Hemicrania continua is not that rare

The critical role of neuroimaging in hemicrania continua: A systematic review and case series

BACKGROUND

Hemicrania continua is a primary unilateral headache characterized by ipsilateral parasympathetic and sympathetic autonomic features. A key diagnostic criterion is its dramatic response to indomethacin treatment; however, various vascular or structural abnormalities have been reported to cause secondary hemicrania continua, presenting with clinical features similar to those of the primary headache presentation.

OBJECTIVE

We reviewed the literature to compile secondary hemicrania continua cases, highlighting the importance of imaging during the evaluation. Additionally, we also contributed our three cases to the existing studies.

METHODS

We conducted a review of articles from the PubMed and EMBASE databases that described reported cases of secondary hemicrania continua, covering the period from 1993 to 2021. Our review included detailed patient information, signs, and symptoms of hemicrania continua, as well as information on indomethacin usage and headache resolution (if pertinent).

RESULTS

Secondary hemicrania continua can result from a remarkably diverse range of structural and vascular lesions, yet clinical reports on long-term follow-up are lacking. Notably, cases may exhibit a classical response to indomethacin, emphasizing the importance of neuroimaging in excluding secondary cases. Our search yielded 41 cases meeting our criteria. We excluded six cases that were not treated with indomethacin or were unresponsive to it. Additionally, we present three cases that highlight the necessity of neuroimaging in evaluating hemicrania continua, along with short- and long-term clinical outcomes following indomethacin and lesion-directed treatments. Case 1 presented with daily right-sided headaches and cranial autonomic symptoms. Her pain completely resolved with indomethacin use. Neuroimaging of the brain revealed a laterally directed saccular aneurysm of the right internal carotid artery. Case 2 presented with continuous left-sided unilateral headaches with superimposed exacerbations. She complained of left-sided photophobia with a dull sensation in the left ear. Her symptoms decreased after 2 weeks of indomethacin use. Neuroimaging of the head indicated a benign tumor with mass effect into the left lateral medulla and inferior cerebellar peduncle. Case 3 presented with a right side-locked headache with daily, severe superimposed exacerbations. She had photophobia in the right eye and a right-sided Horner's syndrome, along with tearing during her exacerbations. Neuroimaging of the brain revealed a pituitary tumor and her pain completely resolved with indomethacin.

CONCLUSION

Hemicrania continua is a rare headache disorder that can be either primary or secondary. Importantly, response to indomethacin can still occur in secondary hemicrania continua. Thus, neuroimaging should be considered to rule out underlying structural etiology in all cases, regardless of their clinical responsiveness to indomethacin therapy.

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.

Cigarette smoking history (personal and secondary childhood exposure) in non-cluster headache trigeminal autonomic cephalalgias: A clinic based study

OBJECTIVE

To look at cigarette smoking history (personal and secondary exposure as a child) in non-cluster headache trigeminal autonomic cephalalgias seen at a headache clinic and to determine smoking exposure prevalence utilizing previously published data.

METHODS

Retrospective chart review and PubMed/Google Scholar search.

RESULTS

Forty-eight clinic patients met ICHD-3 criteria for non-cluster headache trigeminal autonomic cephalalgias. Four had paroxysmal hemicrania, 75% were smokers and secondary exposure was noted in all. 16 patients had short lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) or short lasting unilateral neuralgiform headache attacks with autonomic symptoms (SUNA), 12.5% were smokers and secondary exposure was noted in 91%. Twenty-eight patients had hemicrania continua, 21% were smokers and secondary exposure was found in 62.5%.Since 1974 there have been 88 paroxysmal hemicrania, 50 SUNCT or SUNA and 89 hemicrania continua patients with a documented smoking exposure history. From current data and previous studies, a smoking history was noted in 60% paroxysmal hemicrania, 18% SUNCT and SUNA and 21% hemicrania continua patients.

CONCLUSION

A cigarette smoking history appears to be connected to paroxysmal hemicrania (personal and secondary exposure) and possibly to SUNCT/SUNA (secondary) and hemicrania continua (secondary).

