Neurological complications of excessive recreational nitrous oxide use: a case series based on a text mining algorithm.

BACKGROUND: The recreational use of nitrous oxide (N2O) has gained popularity over recent years. We present a case series of excessive N2O users with neurological complications. METHODS: In this retrospective three-centre study, we used a text mining algorithm to search for patients who used N2O recreationally and visited a neurologist. RESULTS: We identified 251 patients. The median duration of N2O use was 11 months (interquartile range [IQR], 3-24) and the median amount of N2O used per occasion 1.6 kg (IQR 0.5-4.0). Clinically, polyneuropathy (78%), myelopathy (41%), and encephalopathy (14%) were the most common diagnoses. An absolute vitamin B12 deficiency of < 150 pmol/L was found in 40% of cases. In 90%, at least one indicator of functional vitamin B12 status (vitamin B12, homocysteine, or methylmalonic acid) was abnormal. MRI showed signs of myelopathy in 30/55 (55%) of cases. In 28/44 (64%) of those who underwent electromyography, evidence of axonal polyneuropathy was found. Most (83%) patients were treated with vitamin B12 supplementation, and 23% were admitted to the hospital. Only 41% had follow-up for ≥ 30 days, and 79% of those showed partial or complete recovery. CONCLUSIONS: In this case series of excessive N2O users, we describe a high prevalence of polyneuropathy, myelopathy, and encephalopathy. Stepwise testing for serum levels of vitamin B12, homocysteine, and methylmalonic acid may support the clinical diagnosis. Due to low sensitivity, MRI of the spinal cord and electromyography have limited value. Effective treatment should incorporate supplementation of vitamin B12 and strategies to prevent relapses in N2O use.

Patient with Cluster Headache and Harlequin Sign - Related or Not?

BACKGROUND: The harlequin sign or syndrome is a rare cranial autonomic condition characterized by unilateral diminished flushing and sweating of the face (and sometimes arm), in response to heat or exercise. It results from autonomic, mainly sympathetic dysfunction. Although the idiopathic form is the most common, underlying structural abnormalities in the head, neck, and thorax need to be excluded. METHODS AND RESULTS: Here, we describe the first case of the combination of primary cluster headache and the harlequin syndrome in a 49-year-old female patient. The patient presented with a first bout of cluster headache with persisting Horner syndrome and new harlequin sign after the bout. Additional neuroimaging did not reveal underlying pathologies. This report provides an overview of cases from the literature and then discusses the association between primary headaches and the harlequin syndrome. Relevant anatomy, diagnostic tools, and therapeutic options are all considered. CONCLUSION: This case reports a rare combination of cluster headache and harlequin sign that warrants further testing to exclude pathology in the brain, neck or mediastinum. It also illustrates the underlying anatomy and physiology of the autonomic nervous system.

[Vertigo as the first manifestation of ovarian cancer]. / Vertigo als eerste teken van een ovariumcarcinoom.

BACKGROUND: Vertigo is a common complaint and may rarely be the presenting symptom of a paraneoplastic neurological syndrome (PNS). CASE DESCRIPTION: A 76-year-old woman presented at the ER with subacute cerebellar syndrome and severe vertigo. Laboratory testing revealed mild anaemia. A cerebral CT scan showed no intracranial pathology. The patient was admitted for observation. History-taking revealed she been suffering from general malaise and had unintentionally lost 16 kg in weight over recent months. Further PET-CT investigations revealed multiple enlarged mediastinal and abdominal lymph nodes with high metabolic activity. Histopathological investigation of a lymph node biopsy showed a malignancy originating from the genital tract. Positive anti-neuronal antibodies (anti-Yo) and an elevated CA-125 concentration were found in peripheral blood. We diagnosed paraneoplastic cerebellar degeneration as the first manifestation of hitherto undiagnosed occult ovarian cancer. CONCLUSION: In a patient with subacute, cerebellar syndrome with severe vertigo, after ruling out other causes, the diagnosis of PNS should be considered. Determination of anti-neuronal antibodies can help in the diagnosis. Early recognition of PNS is important for the diagnosis and treatment of the underlying malignancy.

Alcoholic beverages as trigger factor and the effect on alcohol consumption behavior in patients with migraine.

