Neuron-specific enolase (NSE) and S100B protein are brain-origin proteins commonly described to assess the presence and severity of neurological injury. To date, there are limited data examining the ...influence of scuba diving on these biomarkers, particularly when symptoms of decompression sickness (DCS) occur. The purpose of this controlled study was to determine whether these serum neurochemical markers could be used as 1) indicators of neurological DCS and 2) predictors of incomplete recovery.
Fifty-nine divers with neurological DCS and 37 asymptomatic divers admitted for inadequate decompression, serving as controls, were consecutively enrolled between 2010 and 2012. Blood samples were collected at initial presentation up to 6 hours after dive completion (controls) or onset of symptoms (DCS divers). Biomarkers were quantified in nonhaemolysed samples only. Clinical outcome was assessed at 6 months post-injury.
The two groups did not differ regarding the variables examined, except for the total dive time which was slightly shorter in the control group. NSE, but not S100B protein, was higher in the DCS group than in controls (P < 0.0001). An NSE level > 15.9 µg L⁻¹ determined by ROC analysis predicted DCS development with a specificity of 100% (95% confidence interval (CI) 90 to 100) and a sensitivity of 24% (95% CI 14 to 36). There was a trend towards a higher likelihood of residual neurological deficits above this cut-off value (P = 0.08).
Early determination of NSE was found to be useful for the diagnosis of neurological DCS with a high specificity. However, its clinical applicability in decision making for determining treatment as well as its prognostic value remains to be established. Reliability of S100B protein was not demonstrated in the present study.
Prior reports have shown that decompression sickness (DCS) in scuba divers is accompanied by vascular endothelium damage attributed to gas emboli formation, resulting in capillary leak with ...hemoconcentration. The significance of serum albumin as a biomarker of vascular permeability in this condition has been insufficiently investigated. We studied whether there was a relationship between low serum albumin values on admission and the occurrence of neurological DCS.
Demographic, diving, and laboratory data of 52 randomly selected DCS divers were compared with those of 52 asymptomatic divers referred for inadequate decompression. The diagnostic performance of serum albumin in predicting neurological DCS was assessed.
Both groups did not differ from the variables examined. Serum albumin was significantly lower in injured divers than in controls (38.7 ± 3 g · L(-1) vs. 41 ± 2.9 g · L(-1)). At a cut-off value of 35.2 g · L(-1), we found a specificity of 98% (95% CI 90-100) and a sensitivity of 16% (95% CI 7-28) for the prediction of neurological DCS development.
Our findings suggest that hypoalbuminemia at initial presentation, albeit rare, accurately predicts the occurrence of neurological DCS in scuba divers. The prognostic value of this biomarker and the potential beneficial role of albumin infusion in more severe cases remain to be investigated.
We conducted a controlled study to assess the prevalence of brain MRI hyperintense signals and their correlation with right-to-left shunting (RLS) in military divers.
We prospectively enrolled 32 ...asymptomatic military divers under 41 yr of age and 32 non-diving healthy subjects matched with respect to age and vascular disease risk factors. We examined both groups with a 3-Tesla brain MRI; RLS was detected using transcranial pulsed Doppler in divers only.
Hyperintense spots were observed in 43.7% of the divers and 21.8% of the control subjects. In particular, divers with significant shunting exhibited a higher prevalence of hyperintensities compared to those with slight or no RLS (75% vs. 25%, respectively). Linear trend analysis also revealed a positive correlation between focal white matter changes, determined using a validated visual rating scale and the RLS grade.
Healthy military divers with a hemodynamically relevant RLS have an increased likelihood of cerebral hyperintense spots compared to age-matched normal subjects. The clinical relevance of these MRI signal abnormalities and their causal relationship with diving remain unclear.
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