Epicranial headaches part 2: Nummular headache and epicrania fugax

Are there differences between patients with unifocal nummular headache and those who progress to bifocal nummular headache? A retrospective observational study

OBJECTIVES

This retrospective observational cohort study aimed to compare clinical characteristics and treatment responses in patients exclusively experiencing unifocal nummular headache (NH) with those who develop the bifocal variant.

METHODS

A retrospective study was conducted on patients diagnosed with NH who attended a neurology (headache) outpatient clinic between January 2018 and December 2022. The cohort was divided into two groups: Group 1, exclusive unifocal NH; and Group 2, those developing a secondary focal area of pain, i.e., bifocal NH. Data were collected on demographic characteristics, clinical features, other headache comorbidities, and treatment-related information.

RESULTS

A total of 23 patients were included in this study: 12 were categorized as unifocal NH (Group 1) and 11 as bifocal NH (Group 2). There were no differences between the two groups in terms of demographic characteristics, clinical features, or treatment response. Nonetheless, patients with bifocal NH exhibited spontaneous remission rates in the first pain area when compared to the unifocal NH group, with statistically significant differences (36% vs. 0%, p = 0.020).

CONCLUSION

In our sample, patients with bifocal NH demonstrated spontaneous remission rates in the initial pain area, a phenomenon not observed in patients with unifocal NH. It is worth noting the limited sample size in the present study, highlighting the need for larger cohorts to validate and further explore our findings.

Neurovascular Compression-Induced Intracranial Allodynia May Be the True Nature of Migraine Headache: an Interpretative Review

PURPOSE OF REVIEW

Surgical deactivation of migraine trigger sites by extracranial neurovascular decompression has produced encouraging results and challenged previous understanding of primary headaches. However, there is a lack of in-depth discussions on the pathophysiological basis of migraine surgery. This narrative review provides interpretation of relevant literature from the perspective of compressive neuropathic etiology, pathogenesis, and pathophysiology of migraine.

RECENT FINDINGS

Vasodilation, which can be asymptomatic in healthy subjects, may produce compression of cranial nerves in migraineurs at both extracranial and intracranial entrapment-prone sites. This may be predetermined by inherited and acquired anatomical factors and may include double crush-type lesions. Neurovascular compression can lead to sensitization of the trigeminal pathways and resultant cephalic hypersensitivity. While descending (central) trigeminal activation is possible, symptomatic intracranial sensitization can probably only occur in subjects who develop neurovascular entrapment of cranial nerves, which can explain why migraine does not invariably afflict everyone. Nerve compression-induced focal neuroinflammation and sensitization of any cranial nerve may neurogenically spread to other cranial nerves, which can explain the clinical complexity of migraine. Trigger dose-dependent alternating intensity of sensitization and its synchrony with cyclic central neural activities, including asymmetric nasal vasomotor oscillations, may explain the laterality and phasic nature of migraine pain. Intracranial allodynia, i.e., pain sensation upon non-painful stimulation, may better explain migraine pain than merely nociceptive mechanisms, because migraine cannot be associated with considerable intracranial structural changes and consequent painful stimuli. Understanding migraine as an intracranial allodynia could stimulate research aimed at elucidating the possible neuropathic compressive etiology of migraine and other primary headaches.

Long-term outcomes of nummular headache: A series of 168 patients and 1198 patient-years of follow-up

BACKGROUND

Since the first description of nummular headache (NH), more than 500 cases have been described, delineating its clinical phenotype and response to treatment. However, data on the natural history of NH and outcomes during long-term follow-up are not currently available. The present study aimed to describe the long-term outcomes and follow-up of a large series of patients with NH.

METHODS

A descriptive observational ambisective study with a series of cases was conducted. The study population included adult patients with primary NH and a minimum of 12 months of follow-up. Demographic variables, previous medical history, clinical phenotype, diagnosis and treatment of NH, temporal pattern, and long-term evolution were analysed.

RESULTS

In total, 168 patients were enrolled and followed for a median [interquartile range (IQR)] of 80.5 (55-118.5) months. The temporal pattern after NH onset was chronic in 67.9% and, at diagnosis, the median (IQR) number of pain days per month was 20 [10-30] days with 138 (82.1%) patients with ≥8 days of pain per month. Preventive treatment was needed by 112 (66.7%) patients. The most frequently used drugs were gabapentin (69/112; 61.6%), onabotulinumtoxinA (38/112; 33.9%), amitriptyline (31/112; 27.7%) and lamotrigine (21/112; 18.7%). Response to preventive treatment was at least partial in 91/112 (81.3%) patients. At the end of follow-up, 81 (48.2%) patients had inactive NH. Of patients with active NH, the median (IQR) number of headache days per month was 3 (1-12) days and patients had ≥8 days of pain in 35 (20.8%) cases.

CONCLUSIONS

Long-term outcomes of NH were positive in most patients. After a median of 6.7 years of follow-up, 48% of cases were inactive. Two-thirds of patients required preventive treatment, and 80% of them were treatment-responsive. In NH cases that remained symptomatic, the headache frequency was lower, and the proportion of patients with chronic NH decreased from 68% to 11%.

Drug-resistant epicrania fugax: Responding to onabotulinumtoxinA

Epicrania fugax (EF) is a primary headache consisting of brief paroxysms of pain, lasting 1-10 s, that move through different nerve territories of one hemicranium with a linear or zigzag trajectory, although there are some clinical variants. Preventive therapy with anti-seizure medication such as gabapentin and lamotrigine are most commonly used in patients presenting with frequent and non-remitting attacks. In some cases, greater occipital nerve blockades are used for short- or long-term relief. Here, we report two patients with a paroxysmal EF-type pain who meet the criteria for EF of the International Classification of Headache Disorders, 3rd edition, with clear triggers and autonomic ocular signs and who failed multiple preventive treatments, but had a sustained response to onabotulinumtoxinA.

Botulinum Toxin-A for the Treatment of Neuropathic Pain after Decompressive Craniotomy in Stroke: Two Cases

Botulinum toxin-A (BoNT-A) is recommended as third-line off-label treatment for the management of neuropathic pain. BoNT-A has been reported as treatment for different neuropathic pain conditions; however, not for neuropathic pain after decompressive craniotomy for stroke. The aim of this retrospective case series is to provide information on safety, the effect, and the application method of BoNT-A in clinical practice for the treatment of neuropathic pain after trepanation. This case series describes 2 patients treated in 2021 at a BoNT outpatient clinic for chronic neuropathic pain at the incisional site after decompressive craniotomy for stroke who were resistant to pain medication. Cases were a 48-year-old woman and a 63-year-old man suffering from chronic neuropathic pain since 3 and 6 years, respectively. They were treated regularly with BoNT-A with a total dose of 100 mouse units of incobotulinumtoxin-A injected into peri-incisional sites of the scalp. Both patients reported subjective decrease in pain frequency (40% and 60%), in pain intensity (60% and 90%), and an increase of quality of life (80%). BoNT-A should be further investigated as treatment for neuropathic pain - especially in underreported conditions such as neuropathic pain after craniotomy in stroke.