Marked elevation of interleukin-6 in mild encephalopathy with a reversible splenial lesion (MERS) associated with acute focal bacterial nephritis caused by Enterococcus faecalis

Brain Dev. 2014 Jun;36(6):551-3. doi: 10.1016/j.braindev.2013.07.012. Epub 2013 Aug 24.


This report describes two cases of mild encephalitis/encephalopathy with reversible splenial lesion (MERS) associated with acute focal bacterial nephritis (AFBN). The patients, who presented with fever and delirious behavior, exhibited hyponatremia and markedly elevated interleukin (IL)-6 in cerebrospinal fluid (CSF) and serum. Enterococcus faecalis was detected in the urine culture. After ampicillin treatment, their consciousness improved without neurological sequelae. Moreover, a diffusion-weighted MRI abnormality, i.e., intensified signals in splenium of the corpus callosum, disappeared. MERS is a possible complication of AFBN. Elevated CSF IL-6 levels suggest that remote activation of intracerebral immune response through the immune-neuroendocrine pathway might play an important role in the pathophysiology of MERS.

Keywords: Acute focal bacterial nephritis; Corpus callosum; Cytokine; Encephalitis; Encephalopathy; Splenium.

Publication types

  • Case Reports

MeSH terms

  • Ampicillin / therapeutic use
  • Anti-Bacterial Agents / therapeutic use
  • Child
  • Corpus Callosum / drug effects
  • Corpus Callosum / pathology
  • Diagnosis, Differential
  • Encephalitis / drug therapy
  • Encephalitis / metabolism*
  • Encephalitis / pathology
  • Enterococcus faecalis*
  • Gram-Positive Bacterial Infections / metabolism*
  • Humans
  • Interleukin-6 / metabolism*
  • Magnetic Resonance Imaging
  • Male
  • Nephritis / drug therapy
  • Nephritis / metabolism*
  • Nephritis / pathology
  • Tomography, X-Ray Computed
  • Treatment Outcome


  • Anti-Bacterial Agents
  • Interleukin-6
  • Ampicillin