Causes of Acute Neurological Deterioration


Published: 17 May 2023

Early detection of neurological deterioration in patients means interventions are more likely to be successful (Shahrokhi & Asuncion 2023).

Therefore, you must be informed about the possible causes of neurological deterioration, know how to correctly assess the patient and intervene appropriately.

A decrease of two or more points on the Glasgow Coma Scale (GCS), which measures a patient's level of consciousness on a scale of 3 to 15, is a warning sign of neurological deterioration (Shkirkova et al. 2018; Trauma Victoria 2023).

Patients may present in a variety of consciousness states ranging from full alertness and awareness, to some level of impairment, to complete unawareness and unresponsiveness (Cooksley, Rose & Holland 2018).

A patient with a GCS score of less than eight is considered to be neurologically compromised, which is a medical emergency relying on prompt diagnosis and medical management for a favourable patient outcome (Cooksley et al. 2018).

neurological deterioration gcs
A decrease of two or more points on the Glasgow Coma Scale is a warning sign of neurological deterioration.

Read: Performing a Neurological Assessment

Common Causes of Neurological Deterioration

While a neurological assessment is useful for recognising deterioration, the cause will need to be identified so that the patient can be appropriately treated. The following are some common causes of neurological deterioration:


Sedation-related neurological deterioration may be caused by opiate overdose or anaesthetic that has not been reversed effectively, causing the patient to remain heavily sedated.

The patient may present with:

  • Pinpoint pupils
  • Respiratory decline or a decrease in respiratory rate. This may cause apnoea, which is a medical emergency
  • Drowsiness or unresponsiveness (in the case of opiate overdose)
  • Airway obstruction or hypoxia (may occur if an anaesthetic has not been reversed appropriately).

(Vincent et al. 2018; CEC 2013; Schiller et al. 2022)


Neurological deterioration may be caused by a:

  • Ischaemic stroke
  • Haemorrhagic stroke
  • Space-occupying lesion.

The patient’s pupils may appear unequal. A stroke is a medical emergency and requires early intervention.

(Jeffery et al. 2019; Stroke Foundation 2022)


A patient experiencing a seizure may present with mydriasis (dilated pupils) (Kutlu et al. 2014).

In the case of a seizure, protect the patient and call for assistance.


Hypoglycaemia (abnormally low glucose levels) can cause neurological deterioration, as the brain relies on blood glucose for energy (Harvard Health Publishing 2022). It may be caused by:

  • Fasting
  • Poor nutrition
  • Administration of insulin
  • Medications
  • Excessive alcohol consumption
  • Endocrine disorders.

(Brutsaert 2019)

Other Causes

Other causes of neurological deterioration include:

  • Traumatic brain injury
  • Tumour
  • Lack of oxygen (e.g. from drowning or a heart attack)
  • Infection
  • Toxins (e.g. carbon monoxide)
  • Drugs and alcohol.

(Mayo Clinic 2018)

Managing Neurological Deterioration

  • Assess the patient using the GCS in conjunction with a head-to-toe assessment.
  • Assess the patient’s level of consciousness.
  • Ensure the patient is free from any environmental danger. If the patient is on the floor, call for assistance and only move them to the bed if they are haemodynamically stable and all manual handling equipment is available.
  • Support the patient’s respiratory demands.
  • Increase the frequency of observations.
  • Coordinate relevant scans and tests.
  • Implement 3 or 5-lead cardiac monitoring if appropriate.
  • Optimise oxygenation and perfusion status.
  • Perform basic life support if required.
  • Care may need to be escalated to critical care services.


  • The patient may be unable to protect their own airway - this is an emergency situation.
  • If the patient is unresponsive, commence basic life support.
  • If a post-collapse injury occurs, escalate care as required.
  • Consider critical care admission if required.


Early detection of neurological deterioration contributes to successful intervention and favourable patient outcomes. Ensure you:

  • Treat the patient’s signs and symptoms promptly
  • Increase the frequency of observation
  • Identify the cause of the deterioration
  • Correct any metabolic and electrolyte imbalances
  • Support the patient’s haemodynamic status.

Note: This article is intended as a refresher and should not replace best-practice care. Always refer to your facility's policy on recognising and responding to acute neurological deterioration.


Test Your Knowledge

Question 1 of 3

What change to a patient’s GCS score might indicate neurological deterioration?


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