Hemicrania Continua: An Update

PURPOSE OF REVIEW

Hemicrania Continua (HC) is a rare and disabling primary headache disorder that is characterized by persistent, unilateral headache with ipsilateral, cranial autonomic symptoms and restlessness or agitation. The diagnosis requires patients to experience an absolute response to therapeutic doses of indomethacin.

RECENT FINDINGS

HC is diagnosed in in about 1.8% of adult patients who were evaluated for headache in tertiary care services, albeit this estimate should be interpreted with caution. The most prevalent accompanying symptoms appear to be lacrimation, conjunctival injection and restlessness or agitation. However, the available literature is limited by methodologic issues, and the current diagnostic criteria lack clarity on what defines absolute response to indomethacin. More rigorous studies are thus needed to improve our understanding of HC which, in turn, will facilitate better disease management in clinical practice. Here, we provide a comprehensive overview of HC, including its epidemiology, clinical presentation, diagnostic evaluation, and management.

Trigeminal Autonomic Cephalalgias and Neuralgias in Children and Adolescents: a Narrative Review

PURPOSE OF REVIEW

To summarize the available literature as well as the authors' experience on trigeminal autonomic cephalalgias (TACs) and cranial neuralgias in children and adolescents.

RECENT FINDINGS

While TACs and cranial neuralgias are rare in children, several recent case series have been published. TACs in children share most of the clinical features of TACs in adults. However, there are many reported cases with clinical features which overlap more than one diagnosis, suggesting that TACs may be less differentiated in youth. Indomethacin-responsive cases of cluster headache and SUNCT/SUNA have been reported in children, whereas in adults indomethacin is usually reserved for paroxysmal hemicrania and hemicrania continua. Neuralgias appear to be rare in children. Clinical features are often similar to adult cases, though clinicians should maintain a high index of suspicion for underlying causes.

Prevalence and clinical features of hemicrania continua in clinic-based studies: A systematic review and meta-analysis

OBJECTIVE

To estimate the relative frequencies of hemicrania continua and its clinical features in adult patients who were evaluated for headache in a clinic-based setting.

METHODS

PubMed and Embase were searched for observational, clinic-based studies published between 1 January 2004 and 1 February 2022, that reported on the relative frequencies of hemicrania continua and its clinical features. Two independent investigators (HMA and SA-K) screened titles, abstracts, and full text-articles. A random-effects meta-analysis was conducted to estimate pooled relative frequencies of hemicrania continua and its clinical features across clinic-based studies.

RESULTS

Eleven clinic-based studies were deemed eligible for inclusion. Of these, eight studies reported on the relative frequency of hemicrania continua among adult patients (n = 9854) who were evaluated for headache in a tertiary care unit. The pooled relative frequency of hemicrania continua was found to be 1.8% (95% CI; 1.0-3.3). Considerable heterogeneity was noted across studies (I² = 89.8%). The three most common symptoms associated with hemicrania continua were lacrimation (72.3%), conjunctival injection (69.8%), and restlessness/agitation (60.2%).

CONCLUSION

The findings of this meta-analysis suggest that there is limited epidemiologic data on the relative frequencies of hemicrania continua and its clinical features. Standardized data acquisition and reporting are needed to estimate prevalence rates more accurately and to better understand epidemiologic patterns. This, in turn, should increase awareness of the impact that hemicrania continua has in clinical practice.

Hemicrania Continua: An Update

Background

Hemicrania continua (HC) is not uncommon in clinical practice, and several large case series have been published in the recent past.

Objectives

This review provides an overview of the recent advancement in different aspects of HC.

Methods

We reviewed the articles published on HC in the last 2 decades.

