The utility of neuroimaging in the evaluation of children with migraine or chronic daily headache who have normal neurological examinations

OBJECTIVES: To assess the utility of neuroimaging in the evaluation of children presenting with two of the most common forms of headache, migraine and chronic daily headache, and to determine the utility and pathological yield of neuroimaging in specific headache syndromes in children whose neurological examinations are normal. METHODS: We retrospectively reviewed the medical records of patients coded for headache (ICD 784) in the Pediatric Neurology Clinic at Children's Hospital of the King's Daughters between 1997 and 1999. The age range considered was between 6 and 18 years. The study focused on the two most common types of headache, uncomplicated migraine and chronic daily headache. Only patients with normal physical and neurological examinations were considered in this analysis. RESULTS: Three hundred two patients were coded for headache within the defined age group. One hundred seven (35.4%) patients fulfilled IHS-R criteria as having uncomplicated migraine with a normal examination, and 30 (9.9%) patients fulfilled criteria for chronic daily headache. Twenty-nine (9.6%) patients presented with migrainelike symptoms, and 6 (2.0%) presented with chronic daily symptoms, but had neurological abnormalities present on examination. The remainder of the patients with headache had the following etiologies: 50 (16.6%) with secondary headache, 22 (7.3%) with complicated migraine, 20 (6.6%) with posttraumatic headache, 13 (4.3%) with seizure-related headache, 11 (3.6%) with brain tumors, 10 (3.3%) with tension-type headache, and 4 (1.3%) with pseudotumor cerebri. Of the 107 patients with migraine, 42 (39.3%) received CT scans; 2 (4.8%) of which were considered "abnormal." One of the abnormalities was an arachnoid cyst and the other was a dilated Virchow-Robin space. Twelve (11.2%) patients with migraine received an MRI, 2 (16.7%) of which were considered abnormal. Both of the abnormal findings were Chiari type I malformations. Of the 30 patients with chronic daily headache, 17 (56.7%) received CT scans, 3 (17.6%) of which were considered abnormal. The abnormalities consisted of a maxillary opacification, a mucous retention cyst, and an occult vascular malformation. Eight (26.7%) of the patients with chronic daily headache had an MRI, 2 (25.0%) of which were abnormal. One of the abnormalities was a Chiari I malformation, and the other was an occult vascular malformation. CONCLUSION: The yield of neuroimaging in children with uncomplicated migraine and normal neurological examination was 3.7%. The yield in children with chronic daily headache and normal neurological examination was higher at 16.6%. The abnormalities discovered included arachnoid cysts, Chiari I malformations, sinus disease, occult vascular malformations and "dilated Virchow-Robin spaces." While none of the neuroimaging findings were apparent clinically, their discovery did not influence the diagnosis, management, or outcome of the patients. None of the abnormalities necessitated surgical intervention or were associated with the headache presentation. Therefore, neuroimaging is not warranted in children and adolescents with defined clinical headache syndrome diagnoses whose neurological examinations are normal.     

Idiopathic Hypertrophic Cranial Pachymeningitis: An Unusual Cause of Subacute and Chronic Headache

Three cases of idiopathic hypertrophic cranial pachymeningitis are presented. The diagnosis was based on the CT scan or MRI findings (or both) of thickened enhancing dura. In all cases, meningeal biopsies were performed and microscopic findings were compatible with non-specific inflammation. All cases presented with subacute and chronic localized headache. Two cases had associated chronic meningitis. One case presented with a syndrome of multiple cranial nerve involvement (polyneuritis cranialis). Corticosteroids, in the form of prednisolone 60 mg/day, were effective in all cases. Two cases with less severe pachymeningitis received corticosteroids for 2 weeks, then were tapered off in 4 to 6 weeks. A case with extensive lesions needed a long-term low dosage of prednisolone, 5 to 10 mg/day for maintenance therapy. Idiopathic hypertrophic cranial pachymeningitis may be related to the Tolosa-Hunt syndrome, the syndrome of polyneuritis cranialis, and multifocal fibrosclerosis.     

