High-dose melphalan (HDM) with peripheral blood stem cell transplant (PBSCT
) is a common treatment for patients with multiple myeloma (MM) and more re
cently also with AL amyloidosis (ALA), We report two female patients with s
evere renal failure who underwent treatment with HDM for MM (patient 1) and
ALA (patient 2), Both patients developed severe encephalopathy with genera
lised tonic-clonic seizures and a Glasgow Coma Scale (GCS) of 3/15. Causes
for coma such as infections, metabolic disturbances, cerebral ischaemia or
haemorrhage were excluded. Patient 1 died on day 25 post transplant while c
omatose. Patient 2 recovered from her comatose state 18 days after transpla
ntation. To our knowledge this is the first report on a possible role of hi
gh-dose melphalan in the development of encephalopathy.