they can have on an individual’s quality of life, particularly in young patients. Until now, published cases suggest that no chronic variants occur in childhood and adolescents. In light of this evidence, the authors offer a review that may serve as a source to be drawn upon in the implementation of suitable treatments in children and adolescents suffering from these headaches, focusing on therapies that are non-invasive and as risk-free as possible for pediatric patients.

Indomethacin-responsive headaches-A narrative review

BACKGROUND

Indomethacin is a nonsteroidal anti-inflammatory drug whose mechanism of action in certain types of headache disorders remains unknown. The so-called indomethacin-responsive headache disorders consist of a group of conditions with a very different presentation that have a particularly good response to indomethacin. The response is so distinct as to be used in the definition of two: hemicrania continua and paroxysmal hemicrania.

METHODS

This is a narrative literature review. PubMed and the Cochrane databases were used for the literature search.

RESULTS

We review the main pharmacokinetic and pharmacodynamics properties of indomethacin useful for daily practice. The proposed mechanisms of action of indomethacin in the responsive headache disorders, including its effect on cerebral blood flow and intracranial pressure, with special attention to nitrergic mechanisms, are covered. The current evidence for its use in primary headache disorders, such as some trigeminal autonomic cephalalgias, cough, hypnic, exertional or sexual headache, and migraine will be covered, as well as its indication for secondary headaches, such as those of posttraumatic origin.

CONCLUSION

Increasing understanding of the mechanism(s) of action of indomethacin will enhance our understanding of the complex pathophysiology that might be shared by indomethacin-sensitive headache disorders.

Long-Term Outcome of Indomethacin Treatment in Pediatric Patients with Paroxysmal Hemicrania-A Case Series

Paroxysmal Hemicrania is a rare form of primary headache in children and adolescents, belonging to the group of trigeminal autonomic cephalalgias. Patients suffer from severe, short-lasting unilateral headaches accompanied by symptoms of the autonomic system on the same side of the head. The short duration of attacks distinguishes Paroxysmal Hemicrania from other trigeminal autonomic cephalalgias. Indomethacin is the treatment of choice, and its effectiveness provides a unique diagnostic criterion. However, the long-term outcomes in children are highly underreported. In this case-series, n = 8 patients diagnosed with Paroxysmal Hemicrania were contacted via telephone 3.1 to 10.7 years after initial presentation. A standardized interview was conducted. n = 6 patients were headache-free and no longer took indomethacin for 5.4 ± 3.4 years. The mean treatment period in these patients was 2.2 ± 1.9 years. Weaning attempts were undertaken after 1.7 ± 1.3 months; in n = 3 patients, more than one weaning attempt was necessary. n = 2 patients were still taking indomethacin (4.5 and 4.9 years, respectively). Both unsuccessfully tried to reduce the indomethacin treatment (two and six times, respectively). Adverse effects appeared in n = 6 (75%) patients and led to a discontinuation of therapy in n = 2 patients. Our long-term follow-up suggests that in a substantial proportion of pediatric patients, discontinuing indomethacin therapy is possible without the recurrence of Paroxysmal Hemicrania.

Histological investigations on the dura mater vascular system of mice

The human dura mater encephali is a well innervated and vascularized membrane. Its vascular system plays a crucial role in disorders and pathological cases like dural hematoma, meningitis, and different headache types. To investigate these diseases mouse models are increasingly being used. However, the literature on the vascular system of the mouse dura mater is sparse and explicit studies concerned exclusively with its vasculature are lacking. Here we present a detailed light and scanning electron microscopic investigation of the supratentorial dura mater of the mouse species, with a focus on the largest part of it, the parietal dura mater. By utilizing different immunohistochemical and classical staining methods, a "cartography" of the vascular system was achieved. Additionally, the different blood vessel types with their mural cells were characterized. In contrast to humans, no arteries were found in the mouse parietal dura mater. Its supply is assured through frontolateral and occipital localized arteriolar branches. These arteriolar vessels exhibit in some specimens arteriolar anastomoses with one another. The venous blood is drained to the superior sagittal and transverse sinus through satellite venules accompanying the arterioles or through solitary venules. In all samples, large ruptured venules were identified in the frontolateral dural area. Scanning electron microscopy revealed that these vessels were ruptured on the dorsal side (skull bones-oriented side) of the dura. Our results contribute to the anatomical data on the mouse species and may set up a basis for fundamental investigation of disorders, for which the role of dural blood vessels is not yet clarified.