2024 American Academy of Neurology Abstract Website

Objective:

Real-time quaking induced conversion (RT-QUIC) test is ~92% sensitive and ~98% specific for Creutzfeldt Jakob disease (CJD). True negatives occur in rapidly progressive, familial or younger cases. False negatives are rare. Through this sporadic case with initially negative RT-QUIC, we highlight the importance of repeat interval testing in cases with strong clinical suspicion.

Background:

Sporadic ‘classic’ CJD manifests as rapidly progressive dementia, myoclonus, and periodic sharp wave complexes (PSWC) on EEG. Heidenhain variant has additional visual symptoms and PSWCs in occipital region. Diagnosis is through positive RT-QUIC, symptom duration <2 years with supportive EEG and MRI findings, and elevated CSF 14-3-3 protein for probable CJD. Neuropathological studies confirm definite CJD.

Design/Methods:

A 71 year old female without prior neurological history presented in Nov'2022 with 10 weeks of progressive memory difficulties and scattered self-resolving episodes of vision changes with intermittent visual hallucinations as flashing lights lasting a few minutes followed by dimming. Exam revealed deficits in executive and visuospatial function, language, orientation and delayed recall (MoCA 18/30).

Results:

MRI brain +/- contrast showed cortical ribboning in the right cortex, left frontal and parietal lobes with old bilateral basal ganglia infarcts. EEG demonstrated PSWCs 1-2 Hz, in posterior head region, lasting 10-40 seconds. CSF analysis revealed normal protein, cell counts, negative RT-QUIC and autoimmune encephalopathy panel with elevated Tau (14632) and 14-3-3 (32866) proteins.

In Dec’2022, she had worsened with additional deficits in calculation, word finding, and abstract thought (MoCA 11/30), more frequent hallucinations and lack of insight. Given continued high suspicion for CJD, we repeated RT-QUIC (positive), total tau (18759) and 14-3-3 (47873) levels. Patient passed away in Jun’23.

Conclusions:

RT-QUIC is based on monitoring real-time conversion of normal prion protein induced by the pathological misfolded form. This case emphasizes the importance of repeating testing in ~4-6 weeks if strong clinical suspicion persists for CJD.