Results

HC constitutes 1.7% of patients with headache in the clinics. It presents with unilateral continuous background pain with periodic exacerbations, usually accompanied by cranial autonomic features and restlessness. The continuous background headache is the most consistent and central feature of HC. Although the duration of exacerbations varies from a few seconds to a few weeks, the frequency ranges from >20 attacks/day to one attack in several months. The background pain is mild to moderate in intensity and does not hamper routine activity. Patients and physicians frequently ignore the basal pain, and a case of HC is misdiagnosed as other headaches, depending on the pattern of exacerbations. The exacerbation mimics several primary headaches and neuralgias. There are about 75 cases of secondary HC, due to 29 different pathologies. Although an absolute response to indomethacin is part of the diagnostic criteria, a subset of patients may respond to several other drugs. Headache reappears immediately on skipping a single dose of effective drug. Several surgical procedures have been tried in patients who are intolerant to indomethacin.

Conclusion

Misdiagnosis of HC is common. Continuous background pain and response to indomethacin are two essential features for the diagnosis of HC.

Treatment of SUNCT/SUNA, Paroxysmal Hemicrania, and Hemicrania Continua: An Update Including Single-Arm Meta-analyses

Purpose of Review

This review presents a critical appraisal of the treatment strategies for short-lasting unilateral neuralgiform headache attacks (SUNHA), paroxysmal hemicrania (PH), and hemicrania continua (HC). We assess the available, though sparse, evidence on both medical and surgical treatments. In addition, we present estimated pooled analyses of the most common treatments and emphasize recent promising findings.

Recent Findings

The majority of literature available on the treatment of these rare trigeminal autonomic cephalalgias are small open-label observational studies and case reports. Pooled analyses reveal that lamotrigine for SUNHA and indomethacin for PH and HC are the preventative treatments of choice. Second-line choices include topiramate, gabapentin, and carbamazepine for SUNHA; verapamil for PH; and cyclooxygenase-2 inhibitors and gabapentin for HC. Parenteral lidocaine is highly effective as a transitional treatment for SUNHA. Novel therapeutic strategies such as non-invasive neurostimulation, targeted nerve and ganglion blockades, and invasive neurostimulation, including implanted occipital nerve stimulators and deep brain stimulation, appears to be promising options.

Summary

At present, lamotrigine as a prophylactic and parenteral lidocaine as transitional treatment remain the therapies of choice for SUNHA. While, by definition, both PH and CH respond exquisitely to indomethacin, evidence for other prophylactics is less convincing. Evidence for the novel emerging therapies is limited, though promising.

Very young age of onset in trigemino-autonomic cephalalgias - case report and review of the literature

BACKGROUND

Trigemino-autonomic cephalalgias are very rare disorders and even rarer in children and adolescents. We report the onset of paroxysmal hemicrania in a very young girl and reviewed the scientific literature for similar cases.

FINDINGS

We describe the case of a 1.6-year-old girl with left-sided headache attacks fulfilling the criteria of paroxysmal hemicrania including prompt responsiveness to indomethacin. In addition, we detected at least two children for every trigemino-autonomic cephalalgias subtype with an age of under 7 years at the onset of the trigemino-autonomic cephalalgias. Remarkable features were a vast majority of chronic course from onset on and left-sided attacks.

CONCLUSION

Although very rare, trigemino-autonomic cephalalgias can occur even in very young children under the age of 6 years. This should be known in neuropaediatrics.

A long-term prospective observational study in 31 patients with hemicrania continua

Introduction:

Till date, there is no prospective study in patients with hemicrania continua (HC).

Methods:

Patients fulfilling the international classification of headache disorders criteria for HC were evaluated prospectively. All patients were subjected to a detailed clinical interview, based on a structured questionnaire. Before starting indomethacin, all patients were instructed to fill a headache diary for at least 5 days. Gradual tapering of indomethacin was done at regular intervals.

Results:

We enrolled 41 patients over 4.5 years, 31 of whom met the criteria after confirming the indomethacin response. The mean age was 41 years, and 55% were female. The mean duration of headache was 43.6 months. All patients had continuous strictly unilateral pain with episodic exacerbations. At least one cranial autonomic feature was noted in 81% of patients. Twenty-five patients (81%) felt a sense of restlessness during exacerbations. The mean follow-up was 2.5 years. Three-fourths of patients noted a reduction in indomethacin dose after an average 2.5 of years follow-up. The mean reduction of the dose in the follow-up was statistically significant (172 mg vs. 110 mg, p < 0.001). All patients missed the drug for various reasons over the observation period. The headache reappeared within 48 h in 97% of patients.

