Neurological pathology is considered rare but serious complications after allogeneic Hematopoietic Stem Cell Transplantation (allo HSCT). The presented case report shows it poses a diagnostic challenge for physicians and a great threat for patients.

A 64-year-old patient was admitted to the hospital due to progressive alteration of consciousness for three weeks. Sixty days prior, the patient had undergone an allo-HSCT due to high-risk Acute Lymphoblastic Leukemia (ALL) with initial infiltration of Cerebrospinal Fluid (CSF). At day 36th post allo HSCT, Complete Remission (CR) with 100% chimerism was confirmed. At day 45th post allo HSCT patient presented with fresh memory alterations. Reactivation of Cytomegalovirus (CMV) was diagnosed, and the patient started therapy with valganciclovir. Despite the decrease of the viral load of CMV, the neurological state of the patient continued to deteriorate, and the patient required hospital admission. At this time, she was disoriented, basic neurologic examination revealed overactive deep reflexes and a negative coherence test. The brain computer tomography ruled out acute ischemia. Bone marrow and CSF analysis excluded relapse of ALL. Viral (except for CMV reactivation), bacterial, fungal and parasite infection were ruled out. Hyponatremia, probably secondary to dehydration, was slowly corrected [1]. All potentially neurotoxic medication, e.g. cyclosporine, tacrolimus were changed or stopped. The patient fell into a coma, shortly afterwards. Horner syndrome and pyramidal-extrapyramidal symptoms were diagnosed. The brain magnetic resonance revealed hyper intensity in left caudate and left lentiform nuclei as well as the left parietal and temporal lobe in T2-weighted image, TIRM and DWI. With suspicion of limbic encephalitis, firstly treatment with plasmapheresis and corticosteroids, and secondly with immunoglobulins, mycophenolate mofetil and anti CD20 was administered with no improvement. Finally, negativity of the antibody tests of blood and CSF excluded autoimmune causes [2]. In literature reports of CNS involvement of chronic graft versus host disease exist, however, the patient did not meet the required criteria [3]. Patient got fully unconscious with preserved pain response, presented progressive tetraplegia, vanishing of deep reflexes, weakening of muscle tension with flaccid paralysis and continuous myoclonic seizures. The EEG showed slow basal activity of both cerebral hemispheres with generalized synchronic periodic sharp wave complexes and spikes within theta waves and suspicion of Creutzfeldt-Jackob Disease (CJD) was suggested. Finally, presence of 14-3-3 protein in CSF confirmed the diagnosis of CJD [4]. Since symptom onset the patient’s neurological state deteriorated quickly within 6 weeks, death occurred within 4 months (Table 1).

Table 1: The course of endoscopic treatments.

The etiology of neurological alterations in patients after allo HSCT is very complex and differential diagnosis is difficult [3]. Creutzfeldt-Jackob disease is rare with morbidity approximately one per million per year [5]. While most probable, prion diseases make definitive diagnosis very difficult as they can occur spontaneously, be genetically linked or caused by inflammatory or contaminated transplant material [6]. As diagnosis of CJD is based mostly on exclusion it should always be considered as potential causes of rapidly progressing neurological disorders during careful survey of laboratory tests and picture examinations.

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