Does hypernatremia cause subdural hematoma in children?: two case reports and a meta-analysis of the literature.

Hypernatremia has been causally linked with subdural hematoma (SDH), but more recently this has been called into question. Conversely, there is a well-established link between SDH and injury. We wish to examine the evidence base that hypernatremia in infants and young children causes SDH.We present 2 cases of children with severe hypernatremia whose intracranial contents were assessed by imaging in the first case and postmortem examination in the second. Neither demonstrated SDH. The first case was important as the hypernatremia was iatrogenic occurring in a controlled hospital environment.We also searched the literature from 1950 to 2007, collecting data on all reported cases of hypernatremia in children younger than 7 years whose intracranial contents were examined by imaging, surgery, and/or postmortem examination. Of 124 cases reported in 31 articles, 112 cases developed hypernatremia in the community, and 12 in the hospital. Subdural hematoma was demonstrated in 7 cases, all of which had developed hypernatremia in the community under circumstances that would make it difficult to exclude nonaccidental injury. None of the 12 cases that developed hypernatremia in a controlled hospital environment had SDH.The evidence base supporting the hypothesis that hypernatremia causes SDH is poor, depending on isolated reports with uncertain histories.

Creatinine assays: time for action?

BACKGROUND: Major differences in creatinine results between different laboratories and apparent inaccuracies when using commercial lyophilized standards were noted. In order to assess the variation and accuracy of the different methods we conducted a local audit. METHODS: To establish the variation between methods, plasma creatinine was measured on 47 human plasma samples by nine different laboratories using four different methods (Roche, Ortho, Olympus, modified Olympus). To establish the accuracy of the different methods, plasma creatinine was also determined on 16 of the plasma samples by tandem mass spectrometry (MS). In addition, all the laboratories measured the creatinine concentration on a commercial authenticated sample. RESULTS: All four methods gave significantly different (P<0.0001) plasma creatinine results when compared with each other. Generally, creatinine results produced by the Ortho method were considerably higher than those of the other methods, especially at higher creatinine concentrations (differences across methods between the lowest and highest result for the same sample ranged between 8% and 33%). All four methods generally gave higher results than those determined by tandem MS for samples with creatinine concentrations of < 250 micromol/L. Above this concentration the Olympus and Roche methods produced creatinine results that were lower then the tandem MS results, whereas results from the Ortho method were higher. Major matrix problems were found when a commercial lyophilized standard was used for creatnine estimation. CONCLUSION: No method gave good agreement with the tandem MS results, and there were major differences in measured plasma creatinine concentrations (up to 30% difference) between the various methods. We suggest that efforts should be made to standardize plasma creatinine measurement across all laboratories to minimize these problems.