Conclusion:

Misdiagnosis of HC is still very common. Patients may not volunteer about the background pain and will focus only on the exacerbations. HC rarely remits, but indomethacin requirements may decrease over time. Skipping of the effective drug leads to the immediate reappearance of pain.

Hemicrania Continua: a Clinical Perspective on Diagnosis and Management

PURPOSE OF REVIEW

Hemicrania Continua (HC) is a daily and persistent form of headache that is characterized by side-locked pain which is continuous, varies in severity and can be associated with conjunctival injection, lacrimation, nasal congestion, rhinorrhea, eyelid edema, forehead or facial sweating and miosis and/or ptosis.

RECENT FINDINGS

Functional imaging studies have shown activation of subcortical structures such as the posterior hypothalamus and dorsal rostral pons, which are known to disinhibit the trigeminal autonomic reflex, a reflex responsible for autonomic outflow through trigeminal efferents. A similar pathway activation is seen in other Trigeminal autonomic cephalalgias (TAC) which solidifies HC as a TAC. While we also discuss promising treatments in our review, more evidence is needed before making them a standard of therapy for HC. This article aims to review the recent research on the diagnosis and clinical management of this potentially underdiagnosed primary headache disorder.

Sex, Gender, and Orofacial Pain

This review examines gender prevalence in orofacial pain to elucidate underlying factors that can explain such differences. This review highlights how gender affects (1) the association of hormonal factors and pain modulation; (2) the genetic aspects influencing pain sensitivity and pain perception; (3) the role of resting blood pressure and pain threshold; and (4) the impact of sociocultural, environmental, and psychological factors on pain.

Headaches and facial pain in rhinology

"Sinus headache" is a common chief complaint that often leads patients to an otolaryngologist's office. Because facial pain may or may not be sinogenic in origin, the otolaryngologist should be equipped to evaluate and treat or to appropriately refer these patients. Analysis of current data indicates that the majority of patients who present with sinus headaches actually have migraines. Furthermore, the downstream effect of the cytokine cascade initiated in migraine physiology can cause rhinologic symptoms, including rhinorrhea, congestion, and lacrimation, which may also confound diagnosis. Other causes of sinus headache include the following: cluster headaches, Sluder neuralgia, trigeminal neuralgia, myofascial trigger point pain (tension headaches, temporomandibular joint dysfunction), and contact point headaches. The diagnostic dilemma for an otolaryngologist occurs when a patient has facial pain and symptoms that may indicate chronic rhinosinusitis but with nondiagnostic endoscopy. Traditionally, these patients have been primarily managed with empiric antibiotics. An alternative strategy is to first screen these patients with an upfront computed tomography. This algorithm may ultimately decrease cost; avert unnecessary antibiotics prescriptions; and prompt more timely referrals to other, more appropriate, disciplines, such as neurology, dentistry, and/or pain management specialists.

Functional Neuroimaging in Trigeminal Autonomic Cephalalgias

Functional neuroimaging was able to identify key structures for the pathophysiology of trigeminal autonomic cephalalgias (TACs) including cluster headache, paroxysmal hemicrania, and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing or cranial autonomic features and hemicrania continua. The posterior hypothalamus was the structure most consistently depicted with functional imaging in different states of disease with and without pain. Network-oriented imaging techniques such as resting-state functional resonance imaging were able to show a broader involvement of human trigeminal pain processing in the underlying pathophysiological mechanisms of the different TACs, highlighting similarities between this distinct group of primary headache disorders, while also demonstrating the differences in brain activation across these disorders. The most important clinical assignment for neuroimaging research from the treating physician remains the objective and reliable distinction of each individual TAC syndrome from one another, to make the correct clinical diagnosis as the foundation for proper treatment. More research will be necessary to fulfill this unmet need.

