Elsevier

Critical Care Clinics

Volume 24, Issue 1, January 2008, Pages 1-24
Critical Care Clinics

Mechanisms of Neurologic Failure in Critical Illness

https://doi.org/10.1016/j.ccc.2007.11.004Get rights and content

Critical illness frequently is associated with neurologic failure that may involve the central and peripheral nervous systems. Central nervous system failure is associated with a spectrum of neurobehavioral changes including delirium, coma, and long-term cognitive dysfunction. Peripheral neurologic failure, or critical illness neuromuscular abnormalities, is suggested by diffuse arreflexic weakness and protracted respiratory insufficiency, and may also persist long after the acute hospitalization. While the burden of neurological disease complicating critical illness is considerable, preventive or therapeutic options are limited. This article provides an overview of research evaluating the relationship between critical illness and neurologic function, with a special emphasis on underlying mechanisms.

Section snippets

Neurobehavioral changes in critical illness

Clinical evidence of global disturbances in brain function is frequent in the ICU and includes anxiety, confusion, agitation, stupor, and coma. Terms that have been used to denote these changes include “ICU syndrome,” ICU psychosis,” “organic brain syndrome,” “acute confusional state,” “delirium,” “cerebral insufficiency,” “brain failure,” and “encephalopathy.” In recent years, there has been an effort to rationalize and simplify this terminology, with a special emphasis on the syndrome of

Long-term cognitive dysfunction

Available evidence suggests that 30% to 80% of critical illness survivors suffer from long-term cognitive dysfunction (LTCD), which may include, but is not limited to, significant deficits in memory, attention, and executive function [104], [105], [106], [107], [108]. Together with psychiatric disorders (eg, depression, anxiety, and posttraumatic stress disorder) and neuromuscular sequelae, it is believed that LTCD contributes significantly to the reduced quality of life and functional

Critical illness neuromuscular abnormalities

In addition to NCCI, a subset of critically ill patients acquire a syndrome of neuromuscular dysfunction characterized by generalized weakness, decreased or absent deep tendon reflexes, and an inability to wean from mechanical ventilation [149]. Weakness in this setting is associated with a spectrum of disorders including ICU-acquired polyneuropathy, several subtypes of myopathy, and coexisting polyneuropathy and myopathy, collectively termed CINMA [3], [150]. In a recent systematic review of

Summary

Neurologic failure is frequent in critically ill patients and represents a key facet of multiple organ dysfunction. Types of NCCI such as delirium and coma reflect the brain's response to a diverse array of insults, including perturbations in systemic physiology, metabolism, inflammation, and iatrogenic factors such as neuroactive drug administration. NCCI is associated with profound derangements in brain electrophysiology, structure, metabolism, inflammatory state, and neurotransmitter

References (213)

  • J.P. Konsman et al.

    Cytokine-induced sickness behaviour: mechanisms and implications

    Trends Neurosci

    (2002)
  • K. Plaschke et al.

    Significant correlation between plasma and CSF anticholinergic activity in presurgical patients

    Neurosci Lett

    (2007)
  • M.J. Burns et al.

    A comparison of physostigmine and benzodiazepines for the treatment of anticholinergic poisoning

    Ann Emerg Med

    (2000)
  • R.C. van der Mast et al.

    Is postoperative delirium related to reduced plasma tryptophan?

    Lancet

    (1991)
  • M.C. Lewis et al.

    Postoperative delirium: the tryptophan dysregulation model

    Med Hypotheses

    (2004)
  • P. Ferenci et al.

    Serum levels of gamma-aminobutyric-acid-like activity in acute and chronic hepatocellular disease

    Lancet

    (1983)
  • R.D. Stevens et al.

    The spectrum of encephalopathy in critical illness

    Semin Neurol

    (2006)
  • D. Crippen

    Life-threatening brain failure and agitation in the intensive care unit

    Crit Care

    (2000)
  • C.F. Bolton

    Neuromuscular manifestations of critical illness

    Muscle Nerve

    (2005)
  • M.S. Herridge

    Long-term outcomes after critical illness: past, present, future

    Curr Opin Crit Care

    (2007)
  • W.L. Wright et al.

