Treatment pattern and response for cluster headache in Korea: A prospective multicenter observation study.

BACKGROUND: Only limited data are available regarding the treatment status and response to cluster headache in an Asian population. Therefore, this study aimed to provide a real-world treatment pattern of cluster headache and the response rate of each treatment in an Asian population. METHODS: Patients with cluster headache were recruited between September 2016 and January 2019 from 16 hospitals in Korea. At the baseline visit, we surveyed the patients about their previous experience of cluster headache treatment, and acute and/or preventive treatments were prescribed at the physician's discretion. Treatment response was prospectively evaluated using a structured case-report form at 2 ± 2 weeks after baseline visit and reassessed after three months. RESULTS: Among 295 recruited patients, 262 experiencing active bouts were included. Only one-third of patients reported a previous experience of evidence-based treatment. At the baseline visit, oral triptans (73.4%), verapamil (68.3%), and systemic steroids (55.6%) were the three most common treatments prescribed by the investigators. Most treatments were given as combination. For acute treatment, oral triptans and oxygen were effective in 90.1% and 86.8% of the patients, respectively; for preventive treatment, evidence-based treatments, i.e. monotherapy or different combinations of verapamil, lithium, systemic steroids, and suboccipital steroid injection, helped 75.0% to 91.8% of patients. CONCLUSION: Our data provide the first prospective analysis of treatment responses in an Asian population with cluster headache. The patients responded well to treatment despite the limited availability of treatment options, and this might be attributed at least in part by combination of medications. Most patients were previously undertreated, suggesting a need to raise awareness of cluster headache among primary physicians.

Characteristics of pre-cluster symptoms in cluster headache: A cross-sectional multicentre study.

BACKGROUND: Contrary to pre-attack symptoms before an individual cluster headache attack, little is known about the pre-cluster symptoms before the onset of cluster bouts. We previously described pre-attack symptoms before cluster headache attacks. The aim of this study was to investigate characteristics of pre-cluster symptoms in patients with episodic cluster headache. METHODS: In this multicentre study, 184 patients with episodic cluster headache were recruited between October 2018 and December 2020. They were interviewed by investigators and completed a structured questionnaire. To investigate pre-cluster and pre-attack symptoms, we assessed 20 symptoms and signs using the questionnaire. RESULTS: The upcoming cluster bout was predictable in 35.3% (n = 65/184) of the patients. When present, pre-cluster symptoms occurred at a median duration of 7 days (interquartile range, 2.3-14 days) before the onset of the cluster bout. Patients with pre-cluster symptoms showed a higher proportion of women, prevalence of pre-attack symptoms and seasonal rhythmicity, frequency of cluster headache attacks per day, and total number of cluster bouts compared to patients without pre-cluster symptoms. In univariable and multivariable logistic regression analyses, female sex was associated with the predictability of pre-cluster symptoms (odds ratio = 2.297, p = 0.016). CONCLUSIONS: The upcoming cluster bout was predicted in approximately 35% of patients with episodic cluster headache, which may allow for an earlier preventive treatment and help understand the pathophysiology.

Clinical characteristics of pre-attack symptoms in cluster headache: A large series of Korean patients.

BACKGROUND: Previous studies have reported notable differences in demographic and clinical features of cluster headache between Western and Asian populations, including lower prevalence of the chronic type and in women. Recently, prodromal symptoms of migraine and pre-attack symptoms of cluster headache have drawn attention regarding their potential pathophysiological implications and pre-emptive treatment. However, pre-attack symptoms of cluster headache have not been studied in the Asian population. METHODS: A total of 136 patients with cluster headache (21 first-onset, 110 episodic, and five chronic cases) were recruited in this multi-center study between October 2018 and December 2019. We evaluated the characteristics of pre-attack symptoms in a current bout using a structured questionnaire. Univariable and multivariable logistic regression analyses were performed to evaluate the factors associated with presence of pre-attack symptoms. RESULTS: Pre-attack symptoms were reported in 71.3% of our patients with cluster headache. When present, pre-attack symptoms occurred at a median of 20 minutes (range 1-120) before the attack. The prevalence of local and painful, local and painless sensory, autonomic, and general symptoms was 58.8%, 14.7%, 11.0%, and 30.1%, respectively. Multivariable logistic regression analysis revealed that higher number of bouts was associated with higher prevalence of pre-attack symptoms (OR = 1.464, p = 0.044). CONCLUSIONS: Pre-attack symptoms were frequently observed in Korean patients with cluster headache, which was consistent with previous Western studies.

