Indomethacin-Responsive Headache Disorders

OBJECTIVE

This article describes the clinical features and treatment of the indomethacin-responsive headache disorders paroxysmal hemicrania and hemicrania continua.

LATEST DEVELOPMENTS

Both paroxysmal hemicrania and hemicrania continua are treated with indomethacin at the lowest clinically useful dose. It has recently become clear that some patients with either condition may respond to treatment with noninvasive vagus nerve stimulation, which can be both indomethacin sparing and, in some cases, headache controlling. Given the lifelong nature of both paroxysmal hemicrania and hemicrania continua, brain imaging with MRI is recommended when the conditions are identified, specifically including pituitary views.

ESSENTIAL POINTS

Paroxysmal hemicrania and hemicrania continua are indomethacin-responsive headache disorders that offer a rewarding and unique opportunity to provide marked clinical improvement when recognized and treated appropriately. These disorders share the final common pathway of the trigeminal-autonomic reflex, with head pain and cranial autonomic features, and are differentiated pathophysiologically by the pattern of brain involvement, which can be seen using functional imaging. They have distinct differential diagnoses to which the clinician needs to remain alert.

One-year prevalence of cluster headache, hemicrania continua, paroxysmal hemicrania and SUNCT in Norway: a population-based nationwide registry study

BACKGROUND

There is lack of population-based studies evaluating the prevalence of paroxysmal hemicrania, hemicrania continua and short-lasting unilateral neuralgiform headache attacks.

OBJECTIVES

The aim of this study was to investigate the gender-specific 1-year prevalence of cluster headache, paroxysmal hemicrania, hemicrania continua, and short-lasting unilateral neuralgiform headache attacks.

METHODS

A nationwide study was conducted from January 1 2022 and December 31 2022 by linking diagnostic codes from Norwegian Patient Registry and prescription of relevant drugs from Norwegian Prescription Database on an individual basis. The 1-year prevalence with 95% confidence intervals (CI) of cluster headache, paroxysmal hemicrania, hemicrania continua and short-lasting unilateral neuralgiform headache attacks are estimated based on the combination of diagnostic codes, prescription of drugs and corresponding reimbursement codes.

RESULTS

Among 4,316,747 individuals aged ≥ 18 years, the 1-year prevalence per 100,000 was 14.6 (95% CI 13.5-15.8) for cluster headache, 2.2 (95% CI 1.8-2.7) for hemicrania continua, 1.4 (95% CI 1.0-1.8) for paroxysmal hemicrania, and 1.2 (95% CI 0.8-1.4) for short-lasting unilateral neuralgiform headache attacks. For all the trigeminal autonomic cephalalgies, cluster headache included, the prevalence was higher for women than men.

CONCLUSIONS

In this nationwide register-based study, we found a 1-year prevalence per 100,100 of 14.6 for cluster headache, 2.2 for hemicranias continua, 1.4 for paroxysmal hemicranias, and 1.2 for short-lasting unilateral neuralgiform headache attacks. This is the first study reporting higher prevalence of cluster headache for women than men.

Melatonin in hemicrania continua and paroxysmal hemicrania

BACKGROUND

Hemicrania continua (HC) and paroxysmal hemicrania (PH) belong to a group of primary headache disorders called trigeminal autonomic cephalalgias. One of the diagnostic criteria for both HC and PH is the absolute response to the therapeutic dose of indomethacin. However, indomethacin is discontinued in many patients as a result of intolerance to its side effects. Melatonin, a pineal hormone, which shares similar chemical structure to indomethacin, has been reported to have some efficacy for HC in previous case reports and series. To our knowledge, there is no literature regarding the use of melatonin in PH. We aimed to describe the clinical use of melatonin in the preventive management of HC and PH.

METHODS

Patient level data were extracted as an audit from routinely collected clinical records in consecutive patients seen in outpatient neurology clinic at King's College Hospital, London, UK, from September 2014 to April 2023. Our cohort of patients were identified through a search using the keywords: hemicrania continua, paroxysmal hemicrania, melatonin and indomethacin. Descriptive statistics including absolute and relative frequencies, mean ± SD, median and interquartile range (IQR) were used.

