Delayed posthypoxic leukoencephalopathy: a case series and review of the literature

Abstract

BackgroundDelayed posthypoxic leukoencephalopathy (DPHL) is a rare and underrecognized entity where patients manifest a neurological relapse after initial recovery from an acute hypoxic episode. We sought to describe the magnetic resonance imaging (MRI) findings in a group of patients with DPHL and review the available literature.MethodsRetrospective case series including patients who presented with neurological and/or psychiatric symptoms after recovery from an acute hypoxic episode. The history and clinical presentation were reviewed from the electronic medical records. MRI scans were evaluated from the picture archiving and communication system. We performed a comprehensive review of the English medical literature for prior published cases of DPHL and describe the key imaging findings that have been reported related to this condition.ResultsA total of five patients were identified, including four patients with respiratory failure due to drug overdoses from benzodiazepines, opioids, and/or barbiturates, and one patient who presented after cardiopulmonary arrest due to pulmonary embolism. All patients showed diffuse, extensive, and confluent white matter signal abnormalities including prominent restricted diffusion, extending to the subcortical white matter and respecting the U-fibers. There was no gyral edema or contrast enhancement. In one case histopathology was available, which highlighted patchy subcortical myelin loss with sparing of U-fibers and demonstrated prominent macrophage/microglial inflammation with extensive axonal damage. Of the other four patients, two were at their neurological baselines and two had persistent neurological deficits at the time of discharge.ConclusionsThe described constellation of MRI findings is highly suggestive of DPHL in the appropriate clinical setting.

Clinical Reasoning: A case of altered mental status, not otherwise specified

“…7 Other suggested mechanisms include direct toxicity of carbon monoxide or heroin (heroin-associated delayed spongiform leukoencephalopathy) 8 to oligodendrocytes as well as disruption of myelin-producing pathways due to pseudodeficiency of arylsulfatase A. 9 The fact that a number of cases have shown significant recovery may relate to the ability of oligodendrocytes to repair their myelin sheaths, and oligodendrocyte progenitors to differentiate into mature myelinforming oligodendrocytes.…”

Delayed Posthypoxic Leucoencephalopaty: Is a Rare Condition in Patients after Episodes with Hypoxia Due to Drug Overdose with Opioids, Benzodiazepines and Barbiturates, Among Other Causes

“…Other reported symptoms are hyper reflexia, increased tone, ataxia and global weakness. In the majority of case reports patients recover within a year to their baseline or near baseline neurological status [2][3][4]. Figure 1: Baseline MRI (top two pictures) and follow-up MRI after 7 months in 42 year old patient with DPHL after intentional opioid overdose.…”

“…Myelin-related proteins as arylsulfatase A, ischemic-based necrosis of oligodendrocytes and inflammatory and oxidative processes are suspected to be involved [3].…”

“…Patients present with subacute onset of neurological and neuropsychological symptoms after an episode of acute hypoxia with initial recovery [1][2][3]. DPHL typically occurs 1 to 4 weeks after an episode of acute hypoxia.…”

“…Hypoxia may be due to respiratory failure associated with an overdose of opioids, benzodiazepines or barbiturates [4][5][6]. Previous case reports of DPHL are after respiratory failure due to carbon monoxide intoxication, cardiac arrest or strangulation [3].…”