Temporal changes of circadian rhythmicity in cluster headache.

OBJECTIVE: To investigate the temporal changes of circadian rhythmicity in relation to the disease course in patients with cluster headache. METHODS: In this multicenter study, patients with cluster headache were recruited between September 2016 and July 2018. We evaluated the patients for circadian rhythmicity and time of cluster headache attacks in the current bout and any experience of bout-to-bout change in circadian rhythmicity. We analyzed the patterns of circadian rhythmicity in relation to the disease progression (the number of total lifetime bouts, grouped into deciles). RESULTS: Of the 175 patients in their active, within-bout period, 86 (49.1%) had circadian rhythmicity in the current bout. The prevalence of circadian rhythmicity in the active period was overall similar regardless of disease progression. Sixty-three (46.3%) out of 136 patients with ≥2 bouts reported bout-to-bout changes in circadian rhythmicity. The most frequent time of cluster headache attacks was distributed evenly throughout the day earlier in the disease course and dichotomized into hypnic and midday as the number of lifetime bouts increased (p = 0.037 for the homogeneity of variance). When grouped into nighttime and daytime, nighttime attacks were predominant early in the disease course, while daytime attacks increased with disease progression (up to 7th deciles of total lifetime bouts, p = 0.001) and decreased in patients with the most advanced disease course (p = 0.013 for the non-linear association). CONCLUSIONS: Circadian rhythmicity is not a fixed factor, and changes according to the disease course. Our findings will be valuable in providing a new insight into the stability of functional involvement of the suprachiasmatic nucleus in the pathophysiology of cluster headache.

The impact of remission and coexisting migraine on anxiety and depression in cluster headache.

BACKGROUND: Our aim was to investigate the relationship between coexisting cluster headache (CH) and migraine with anxiety and depression during active cluster bouts, and how symptoms change during remission. METHODS: We analyzed data from 222 consecutive CH patients and 99 age- and sex-matched controls using a prospective multicenter registry. Anxiety or depression was evaluated using the Generalized Anxiety Disorder-7 (GAD-7) or Patient Health Questionnaire-9 (PHQ-9), respectively. Moderate-to-severe anxiety or depression was defined as a score of ≥10 at baseline (during a cluster bout). We assessed for changes in anxiety and depression during CH remission periods. RESULTS: Among the CH patients, the prevalence of moderate-to-severe anxiety and depression was seen in 38.2% and 34.6%, respectively. Compared with controls, CH patients were associated with moderate-to-severe anxiety and depression (multivariable-adjusted odds ratio [aOR] = 7.32, 95% confidence intervals [CI] = 3.35-15.99 and aOR = 4.95, 95% CI = 2.32-10.57, respectively). CH patients with migraine were significantly more likely to have moderate-to-severe anxiety and depression (aOR = 32.53, 95% CI = 6.63-159.64 and aOR = 16.88, 95% CI = 4.16-68.38, respectively), compared to controls without migraine. The GAD-7 and PHQ-9 scores were significantly reduced between cluster bout and remission periods (from 6.8 ± 5.6 to 1.6 ± 2.8; P < 0.001, and from 6.1 ± 5.0 to 1.8 ± 2.4; P < 0.001, respectively). CONCLUSIONS: Our results indicate that CH patients are at increased risk of anxiety and depression, especially in the presence of coexisting migraine. However, the anxiety and depression can improve during remission periods.