Hemicrania Continua Associated with Classic Scintillating Scotoma

Hemicrania continua (HC) is a rare primary headache disorder, characterized by persistent unilateral pain associated with cranial autonomic symptoms and prompt response to indomethacin. While migrainous features (including aura) have been recognized in cluster headache, there have been only single reports of HC with aura. Here, we report the case of a 53-year-old man with constant right-sided headache and superimposed exacerbations to severe pain lasting for several hours. Secondary etiologies were excluded, and a diagnosis of HC was established after prompt and complete response to treatment with indomethacin. During an episode of pain exacerbation, for the first time the patient experienced an episode of transient visual disturbances compatible with scintillating scotoma. We propose a potential link between HC and visual aura, which parallels similar observations in other trigeminal autonomic cephalalgias and more specifically confirms previous observational data on aura in HC, thus highlighting potentially shared pathophysiological mechanisms.

Hemicrania Continua

Hemicrania continua (HC) is an indomethacin responsive primary chronic headache disorder which is currently classified as a subtype of trigeminal autonomic cephalalgias (TACs). It is not very uncommon. There are >1000 cases of HC in the literature, and it constitutes 1.7% of total headache in the clinic settings. Misdiagnosis for HC is very common at all clinical settings. A diagnosis of HC is missed even by neurologists and headache specialists. It is characterized by a continuous strictly unilateral headache with superimposed exacerbations. Just like other TACs, exacerbations are associated with cranial autonomic symptoms and restlessness. A large number of patients may have migrainous features (nausea, vomiting, photophobia, and phonophobia) during exacerbations phase. The “key” feature of HC is persistent featureless background headaches. However, patients and physicians may focus only on the exacerbation part. As durations, frequency and associated symptoms of exacerbations are highly variables; it may mimic a large number of primary and secondary headache disorders. Migraine and cluster headache are two most common misdiagnosed conditions. Another specific feature of HC is remarkable repose to indomethacin. A “complete” response to indomethacin is as “sine qua non” for HC. However, a few other medications may also be effective in a subset of HC patients. Various surgical procedures have been tried with mixed results in patients who were intolerant to indomethacin or other drugs.

Hemicrania continua: clinical review, diagnosis and management

Hemicrania continua (HC) is an indomethacin-responsive primary headache disorder which is currently classified under the heading of trigeminal autonomic cephalalgias (TACs). It is a highly misdiagnosed and underreported primary headache. The pooled mean delay of diagnosis of HC is 8.0 ± 7.2 years. It is not rare. We noted more than 1000 cases in the literature. It represents 1.7% of total headache patients attending headache or neurology clinic. Just like other TACs, it is characterized by strictly unilateral pain in the trigeminal distribution, cranial autonomic features in the same area and agitation during exacerbations/attacks. It is different from other TACs in one aspect. While all other TACs are episodic, HC patients have continuous headaches with superimposed severe exacerbations. The central feature of HC is continuous background headache. However, the patients may be worried only for superimposed exacerbations. Focusing only on exacerbations and ignoring continuous background headache are the most important factors for the misdiagnosis of HC. A large number of patients may have migrainous features during exacerbation phase. Up to 70% patients may fulfill the diagnostic criteria for migraine during exacerbations. Besides migraine, its exacerbations can mimic a large number of other primary and secondary headaches. The other specific feature of HC is a remarkable response to indomethacin. However, a large number of patients develop side effects because of the long-term use of indomethacin. A few other medications may also be effective in a subset of patients with HC. Various surgical interventions have been suggested for patients who are intolerant to indomethacin. Several aspects of HC are still not defined. There is a great heterogeneity in types of patients or articles on the HC in the literature. Diagnostic criteria have been modified several times over the years. The current diagnostic criteria are too restrictive in some aspects. We suggest a more accommodating type of criteria for the appendix of International Classification of Headache Disorder (ICHD).

Case Studies of Uncommon and Rare Headache Disorders

The following 6 case studies are presented: a 12-day migraine with recurring aura?; a migraineur with a new constant headache for 1 month; an orthostatic headache; a unilateral headache; migraine with aura and limb pain without headache; and nocturnal headaches. These cases illustrate the fascinating diversity and challenges of primary and secondary headaches that neurologists commonly encounter.

