A retrospective review of the ambulatory blood pressure patterns and diurnal urine production in subgroups of spinal cord injured patients

Obstructive sleep apnoea triggering autonomic dysreflexia: Isn't it time for sleep studies to be routine in SCI?

Autonomic dysreflexia is a known complication after spinal cord injury. It is defined as a reflexive increase in blood pressure as a result of a painful or irritating stimulus below the level of the lesion. Although commonly caused by stimuli from the bladder, other rare triggers are still being described. Herein, we present a case with autonomic dysreflexia triggered by obstructive sleep apnoea. A 43-year-old smoker suffered a spinal cord injury after a road traffic accident secondary to multiple cervical spine vertebrae fractures. He presented to our rehabilitation centre 6 months post-injury as a case of complete spinal cord injury with C4 neurological level. Autonomic dysfunction in the form of autonomic dysreflexia was occurring on a daily basis. After exclusion of known inciting factors, it was noticed that early morning episodes of autonomic dysreflexia were persistent. He was also reporting daytime fatigue and sleepiness and multiple night-time awakenings. Therefore, work up for sleep apnoea was done. A diagnosis of moderate obstructive sleep apnoea was made. With continuous positive airway pressure treatment, his daily early morning episodes of autonomic dysreflexia settled. This case illustrates the importance of the pattern of blood pressure elevation to pinpoint specific triggers of autonomic dysreflexia.

Quantitative analysis of dysautonomia in patients with autonomic dysreflexia

Autonomic dysreflexia (AD) is a life-threatening condition for individuals with cervical or high-thoracic spinal cord injury (SCI). The profile of autonomic dysfunction in AD using validated clinical autonomic tests has not been described so far, although it could be useful to identify SCI patients at greater risk of developing AD non-invasively. With this objective, 37 SCI patients (27% female) were recruited, and hemodynamic and cardiac parameters were continuously monitored to determine the presence of AD, defined as an increase of systolic blood pressure of 20 mmHg or higher after bladder filling with saline. Then, standard autonomic function testing was performed, including Deep Breathing, Valsalva Manoeuvre and Tilt Table Test. Finally, baroreflex sensitivity (BRS), and spectral analysis of heart rate and blood pressure variability were measured at rest. Catecholamines and vasopressin levels were also measured at supine and upright positions. The severity of SCI was assessed through clinical and radiological examinations. AD was observed in 73.3% of SCI patients, being 63.6% of them asymptomatic during the dysreflexive episode. AD patients displayed a drop in sympathetic outflow, as determined by decreased noradrenalin plasma levels, reduced sympathovagal balance and increased BRS. In line with decreased sympathetic activity, the incidence of neurogenic orthostatic hypotension was higher in AD patients. Our results provide novel evidence regarding the autonomic dysfunction in SCI patients with AD compared to non-AD patients, posing non-invasively measured autonomic parameters as a powerful clinical tool to predict AD in SCI patients.

Nocturia and Nocturnal Polyuria in Neurological Patients: From Epidemiology to Treatment. A Systematic Review of the Literature

CONTEXT

Nocturia is among the most common and bothersome lower urinary tract symptoms (LUTS), but there is no clear consensus on how to identify and manage this symptom in the neurological population.

OBJECTIVE

To systematically review the literature about nocturia in neurological patients.

EVIDENCE ACQUISITION

Studies were identified by electronic search of Cochrane and Medline databases. The studies were included if their participants had acquired neurological pathology among multiple sclerosis (MS), Parkinson's disease (PD), stroke, spinal cord injury (SCI), and reported data on the epidemiology, aetiology, diagnosis, or treatment of nocturia. An independent extraction of the articles was performed by two authors using predetermined datasets, including quality-of-study indicators.

EVIDENCE SYNTHESIS

A total of 132 studies were included; 46 evaluated the epidemiology of nocturia, 28 the possible aetiologies, 10 the diagnostic tools, and 60 the treatments. Nocturia prevalence ranged from 15% to 96% depending on the pathology and definition used. It was one of the most frequently reported LUTS in PD and stroke patients. Several validated questionnaires were found to screen for nocturia in this population. Causalities were numerous: LUT, renal, sleep, cardiovascular dysfunctions, etc. Treatments targeted these mechanisms, with an overall risk of bias assessed as high or serious. The highest level of evidence was seen in MS patients: pelvic floor muscle training, cannabinoids, and desmopressin were effective, but not melatonin. In stroke patients, transcutaneous sacral and transcutaneous tibial nerve stimulation (TTNS) improved nocturia; in PD patients, TTNS, solifenacin, and rotigotine did not.