BACKGROUND AND PURPOSE: Alcoholic beverages are frequently reported migraine triggers. We aimed to assess self-reported alcohol consumption as a migraine attack trigger and to investigate the effect on alcohol consumption behavior in a large migraine cohort. METHODS: We conducted a cross-sectional, web-based, questionnaire study among 2197 patients with migraine from the well-defined Leiden University MIgraine Neuro-Analysis (LUMINA) study population. We assessed alcoholic beverage consumption and self-reported trigger potential, reasons behind alcohol abstinence and time between alcohol consumption and migraine attack onset. RESULTS: Alcoholic beverages were reported as a trigger by 35.6% of participants with migraine. In addition, over 25% of patients with migraine who had stopped consuming or never consumed alcoholic beverages did so because of presumed trigger effects. Wine, especially red wine (77.8% of participants), was recognized as the most common trigger among the alcoholic beverages. However, red wine consistently led to an attack in only 8.8% of participants. Time of onset was rapid (<3 h) in one-third of patients and almost 90% had an onset <10 h independent of beverage type. CONCLUSIONS: Alcoholic beverages, especially red wine, are recognized as a migraine trigger factor by patients with migraine and have a substantial effect on alcohol consumption behavior. Rapid onset of provoked migraine attacks in contrast to what is known about hangover headache might point to a different mechanism. The low consistency of provocation suggests that alcoholic beverages acting as a singular trigger is insufficient and may depend on a fluctuating trigger threshold.

[A patient with Melkersson-Rosenthal syndrome]. / Een patiënt met het syndroom van Melkersson-Rosenthal.

BACKGROUND: Melkersson-Rosenthal syndrome (MRS) is a relatively rare syndrome characterised by the clinical triad of persisting or recurrent facial oedema, recurrent peripheral facial palsy, and a fissured tongue. CASE DESCRIPTION: A 30-year-old male patient presented with a left peripheral facial palsy spreading to the right side of the face. The left-sided facial paralysis recurred twice after initial recovery. The patient had also suffered from oedema of the lip and face, which sometimes occurred simultaneously with the paralysis, and he had always had a fissured tongue. Extensive biochemical tests, tests for infection and imaging tests revealed no abnormalities, and MRS was diagnosed. No treatment was required as the symptoms always disappeared spontaneously. CONCLUSION: Patients with MRS can present to the general practitioner, dermatologist, or ENT-specialist as well as to the neurologist. As this is a relatively unknown syndrome, the diagnosis is often made late, and it is often over-diagnosed and over-treated. There is no proven effective treatment, but systemic corticosteroids can be considered.

Restless legs syndrome in migraine patients: prevalence and severity.

BACKGROUND AND PURPOSE: Our aim was to study not only the prevalence but more importantly the severity and the correlation between sleep quality and restless legs syndrome (RLS) in a large population of well-defined migraine patients as poor sleep presumably triggers migraine attacks. METHODS: In a large cross-sectional and observational study, data on migraine and RLS were collected from 2385 migraine patients (according to the International Classification of Headache Disorders ICHD-IIIb) and 332 non-headache controls. RLS severity (International RLS Study Group severity scale) and sleep quality (Pittsburgh Sleep Quality Index) were assessed. Risk factors for RLS and RLS severity were calculated using multivariable-adjusted regression models. RESULTS: Restless legs syndrome prevalence in migraine was higher than in controls (16.9% vs. 8.7%; multivariable-adjusted odds ratio 1.83; 95% confidence interval 1.18-2.86; P = 0.008) and more severe (adjusted severity score 14.5 ± 0.5 vs. 12.0 ± 1.1; P = 0.036). Poor sleepers were overrepresented amongst migraineurs (50.1% vs. 25.6%; P < 0.001). Poorer sleep quality was independently associated with RLS occurrence (odds ratio 1.08; P < 0.001) and RLS severity (P < 0.001) in migraine patients. CONCLUSION: Restless legs syndrome is not only twice as prevalent but also more severe in migraine patients, and associated with decreased sleep quality.

The presence of brain white matter lesions in relation to preeclampsia and migraine.

