Rationale:
We report a case of progressive encephalopathy in a 76-year-old male along with EEG correlates.
Methods: A 76-years-old man who initially presented with shortness of breath about 1 month after receiving kidney transplant from a cadaveric donor. Workup revealed non-ST elevated myocardial infarction. He was started on symptomatic treatment and neurology consulted for suspected encephalopathy.
Results:
On the initial evaluation, he was intermittently inattentive, with mild dysarthria. Later on, he started having asynchronous, myoclonic jerks in all four extremities along with asterixis.
EEG monitoring was started which showed evidence of background slowing. Over the next 48 hours, he became increasingly somnolent. Episodes of leftward gaze deviation and eyelid myoclonus were observed, along with reduced spontaneous movements as well as appearance of myoclonic jerking of all extremities. On day 5, he had preserved pupillary light-reflex, but there was a progressive loss of other brainstem reflexes. On day 6, the corneal reflex was absent bilaterally. New-onset rotary nystagmus was noted, with fast-phase to the left.
CSF analysis revealed lymphocytic pleocytosis (67%), elevated protein (115 mg/dL), and normal glucose. Empiric treatment with IVIG, high-dose thiamine, and corticosteroids was initiated. The patient’s condition rapidly worsened, with eventual loss of cough and corneal reflexes, unresponsiveness to pain, and apnea by day 7. Pupillary responses remained preserved throughout.
On day 1-2, the EEG showed background slowing with intermittent generalized slowing.There was frequent intrusion of sleep structures into awake state, with frequent epochs of REM sleep (appearance of REM-artifacts with relative decrease in EMG artifact). This finding disappeared as the study progressed. Multifocal non-epileptic myoclonic jerking of limbs was captured on EEG.
On days 1-2, the EEG showed identifiable sleep spindles indicating non-REM sleep, which were then absent on re-evaluation on days 4-5. The background progressively attenuated, with near-suppression on day-8. On day-7 the EEG demonstrated a near continuous artifact in frontotemporal channels, consistent with a combination of left-beating rotary nystagmus and other rapid eye movements. Throughout the recording, no epileptiform discharges or seizures were recorded. Overall, these findings pointed toward progressive brainstem dysfunction.
Given the scenario, rabies encephalitis was suspected, with concerns for donor-derived rabies. It was reported that the kidney donor was allegedly scratched by a wild skunk. RT-PCR testing was performed which confirmed Rabies lyssavirus. Prior to the results, the patient transitioned to comfort care and passed away shortly afterwards.
Conclusions:
The absence of classical rabies symptoms is consistent with paralytic or brainstem predominant rabies, more frequently reported in immunocompromised and organ transplant recipients. In such cases, diagnosis may be delayed until autopsy or late-stage PCR testing. In our case, neurologic consultation and continuous EEG monitoring were instrumental in identifying an encephalitic process despite the absence of clear radiographic or laboratory markers. Funding: None