Field testing the diagnostic criteria of cluster headache in the third edition of the International Classification of Headache Disorders: A cross-sectional multicentre study.

BACKGROUND: *These authors are shared first authors. The recently published third edition of the International Classification of Headache Disorders (ICHD-3) revised the criteria for accompanying symptoms of cluster headache (CH) and the remission period of chronic cluster headache (CCH). This study aimed at testing the validity of the ICHD-3 criteria for CH by using data from the Korean Cluster Headache Registry. METHODS: Consecutive patients with CH and probable cluster headache (PCH) were prospectively recruited from 15 hospitals. We analysed the validity of the revised ICHD-3 criteria for CH against the beta version of the third edition of the ICHD (ICHD-3ß). RESULTS: In total, 193 patients were enrolled: 140 (72.5%), 5 (2.6%) and 22 (11.4%) had episodic cluster headache (ECH), CCH, and PCH, respectively. The remaining 26 (13.5%) had CH with undetermined remission periods. One patient with ECH and one with PCH had only forehead and facial flushing and were diagnosed with PCH and non-cluster headache, respectively, according to the ICHD-3. Four participants with ECH according to the ICHD-3ß had remission periods of > 1 month and between 1 and 3 months and were newly diagnosed with CCH according to the ICHD-3. CONCLUSION: The change from ICHD-3ß to ICHD-3 resulted in few differences in the diagnoses of CH and PCH.

Differences of Cluster Headache on the Basis of Sex in the Korean Cluster Headache Registry.

BACKGROUND: Most of the clinical characteristics of cluster headache (CH) have been established through the observation of men with CH. Epidemiological data of CH in women are scarce especially in the Asian population. Here, we sought to assess the prevalence and clinical characteristics of women with CH in comparison to men in a prospective CH registry. METHODS: Data used in this study were obtained from the Korean Cluster Headache Registry, a prospective, cross-sectional, multicenter headache registry that collected data from consecutive patients diagnosed with CH. Demographics and clinical characteristics were compared between the sexes. RESULTS: In total, 250 patients were enrolled in this study; 41 (16.4%) were women (male to female ratio 5.1:1). Mean age of onset did not differ between women and men (30.7 ± 15.5 vs 29.0 ± 11.1 years). The clinical features of CH in women and men were similar, with no differences in pain severity, duration, and attack frequency. Among autonomic features, facial and forehead sweating was significantly rare in women (4.9%) compared to men with CH (33.0%). Headache-related disability assessed by Headache Impact Test-6 did not differ between the sexes; however, depression scale assessed by Patients Health Questionnaire-9 (11.0 ± 8.5 vs 7.0 ± 5.8, P = .009) and stress (Perceived Stress Scale 4, 7.5 ± 3.4 vs 6.4 ± 3.0, P = .045) were significantly higher in women with CH. CONCLUSIONS: Although decreasing male preponderance was suggested in recent Western CH studies, CH in women is still far less prevalent than in men in the Korean population. Clinical and demographic characteristics were similar between the sexes. However, psychiatric comorbidities might be highly associated in women with CH.

Stress Is Associated with Poor Outcome of Acute Treatment for Chronic Migraine: A Multicenter Study.

