Relation between urinary hydration biomarkers and total fluid intake in healthy adults.

BACKGROUND/OBJECTIVES: In sedentary adults, hydration is mostly influenced by total fluid intake and not by sweat losses; moreover, low daily fluid intake is associated with adverse health outcomes. This study aimed to model the relation between total fluid intake and urinary hydration biomarkers. SUBJECTS/METHODS: During 4 consecutive weekdays, 82 adults (age, 31.6±4.3 years; body mass index, 23.2±2.7 kg/m(2); 52% female) recorded food and fluid consumed, collected one first morning urine (FMU) void and three 24-h (24hU) samples. The strength of linear association between urinary hydration biomarkers and fluid intake volume was evaluated using simple linear regression and Pearson's correlation. Multivariate partial least squares (PLS) modeled the association between fluid intake and 24hU hydration biomarkers. RESULTS: Strong associations (|r| ≥ 0.6; P<0.001) were found between total fluid intake volume and 24hU osmolality, color, specific gravity (USG), volume and solute concentrations. Many 24hU biomarkers were collinear (osmolality versus color: r=0.49-0.76; USG versus color: r=0.46-0.78; osmolality versus USG: 0.86-0.97; P<0.001). Measures in FMU were not strongly correlated to intake. Multivariate PLS and simple linear regression using urine volume explained >50% of the variance in fluid intake volume (r(2)=0.59 and 0.52, respectively); however the error in both models was high and the limits of agreement very large. CONCLUSIONS: Hydration biomarkers in 24hU are strongly correlated with daily total fluid intake volume in sedentary adults in free-living conditions; however, the margin of error in the present models limits the applicability of estimating fluid intake from urinary biomarkers.

[Severe hyponatraemia and central pontine myelinolysis: be careful with other factors!]. / Hyponatrémie sévère et myélinolyse centropontine : attention aux cofacteurs !

Central pontine myelinolysis covers very different clinical aspects, ranging from discrete tremor to quadriplegia. Rapid correction of hyponatraemia is a well-known risk factor, particularly in chronic alcohol abusers. We describe the case of a 46-year-old chronic alcoholic, suffering from denutrition. He developed a quadriplegia and a facial diplegia two weeks after a slow correction of a chronic hyponatraemia associated with hypokalaemia. Central pontine myelinolysis was formally diagnosed by MRI findings. In our case, the correction of hyponatraemia is not the only causal agent of this syndrome; hypokalaemia and denutrition seem to be predisposing factors too. For these reasons, glial cells are more vulnerable to osmotic variations. Despite of severe initial symptoms, the evolution was favourable with a quasi complete recovery.

[Severe Legionnaire's disease revealing an invasive aspergillosis in an apparently immunocompetent patient]. / Légionellose grave révélant une aspergillose invasive chez un sujet immunocompétent.

INTRODUCTION: Invasive aspergillosis, a sever disease, usually occurs in immuno-depressed patients. However, it may also develop in presumably immuno-competent patients. OBSERVATION: A 54-year-old man, smoker, was hospitalised for hypoxemia of the right lung and septic shock, rapidly requiring mechanical ventilation combined with administration of vasopressors, and followed by dialysis because of the rapid worsening of an acute kidney failure. The diagnosis of pulmonary Legionnaire's disease was made on the second day in view of the positivity of the urinary legionella antigen. The progression of the disease was marked by the discovery of a histologically documented gastric aspergillosis and three abscessed intracerebral lesions within the context of a strongly positive aspergillus antigenemia. The disease worsened and the patient died on D 17, despite the antibiotic and anti-aspergillus treatments, haemodynamic support and dialysis. DISCUSSION: To our knowledge, the association of invasive aspergillosis and severe Legionnaire's disease has never been described in an presumably immunocompetent patient. This clinical case suggests the existence, other than the usual risk factors of invasive aspergillosis that characterise profound states of immunodepression, of more subtle alterations in the immune system that may enhance this type of infection.