Human herpesvirus 6 (HHV-6) encephalitis has a high mortality rate. Among those who survive, ~80% develop some type of permanent neurologic disorder. Early diagnosis and treatment may help prevent long-term sequelae. There have been several case reports as well as retrospective and prospective studies associating HHV-6 encephalitis with some form of sodium imbalance, either hyponatremia or hypernatremia; however, the exact frequency post-HCT is unknown, with reports ranging from 30% to 100%. We performed a systematic review of the literature and found 34 cases of HHV-6 encephalitis reported in conjunction with sodium imbalance that documented the timing of that imbalance relative to the onset of encephalitis. Sodium imbalance occurred before or at the onset of HHV-6 encephalitis in all but 2 cases (94%). This finding supports previous suggestions that sodium imbalance can be considered an early indicator of the potential development or presence of HHV-6 encephalitis in at-risk patient populations.

中文翻译：

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HHV-6脑炎中钠异常的系统评价。

人疱疹病毒6（HHV-6）脑炎的死亡率很高。在幸存者中，约80％会发展出某种类型的永久性神经系统疾病。早期诊断和治疗可能有助于预防长期后遗症。已有数例病例报告以及回顾性和前瞻性研究将HHV-6脑炎与某种形式的钠失衡（低钠血症或高钠血症）相关；但是，尚不清楚HCT之后的确切频率，报告范围为30％至100％。我们对文献进行了系统的回顾，发现34例HHV-6脑炎与钠失衡有关，记录了这种失衡相对于脑炎发作的时间。除2例（94％）外，所有病例均在HHV-6脑炎发作之前或发作时出现钠不平衡。