RESULTS

Fifty-six HC patients were included with a mean ± SD age of 52 ± 16 years; 43 of 56 (77%) patients were female. Melatonin was taken by 23 (41%) patients. Of these 23 patients, 19 (83%) stopped indomethacin because of different side effects. The doses of melatonin used ranged from 0.5 mg to 21 mg, with a median dose of 10 mg (IQR = 6-13 mg). Fourteen (61%) patients reported positive relief for headache, whereas the remaining nine (39%) patients reported no headache preventive effect. None of the patients reported that they were completely pain free. Two patients continued indomethacin and melatonin concurrently for better symptom relief. Eight patients continued melatonin as the single preventive treatment. Side effects from melatonin were rare. Twenty-two PH patients were included with mean ± SD age of 50 ± 17 years; 17 of 22 (77%) patients were female. Melatonin was given to six (27%) patients. The median dose of melatonin used was 8 mg (IQR = 6-10 mg). Three (50%) patients responded to melatonin treatment. One of them used melatonin as adjunctive treatment with indomethacin.

CONCLUSIONS

Melatonin showed some efficacy in the treatment of HC and PH with a well-tolerated side effect profile. It does not have the same absolute responsiveness as indomethacin, at the doses used, although it does offer a well-tolerated option that can have significant ameliorating effects in a substantial cohort of patients.

Epidemiology and clinical features of paroxysmal hemicrania: A systematic review and meta-analysis

OBJECTIVE

To assess the prevalence or relative frequency of paroxysmal hemicrania and its clinical features in the adult general population and among adult patients evaluated for headache in tertiary care.

BACKGROUND

Paroxysmal hemicrania is a rare trigeminal autonomic cephalalgia with characteristic attacks of headache, associated cranial autonomic symptoms and signs, and an absolute response to indomethacin. Its epidemiological burden remains unknown in both the adult general population and among adult patients evaluated for headache in a tertiary care setting. Moreover, the frequencies of the clinical features associated with paroxysmal hemicrania have not been well established.

METHODS

A literature search of PubMed and Embase was conducted from January 1, 1988, to January 20, 2023. Eligible for inclusion were observational studies reporting the point prevalence or relative frequency of paroxysmal hemicrania or its clinical features in the adult general population or among adult patients evaluated for headache in tertiary care. Two independent investigators (M.J.H. and J.G.L.) performed the title, abstract, and full-text article screening. Each included study's risk of bias was critically appraised using the Joanna Briggs Institute Critical Appraisal Checklist for Studies Reporting Prevalence Data. Estimates of prevalence or relative frequency were calculated using a random-effects meta-analysis. The between-study heterogeneity was assessed using the I2 statistic and further explored with meta-regression. This study was pre-registered on PROSPERO (identifier: CRD42023391127).

RESULTS

A total of 17 clinic-based studies and one population-based study met the eligibility criteria. Importantly, an overall high risk of bias was observed across the eligible studies. The relative frequency of paroxysmal hemicrania was estimated to be 0.3% (95% CI, 0.2%-0.5%) among adult patients evaluated for headache in tertiary care with considerable heterogeneity (I2  = 76.4%). No cases with paroxysmal hemicrania were identified among 1,838 participants in a population-based sample. Moreover, the most prevalent cranial autonomic symptoms were lacrimation (77.3% [95% Cl, 62.7%-87.3%]), conjunctival injection (75.0% [95% Cl, 60.3%-85.6%]), and nasal congestion (47.7% [95% Cl, 33.6%-62.3%]).

CONCLUSIONS

Our findings suggest that paroxysmal hemicrania is a rare disorder among adults evaluated for headache in tertiary care, while its prevalence in the general population remains unknown. Further studies focusing on the clinical features of paroxysmal hemicrania are warranted.

Paroxysmal hemicrania and hemicrania continua: Review on pathophysiology, clinical features and treatment