INTRODUCTION: Identifying female-specific risk markers for cerebrovascular disease is becoming increasingly important. Both migraine and preeclampsia have been associated with higher incidence of brain white matter lesions (WML) and stroke. We assessed the association between WML and migraine among formerly (pre)eclamptic women. METHODS: A total of 118 women (76 formerly (pre)eclamptic and 42 control women) were screened for migraine and WML presence. Independent effects of migraine and (pre)eclampsia on WML were assessed. RESULTS: Migraine prevalence did not differ between the (pre)eclamptic (26/76; 34%); and control group (10/42; 24%), p = 0.17. Age-adjusted regression analysis failed to show a significant independent effect of migraine (OR 1.14; 95% CI 0.47-2.76; p = 0.77) on WML presence, and showed a non-significant effect of (pre)eclampsia (OR 2.30; 95% CI 0.90-5.83; p = 0.08). CONCLUSION: Migraine prevalence was not found to be an independent risk factor for WML prevalence in formerly (pre)eclamptic women. Since this study had a small sample size, larger prospective studies are needed to examine female-specific risk factors for WML and its consequences.

A human capsaicin model to quantitatively assess salivary CGRP secretion.

BACKGROUND: Capsaicin induces the release of calcitonin gene-related peptide (CGRP) via the transient receptor potential channel V1 (TRPV1). The CGRP response after capsaicin application on the tongue might reflect the "activation state" of the trigeminal nerve, since trigeminal CGRP-containing vesicles are depleted on capsaicin application. We tested (i) the quantitative CGRP response after oral capsaicin application; (ii) the optimal concentration of red chili homogenate; and (iii) the day-to-day variability in this response. METHODS: Saliva was collected for two consecutive days after oral application of eight capsaicin dilutions (red chili homogenates) of increasing concentrations in 13 healthy individuals. Effects of homogenate concentration were assessed. Consecutively, saliva was sampled after application of vehicle and undiluted homogenates. RESULTS: CGRP secretion (pg/ml) increased dose-dependently with homogenate concentration (p < 0.001). CGRP levels were highest after application of nondiluted homogenate (vs. baseline: 13.3 (5.0) vs. 9.7 (2.9); p = 0.003, as was total CGRP secretion in five minutes (pg) with undiluted (vs. baseline): 89.2 (44.1) vs. 14.1 (2.8); p < 0.001. The dose-dependent response in CGRP was not affected by day (p = 0.14) or day*concentration (p = 0.60). Increase in CGRP (undiluted - baseline; pg/ml) did not differ between measurements on dose-finding (p = 0.67) and follow-up days (p = 0.46). CONCLUSION: Oral application of red chili homogenate is well tolerated and causes a dose-dependent CGRP release in saliva, without day-to-day effects in this response. This model could be used to noninvasively study the activation state of the trigeminal nerve innervating salivary glands.

Space headache on Earth: head-down-tilted bed rest studies simulating outer-space microgravity.

BACKGROUND: Headache is a common symptom during space travel, both isolated and as part of space motion syndrome. Head-down-tilted bed rest (HDTBR) studies are used to simulate outer space microgravity on Earth, and allow countermeasure interventions such as artificial gravity and training protocols, aimed at restoring microgravity-induced physiological changes. OBJECTIVES: The objectives of this article are to assess headache incidence and characteristics during HDTBR, and to evaluate the effects of countermeasures. METHODS: In a randomized cross-over design by the European Space Agency (ESA), 22 healthy male subjects, without primary headache history, underwent three periods of -6-degree HDTBR. In two of these episodes countermeasure protocols were added, with either centrifugation or aerobic exercise training protocols. Headache occurrence and characteristics were daily assessed using a specially designed questionnaire. RESULTS: In total 14/22 (63.6%) subjects reported a headache during ≥1 of the three HDTBR periods, in 12/14 (85.7%) non-specific, and two of 14 (14.4%) migraine. The occurrence of headache did not differ between HDTBR with and without countermeasures: 12/22 (54.5%) subjects vs. eight of 22 (36.4%) subjects; p = 0.20; 13/109 (11.9%) headache days vs. 36/213 (16.9%) headache days; p = 0.24). During countermeasures headaches were, however, more often mild (p = 0.03) and had fewer associated symptoms (p = 0.008). CONCLUSIONS: Simulated microgravity during HDTBR induces headache episodes, mostly on the first day. Countermeasures are useful in reducing headache severity and associated symptoms. Reversible, microgravity-induced cephalic fluid shift may cause headache, also on Earth. HDTBR can be used to study space headache on Earth.

