Management of children and young people with an acute decrease in conscious level - Clinical guideline

Decreased conscious level can be considered an acute neurological emergency. It is characterised by significant brain impairment, which needs a rapid and methodical approach to evaluation and treatment.

Our NICE accredited 2015 evidence-based clinical guideline provides practitioners working acutely a framework and recommendations to aid the timely and safe care of children and young people presenting with a decreased conscious level of unknown cause.

The current guideline was published in 2015 and subsequently reviewed in 2016 and 2019. It will next be reviewed in 2020.

About the current guideline

Regardless of the underlying cause, a decreased conscious ('DeCon') level indicates a primary insult to the brain which, if left untreated, could rapidly progress to secondary damage leading to significant morbidity or even death.

Since publication of the 2005 Paediatric Accident and Emergency Research Group’s guideline, The management of a child with a decreased conscious level, there had been significant changes in the demographics of the children and young people presenting to emergency settings with a decreased conscious level. This change was identified by a multi-centre audit carried out in 2010-11.

The update was considered necessary due to suggestions for improvement being raised including, for example, other common causes of decreased conscious level such as post-convulsive states, alcohol intoxication and febrile seizures. The continuing support of The National Reye's Syndrome Foundation UK allowed all of this work to be carried out.


The guideline is NICE accredited and has been developed in accordance with the RCPCH Guideline development process manual, RCPCH Setting standards for development of clinical guidelines in paediatrics and child health, 2020.

Consistent with the 2005 guideline, this 2015 guideline emphasises the importance of managing this condition in a standard manner from first presentation to health services, to ensure the best outcome for patients and their families.

You can download below the full clinical guideline, appendicessummary of recommendations and printable algorithm poster looking at the management of children and young people with an acute decrease in conscious level.

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August 2016

The following corrections are included in the clinical guideline and the algorithm poster.

  • The measurement unit for the ammonia levels for hyperammonaemia which is referred to in the metabolic section was incorrect. It has been changed to micromol/l instead of mmol/l.
  • The description on how best to take the plasma ammonia sample has been extended for clarity in the algorithm.

March 2019

The following correction is included in the clinical guideline.

  • The description on how to best transport the plasma ammonia sample has been updated.

You can download below the erratum documents from 2016 and 2019, which each full details on where the changes have been inserted.

March 2020

An assessment on the need to update the guideline and which section(s) in particular started this year.. Unfortunately, due to COVID-19, delays to this are likely to occur. An estimated publication date will be published shortly.

Training resource - slide set

You can download below a detailed slide set, which introduces the guideline, provides an overview of its methodology and development, reviews the key recommendations and provides a quick guide on how to use it.