BACKGROUND

Paroxysmal hemicrania and hemicrania continua are indometacin-sensitive trigeminal autonomic cephalalgias, a terminology which reflects the predominant distribution of the pain, observable cranial autonomic features and shared pathophysiology. Understanding the latter is limited, both by low prevalence and the intricacies of studying brain function, requiring multimodal techniques to glean insights into such disorders. Similarly obscure is the curious response to indometacin. This review will address what is currently known about pathophysiology, the rationale for the current classification and, features which may confound the diagnosis, such as lack of cranial autonomic symptoms and those which are typically associated with migraine such as nausea, photophobia, phonophobia and aura. Despite these characteristics, a dramatic response to indometacin, which is not seen in migraine nor the other trigeminal autonomic cephalalgias , provides the hallmark of the diagnosis. The main clinical differential for paroxysmal hemicrania is based on temporal pattern and lies between cluster headache and short-lasting-neuralgiform headache attacks with tearing or additional cranial autonomic symptoms. For hemicrania continua it is more challenging as the main differential for which the disorder is often treated is migraine. A prior episodic pattern, often days at a time, and the tendency to exacerbation with analgesics will further deflect from the diagnosis. The relevance of this is that there is little overlap in therapeutics between paroxysmal hemicrania and hemicrania continua and other headache disorders and there are limited effective alternatives to indometacin. The most effective are other non-steroidal anti-inflammatory drugs including the newer COX-II inhibitors. Even though early reports suggest that a higher indometacin dose-requirement may herald a secondary precipitating pathology, this does not seem to be the case, with syndrome and response to treatment being similar with the primary disorder. In this context imaging of new onset paroxysmal hemicrania or hemicrania continua and implication of the results will be discussed as will alternative treatment options.

A Combination of Indomethacin Farnesyl and Amitriptyline Is Effective for Continuous Interictal Pain with Probable Chronic Paroxysmal Hemicrania

A 26-year-old woman with a history of migraine reported right-sided, severe stabbing orbital pain with cranial autonomic symptoms (CASs) for approximately 2 years. The attack duration was approximately 30 minutes, with a frequency of twice per day. Taking loxoprofen was ineffective. Six months earlier, moderate pressing continuous interictal pain without CASs had developed. Indomethacin farnesyl completely resolved the attacks but had no effect on the interictal pain. The patient was diagnosed with probable chronic paroxysmal hemicrania in accordance with the International Classification of Headache Disorders (ICHD-3) (third version). Continuous interictal pain gradually disappeared with a combination of indomethacin farnesyl and amitriptyline.

Are repetitive pericranial nerve blocks effective in the management of chronic paroxysmal hemicrania?: A case report

INTRODUCTION

Paroxysmal hemicrania (PH) is a chronic headache disorder characterized by unilateral pain attacks accompanied by cranial autonomic symptoms and responds to indomethacin completely. There are few alternative treatment options for the patients who cannot tolerate indomethacin. Studies exploring the effects of repetitive peripheral cranial nerve blocks in the management of chronic PH are limited.

PATIENT CONCERNS AND DIAGNOSIS

A 34-year-old woman with a 4-year history of PH was evaluated. Her pain was prevented by indomethacin without side effects; however, she wanted to try to conceive.

INTERVENTIONS

Repetitive pericranial nerve blocks, great occipital nerve, infraorbital nerve, supraorbital nerve, and sphenopalatine ganglion block, using local anesthetics and steroids were performed once a week for a 6 weeks period.

OUTCOMES

A follow-up of 3 months showed that there was no pain relief following the injections and patient was needed to be maintained on indomethacin.

CONCLUSION

Although pericranial nerve blocks have been tried in chronic PH cases with positive influences, this case indicated that repetitive nerve blocks were not always a successful therapy option.

Chronic Paroxysmal Hemicrania in a Patient with a Macroprolactinoma

We report a patient with headaches meeting the criteria of chronic paroxysmal hemicrania, as defined by the International Headache Society classification. Headaches were fully responsive to indomethacin during the first 3 months of treatment but recurred when daily doses were lowered. Investigations revealed a macroprolactinoma. Headaches stopped after cabergoline treatment. This report further suggests that patients with paroxysmal hemicrania should be investigated for pituitary abnormalities.

Hemicrania Continua Evolving from Episodic Paroxysmal Hemicrania

A 45-year-old woman, who had been diagnosed in our unit with episodic paroxysmal hemicrania, was seen 2 years later for ipsilateral hemicrania continua in remitting form. Both types of headache had a complete response to indomethacin and did not occur simultaneously. The patient had a previous history of episodic moderate headaches that met criteria for probable migraine without aura and also had a family history of headache. The clinical course in this case suggests a pathogenic relationship between both types of primary headache.

