Cerebro-spinal decompression sickness: report of two cases

Jallul, S; Osman, Aheed; El-Masry, W S

doi:10.1038/sj.sc.3101923

Cited by 19 publications

(18 citation statements)

References 4 publications

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“…In a case study involving a male diver who died from severe DCS after a rapid ascent from 120 m, extensive gas embolism in cerebral and spinal arteries as well as cerebrospinal fluid spaces using postmortem CT and MRI were found (20). This case study has been confirmed in another recent study, which also found cerbrospinal dysfunction in two divers (11). Thus, given this evidence and the fact that the heart receives the ANS inputs from the spinal cord, we speculate that the injury to the spinal cord is most likely the culprit in the impairment of the ANS seen in our swine with DCS.…”

Section: Discussionsupporting

confidence: 68%

Impairment of the autonomic nervous function during decompression sickness in swine

Yan¹,

Mahon²,

White³

et al. 2009

Journal of Applied Physiology

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Dysautonomia has been observed in many cardiac diseases; however, its effect in decompression sickness (DCS) has not been well examined largely due to the difficulty in obtaining experimental data in human or animal subjects. In this study, we examine how DCS affects the autonomic nervous system's (ANS) dynamics in swine. Baseline and post-DCS electrocardiograms were obtained via telemetry recordings and compared. These data were analyzed using both the power spectrum method and our recently developed principal dynamic mode (PDM) analysis. PDM is able to separate the dynamic tones of the sympathetic and parasympathetic nervous systems. Both methods demonstrated a statistically significant decrease (Ͼ55%; P Ͻ 0.05) in the dynamics of both branches of the autonomic nervous system in the swine with DCS compared with the control condition. In cardiac diseases such as myocardial infarction, ANS imbalance is often associated with a significant increase in sympathetic tone, which may or may not be counterbalanced by parasympathetic nervous activity. However, the effect of DCS is such that both branches of the ANS are depressed Ͼ55% compared with the control condition, suggesting impairment, but not imbalance, of the ANS. principal dynamic mode; autonomic nervous system; sympathetic; parasympathetic; heart rate variability DECOMPRESSION SICKNESS (DCS) results from a sudden change from higher to lower ambient pressure. These changes in pressure result in the release of inert gases from body tissues, and depending on the severity can lead to symptoms of pain (type I DCS) or neurological dysfunction or cardiopulmonary injury (type II DCS). To date, accurate predictions of DCS incidence have not been possible. U.S. Navy divers strictly following the Navy dive tables designed to minimize DCS are not fully protected. Moreover, there is considerable individual variability in response to a given dive profile, further complicating DCS risk prediction. Recent studies have discussed possible preventive techniques (6), but they do not address the question of how to detect the early onset of DCS.There have been a few studies implicating an autonomic nervous system (ANS) imbalance in hyperbaric saturation diving (8, 16). For example, it has been reported that there are elevated sympathetic nervous system activities and reduced parasympathetic nervous activities following decompression after saturation diving (8). Yet the effect of DCS on the ANS is largely absent from the literature. It remains to be determined whether ANS dysfunction is also present in DCS and, if so, how the dynamics of sympathetic and parasympathetic nervous tones are affected. Our aim is to examine whether early detection of an ANS imbalance could be a bellwether for DCS and a warning to initiate an intervention to prevent its onset.Although evidence supporting the implication of cardiac autonomic imbalance in hyperbaric saturation diving is unquestionable and clear, noninvasive approaches to measure it have been elusive. One widely utilized noninvasive approach ...

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Section: Discussionsupporting

confidence: 68%

Impairment of the autonomic nervous function during decompression sickness in swine

Yan¹,

Mahon²,

White³

et al. 2009

Journal of Applied Physiology

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“…In fact, on follow-up 1 and 2 weeks after the decompression, changes in T 2 were found in brain stem and thalamus among decompressed animals. These delayed findings are in accordance with previously published clinical reports, where MRI abnormalities, especially increased T 2 indicating focal CNS injuries, have been found several weeks after the decompression (Reuter et al 1997; Hierholzer et al 2000; Jallul et al 2007). These studies showed MRI abnormalities mostly in the spinal cord, and this is despite the fact that MRIs made during the first 24 h after onset of symptoms (Jallul et al 2007) were normal.…”

Section: Discussionsupporting

confidence: 93%

“…However, the lack of signs of injury on acute MRI is not surprising, since all but one of the animals showed no neurological signs at that time. In previous studies, focal CNS injuries on conventional MRI were found in the presence of neurological symptoms and signs (Yoshiyama et al 2007; Jallul et al 2007; Gronning et al 2005; Reuter et al 1997). Moreover, even in the presence of clinical neurological signs suggesting brain involvement, abnormalities on cerebral MRI are uncommon, occurring only in 25 % of the patients in one study (Reuter et al 1997) and none in another (Gronning et al 2005).…”

Section: Discussionmentioning

confidence: 92%

“…Acute effects can be caused by extravascular bubbles producing pain, or vascular bubbles obstructing and causing stroke-like symptoms (Vann et al 2011). High intensity signals in the white matter on T 2 weighted magnetic resonance images (MRI) have been seen in divers after dive injuries (Cordes et al 2000; Hutzelmann et al 2000), while interestingly, cerebral abnormalities observed in case studies seem to appear at different times-points and are of varying permanence (Jallul et al 2007). Abnormal electroencephalography (EEG) results have been noted in the temporal or frontal regions after recompression treatment in divers with cerebral DCS (Gronning et al 2005).…”

Section: Introductionmentioning

confidence: 99%

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Simulated dive in rats lead to acute changes in cerebral blood flow on MRI, but no cerebral injuries to grey or white matter

et al. 2012

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In this study, the effect of a simulated dive on rat brain was investigated using several magnetic resonance imaging (MRI)-methods and immunohistochemistry. Rats were randomly assigned to a dive- or a control group. The dive group was exposed to a simulated air dive to 600 kPa for 45 min. Pulmonary artery was monitored for vascular gas bubbles by ultrasound. MRI was performed 1 h after decompression and at one and 2 weeks after the dive with a different combination of MRI sequences at each time point. Two weeks after decompression, rats were sacrificed and brains were prepared for histology. Dived rats had a different time-curve for the dynamic contrast-enhanced MRI signal than controls with higher relative signal intensity, a tendency towards longer time to peak and a larger area under the curve for the whole brain on the acute MRI scan. On MRI, 1 and 2 weeks after dive, T2-maps showed no signal abnormalities or morphological changes. However, region of interest based measurements of T2 showed higher T2 in the brain stem among decompressed animals than controls after one and 2 weeks. Microscopical examination including immunohistochemistry did not reveal apparent structural or cellular injuries in any part of the rat brains. These observations indicate that severe decompression does not seem to cause any structural or cellular injury to the brain tissue of the rat, but may cause circulatory changes in the brain perfusion in the acute phase.

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“…Although the overall incidence of diving‐related DCS is low, 7 we have managed to collect the data and MRI findings of seven patients who have been diagnosed with and treated for DCS at our local hyperbaric facility. This paper will describe the clinical presentation, MRI spinal cord findings, treatment administered and outcome of these patients.…”

Section: Introductionmentioning

confidence: 99%