Background: Chronic migraine (CM) is associated with severe psychological symptoms and disabilities. Information on the relationship between stress and the outcomes of acute CM treatment is limited. Methods: We evaluated the clinical presentation and stress levels of patients with CM who visited the neurology departments of 14 hospitals between September and December 2015. The patients were divided into stress and reference groups on the basis of the Korean version of the Brief Encounter Psychosocial Instrument (BEPSI-K). Quality of life was evaluated using EuroQol Five Dimension Questionnaire Three-Level. The Migraine Assessment of Current Therapy questionnaire was used to assess the outcomes of acute treatment. Results: This study included 186 CM patients. On the basis of the BEPSI-K score, 79 and 107 patients were assigned to the stress and reference groups, respectively. The stress group had more patients with poor outcomes of acute treatment than the reference group (67.1% vs 40.2%, P < 0.001). In a multivariate analysis, female gender (odds ratio [OR] = 3.266, 95% confidence interval [CI] = 1.172-9.103, P = 0.024), the number of headache-free days per month (OR = 0.932, 95% CI = 0.883-0.985, P = 0.012), and BEPSI-K score (OR = 1.667, 95% CI = 1.051-2.643, P = 0.030) predicted poor outcomes of acute treatment. Conclusions: High levels of stress were reported by 42.5% of patients with CM. The association between stress and the outcomes of acute treatment suggests that stress is an important clinical variable for improving the management of CM.

Impact of cluster headache on employment status and job burden: a prospective cross-sectional multicenter study.

BACKGROUND: Cluster headaches (CH) are recurrent severe headaches, which impose a major burden on the life of patients. We investigated the impact of CH on employment status and job burden. METHODS: The study was a sub-study of the Korean Cluster Headache Registry. Patients with CH were enrolled from September 2016 to February 2018 from 15 headache clinics in Korea. We also enrolled a headache control group with age-sex matched patients with migraine or tension-type headache. Moreover, a control group including individuals without headache complaints was recruited. All participants responded to a questionnaire that included questions on employment status, type of occupation, working time, sick leave, reductions in productivity, and satisfaction with current occupation. The questionnaire was administered to participants who were currently employed or had previous occupational experience. RESULTS: We recruited 143 patients with CH, 38 patients with other types of headache (migraine or tension-type headache), and 52 headache-free controls. The proportion of employees was lower in the CH group compared with the headache and headache-free control groups (CH: 67.6% vs. headache controls: 84.2% vs. headache-free controls: 96.2%; p = 0.001). The CH group more frequently experienced difficulties at work and required sick leave than the other groups (CH: 84.8% vs. headache controls: 63.9% vs. headache-free controls: 36.5%; p <  0.001; CH: 39.4% vs. headache controls: 13.9% vs. headache-free controls: 3.4%; p <  0.001). Among the patients with CH, sick leave was associated with younger age at CH onset (25.8 years vs. 30.6 years, p = 0.014), severity of pain rated on a visual analogue scale (9.3 vs. 8.8, p = 0.008), and diurnal periodicity during the daytime (p = 0.003). There were no significant differences with respect to the sick leave based on sex, age, CH subtypes, and CH recurrence. CONCLUSIONS: CH might be associated with employment status. Most patients with CH experienced substantial burdens at work.

Relationship between clinical and radiologic findings of spinal cord injury in decompression sickness.

BACKGROUND: Decompression sickness may involve the central nervous system. The most common site is spinal cord. This study was conducted to determine the relationship between magnetic resonance(MR) imaging findings of spinal damage. METHODS: We conducted a retrospective review of 12 patients (male=10, female=2) who presented with spinal cord symptoms. We investigated their clinical features, neurological findings and radiologic findings. RESULTS: The depth and bottom time of the dive were 34.5 meters (range 22-56) and 22.7 minutes (range 10-55) respectively. Most divers ascended within appropriate time frame as shown by the decompression tables. The most frequent initial symptoms were lower limb weakness (n=12), followed by sensory disturbances (n=10) and bladder dysfuction (n=5). The chief radiologic abnormalities were continuous (n=3), or non-continuous (n=5) high-signal intensity on T2-weighted images at posterior paramedian portion of the spinal cord, mainly thoracic level. There were no abnormal findings in the remaining four (4) patients, and they showed good prognosis. All patients were treated with hyperbaric oxygen therapy and some received high-dose dexamethasone. On discharge, five (5) patients had made a full recovery, seven (7) had some residual neurological sequelae, and all patients except one (1) regained normal bladder function. CONCLUSIONS: Spinal cord decompression sickness is a neurological emergency. Early recognition and treatment may minimize neurological damage. Initial normal finding in MR imaging was a good predictor for prognosis in spinal decompression sickness.