特发性肥厚性硬脑膜炎5例临床分析并文献复习

目的:探讨特发性肥厚性硬脑膜炎(IHP)的临床特点。方法:回顾性分析5例IHP患者的临床资料、实验室检查、影像资料及治疗情况。结果:5例患者均为男性,中位年龄57岁,均以头痛为首发症状,5例脑脊液蛋白水平偏高,4例血沉结果异常,1例C-反应蛋白水平偏高,5例ANA结果均异常,5例头颅MRI+增强检查可见弥漫性或局灶性硬脑膜强化,2例经病理活检确诊。5例患者均接受大剂量激素冲击继予小剂量激素长期维持治疗后,头痛均基本缓解。随访期1年,失联1例,另4例头痛无复发。结论:IHP临床较少见,多以头痛为主要表现,同时可伴颅神经受损表现,该病患者血沉、C反应蛋白可升高,风湿免疫系列中ANA结果普遍异常,头颅MRI+增强是其诊断的重要手段,病理活检是确诊的金标准,预后较好,但有复发风险。     

特发性低颅压头痛的临床及影像学特点

目的:探讨特发性低颅压头痛的临床及影像学特点.方法:回顾性分析29例特发性低颅压头痛患者的临床表现、腰椎穿刺结果、头颅MRI特征以及治疗方法.结果:28例患者存在体位性头痛,卧位时缓解,1例患者出现体位性头晕;28例腰穿压力低,其中压力为0 mm H2O者9例,蛋白增高是较常见的脑脊液改变;26例行头颅MRI检查,其中16例可见异常,9例为硬膜下出血或积液,9例为硬脑膜强化;除1例患者因硬膜下出血转至外科手术治疗外,其余均经保守治疗后痊愈.结论:熟悉特发性低颅压头痛的临床特点、脑脊液改变和头颅MRI特征,有利于早期诊断和治疗.     

Chronic Migraine: An Update on Physiology,Imaging, and the Mechanism of Action of Two Available Pharmacologic Therapies

Several lines of research support the hypothesis that migraine is a spectrum of illness, with clinical symptoms that vary along a continuum from episodic migraine to chronic migraine. Physiologic changes may result in episodic migraine evolving into chronic migraine over months to years in susceptible individuals. With chronification, headache frequency increases, becoming more disabling and less responsive to therapy. Neurophysiologic and functional imaging research has reported that chronic migraine may be associated with severity‐specific metabolic, functional, and structural abnormalities in the brainstem. Without longitudinal studies, it is unclear whether these changes may represent a continuum of individual progression and/or are reversible. Furthermore, chronic migraine is associated with larger impairments in cortical processing of sensory stimuli when compared with episodic migraine, possibly caused by more pronounced cortical hyperexcitability. Progressive changes in nociceptive thresholds and subsequent central sensitization due to recurrent migraine attacks in vulnerable individuals contribute to the chronic migraine state. This may result in changes to baseline neurologic function between headache attacks, evident in both electrophysiological and functional imaging research. Patients experiencing migraine chronification may report increased non‐headache pain, fatigue, psychiatric disorders (eg, depression, anxiety), gastrointestinal complaints, and other somatic conditions associated with their long‐term experience with migraine pain. Recent research provides a foundation for differentiating episodic and chronic migraine based on neurophysiologic and neuroimaging tools. In this literature review, we consider these findings in the context of models designed to explain the physiology and progression of episodic migraine into chronic migraine, and consider treatment of chronic migraine in susceptible individuals. Advances in pharmacotherapy provide treatment options for chronic migraine. Of the currently available treatment options, only onabotulinumtoxinA and topiramate have received regulatory approval and have demonstrated efficacy in patients with chronic migraine, although the exact mechanisms of action are not fully elucidated.     