Allodynia is associated with a higher prevalence of depression in migraine patients.

INTRODUCTION: There is a strong association between migraine and depression. The aim of this study is to identify migraine-specific factors involved in this association. METHODS: We conducted a cross-sectional study in a large, well-defined cohort of migraine patients (n=2533). We assessed lifetime depression using validated questionnaires, and diagnosed migraine based on the International Classification of Headache Disorders III-beta criteria. Multivariate regression analyses were conducted. RESULTS: Of the 2533 migraineurs that were eligible, 1137 (45%) suffered from lifetime depression. The following independent factors were associated with an increased depression prevalence: i) migraine-specific risk factors: high migraine attack frequency and the presence of allodynia, ii) general factors: being a bad sleeper, female gender, high BMI, being single, smoking, and a low alcohol consumption. CONCLUSION: This study identified allodynia, in addition to high migraine attack frequency, as a new migraine-specific factor associated with depression.

Postdural puncture headache in migraineurs and nonheadache subjects: a prospective study.

OBJECTIVES: To prospectively assess 1) the incidence and duration of postdural puncture headache (PDPH) in migraineurs and healthy subjects; 2) the associated risk factors; and 3) the risk of getting a migraine attack shortly before or after lumbar puncture (LP). METHODS: As part of an extensive biochemical migraine research program, we assessed the occurrence, duration, and characteristics of PDPH in 160 migraineurs and 53 age- and sex-matched healthy controls. In addition, we evaluated potential risk factors for PDPH as well as the risk of developing a migraine attack before or after LP. RESULTS: In total, 64 of 199 subjects (32.2%) developed PDPH. Young age, low body mass index, severe headache immediately after LP, and sitting sampling position, but not being a migraineur, increased the risk of PDPH (all p < 0.05). Duration of PDPH was prolonged by history of depression, sitting sampling position, high perceived stress during the LP procedure, and multiple LP efforts (all p < 0.05). Migraine attacks were less likely to occur before or shortly after LP. CONCLUSIONS: Migraineurs are not at increased risk of developing PDPH. PDPH duration is similar in migraineurs and age- and sex-matched controls. LP does not trigger migraine attacks, and the stress of an upcoming LP might even have a protective effect against onset of migraine attacks.

Validation of the web-based LUMINA questionnaire for recruiting large cohorts of migraineurs.

OBJECTIVE: To assess validity of a self-administered web-based migraine-questionnaire in diagnosing migraine aura for the use of epidemiological and genetic studies. METHODS: Self-reported migraineurs enrolled via the LUMINA website and completed a web-based questionnaire on headache and aura symptoms, after fulfilling screening criteria. Diagnoses were calculated using an algorithm based on the International Classification of Headache Disorders (ICHD-2), and semi-structured telephone-interviews were performed for final diagnoses. Logistic regression generated a prediction rule for aura. Algorithm-based diagnoses and predicted diagnoses were subsequently compared to the interview-derived diagnoses. RESULTS: In 1 year, we recruited 2397 migraineurs, of which 1067 were included in the validation. A seven-question subset provided higher sensitivity (86% vs. 45%), slightly lower specificity (75% vs. 95%), and similar positive predictive value (86% vs. 88%) in assessing aura when comparing with the ICHD-2-based algorithm. CONCLUSIONS: This questionnaire is accurate and reliable in diagnosing migraine aura among self-reported migraineurs and enables detection of more aura cases with low false-positive rate.

[A 'connecting year' is useful in the medical curriculum]. / Wel een schakeljaar in de basisopleiding geneeskunde.

The 'schakeljaar' (connecting year) is the final year of the medical curriculum in which both education and the preparation for clinical activity as a resident are important features. Thus, a smooth transition from medical study to residency is guaranteed. However, a few criteria must be met. Firstly, sufficient knowledge, skills and clinical independence must have been accumulated during the preceding years. Secondly, intensive supervision during the connecting year is indispensable for professional and personal development. Thirdly, a connecting year spent in a certain specialty should not interfere with the choice for residency in another specialty. The students ofthe Dutch Medical Association support a rapid and nationwide introduction ofa connecting year in all eight medical faculties.