An Analysis of the Determinants of the Health-Related Quality of Life in Asian Patients With Cluster Headaches During Cluster Periods Using the Time Trade-Off Method.

BACKGROUND AND PURPOSE: Patients with cluster headache (CH) exhibit impaired health-related quality of life (HRQoL). However, there have been few studies related to the HRQoL of patients with CH from Asian backgrounds. This study aimed to determine the impact of CH on HRQoL and to identify the factors affecting HRQoL in patients with CH during cluster periods. METHODS: This prospective study enrolled patients with CH from 17 headache clinics in South Korea between September 2016 and February 2021. The study aimed to determine HRQoL in patients with CH using the EuroQol 5 Dimensions (EQ-5D) index and the time trade-off (TTO) method. Age- and sex-matched headache-free participants were recruited as a control group. RESULTS: The study included 423 patients with CH who experienced a cluster period at the time. EQ-5D scores were lower in patients with CH (0.88±0.43, mean±standard deviation) than in the controls (0.99±0.33, p<0.001). The TTO method indicated that 58 (13.6%) patients with CH exhibited moderate-to-severe HRQoL deterioration. The HRQoL states in patients with CH were associated with current smoking patterns, headache severity, frequency, and duration, and scores on the Generalized Anxiety Disorder 7-item scale (GAD-7), Patient Health Questionnaire 9-item scale (PHQ-9), 6-item Headache Impact Test, and 12-item Allodynia Symptom Checklist. Multivariable logistic regression analyses demonstrated that the HRQoL states in patients with CH were negatively correlated with the daily frequency of headaches, cluster period duration, and GAD-7 and PHQ-9 scores. CONCLUSIONS: Patients with CH experienced a worse quality of life during cluster periods compared with the headache-free controls, but the degree of HRQoL deterioration varied among them. The daily frequency of headaches, cluster period duration, anxiety, and depression were factors associated with HRQoL deterioration severity in patients with CH.

Diagnostic Delay and Its Predictors in Cluster Headache.

OBJECTIVE: Cluster headache (CH) is a rare, primary headache disorder, characterized of excruciating, strictly one-sided pain attacks and ipsilateral cranial autonomic symptoms. Given the debilitating nature of CH, delayed diagnosis can increase the disease burden. Thus, we aimed to investigate the diagnostic delay, its predictors, and clinical influence among patients with CH. METHODS: Data from a prospective multicenter CH registry over a 4-year period were analyzed. CH was diagnosed according to the International Classification of Headache Disorders (ICHD)-3 criteria, and diagnostic delay of CH was assessed as the time interval between the year of the first onset and the year of CH diagnosis. Patients were classified into three groups according to the tertiles of diagnostic delay (1st tertile, <1 year; 2nd tertile, 1-6 years; and 3rd tertile, ≥7 years). RESULTS: Overall, 445 patients were evaluated. The mean duration of diagnosis delay was 5.7 ± 6.7 years, (range, 0-36 years). Regarding the age of onset, majority of young patients (age <20 years) belonged to the third tertile (60%), whereas minority of old patients (>40 years) belonged to the third tertile (9.0%). For year of onset, the proportion of patients in the 3rd tertile was the highest for the groups before the publication year of the ICHD-2 (74.7%) and the lowest for the groups after the publication year of the ICHD-3 beta version (0.5%). Compared with the first CH, episodic CH [multivariable-adjusted odds ratio (aOR) = 5.91, 95% CI = 2.42-14.48], chronic CH (aOR = 8.87, 95% CI = 2.66-29.51), and probable CH (aOR = 4.12, 95% CI = 1.48-11.43) were associated with the tertiles of diagnostic delay. Age of onset (aOR = 0.97, 95% CI = 0.95-0.99) and PHQ-9 score (aOR = 0.96, 95% CI = 0.93-0.99) were inversely associated with the tertile of diagnostic delay. The prevalence of suicidal ideation was highest in the patients of the third tertile. The mean HIT-6 score increased significantly with the diagnostic delay (p = 0.041). CONCLUSIONS: Patients with a younger onset of CH have a higher risk of diagnostic delay. Nevertheless, the rate of delayed diagnosis gradually improved over time and with the publication of the ICHD criteria, supporting the clinical significance of diagnostic clinical criteria and headache education to reduce the disease burden of CH.