Long-term improvement of idiopathic hypertrophic cranial pachymeningitis by lymphocytapheresis.

We report on a 48-year-old man with idiopathic hypertrophic cranial pachymeningitis (IHCP) manifesting headache, facial pain, and tongue pain with unilateral atrophy, dysarthria, and dysphagia. Although steroid therapy ameliorated these symptoms, they recurred after he developed steroid-induced diabetes mellitus. We treated the patient by lymphocytapheresis (LCP), which resulted in an improvement of his symptoms, a reduction in the CD4 lymphocyte population, a reduction of the CD4/CD8 ratio, and a reduced thickening of the dura mater that lasted for more than 14 months. Results presented here suggest that LCP can be effective in the treatment of IHCP.     

Opiate use to control bowel motility may induce chronic daily headache in patients with migraine

OBJECTIVES: To investigate whether opiate overuse might cause chronic daily headache in those with migraine, we studied patients who were taking codeine (or other opiates) for control of bowel motility after colectomy for ulcerative colitis. BACKGROUND: Analgesic overuse is considered by many to be one factor which can result in the transformation of migraine into a chronic daily headache pattern. Most of the evidence for this comes from patients with migraine who are taking increasing amounts of analgesia for headache. Many of these patients revert to an intermittent migraine pattern once the analgesics are stopped. METHODS: Women who were 1 year postcolectomy for ulcerative colitis were identified in several colorectal surgery practices in Calgary. They were sent a questionnaire designed to determine if they had a history of migraine prior to surgery, if they currently had chronic daily headache, what medications they were taking to control bowel motility, and what medications they were taking for headache. RESULTS: Twenty-eight patients who met our inclusion criteria returned completed questionnaires. Eight of these exceeded the recommended limits for opiate use in patients with headache. Eight patients met diagnostic criteria for migraine. Two patients had chronic daily headache starting after surgery. Both used daily opiates beginning after their surgery, and both had a history of migraine. The other six patients who used opiates daily did not have a history of migraine and did not have chronic daily headache. All patients with migraine who used daily opiates to control bowel motility following surgery developed chronic daily headache after surgery. CONCLUSIONS: Patients with migraine who use daily opiates for any reason are at high risk of developing transformed migraine with chronic daily headache. This risk appears much lower in patients without a history of migraine who use opiates for nonpain indications.     

Chronic daily headache. How should it be included in the IHS classification?

A number of patients attending specialty headache centers complain of very frequent, almost continuous or continuous headaches, which are usually grouped together under the term chronic daily headache , a category which does not appear in the International Headache Society (IHS) classification. On the basis of the IHS criteria, these patients can only be classified as having a chronic tension-type headache with the possible addition of migraine, if migrainous attacks are superimposed on the "background" headache. However, several studies have demonstrated that most patients with chronic daily headache originally suffered from migraine and that their migraine has transformed, in the course of time, into a chronic headache picture in which isolated migraine attacks may or may not persist. Despite some differences in the personal opinions of authors involved in the care of patients with chronic daily headache, some views seem to be generally accepted: (1) the great majority of chronic daily headaches are transformations of an original episodic migraine and cannot be included in the chronic tension-type headache category, (2) the current IHS classification does not allow many patients presenting with chronic daily headache to be classified correctly, (3) an important nosological category (transformed migraine) has emerged from all the studies on this subject, (4) it is impossible to diagnose transformed migraine merely by "photographing" the picture of single attacks. Although some theoretical problems remain unresolved, it seems to us that the next revision of the IHS classification can no longer ignore the existence of chronic daily headache.     

Understanding the patient with migraine: the evolution from episodic headache to chronic neurologic disease. A proposed classification of patients with headache

Traditionally, episodic primary headache disorders are characterized by a return of preheadache (normal) neurologic function between episodes of headache. In contrast, patients with chronic headache often do not return to normal neurologic function between headache attacks. This article proposes that the evolution from episodic migraine to chronic headache may parallel the neurologic disruption observed during the progression of an acute migraine attack and that changes in baseline neurologic function between episodes of headache may be a more sensitive indicator of headache transformation than headache frequency alone. Early recognition of nonheadache changes in nervous system function may offer a more sensitive and specific approach to migraine prevention.     

