CJD is a rare and deadly neurodegenerative disease that rapidly transforms minds, taking patients from health to profound cognitive and motor decline in a matter of months. The typical triad of symptoms include- Rapidly progressive dementia, myoclonus and ataxia along with some visual disturbances and behavioural changes.

CASE: 

Here we present a case of a 71 year old female who presented to the ophthalmologist with complaint of vision loss predominantly in the left eye. Her vision in left eye was 6/60 and in the right eye it was 6/18. Her fundus and MRI brain with contrast were normal. The visual evoked potentials showed increased P100 latencies. This patient received Solumedrol pulse for five days on OPD basis with a presumptive diagnosis of left eye retrobulbar optic neuritis, By the fifth day of pulse, she presented to us with complains of visuo- spatial disorientation ,ataxia and new onset recent memory loss. She was admitted under neurology and we evaluated her for neurodegenerative disorder. Her CSF analysis including CSF 14.3.3 protein was negative and EEG was normal at this stage. Patient was discharged with the umbrella diagnosis of Rapidly progressive neurodegenerative disorder. On follow up after 10 days, this patient had complete cortical blindness, severe cognitive decline, startle myoclonus and landed up in a wheel chair bound state. Her serial EEG showed typical periodic sharp wave pattern seen in CJD and repeat MRI Brain showed diffusion restriction in the occipital areas. At this stage the family history was revealed that this patient's brother also suffered from CJD around 10 years back, so we got a PRPN mutation analysis which came out to be positive.

Peculiarities in this case:

• Although ophthalmological features can be an initial presentation of CJD ,so far we have seen reports of patients presenting with cortical blindness, visual agnosia or hemifield defects but this patient was different as this patient presented with predominantly monocular vision loss.
• This is a rare case of familial CJD (PRPN mutation positive) that presented initially  with opthalmological features which are more commonly observed in sporadic Heidenhain variant of CJD.

Take home message:

• Early visual disturbances may be the first sign of CJD, prompt recognition is important for timely diagnosis.

• Importance of serial investigations in CJD (EEG and MRI) as initial investigations may be normal.

Dilemma- Should we conduct genetic testing in the children of this patient? As the psychosocial aftermath outweighs the benefits we would gain by detecting the mutation of this deadly and untreatable disease.