Metronidazole neurotoxicity: sequential neuroaxis involvement.

Neurological manifestation of metronidazole toxicity include neuropathy and encephalopathy. We report a 67-year-old man with progressive painful paresthesias involving all the four limbs of 3 weeks' duration before admission. He had been treated with metronidazole and cephalosporin for 10 weeks for a hepatic abscess. Five weeks after the symptom onset, he complained of dysarthria and limb ataxia. Magnetic resonance imaging revealed signal abnormalities in the splenium of the corpus callosum and bilateral dentate nuclei. A few hours after brain imaging, the patient exhibited excessive diaphoresis and fluctuation in blood pressure, which resolved within several hours after discontinuation of metronidazole. Whereas his speech returned to near normal within approximately 1 week, a burning sensation was not completely relieved, even 6 months after discharge.

Clinical features of cluster headache without cranial autonomic symptoms: results from a prospective multicentre study.

Although cranial autonomic symptoms (CAS) are typical in cluster headache (CH), some individuals with CH show no CAS during their headache attacks. Probable cluster headache (PCH) is a subtype of CH that fulfils all but one criterion of CH. This study aimed to investigate the frequency and clinical features of CH and PCH without CAS in comparison to those with CAS. We analysed data from the Korea Cluster Headache Registry, a prospective multicentre registry involving data from 16 hospitals. Of the 216 participants with CH and 26 with PCH, 19 (8.8%) and 7 (26.9%), respectively, did not have CAS. Participants with CH without CAS exhibited less severe anxiety (General Anxiety Disorder-7 score, median [interquartile range], 2.0 [1.0-6.0] vs 8.0 [3.0-12.0], p = 0.001) and depression (Patient Health Questionnaire-9 score, 3.0 [1.0-7.0] vs 7.0 [3.0-11.0], p = 0.042) than those with CAS. Among participants with PCH, headache intensity was less severe in participants without CAS than in those with CAS (numeric rating scale, 8.0 [7.0-8.0] vs 9.5 [8.0-10.0], p = 0.015). In conclusion, a significant proportion of participants with CH and PCH did not have CAS. Some clinical features of CH and PCH differed based on the presence of CAS.

Smoking History and Clinical Features of Cluster Headache: Results from the Korean Cluster Headache Registry.

BACKGROUND AND PURPOSE: Epidemiologic data suggest that cluster headache (CH) is significantly associated with cigarette smoking. The aim of this study was to determine differences in features between patients with a smoking history and those who are never-smokers, using data from a prospective multicenter registry. METHODS: Data used in this study were obtained from the Korean Cluster Headache Registry that collected data from consecutive patients diagnosed with CH. We compared clinical and demographic features between ever-smokers (current or former smokers) and never-smokers. RESULTS: This study enrolled 250 patients who were diagnosed with CH, of which 152 (60.8%) were ever-smokers and 98 (39.2%) were never-smokers. The age at CH onset was significantly lower in the never-smoker group than in the ever-smoker group [27.1±12.9 years vs. 30.6±10.9 years (mean±standard deviation), p=0.024]. Seasonal rhythmicity (58.1% vs. 44.7%, p=0.038) and triptan responsiveness (100% vs. 85.1%, p=0.001) were higher in never-smokers, while other clinical features such as pain severity, duration, attack frequency, and associated autonomic symptoms did not differ significantly between the groups. The male-to-female ratio was markedly higher in ever-smokers (29.4:1) than in never-smokers (1.7:1). CONCLUSIONS: Most of the clinical features did not differ significantly between patients with a smoking history and never-smokers. However, the age at CH onset, sex ratio, and seasonal rhythmicity were significantly associated with smoking history.