Rapid and sensitive paradigm for screening patients with headache in primary care settings

OBJECTIVE: To determine the sensitivity and specificity of a brief headache screening paradigm for primary care clinicians. BACKGROUND: Migraine and drug rebound headache are disabling primary headache disorders. Both are underdiagnosed and undertreated. A method for rapid screening of migraine, drug rebound headache, and other daily headache syndromes would be useful. The Brief Headache Screen uses 3 questions-the frequency of severe (disabling) headache, other (mild) headache, and use of symptomatic medication-to generate diagnoses. METHODS: The Brief Headache Screen was evaluated in an emergency department, a family practice department, and a referral headache clinic. Diagnoses from the Brief Headache Screen were compared to diagnoses of trained researchers and headache specialists. RESULTS: Three hundred ninety-nine patients were screened and interviewed. The criterion of episodic severe (disabling) headache correctly identified migraine in 136 (93%) of 146 patients with episodic migraine and 154 (78%) of 197 patients with chronic migraine, with a specificity for any migraine (episodic or chronic) of 32 (63%) of 51. The inclusion of episodic or daily severe headache identified migraine in 100% of patients with chronic migraine. Only 6 (1.7%) of 343 patients with migraine were not identified by severe (disabling) headache. The combination of severe and mild headache frequency was sensitive to daily headache syndromes in 218 (94%) of 232 patients with a specificity of 87 (54%) of 162. Medication overuse was correctly identified in 146 (86%) of 169 patients with a specificity of 22 (79%) of 28. CONCLUSIONS: The frequency of severe (disabling) and mild headaches and use of symptomatic medications, rapidly and sensitively screens for migraine, daily headache syndromes, and medication overuse. The use of this paradigm in primary care settings may improve the recognition of these important headache syndromes.     

Assessment of migraine disability using the migraine disability assessment (MIDAS) questionnaire: a comparison of chronic migraine with episodic migraine

BACKGROUND: Chronic migraine is the most common type of chronic daily headache seen in headache tertiary care centers. Most patients with chronic migraine report their ability to function and feeling of well-being as severely impaired. OBJECTIVE: To measure the headache-related disability of patients with chronic migraine using the Migraine Disability Assessment (MIDAS) Questionnaire, comparing it with that obtained in a control group of patients with episodic migraine. METHODS: The clinical records of 703 patients with chronic daily headache treated in a headache specialty clinic were reviewed to identify 182 with chronic migraine who were evaluated using the MIDAS at their initial visit. Our control group consisted of 86 patients with episodic migraine. RESULTS: Of the 182 patients with chronic migraine, 127 (69.8%) were overusing acute-care medication. Patients were predominantly women (72.5%), with a mean age of 38.3 years. The group with episodic migraine consisted of 59 women (68.6%), with a mean age of 36.1 years. No statistically significant demographic differences were observed between the two groups. The group with chronic migraine had more total headache days over 3 months (66.7 versus 15.5, P<.001), missed more days of work or school (5.3 versus 2.3, P =.0007), had more reduced effectiveness days at work or school (11.9 versus 4.6, P =.0001), missed more days of housework (16.5 versus 3.3, P<.0001), and missed more days of family, social, or leisure activities (7.0 versus 5.5, P =.03). The group with chronic migraine was more likely to be in MIDAS grade IV (64.3% versus 43.2%, P =.001), reflecting the great likelihood of severe disability in this group. The average total MIDAS score was 34.9 in the group with chronic migraine versus 19.3 in the group with episodic migraine (P<.001). CONCLUSION: In subspecialty centers, patients with chronic migraine demonstrate remarkable impairment of their daily activities and are severely burdened by their headache syndrome, reflected by their high MIDAS scores. The chronicity and pervasiveness of migraine thus is associated with increased functional impairment as well as increase in headache frequency.     