CONCLUSIONS

Nocturia is highly prevalent in patients with neurological disorders. Causalities and treatments are not different from the general population, but are poorly studied in neurological patients.

PATIENT SUMMARY

In this report, we looked at the published studies about nocturia-the fact of waking to void during the hours of sleep-in patients with neurological diseases. We found that nocturia is very frequent in this population, that the causes are the same as in the general population but may be combined, and that treatments are also the same but have an overall weak level of evidence. We conclude that more research is needed on this topic.

Sleep-Disordered Breathing and Spinal Cord Injury: A State-of-the-Art Review

Individuals living with spinal cord injury or disease (SCI/D) are at increased risk for sleep-disordered breathing (SDB), with a prevalence that is three- to fourfold higher than the general population. The main features of SDB, including intermittent hypoxemia and sleep fragmentation, have been linked to adverse cardiovascular outcomes including nocturnal hypertension in patients with SCI/D. The relationship between SDB and SCI/D may be multifactorial in nature given that level and completeness of injury can affect central control of respiration and upper airway collapsibility differently, promoting central and/or obstructive types of SDB. Despite the strong association between SDB and SCI/D, access to diagnosis and management remains limited. This review explores the role of SCI/D in the pathogenesis of SDB, poor sleep quality, the barriers in diagnosing and managing SDB in SCI/D, and the alternative approaches and future directions in the treatment of SDB, such as novel pharmacologic and nonpharmacologic treatments.

A Community Perspective on Bowel Management and Quality of Life after Spinal Cord Injury: The Influence of Autonomic Dysreflexia

Autonomic dysfunction is common in individuals with spinal cord injury (SCI) and leads to numerous abnormalities, including profound cardiovascular and bowel dysfunction. In those with high-level lesions, bowel management is a common trigger for autonomic dysreflexia (AD; hypertension provoked by sensory stimuli below the injury level). Improving bowel care is integral for enhancing quality of life (QoL). We aimed to describe the relationships between bowel care, AD, and QoL in individuals with SCI. We performed an online community survey of individuals with SCI. Those with injury at or above T7 were considered at risk for AD. Responses were received from 287 individuals with SCI (injury levels C1-sacral and average duration of injury 17.1 ± 12.9 [standard deviation] years). Survey completion rate was 73% (n = 210). Bowel management was a problem for 78%: it interfered with personal relationships (60%) and prevented staying (62%) and working (41%) away from home. The normal bowel care duration was >60 min in 24% and most used digital rectal stimulation (59%); 33% reported bowel incontinence at least monthly. Of those at risk for AD (n = 163), 74% had AD symptoms during bowel care; 32% described palpitations. AD interfered with activities of daily living in 51%. Longer durations of bowel care (p < 0.001) and more severe AD (p = 0.04) were associated with lower QoL. Bowel management is a key concern for individuals with SCI and is commonly associated with symptoms of AD. Further studies should explore ways to manage bowel dysfunction, increase self-efficacy, and ameliorate the impact of AD to improve QoL.

Relationship between autonomic cardiovascular control and obstructive sleep apnoea in persons with spinal cord injury: a retrospective study

Study design

Retrospective study.

Objective

To determine if there is an association between obstructive sleep apnoea (OSA) and blood pressure (BP) pattern or heart rate variability (HRV) in people with spinal cord injury (SCI).

Setting

A state-based spinal cord service in Victoria, Australia.

Methods

We identified 42 subjects who had ambulatory BP monitoring (ABPM) within 6 months of a diagnostic sleep study at Austin Hospital between 2009 and 2014. Markers for autonomic function, including circadian BP pattern and HRV were extracted from the ABPM study database. Apnoea/hypopnoea index (AHI), arousals/hour and oxygen desaturation index were extracted from the sleep study database. Subjects with a nocturnal systolic BP dipping more than 10% of daytime value were defined as dippers, between 10 and 0% were non-dippers and those with a higher night than day systolic BP were reverse dippers. Severity of OSA is classified as non-OSA (AHI < 5), mild (AHI 5-15), moderate (AHI 15-30) and severe (AHI > 30).