Clinical factors influencing the impact of cluster headache from a prospective multicenter study.

Although many patients with cluster headaches (CH) are disabled by their condition, few studies have examined this in detail. This cross-sectional, multicenter observational study prospectively collected demographic and clinical questionnaire data from 224 consecutive patients with CH. We assessed headache impact using the six-item Headache Impact Test (HIT-6) and evaluated the factors associated with the impact of CH. Participants with a HIT-6 score ≥ 60 were classified into a severe impact group. The majority (190, 84.8%) of the participants were classified into the severe impact group. These patients were characterized by younger age, earlier onset of CH, longer duration of each headache attack, higher pain intensity, more cranial autonomic symptoms, a higher proportion of depression or anxiety, higher score of stress, and lower score of quality of life. The anxiety (OR = 1.19, 95% CI: 1.08-1.31, p = 0.006), greater pain intensity (OR = 1.06, 95% CI: 1.02-1.10, p = 0.002), and age (OR = 0.99, 95% CI: 0.99-1.00, p = 0.008) were significant predictors for a severe impact of CH patients. According to the HIT-6 results, most of the CH patients were significantly affected by CH. As well as pain intensity, anxiety and age modulated CH's impact on their lives.

Differences in Characteristics and Comorbidity of Cluster Headache According to the Presence of Migraine.

BACKGROUND AND PURPOSE: Cluster headache (CH) can present with migrainous symptoms such as nausea, photophobia, and phonophobia. In addition, an overlap between CH and migraine has been reported. This study aimed to determine the differences in the characteristics of CH according to the presence of comorbid migraine. METHODS: This study was performed using data from a prospective multicenter registry study of CH involving 16 headache clinics. CH and migraine were diagnosed by headache specialists at each hospital based on third edition of the International Classification of Headache Disorders (ICHD-3). We interviewed patients with comorbid migraine to obtain detailed information about migraine. The characteristics and psychological comorbidities of CH were compared between patients with and without comorbid migraine. RESULTS: Thirty (15.6%) of 192 patients with CH had comorbid migraine, comprising 18 with migraine without aura, 1 with migraine with aura, 3 with chronic migraine, and 8 with probable migraine. Compared to patients with CH without migraine, patients with CH with comorbid migraine had a shorter duration of CH after the first episode [5.4±7.4 vs. 9.0±8.2 years (mean±standard deviation), p=0.008], a lower frequency of episodic CH (50.0% vs. 73.5%, p=0.010), and a higher frequency of chronic CH (13.3% vs. 3.7%, p=0.033). Psychiatric comorbidities did not differ between patients with and without comorbid migraine. The headaches experienced by patients could be distinguished based on their trigeminal autonomic symptoms, pulsating character, severity, and pain location. CONCLUSIONS: Distinct characteristics of CH remained unchanged in patients with comorbid migraine with the exception of an increased frequency of chronic CH. The most appropriate management of CH requires clinicians to check the history of preceding migraine, particularly in cases of chronic CH.

Associated Factors and Clinical Implication of Cutaneous Allodynia in Patients with Cluster Headache: A Prospective Multicentre Study.

