Seasonal Variation in Spontaneous Cervical Artery Dissection: Comparing between UK and Australian Sites.

BACKGROUND: Cervical artery dissection (CAD) is a leading cause of stroke among middle-aged adults, but the etiology is unclear. Some reports of seasonal variation in CAD incidence have been suggested but may reflect extreme climatic conditions. Seasonal variation may implicate more transient seasonal causes such as proinflammatory or hypercoagulable states. This study aimed to assess whether CAD incidence varied with season between UK and Australian sites. Also, this study aimed to determine whether there was a different pattern of seasonal variation between arteries (carotid and vertebral) and any association between CAD incidence and clinical factors. METHODS: This was a retrospective observational study of patients older than 18 years with radiological diagnosis of internal carotid or vertebral arterial dissection, from sites in Australia and the UK. Clinical variables were compared between autumn-winter and spring-summer and site of dissection. RESULTS: A total of 133 CAD cases were documented in Australia and 242 in the UK. There was a seasonal pattern to CAD incidence in countries in both the northern and the southern hemispheres, with a trend for dissection to occur more commonly in autumn, winter, and spring than in summer (incidence rate ratios [IRR] 1.4-1.5, P < .05). CAD counts were also slightly higher in internal carotid than in vertebral artery (IRRs 1.168, 1.43, and 1.127, respectively). Neither systolic blood pressure nor pulse pressure was significantly associated with CAD counts. CONCLUSIONS: CAD occurs more commonly in cooler months regardless of geographical location, suggesting transient seasonal causes may be important in the pathophysiology. This effect was slightly higher in internal carotid than in vertebral artery, suggesting differing trigger mechanisms between dissection sites.

Ocrelizumab-induced inflammatory bowel disease-like illness characterized by esophagitis and colitis.

Ocrelizumab is an intravenous anti-CD20 monoclonal antibody, approved for use in primary progressive multiple sclerosis due to its selective depletion of B-lymphocytes. Herein we describe the case of a 56-year-old female who developed odynophagia and bloody diarrhea following treatment with ocrelizumab. This was characterized endoscopically by ulcerations in the esophagus and colon. The patient was treated with high-dose intravenous glucocorticoids with good clinical response.

Reliability of the biceps brachii M-wave.

BACKGROUND: The peak-to-peak (P-P) amplitude of the maximum M-wave and the area of the negative phase of the curve are important measures that serve as methodological controls in H-reflex studies, motor unit number estimation (MUNE) procedures, and normalization factors for voluntary electromyographic (EMG) activity. These methodologies assume, with little evidence, that M-wave variability is minimal. This study therefore examined the intraclass reliability of these measures for the biceps brachii. METHODS: Twenty-two healthy adults (4 males and 18 females) participated in 5 separate days of electrical stimulation of the musculocutaneous nerve supplying the biceps brachii muscle. A total of 10 stimulations were recorded on each of the 5 test sessions: a total of fifty trials were used for analysis. A two-factor repeated measures analysis of variance (ANOVA) evaluated the stability of the group means across test sessions. The consistency of scores within individuals was determined by calculating the intraclass correlation coefficient (ICC). The variance ratio (VR) was then used to assess the reproducibility of the shape of the maximum M-wave within individual subjects. RESULTS: The P-P amplitude means ranged from 12.62 +/- 4.33 mV to 13.45 +/- 4.07 mV across test sessions. The group means were highly stable. ICC analysis also revealed that the scores were very consistent (ICC = 0.98). The group means for the area of the negative phase of the maximum M-wave were also stable (117 to 126 mV.ms). The ICC analysis also indicated a high degree of consistency (ICC = 0.96). The VR for the sample was 0.244 +/- 0.169, which suggests that the biceps brachii maximum M-wave shape was in general very reproducible for each subject. CONCLUSION: The results support the use of P-P amplitude of the maximum M-wave as a methodological control in H-reflex studies, and as a normalization factor for voluntary EMG. The area of the negative phase of the maximum M-wave is both stable and consistent, and the shape of the entire waveform is highly reproducible and may be used for MUNE procedures.