Results

Subjects (n = 42) were predominantly male (85.7%), aged 44 ± 15.4 (mean ± SD), with a BMI of 24.4 ± 5.7 (mean ± SD) and mainly tetraplegic (92.9%). There was no difference in AHI, oxygen desaturation index or arousals/hour between dippers, non-dippers and reverse dippers. None of the HRV parameters differed between dippers, non-dippers and reverse dippers. No differences were found in 24 h, night-time, daytime or nocturnal dip in BP between subjects with non-OSA, mild, moderate and severe OSA.

Conclusion

We found no relationship between BP pattern or HRV and the severity of OSA in persons with SCI.

Sleep Disordered Breathing and Spinal Cord Injury: Challenges and Opportunities

Purpose of review

This paper focuses on the sleep disorders in patients with spinal cord injury (SCI/D), particularly mechanism of sleep disordered breathing (SDB) and challenges in diagnosis and management. Based on a review of recent literatures and studies the paper summarizes some main challenges with respect to management of SDB in patients with SCI; and what are the responsible mechanisms of disease? What are the barriers in diagnosing and treating SDB using standard treatment such as positive airway pressure (CPAP)?.

Recent findings

Previous studies have shown that most SCI/D patients have SDB with heterogeneity in prevalence mainly related to using different definition or methods of diagnosing SDB, while recent studies using new definition of SDB based on recommended criteria from the American Academy of Sleep Medicine (AASM) and also include the data on effect of SCI/D level on prevalence and describe different type of SDB. Furthermore, recent data describes simplified method of diagnosing SDB by using a combination of home sleep apnea testing and transcutaneous CO2 monitoring. Finally, emerging data has been pointing at strong relationship between SDB and cardiovascular disease including nocturnal hypertension in patients with SCI/D.

Summary

The findings indicate that early testing for SDB and associated cardiovascular disease in patients with SCI is recommended and could be beneficial in reduced the high morbidity and mortality in this group of patients with disability. In addition, studies on treatment of other sleep disorders in SCI/D are not available to inform clinical decision making. Understanding the pathophysiology of sleep disorders in SCI/D is critical for the development of new effective therapies. This review provides evidence for best practices; highlights new discoveries for the diagnosis and management of sleep disorders in SCI/D, and discuss challenges and future directions.

Exploring daily blood pressure fluctuations and cardiovascular risk among individuals with motor complete spinal cord injury: a pilot study

BACKGROUND

Clinically silent autonomic dysfunction with bowel and bladder care, are postulated to contribute to cardiovascular disease after chronic spinal cord injury (SCI).

OBJECTIVE

We describe the frequency and severity of dysreflexic episodes, termed transient blood pressure elevations (T-BPE) over 48 hours in adults with cervical or high-thoracic motor-complete SCI.

SETTING

Tertiary SCI Rehabilitation Centre in Toronto, Canada.

PARTICIPANTS

Individuals with chronic SCI, C1-T3 AIS A or B, >1 year post-injury, living in the community (n=19).

OUTCOME MEASURES

Data were obtained via 48-hour ambulatory blood pressure (BP) and heart rate (HR) monitoring, with data captured at 10-minute intervals and a concurrent diary describing activities of daily living, and bladder/bowel routines. T-BPE were defined as a ≥ 40 mmHg elevation in systolic blood pressure (SBP) above the participant's supine baseline. Severe (≥ 60-79 mmHg) and Extreme ≥80 mmHg elevations in SBP were described.

RESULTS

Thirteen participants experienced T-BPE within the assessment period, with 7/13 experiencing "severe", and 3/13 experiencing "extreme" SBP elevations. The median number of T-BPE was 8 (IQR = 3), and the mean ± SD SBP during T-BPE was 150 ± 16 mmHg, These T-BPE were verified as dysreflexic events using a conservative definition of a >40 mmHg increase in SBP, with a concurrent 10 bpm decrease in HR, above the 48-hour average SBP, yielding 12/19 participants with T-BPE.

CONCLUSIONS

T-BPE were frequent, often with severe or extreme elevations in SBP, despite few reported symptoms. Recognition and management of these dysreflexic events associated with T-BPE are needed, which may ameliorate cardiovascular disease risk.