Chronic Daily Headache in Childhood and Adolescence: Clinical Aspects and a 4-Year Follow-up

Chronic daily headache (CDH) represents a challenge in clinical practice and the scientific field. CDH with onset in children and adolescents represent a matchless opportunity to understand mechanisms involved in adult CDH. The aim of this study was to evaluate the diagnosis, prognosis and psychiatric co-morbidity of CDH with young onset in the young. Fifty-nine CDH patients has been followed from 1997 to 2001 in our department. Headache and psychiatric diagnoses were made on the basis of the international system of classification (International Headache Society, 1988; DSM-IV). X2 test and multinomial logistic regressions were applied to analyse factors predicting outcome. The current diagnostic system allows a diagnosis in 80% of CDH patients, even if age-related characteristics have been evidenced. Psychiatric disorders are notable in CDH (about 64% of patients) and predict (mainly anxiety) a poorer outcome. Surprisingly, analgesic overuse is not involved in the chronicization process. Diagnosis of CDH needs further study. Psychiatric disorders predict a worse outcome and greater account should be taken of them in treatment planning.

Facial pain in a Neurological Tertiary Care Centre — Evaluation of the International Classification of Headache Disorders

The aim of this study was to examine the diagnostic spectrum of facial pain and to evaluate the clinical features relevant to the differential diagnosis in a neurological tertiary care centre. This is the first investigation comparing the first with the second edition of the International Classification of Headache Disorders (ICHD-I, ICHD-II) in consecutively referred patients comprising a broad spectrum of disorders without restricting the inclusion to certain diagnoses. Studying 97 consecutive patients referred for facial pain, we found trigeminal neuralgia or other types of cranial neuralgia in 38% and 39% according to ICHD-I and ICHD-II, respectively; persistent idiopathic facial pain was diagnosed in 27% and 21%, respectively. The proportion of patients who could not be classified was 24% in ICHD-I and 29% in ICHD-II. Six per cent of the patients had cluster headache or chronic paroxysmal hemicrania, the remaining 5% had various other disorders. The agreement between ICHD-I and ICHD-II was very good to perfect. In ICHD-II, sensitivity and specificity were similar to ICHD-I, the specificity and negative predictive value were imrpoved in single features of trigeminal neuralgia, but were widely unchanged in persistent idiopathic facial pain. The number of patients who could not be classified was larger in ICHD-II than in ICHD-I. Modifying the diagnostic criteria for different types of facial pain, in particular changes in the criteria of persistent idiopathic facial pain, might be helpful in reducing the number of patients with unclassifiable facial pain.

Hemicrania Continua Postpartum

Hemicrania continua is a common, but unrecognized headache disorder. We describe two patients with hemicrania continua whose symptoms started in the postpartum period, coined as hemicrania continua postpartum.

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.

Indomethacin-responsive headaches

Indomethacin-responsive headaches are a heterogeneous group of primary headache disorders distinguished by their swift and often absolute response to indomethacin. The epidemiology of these conditions is incompletely defined. Traditionally, indomethacin-responsive headaches include a subset of trigeminal autonomic cephalalgias (paroxysmal hemicrania and hemicrania continua), Valsalva-induced headaches (cough headache, exercise headache, and sex headache), primary stabbing headache, and hypnic headache. These headache syndromes differ in extent of response to indomethacin, clinical features, and differential diagnoses. Neuroimaging is recommended to investigate for various organic causes that may mimic these headaches. Case reports of other primary headache disorders that also respond to indomethacin, such as cluster headache, nummular headache, and ophthalmoplegic migraine, have been described. These "novel" indomethacin-responsive headaches beg the question of what headache characteristics are required to qualify a headache as an indomethacin-responsive headache. Furthermore, they challenge the concept of using a therapeutic intervention as a diagnostic criterion.

OnabotulinumtoxinA for hemicrania continua: open label experience in 9 patients

Background

Hemicrania continua is a strictly unilateral, continuous headache, typically mild to moderate in severity, with severe exacerbations commonly accompanied by cranial autonomic features and migrainous symptoms. It is exquisitely responsive to Indomethacin. However, some patients cannot tolerate treatment, often due to gastrointestinal side effects. Therapeutic alternatives are limited and controlled evidence lacking.