Functional Neuroimaging in Migraine: Chances and Challenges

Functional neuroimaging studies are an indispensable tool in headache research and have greatly contributed to our understanding of migraine pathophysiology. The past two decades have identified the brainstem as the target region of interest in migraine pathophysiology: Recent evidence suggests that certain areas of the central nervous system and especially the brainstem periodically change activity during different stages of the migraine cycle. Additionally, the number of resting‐state functional MRI studies in migraine has increased greatly in recent years. Three future trends in migraine neuroimaging can be identified: brainstem optimized functional imaging, longitudinal approaches tracking biological changes through the migraine cycle, and optimized resting‐state fMRI. Consequently, we face a lot of difficulties regarding image noise and artifacts, organizational details, and data interpretation. Optimized neuroimaging studies and new approaches will continue to greatly contribute to our pathophysiological understanding of migraine.     

Results of screening with the brief headache screen compared with a modified IDMigraine.

BACKGROUND: Patients with chronic migraine and chronic daily headache syndromes have greater morbidity than patients with episodic migraine, and are less frequently diagnosed. A screening tool which identifies daily headache syndromes as well as migraine would promote more patients receiving appropriate treatment, including prophylaxis. METHODS: A post-hoc analysis of data obtained to evaluate the prevalence of somatic symptoms in primary care patients was conducted on a convenience sample of primary care patients who completed the Patient Health Questionnaire portion of the PRIME-MD (Primary Care Evaluation of Mental Disorders). Patients who endorsed the symptom of headache were asked to complete the Brief Headache Screen (BHS), a 4-item screening tool, supplemented by 3 clinical questions (nausea, light sensitivity, and noise sensitivity). The data obtained allowed a post-hoc comparison of the BHS with a modified version of the screening tool, IDMigraine(TM) (IDM(TM)). Diagnostic interviews were performed on patients whose diagnoses differed by the 2 screening methods, and on patients who screened positive for daily headache on BHS. RESULTS: Of the 1000 patients who completed the PRIME-MD, 302 (30.2%) indicated headache as a concern, and there were sufficient data for both the BHS and IDM(TM) for 259. There was substantial concordance between the 2 instruments with 82.6% agreement in identified migraine (95% confidence interval: 77.8%-87.4%). The BHS screened positive for migraine in an additional 15.1% of patients who were not identified by IDM(TM), whereas the IDM(TM) identified an additional 2.3% of patients. Of the 173 which both tools recognized as migraine, the BHS identified 42.8% as having a daily headache syndrome (chronic migraine: 23.1%; episodic migraine + chronic tension-type headache [CTTH]: 19.7%). BHS also identified 7 non-migraine patients as having CTTH alone. Diagnostic interviews confirmed that 6/18 (33%) of BHS+ but IDM-, and one of 2 (50%) patients BHS-/IDM+ met full criteria for migraine. Additionally, interviews confirmed the diagnoses of 85.4% of those patients who the BHS identified with daily headache and 67% of those who were identified as medication overuse headache. CONCLUSION: The BHS and a modified IDM(TM) are concordant in screening for migraine in 82.6% of a primary care population who endorsed the symptom of headache. However, the BHS screens effectively not only for migraine but also for chronic daily headache and medication overuse. A screening paradigm based on headache frequency and the frequency of medication use can rapidly and sensitively identify migraine, daily headache syndromes, and medication overuse. This paradigm may improve clinical care by identifying patients who merit preventive as well as acute therapy for migraine.     