Cutaneous allodynia (CA) is an abnormal pain in response to non-painful stimuli. In the present study, we sought to investigate the presence of CA, its associated factors, and its clinical implications in patients with cluster headache (CH). In this cross-sectional study, we analysed data from a prospective multicentre registry enrolling consecutive patients with CH. We identified CA during and between headache attacks using the 12-item Allodynia Symptom Checklist (ASC) administered during the CH bout period. Comorbid depression and anxiety were ascertained using the Patient Health Questionnaire (PHQ-9) and the Generalized Anxiety Disorder (GAD-7) scales. Headache impact was evaluated using the Headache Impact Test-6 (HIT-6). Of 119 eligible patients, 48 and two (40.3% and 1.7%) had CA during and between headache attacks, respectively. In univariable analyses, total CH duration, major depressive disorder (MDD), and generalized anxiety disorder (GAD) were associated with CA during headache attack. They remained significantly associated with CA during headache attack in multivariable analyses. Patients with CA during headache attack had higher headache impact (P = 0.002). A "50% responder" analysis showed no difference in outcome of acute and preventive treatment between patients with and without CA during headache attack. Patients with CH commonly experienced CA during headache attack, but not between headache attacks. CA during headache attack was associated with disease duration, depression, and anxiety.

Clinical features of chronic cluster headache based on the third edition of the International Classification of Headache Disorders: A prospective multicentre study.

The criterion for the remission period of chronic cluster headache (CCH) was recently revised from < 1 month to < 3 months in the third edition of the International Classification of Headache Disorders (ICHD-3). However, information on the clinical features of CCH based on the ICHD-3 criteria is currently limited. The present study aimed to investigate the clinical features of CCH based on ICHD-3 using data from the Korean Cluster Headache Registry (KCHR). The KCHR is a multicentre prospective registry of patients with cluster headache (CH) from 15 hospitals. Among the 250 participants with CH, 12 and 176 participants were classified as having CCH and episodic cluster headache (ECH), respectively. Among 12 participants with CCH, 6 (50%) had remission periods of < 1 month, and the remaining 6 (50%) had a remission period of 1-3 months. Six participants had CCH from the time of onset of CH, and in the other 6 participants, CCH evolved from ECH. CCH subjects had later age of onset of CH, developed the condition after a longer interval after CH onset, and had more migraine and less nasal congestion and/or rhinorrhoea than ECH subjects. Clinical features of CCH with remission periods < 1 month were not significantly different from those of CCH with remission periods of 1-3 months, except for the total number of bouts. More current smoking and less diurnal rhythmicity were observed in participants with CCH evolved from ECH compared to those with ECH. In conclusion, the number of subjects with CCH doubled when the revised ICHD-3 criteria were used. Most of clinical characteristics of CCH did not differ when the previous and current version of ICHD was applied and compared. Some clinical features of CCH were different from those of ECH, and smoking may have a role in CH chronification.

Clinical Features of Probable Cluster Headache: A Prospective, Cross-Sectional Multicenter Study.

Background: Epidemiological data of probable cluster headaches (CH) are scarce in the relevant literature. Here, we sought to assess the prevalence and clinical characteristics of probable CH in comparison with definite CH. Methods: Data used in this study were obtained from the Korean Cluster Headache Registry (KCHR), a prospective, cross-sectional, multicenter headache registry that collected data from consecutive patients diagnosed with CH. Results: In total, 159 patients were enrolled in this study; 20 (12.6%) were diagnosed with probable CH. The most common unfulfilled criterion in patients with probable CH was the duration of attack, which was found in 40% of patients with probable CH. Among clinical characteristics, the number of autonomic symptoms tended to be lower in probable CH than in definite CH (1.7 ± 1.2 vs. 2.4 ± 1.5, p = 0.051) and conjunctival injection and lacrimation showed an increased odds ratio (OR) [OR = 3.03; 95% confidence interval (CI): 1.03-8.33] in definite CH. The groups did not differ with regard to baseline demographic characteristics, disability, impact on life, or treatment response. Conclusions: Probable CH is relatively common among CH disorders, with a clinical impact similar to that of definite CH.