Methods

We present our experience of nine patients treated with OnabotulinumtoxinA for hemicrania continua. All patients were injected using the PREEMPT (Phase 3 REsearch Evaluating Migraine Prophylaxis Therapy) protocol for migraine.

Results

Five of nine patients demonstrated a 50% or more reduction in moderate to severe headache days with OnabotulinumtoxinA with a median reduction in moderate to severe headache days of 80%. Patient estimate of response was 80% or more in five subjects. The median and mean duration of response in the five responders was 11 and 12 weeks (range 6–20 weeks). Improvements were also seen in headache-associated disability

Conclusions

OnabotulinumtoxinA adds a potential option to the limited therapeutic alternatives available in hemicrania continua.

Migraine mimics

The symptoms of migraine are non-specific and can be present in many other primary and secondary headache disorders, which are reviewed. Even experienced headache specialists may be challenged at times when diagnosing what appears to be first or worst, new type, migraine status, and chronic migraine.

[Successful treatment of hemicrania continua with a combination of low-dose indomethacin and pregabalin: a case report]

A 51-year-old man complained of continuous pain lasting about 3 weeks around his forehead and left orbit-locations where pain may indicate conjunctival injection and lacrimation. Upon arrival to our hospital, his neurological examination was normal, and brain MRI showed no abnormality. The headache disappeared with indomethacin treatment (75 mg/day), and a diagnosis of hemicrania continua (HC) was established according to the International Classification of Headache Disorders, 2nd Edition. The headache returned after reducing the dose of indomethacin. After adding pregabalin (150 mg/day) to his treatment regimen, we could reduce the dose of indomethacin from 75 mg/day to 25 mg/day, which the patient tolerated well. Although HC is one of the indomethacin-responsive headaches, continuous administration can cause side effects including gastrointestinal disorders. Such side effects can decrease the tolerability of indomethacin, and may eventually lead to its reduction or discontinuation. Pregabalin can be an alternative to indomethacin for treating HC.

Hemicrania continua: towards a new classification?

Hemicrania continua (HC) was described and coined in 1984 by Sjaastad and Spierings. Later cases, carrying this appellation, should conform to the original description. The proposed classification criteria (ICHD 3rd edition beta version) for HC focus e.g. on localized, autonomic and “vascular” features. Such features do, however, not belong to the core symptomatology of HC and should accordingly be removed. The genuine, original HC will then re-appear.The headache that the new criteria refer to, has in an unfair and unjustified manner been given the designation HC. A revision of the proposed criteria seems mandatory.

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.

Diagnostic and therapeutic errors in trigeminal autonomic cephalalgias and hemicrania continua: a systematic review

Trigeminal autonomic cephalalgias (TACs) and hemicrania continua (HC) are relatively rare but clinically rather well-defined primary headaches. Despite the existence of clear-cut diagnostic criteria (The International Classification of Headache Disorders, 2^nd edition - ICHD-II) and several therapeutic guidelines, errors in workup and treatment of these conditions are frequent in clinical practice. We set out to review all available published data on mismanagement of TACs and HC patients in order to understand and avoid its causes. The search strategy identified 22 published studies. The most frequent errors described in the management of patients with TACs and HC are: referral to wrong type of specialist, diagnostic delay, misdiagnosis, and the use of treatments without overt indication. Migraine with and without aura, trigeminal neuralgia, sinus infection, dental pain and temporomandibular dysfunction are the disorders most frequently overdiagnosed. Even when the clinical picture is clear-cut, TACs and HC are frequently not recognized and/or mistaken for other disorders, not only by general physicians, dentists and ENT surgeons, but also by neurologists and headache specialists. This seems to be due to limited knowledge of the specific characteristics and variants of these disorders, and it results in the unnecessary prescription of ineffective and sometimes invasive treatments which may have negative consequences for patients. Greater knowledge of and education about these disorders, among both primary care physicians and headache specialists, might contribute to improving the quality of life of TACs and HC patients.