The Neuropharmacology of Cluster Headache and other Trigeminal Autonomic Cephalalgias

Trigeminal autonomic cephalalgias (TACs) are a group of primary headaches including cluster headache (CH), paroxysmal hemicrania (PH) and short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT). Another form, hemicrania continua (HC), is also included this group due to its clinical and pathophysiological similarities. CH is the most common of these syndromes, the others being infrequent in the general population. The pathophysiology of the TACs has been partly elucidated by a number of recent neuroimaging studies, which implicate brain regions associated with nociception (pain matrix). In addition, the hypothalamic activation observed in the course of TAC attacks and the observed efficacy of hypothalamic neurostimulation in CH patients suggest that the hypothalamus is another key structure. Hypothalamic activation may indeed be involved in attack initiation, but it may also lead to a condition of central facilitation underlying the recurrence of pain episodes. The TACs share many pathophysiological features, but are characterised by differences in attack duration and frequency, and to some extent treatment response. Although alternative strategies for the TACs, especially CH, are now emerging (such as neurostimulation techniques), this review focuses on the available pharmacological treatments complying with the most recent guidelines. We discuss the clinical efficacy and tolerability of the currently used drugs. Due to the low frequency of most TACs, few randomised controlled trials have been conducted. The therapies of choice in CH continue to be the triptans and oxygen for acute treatment, and verapamil and lithium for prevention, but promising results have recently been obtained with novel modes of administration of the triptans and other agents, and several other treatments are currently under study. Indomethacin is extremely effective in PH and HC, while antiepileptic drugs (especially lamotrigine) appear to be increasingly useful in SUNCT. We highlight the need for appropriate studies investigating treatments for these rare, but lifelong and disabling conditions.

[Hemicrania continua and paroxysmal hemicrania: clinical and therapeutic characteristics in a series of 23 patients]

INTRODUCTION

Hemicranias are an uncommon type of headache characterised by strictly unilateral pain, either as a continuous, although fluctuating, headache in hemicrania continua (HC) or in the form of recurring attacks in paroxysmal hemicrania (PH). In both types of headache, an absolute response to indomethacin is reported. AIMS. To analyse the fulfilment of current diagnostic criteria for HC and PH and the recent introduction of HC within the group of trigeminal-autonomic cephalgias.

PATIENTS AND METHODS

The clinical and therapeutic characteristics of patients diagnosed with HC or PH were evaluated retrospectively. Demographic and symptomatological information as well as data regarding the analogical pain scale and response to indomethacin were included.

RESULTS

A sample of 12 HC (four males and eight females) was evaluated from a total of 520 cases (2.3%). Mean age at onset: 47.1 ± 16.4 years. Baseline pain intensity: 3.3 ± 1,9. Exacerbations: 9.2 ± 1.1. Eight cases (66.7%) presented autonomic symptoms, four (33.3%) followed a time pattern, and two (16.7%) did not respond to indomethacin. We evaluated a sample of 11 PH (100% females) from 520 cases (2.1%). Mean age at onset: 37.0 ± 13.9 years. Pain intensity: 8.7 ± 2.7. Nine cases (81.8%) presented autonomic symptoms, three (27.3%) followed a time pattern and one (9.1%) did not respond to indomethacin.

CONCLUSIONS

Hemicranias are not frequently diagnosed in day-to-day clinical practice. Their diagnosis requires the fulfilment of certain criteria that are sometimes not fully satisfied. We believe that the criteria need revising and we also support the recent inclusion of HC within the group of trigeminal-autonomic cephalgias.

Primary headache disorders

Primary headache disorders include migraine, tension-type headaches, and the trigeminal autonomic cephalgias (TACs). "Primary" refers to a lack of clear underlying causative pathology, trauma, or systemic disease. The TACs include cluster headache, paroxysmal hemicrania, and short-lasting neuralgiform headache attacks with conjunctival injection and tearing; hemicrania continua, although classified separately by the International Headache Society, shares many features of both migraine and the TACs. This article describes the features and treatment of these disorders.

Chronic paroxysmal hemicrania in paediatric age: report of two cases

Chronic paroxysmal hemicrania (CPH) is a rare primary headache syndrome, which is classified along with hemicrania continua and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) as trigeminal autonomic cephalalgia (TACs). CPH is characterised by short-lasting (2-30 min), severe and multiple (more than 5/day) pain attacks. Headache is unilateral, and fronto-orbital-temporal pain is combined with cranial autonomic symptoms. According to the International Classification of Headache Disorders, 2nd edition, the attacks are absolutely responsive to indomethacin. CPH has been only rarely and incompletely described in the developmental age. Here, we describe two cases concerning a 7-year-old boy and a 11-year-old boy with short-lasting, recurrent headache combined with cranial autonomic features. Pain was described as excruciating, and was non-responsive to most traditional analgesic drugs. The clinical features of our children's headache and the positive response to indomethacin led us to propose the diagnosis of CPH. Therefore, our children can be included amongst the very few cases of this trigeminal autonomic cephalgia described in the paediatric age.

