POUNCE syndrome is a rare phenomenon speculated to occur due to the direct neurotoxicity caused by opioids resulting in preferential cerebellar cytotoxic edema with variable supratentorial involvement. The preferential neurotoxic involvement of the cerebellum in children is thought to be secondary to the greater cerebellar expression of mu-opioid receptors with high opioid affinity.  As of 2020, only about 20 cases have been reported in literature.

We present the case of a 6-year-old female who was transferred to our facility with acute hypoxic respiratory failure and encephalopathy, which required intubation for airway protection. Seizures were also reported at the outside hospital.  It was then discovered that patient had developed a cough and was accidentally given cough syrup in which a family member was hiding methadone.

Initial work up with MRI brain showed restricted diffusion with ADC correlate and associated T2-FLAIR hyperintensities in the bilateral cerebellar hemispheres as well as small, scattered areas in the bilateral posterior cerebral hemispheres. No large vessel occlusions were identified on vessel imaging. On EEG, there was slowing in the left posterior hemisphere, but no epileptiform discharges or overt seizures were noted. In conjunction with the history of opioid ingestion, these imaging findings were suggestive of POUNCE syndrome. As our patient required continued analgesia, fentanyl was transitioned to non-opioid alternatives.

This case demonstrates the importance of early recognition of POUNCE syndrome as this could alter management decisions. Although a reliable history was presented in this case, the recognition of typical imaging findings seen in POUNCE syndrome may allow for accurate diagnosis based on imaging alone.