Thursday morning, Brian Coburn, one of amazing second year Med/Peds residents, presented an interesting case of a 35-year-old patient who presented with hypoactive delirium. The patient’s medical history was significant for epilepsy and opioid use disorder. We started our investigation of possible causes of the patient’s encephalopathy by going through the AEIOUTIPS mnemonic of common causes of altered mental status that can be investigated with basic history, exam, labs, and imaging. Our expert discussants from the Toxicology services provided us a comprehensive overview of the approach to hypoactive toxidromes and judicious interpretation of urine tox screening. After the initial work-up was unrevealing, the team pursued additional investigation with lumbar puncture, EEG, and MRI without contrast that were also negative. The team asked our friends from psychiatry to help elucidate whether the patient’s symptoms may be due to an underlying psychiatric disorder, but the determination was made that a primary medical disease was still the most likely cause.
The patient’s condition continued to progress, and an MRI with contrast ultimately revealed acute, diffuse white matter lesions. Per our radiology colleagues, the differential for these findings included infection/post-infectious causes (viral encephalitis, acute disseminated encephalomyelitis, acute hemorrhagic leukoencephalitis), autoimmune encephalitis, and toxic leukoencephalopathy. Following a repeat LP that was negative for a broad array of infectious, autoimmune, and malignant/paraneoplastic studies, we were left with a diagnosis of opiate-induced toxic leukoencephalopathy. The disease presentation is extremely variable, ranging from minor cognitive impairment, easily confused with psychiatric illnesses, to severe neurological dysfunction. Our toxicologist reminded us that some of these findings can also be seen with potential transient, out-of-hospital anoxic episodes. While there is no proven treatment for toxic leukoencephalopathy, antioxidant therapy with Coenzyme Q10, Vitamin E, and Vitamin C has been used to treat some patients with variable results in the past. The patient received this treatment and spontaneously improved after several days of therapy.
Thank you to Brian, our expert discussants, and our residents for working through the differential of hypoactive delirium and the sequential investigations we needed to get to the bottom of this fascinating case.