Indomethacin responsive headache syndromes: chronic paroxysmal hemicrania and Hemicrania continua. How they were discovered and what we have learned since

In the indomethacin responsive headaches (IRHs), chronic paroxysmal hemicrania (CPH) and Hemicrania continua (HC), the indomethacin (INDO) response is swift, absolute, and permanent, with moderate doses. Traditionally, CPH has been linked to cluster headache (CH) due to clinical similarities: unilaterality, intensity, and some autonomic phenomena. However, other clinical features differ essentially between these two headaches: sex ratio, mean attack frequency (CPH: 13.6 versus CH: 1.7 attacks/day), and duration of attacks. The therapeutic profile in CPH (indomethacin effect: ++; triptan effect: generally non-existent) is reversed in CH. The autonomic phenomena also differ clearly, a forehead supersensitivity sweating pattern and Horner-like pupil being present only in CH. The chronic/non-chronic stage ratio is 3.9 in CPH, against 0.14 in CH, a >25 times difference. Conversely, CPH and HC are very similar, clinically speaking. Accordingly, we should probably sever the link between CH and CPH and favour, instead, a linking together of CPH and HC, the two principal IRHs.

Trigeminal autonomic cephalalgias. Part 2: Paroxysmal hemicrania

Paroxysmal hemicrania (PH) is characterized by severe, strictly unilateral pain attacks lasting 2 to 30 minutes localized to orbital, supraorbital, and temporal areas accompanied by ipsilateral autonomic features. It represents 1 of 3 primary headaches classified as trigeminal autonomic cephalalgias. Although PH is rare, patients may present to dental offices seeking relief for their pain. It is important for oral health care providers to recognize PH and render an accurate diagnosis. This will avoid the pitfall of implementing unnecessary and inappropriate traditional dental treatments in hopes of alleviating this neurovascular pain. This is part 2 of a review on trigeminal autonomic cephalalgias and focuses on PH. Aspects of PH including epidemiology, genetics, pathophysiology, clinical presentation, classification and variants, diagnosis, medical management, and dental considerations are discussed.

[Trigeminal autonomic cephalgias: diagnostic and therapeutic implications]

Trigeminal autonomic cephalgias (TACs) are primary headache syndromes characterized by severe short-lasting headaches accompanied by ipsilateral facial autonomic symptoms. The group includes cluster headache (CH), paroxysmal hemicrania (PH), and short-lasting neuralgiform headache with conjunctival injection and tearing (SUNCT). By far, Cluster headache is the most frequent of these syndromes. Similar hypothalamic and trigeminovascular mechanisms have been discussed as pathophysiologic mechanisms for all TACs. The therapeutic strategies, however, differ considerably. Although unusual, structural lesions in TACs have been described, affecting the therapeutic management.

Paroxysmal hemicrania responding to topiramate

Chronic paroxysmal hemicrania (CPH) is a rare primary headache syndrome, which is classified along with cluster headache and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) as a trigeminal autonomic cephalalgia. CPH is exquisitely responsive to indomethacin so much so that the response is one of the current diagnostic criteria. The case of a patient with CPH, who had marked epigastric symptoms with indomethacin treatment and responded well to topiramate 150 mg daily, is reported. Cessation of topiramate caused return of episodes, and the response has persisted for 2 years. Topiramate may be a treatment option in CPH.

Chronic paroxysmal hemicrania: from the index patient to the disease

The first patient with chronic paroxysmal hemicrania (CPH), a 41-year-old woman, first seen in 1961, was followed until an adequate treatment was found, 12 years later. Clinically, attack frequency and duration differed widely from the general pattern of cluster headache. Ocular variables, such as intraocular pressure and corneal indentation pulse amplitudes, also differed in our case (clear symptomatic side increment during attacks) and cluster headache. Pupil reactions to directly and indirectly acting sympathicomimetic drugs were also vastly different in our case and cluster headache: no signs of Horner s syndrome in our patient, while cluster headache exhibits a "Horner-like pattern." In cluster headache, there is a relative hypohidrosis in the forehead on the symptomatic side if body temperature is increased, and a clear hyperhidrosis on direct parasympathomimetic stimulation. This was not so in our case. Indomethacin was highly effective in our case, while "cluster headache drugs," such as ergotamine/sumatriptan, were ineffective. Indomethacin was inactive in cluster headache. Accordingly, our case seemed to differ decisively from cluster headache: CPH had been discovered.