Short-lasting unilateral neuralgiform headache with autonomic symptoms syndrome as the initial manifestation of idiopathic hypertrophic cranial pachymeningitis

This is the first report of 2 patients presenting with short-lasting unilateral neuralgiform headache with autonomic symptoms as the initial manifestation of idiopathic hypertrophic cranial pachymeningitis. They both had acute retro-orbital pain ipsilateral to the dural thickening on magnetic resonance imaging of brain, and one had transient miosis as an additional parasympathetic feature. Short-lasting unilateral neuralgiform headache with autonomic symptoms syndrome may be associated with secondary central nervous system pathology, and neuroimaging should be considered in all patients with trigeminal autonomic cephalalgia.     

Comorbidity of depressive and anxiety disorders in chronic daily headache and its subtypes

OBJECTIVE: To investigate the frequency of depressive and anxiety disorders in patients with chronic daily headache. BACKGROUND: There is a lack of data in the literature on the extent of psychiatric comorbidity in patients with different subtypes of chronic daily headache. METHODS: We recruited consecutive patients with chronic daily headache seen in a headache clinic from November 1998 to December 1999. The subtypes of chronic daily headache were classified according to the criteria proposed by Silberstein et al. A psychiatrist evaluated the patients according to the structured Mini-International Neuropsychiatric Interview to assess the comorbidity of depressive and anxiety disorders. RESULTS: Two hundred sixty-one patients with chronic daily headache were recruited. The mean age was 46 years, and 80% were women. Transformed migraine was diagnosed in 152 patients (58%) and chronic tension-type headache in 92 patients (35%). Seventy-eight percent of patients with transformed migraine had psychiatric comorbidity, including major depression (57%), dysthymia (11%), panic disorder (30%), and generalized anxiety disorder (8%). Sixty-four percent of patients with chronic tension-type headache had psychiatric diagnoses, including major depression (51%), dysthymia (8%), panic disorder (22%), and generalized anxiety disorder (1%). The frequency of anxiety disorders was significantly higher in patients with transformed migraine after controlling for age and sex (P =.02). Both depressive and anxiety disorders were significantly more frequent in women. CONCLUSION: Psychiatric comorbidity, especially major depression and panic disorders, was highly prevalent in patients with chronic daily headache seen in a headache clinic. These results demonstrate that women and patients with transformed migraine are at higher risk of psychiatric comorbidity.     

The course of migraine—a diary study in unselected patients

The course of disease and the predictive value of depression and anxiety in patients with migraine were prospectively examined. We recruited 393 migraineurs through articles in newspapers and performed a follow-up examination 30 months later. At baseline and follow-up, patients underwent a semistructured interview, filled out the Headache Impact Test (HIT-6), Self-rating Depression Scale (SDS) and Self-rating Anxiety Scale (SAS) and they kept a headache diary for 30 days. One hundred and fifty-one patients (38.6%) were seen at follow-up. The baseline data of patients with and without follow-up were comparable. At follow-up the number of headache days per month had decreased from 9.6 ± 5.8 to 8.1 ± 6.3 ( P  < 0.001) and the proportion of patients with chronic headache (15.4%) and medication overuse (13%) had remained stable. SDS and SAS scores were associated with a high migraine frequency and high initial SDS scores predicted high migraine frequency at follow-up. This longitudinal study in unselected patients with migraine not excluding subjects with chronic headache, medication overuse, depression or anxiety does not point towards migraine as a progressive disease in the vast majority of patients and confirms the importance of psychiatric comorbidity.     

Intravenous valproate sodium in the treatment of daily headache

BACKGROUND: Treatment of chronic daily headache/transformed migraine is challenging, especially when it is complicated by overuse of analgesics, triptans, or both. One common approach involves the use of repetitive intravenous dihydroergotamine. We investigated the use of intravenous valproate sodium in the treatment of chronic daily headache/transformed migraine in patients who had contraindications to the use of or had failed treatment with dihydroergotamine. METHODS: We administered intravenous valproate sodium (Depacon) to patients with chronic daily headache/transformed migraine (loading dose 15 mg/kg, followed by 5 mg/kg every 8 hours). All analgesics and triptans were discontinued prior to treatment with divalproex sodium, and preventative medications for migraine were begun or continued. All patients received instruction in behavioral modification and the proper use of analgesics and triptans. RESULTS: Improvement in headache was reported by 80% of the patients treated, and valproate sodium was tolerated well by most. CONCLUSION: Intravenous valproate sodium may be of assistance in the initial management of patients with chronic daily headache/transformed migraine and analgesic/triptan overuse, especially when dihydroergotamine is ineffective or contraindicated.     

