Precipitated Opioid Withdrawal Treated With Ketamine in a Hospitalized Patient: A Case Report.

BACKGROUND: Although initiating buprenorphine in the presence of full opioid agonists has always been a clinical dilemma, the transition to primarily fentanyl in the drug supply has increased the urgency to find appropriate treatments for precipitated opioid withdrawal (POW). Although rare, lack of evidence on how to best treat POW threatens clinician and patient comfort in initiating life-saving medication for opioid use disorder. Ketamine has been used in emergency department settings to treat POW; this is the first case report of ketamine use in a hospitalized patient. CASE SUMMARY: A 38-year-old male patient with severe opioid use disorder presented to the emergency department with suicidality and opioid withdrawal 24 hours after last fentanyl use. In the first 24 hours of admission, he received sublingual buprenorphine-naloxone (BNX) 16-4 mg, resulting in Clinical Opiate Withdrawal Scale score increasing from 13 to over 36. The patient was admitted, and addiction medicine was consulted. The patient was diagnosed with POW, started on ketamine infusion, and given additional BNX 8-2 mg. Twelve hours after the ketamine infusion, the patient's Clinical Opiate Withdrawal Scale score improved to 18 but remained elevated. He received a second ketamine infusion plus additional BNX with complete resolution of symptoms within 8 hours, and he was stabilized and discharged on BNX 24-6 mg daily. CLINICAL SIGNIFICANCE: Ketamine is a promising treatment for POW due to its potentiation of µ-opioid receptor-mediated signaling. This is the first case to describe POW in the inpatient hospital setting. More research is needed to establish the effectiveness and feasibility of ketamine as treatment for POW.

Diverse Central Projection Patterns of Retinal Ganglion Cells.

Understanding how >30 types of retinal ganglion cells (RGCs) in the mouse retina each contribute to visual processing in the brain will require more tools that label and manipulate specific RGCs. We screened and analyzed retinal expression of Cre recombinase using 88 transgenic driver lines. In many lines, Cre was expressed in multiple RGC types and retinal cell classes, but several exhibited more selective expression. We comprehensively mapped central projections from RGCs labeled in 26 Cre lines using viral tracers, high-throughput imaging, and a data processing pipeline. We identified over 50 retinorecipient regions and present a quantitative retina-to-brain connectivity map, enabling comparisons of target-specificity across lines. Projections to two major central targets were notably correlated: RGCs projecting to the outer shell or core regions of the lateral geniculate projected to superficial or deep layers within the superior colliculus, respectively. Retinal images and projection data are available online at http://connectivity.brain-map.org.