Hemicrania continua in a patient with concomitant dental disease

BACKGROUND

There are nonodontogenic headache disorders that mimic dental pain. One such headache disorder is hemicrania continua (HC). HC is a primary headache syndrome characterized by a continuous, unilateral headache that is completely responsive to indomethacin. Patients may have signs and symptoms that the dentist should differentiate from odontogenic pain and temporomandibular disorders. These symptoms can make the diagnostic process a challenge for dentists if patients' pain has multiple causes. Dentists, thus, must have thorough knowledge of odontogenic and nonodontogenic causes of pain so they can make accurate diagnoses and prepare treatment plans.

CASE DESCRIPTION

The authors describe the case of a 41-year-old woman with a six-year history of continuous headaches and a one-year history of temporomandibular dysfunction and odontogenic pain. She sought treatment from a number of dentists and received a diagnosis of right-side facial pain and headache on the basis of the results of clinical and radiologic examinations, which was followed by dental treatment. She did not experience any pain relief. Additional results of our examination led to a diagnosis of HC.

CLINICAL IMPLICATIONS

Dentists must consider headache disorders in patients who have continuous headaches after undergoing dental treatment for odontogenic pain.

Chronic daily headaches

Chronic Daily Headache is a descriptive term that includes disorders with headaches on more days than not and affects 4% of the general population. The condition has a debilitating effect on individuals and society through direct cost to healthcare and indirectly to the economy in general. To successfully manage chronic daily headache syndromes it is important to exclude secondary causes with comprehensive history and relevant investigations; identify risk factors that predict its development and recognise its sub-types to appropriately manage the condition. Chronic migraine, chronic tension-type headache, new daily persistent headache and medication overuse headache accounts for the vast majority of chronic daily headaches. The scope of this article is to review the primary headache disorders. Secondary headaches are not discussed except medication overuse headache that often accompanies primary headache disorders. The article critically reviews the literature on the current understanding of daily headache disorders focusing in particular on recent developments in the treatment of frequent headaches.

Trigeminal autonomic cephalgias

1. Trigeminal autonomic cephalgias (TACs) are headaches/facial pains classified together based on:a suspected common pathophysiology involving the trigeminovascular system, the trigeminoparasympathetic reflex and centres controlling circadian rhythms;a similar clinical presentation of trigeminal pain, and autonomic activation. 2. There is much overlap in the diagnostic features of individual TACs. 3. In contrast, treatment response is relatively specific and aids in establishing a definitive diagnosis. 4. TACs are often presentations of underlying pathology; all patients should be imaged. 5. The aim of the article is to provide the reader with a broad introduction to, and an overview of, TACs. The reading list is extensive for the interested reader.

Hemicrania continua in a headache clinic: referral source and diagnostic delay in a series of 22 patients

Hemicrania continua (HC) is a unilateral and continuous primary headache with superimposed exacerbations frequently associated with autonomic features. Diagnostic criteria of HC, according to II Edition of International Classification of Headache Disorders require complete response to indomethacin. HC is probably misdiagnosed more often than other primary headaches. We aim to analyze characteristics of a series of 22 consecutive cases of HC. We recruited patients from a headache outpatient clinic in a tertiary hospital over a 3-year period (January 2008 to January 2011). We prospectively gathered demographic and nosological characteristics and considered referral source and delay between onset of headache and diagnosis of HC. Twenty-two patients (14 females, 8 males) out of 1,150, who attended the mentioned clinic during the inclusion period (1.9 %) were diagnosed with HC. All cases responded to indomethacin. No patient received a diagnosis of HC before attending our headache office. Mean latency of diagnosis was 86.1 ± 106.5 months (range 3–360). 11 patients (50 %) were referred from primary care, with 9 (40.9 %) from other neurology clinics and 2 (9.1 %) from other specialities offices. According to our series, HC is not an infrequent diagnosis in a headache outpatient clinic. Diagnostic delay is comparable to data collected in previous studies. As HC is frequently misdiagnosed, we thing there is a need for increasing the understanding of this entity, potentially responsive to indomethacin.