1515 - Anatomically-Driven Neuropharmacological Management of a Pontine Stroke: A Case Report

Case Diagnosis: Cognitive and arousal dysfunction secondary to noradrenergic dysregulation from pontine stroke treated with methylphenidate

Case Description: 76-year-old male with history of alcohol use disorder, hypertension, and hypothyroidism was initially admitted for encephalopathy in the setting of alcohol withdrawal. During his hospital course, he developed new cognitive deficits including short-term memory loss and inattention, as well as impaired arousal. Patient was admitted to inpatient rehabilitation (IPR) to address these symptoms.



Brain magnetic resonance (MR) imaging showed a new area of restricted diffusion at the dorsolateral pons, suggesting early infarct, and preexisting left frontoparietal strokes.



In IPR, the patient continued to exhibit arousal and cognitive deficits. Rivastigmine was trialed to target cholinergic pathways associated with his prior frontoparietal strokes but had no appreciable effects. The proximity of the patient's lesion to the locus coeruleus, the noradrenergic region of the brain, was considered, and methylphenidate, a norepinephrine reuptake inhibitor, was trialed. The patient improved following this intervention, evidenced by an 11-point improvement on the Montreal Cognitive Assessment.

Discussions: We present a patient who had deficits in cognition and arousal following a pontine stroke. Initial treatment with rivastigmine was unsuccessful, but reclarifying the location of the lesion allowed us to target our treatment towards the appropriate pathways. The locus coeruleus is the primary area of norepinephrine synthesis in the brain and has wide-reaching noradrenergic projections to the hippocampus, amygdala, and hypothalamus. Hypothesizing a hyponoradrenergic state, we initiated methylphenidate, a dopamine and norepinephrine reuptake inhibitor, after which improved memory, attention, and arousal were observed. 

Conclusions: This case highlights the utility of leveraging neuroanatomy in determining appropriate treatment for patients following stroke.  Left untreated, cognitive deficits can impede therapy tolerance, functional gains, and quality of life during a critical recovery period. Using objective data can help us tailor our therapies toward specific pathways and optimize outcomes.