Sudden worsening after subdural haematoma surgery: will there be a corpus callosum injury?

We report a case of mild encephalopathy with a reversible splenial lesion (MERS) which occurred after chronic subdural haematoma (CSDH) surgery. The patient was admitted to our hospital for drowsiness and marked asthenia. The cerebral CT scan revealed a CSDH and surgery allowed to improve the symptoms, but after several days we observed a sudden worsening. The patient developed left-sided myoclonic seizures followed by left hemiplegia and worsening drowsiness. Electrolytes imbalance and inflammatory causes were excluded. The CT scan showed a right cerebral swelling and the subsequent MRI revealed a single lesion in the splenium of the corpus callosum, hyperintense on diffusion-weighted images. After osmotic therapy the patient improved and on day 10 of admission the MRI showed a complete resolution of the lesion. This is the first report that described an association between CSDH and MERS. Possible aetiopathogenetic mechanisms are discussed.