Side-shifting hemicrania continua with aura (migraine with aura with autonomic symptoms responsive to indomethacin?)

Atypical features of hemicrania continua (HC), including both visual aura and side shifting, have been reported previously. However, auras and variable unilaterality have never been reported together in HC. We report two patients with side-shifting HC with aura. These patients' symptoms are unilateral headaches, visual aura, autonomic features, throbbing pain, nausea and photo/phonophobia. One could speculate that the unilaterality and/or the autonomic symptom modules are indomethacin responsive. The patients can also be classified as chronic migraine with aura, with autonomic symptoms, responsive to indomethacin. Neither migraine subtype nor side-shifting HC with aura is included in the current International Headache Society (IHS) classification, so these patients are not classifiable. Side-shifting HC with aura implies the need to revisit the traditional IHS categorization of headaches into unique diagnostic groups. The modular headache theory may be a tool for the understanding of these rare and complex cases.

Black, white and shades of grey: SUNCT or short-lasting chronic paroxysmal hemicrania?

AIM OF THE STUDY: To report a case of unilateral headache with two possibilities of diagnosis. METHOD: Case report. RESULTS: Patient with unilateral, intense, stabbing periocular headache with conjuntival injection and tearing. Although the duration of attacks was typical of SUNCT, there was complete remission of the pain with indomethacin, suggesting that this was a case of chronic paroxysmal hemicrania with unusually short attack duration. CONCLUSION: Therapeutic trials of indomethacin on younger patients presenting clinical diagnosis of SUNCT could be tried on a more regular basis.

Chronic paroxysmal hemicrania in a 3-year, 10-month-old female

This is the report of a 3-year, 10-month-old female with classical symptoms of chronic paroxysmal hemicrania and favorable response to indomethacin therapy. The patient was admitted because of frequent episodes of severe unilateral headaches during the day and nighttime as well as agitation. During the episodes, she complained of severe pains on the left orbital and supraorbital region. Subsequent lacrimation from the left eye was also documented. Initially, focal epileptic attack was diagnosed and during the following 10 months several antiepileptic drugs were used without effect. After 10 months, chronic paroxysmal hemicrania was diagnosed because of the typical symptoms along with a favorable response to indomethacin therapy.

Posterior hypothalamic activation in paroxysmal hemicrania

OBJECTIVE

Paroxysmal hemicrania (PH) is a severe, strictly unilateral headache that lasts 2 to 30 minutes, occurs more than five times daily, is associated with trigeminal autonomic symptoms, and is exquisitely responsive to indomethacin. The purpose of the study was to determine the brain structures active in PH.

METHODS

Seven PH patients were studied using positron emission tomography (PET). Each patient was scanned in three states: (1) acute PH attack-off indomethacin; (2) pain-free-off indomethacin; and (3) pain-free after administration of intramuscular indomethacin 100 mg. The scan images were processed and analyzed using SPM99.

RESULTS

The study showed no significant activations during state 1 compared with state 2, but there was relative activation of the pain neuromatrix in both states 1 and 2 compared with state 3. This suggests that there is persistent activation of the pain neuromatrix during acute PH attacks and during interictal pain-free states off indomethacin that is deactivated by the administration of indomethacin. In addition, the untreated PH state was associated with significant activation of the contralateral posterior hypothalamus and contralateral ventral midbrain, which extended over the red nucleus and the substantia nigra.

INTERPRETATION

These activated subcortical structures may play a pivotal role in the pathophysiology of this syndrome.

Seasonal, extratrigeminal, episodic paroxysmal hemicrania successfully treated with single suboccipital steroid injections

This case report describes a case of extratrigeminal, episodic paroxysmal hemicrania with a clear seasonal temporal pattern, successfully treated with repeated single suboccipital steroid injections. The pathophysiological and clinical implications of this observation are discussed.