Is there a brainstem generator of chronic daily headache?

Using BOLD-fMRI we have previously documented activation of the red nucleus (RN) and substantia nigra (SN) during spontaneously and visually activated migraine headache. These observations prompted us to study brainstem function in chronic daily headache patients using high-resolution magnetic resonance imaging (MRI) techniques. Seventeen chronic daily headache (CDH) patients, ten episodic migraine (EM) patients and fifteen controls (N) were imaged with a 3 tesla MRI system. For each subject, the relaxation rates R2, R2* and R2' were obtained for RN and SN. There was a significant decrease in R2' and R2* values for RN and SN in CDH compared to N and EM groups (p < 0.05), but no significant difference between the N and EM groups. A decrease in R2' and R2* indicates reduced deoxyhemoglobin and hence persistent activation of the RN and SN in CDH patients most likely secondary to ongoing headache at the time of study. The imaging data provide objective evidence of disturbed central nervous system function in CDH.     

Naratriptan in the preventive treatment of refractory chronic migraine: a review of 27 cases

OBJECTIVE: To review the efficacy of naratriptan as preventive treatment in 27 patients with chronic migraine refractory to other commonly used preventive therapies. BACKGROUND: The treatment of chronic migraine often poses a major challenge to the clinician. Even when given expert care, patients with chronic migraine may continue to have daily or near-daily headaches. METHODS: Clinical records and headache calendars were reviewed of 27 patients fulfilling the following inclusion criteria: (1) aged 18 to 65 years; (2) diagnosis of chronic migraine (formerly transformed migraine), according to the criteria proposed by Silberstein et al; (3) previous failure of at least 4 preventive medications prescribed as part of a management program that included nonpharmacological measures, preventive medication, acute care medication, and detoxification from overused medication; and (4) have used daily naratriptan for no less than 2 consecutive months. The dose of naratriptan prescribed was 2.5 mg twice daily. We considered the following outcomes: (1) frequency of headache, (2) intensity of pain, (3) number of days per month with severe headache, (4) headache index (frequency times intensity), and (5) proportion of patients who reverted to an episodic pattern of pain after 6 months of treatment. RESULTS: There was a statistically significant reduction in the frequency of headache days 2 months (15.3 days versus 24.1 days at baseline, P<.001), 6 months (9.1 days, P<.001), and 1 year (7.3 days, P<.001) after daily treatment with naratriptan was initiated. There was also a statistically significant reduction in the number of days per month of severe pain at 1 month (5.6 days versus 12.5 days at baseline, P<.01), 2 months (5.7 days, P<.01), 6 months (2.8 days, P<.01), and 1 year (2.6 days, P<.01). Similarly, there was a statistically significant reduction in the headache index at 2 months (33 versus 56.4 at baseline, P<.001), 6 months (19.5, P<.001), and 1 year (17.2, P<.001). Of the 20 patients who continued to use naratriptan daily for at least 6 months, 13 (65%) reverted to an episodic pattern of pain (migraine). At 1 year, 11 (55%) still continued to experience episodic headache, 1 (5%) relapsed to chronic migraine, and 2 (10%) were lost to follow-up. No patients had intolerability to naratriptan during the treatment period, and no one stopped treatment due to adverse events. CONCLUSIONS: Naratriptan may have a role in the preventive treatment of intractable chronic migraine. Prospective, controlled studies should be considered.