    Postresuscitative intensive care: neuroprotective strategies after cardiac arrest

    Semin Neurol

    (2006)
  • K.E. Wartenberg et al.

    Impact of medical complications on outcome after subarachnoid hemorrhage

    Crit Care Med

    (2006)
  • D.A. Zygun et al.

    Non-neurologic organ dysfunction in severe traumatic brain injury

    Crit Care Med

    (2005)
  • American Psychiatric Association

    American Psychiatric Association task force on DSM-IV. Diagnostic and statistical manual of mental disorders:DSM-IV

    (1994)
  • J.W. Devlin et al.

    Delirium assessment in the critically ill

    Intensive Care Med

    (2007)
  • E.W. Ely et al.

    Delirium as a predictor of mortality in mechanically ventilated patients in the intensive care unit

    JAMA

    (2004)
  • S. Ouimet et al.

    Incidence, risk factors and consequences of ICU delirium

    Intensive Care Med

    (2007)
  • P. Pandharipande et al.

    Motoric subtypes of delirium in mechanically ventilated surgical and trauma intensive care unit patients

    Intensive Care Med

    (2007)
  • S. Ouimet et al.

    Subsyndromal delirium in the ICU: evidence for a disease spectrum

    Intensive Care Med

    (2007)
  • N. Bergeron et al.

    Is disturbance of consciousness an important feature of ICU delirium?

    Intensive Care Med

    (2005)
  • E.W. Ely et al.

    Delirium in mechanically ventilated patients: validity and reliability of the confusion assessment method for the intensive care unit (CAM-ICU)

    JAMA

    (2001)
  • A. Petzold et al.

    Critical illness brain syndrome (CIBS): an underestimated entity?

    Crit Care Med

    (2005)
  • E.B. Milbrandt et al.

    Bench-to-bedside review: critical illness-associated cognitive dysfunction—mechanisms, markers, and emerging therapeutics

    Crit Care

    (2006)
  • P.W. Kaplan

    The EEG in metabolic encephalopathy and coma

    J Clin Neurophysiol

    (2004)
  • A.M. Husain

    Electroencephalographic assessment of coma

    J Clin Neurophysiol

    (2006)
  • E.F. Wijdicks et al.

    Practice parameter: prediction of outcome in comatose survivors after cardiopulmonary resuscitation (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology

    Neurology

    (2006)
  • G.B. Young et al.

    The encephalopathy associated with septic illness

    Clin Invest Med

    (1990)
  • G.B. Young et al.

    The electroencephalogram in sepsis-associated encephalopathy

    J Clin Neurophysiol

    (1992)
  • H.A. Sackeim et al.

    Electrophysiological correlates of the adverse cognitive effects of electroconvulsive therapy

    J ECT

    (2000)
  • H.A. Sackeim et al.

    The effects of electroconvulsive therapy on quantitative electroencephalograms. Relationship to clinical outcome

    Arch Gen Psychiatry

    (1996)
  • S. Jacobson et al.

    EEG in delirium

    Semin Clin Neuropsychiatry

    (2000)
  • N.E. Noldy et al.

    Acute, withdrawal, and chronic alcohol effects in man: event-related potential and quantitative EEG techniques

    Ann Med

    (1990)
  • P.T. Trzepacz et al.

    Delirium: a subcortical phenomenon?

    J Neuropsychiatry Clin Neurosci

    (1989)
  • J. Claassen et al.

    Detection of electrographic seizures with continuous EEG monitoring in critically ill patients

    Neurology

    (2004)
  • A.R. Towne et al.

    Prevalence of nonconvulsive status epilepticus in comatose patients

    Neurology

    (2000)
  • F. Plum et al.

    The diagnosis of stupor and coma

    (1980)
  • J. Parvizi et al.

    Neuroanatomical correlates of brainstem coma

    Brain

    (2003)
  • J.T. Giacino et al.

    The minimally conscious state: definition and diagnostic criteria

    Neurology

    (2002)
  • Medical aspects of the persistent vegetative state (1)

    N Engl J Med

    (1994)
  • Medical aspects of the persistent vegetative state (2)

    N Engl J Med

    (1994)
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