What to order for a patient with acute confusion?

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Last updated: May 1, 2025View editorial policy

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From the Guidelines

If a patient is suddenly confused, I would recommend ordering a comprehensive workup to identify the underlying cause of the acute confusion (delirium). This approach is supported by the most recent evidence, which emphasizes the importance of addressing the underlying causes of delirium 1. The workup should start with vital signs, including temperature, blood pressure, heart rate, respiratory rate, and oxygen saturation.

  • Basic laboratory tests, such as complete blood count, comprehensive metabolic panel, urinalysis, and urine culture, should be ordered to check for infection or metabolic abnormalities.
  • Blood glucose measurement is essential to rule out hypoglycemia or hyperglycemia.
  • Additional tests, such as blood cultures, arterial blood gas, thyroid function tests, vitamin B12 and folate levels, and toxicology screening, including alcohol level, should be considered based on the patient's presentation.
  • Neuroimaging with CT or MRI of the brain should be performed to rule out stroke, hemorrhage, or mass lesions, as recommended by the EULAR guidelines for the management of systemic lupus erythematosus with neuropsychiatric manifestations 1.
  • An electroencephalogram (EEG) may be useful if seizure activity is suspected.
  • Lumbar puncture should be considered if meningitis or encephalitis is a concern.
  • Medication review is crucial, as many drugs can cause confusion, especially in elderly patients.
  • The use of medications, such as antipsychotics or benzodiazepines, should be considered only when other interventions are ineffective in controlling agitation and an underlying cause of delirium has been excluded, and should be used in the lowest effective dose and for the shortest period of time possible 1.

From the Research

Patient Assessment

If a patient is suddenly confused, it is essential to assess their condition promptly. The patient's confusion could be a symptom of a serious underlying condition, such as a central nervous system (CNS) adverse drug reaction (ADR) 2, 3.

Potential Causes

Some potential causes of confusion in patients include:

  • CNS ADRs induced by antibiotics such as ceftriaxone 2 or other cephalosporins 3
  • Status epilepticus, which can cause neurological abnormalities and confusion 4
  • Encephalopathy, which can result in confusion, altered mental status, and other neurological symptoms 2, 3

Diagnostic Tests

To diagnose the cause of confusion, the following tests may be ordered:

  • Electroencephalogram (EEG) to assess brain activity and detect any abnormalities 2, 4, 3
  • Plasma concentration tests to measure the levels of certain medications, such as ceftriaxone, in the patient's blood 2, 3
  • Renal function tests to assess the patient's kidney function and determine if it is contributing to the confusion 2, 3

Treatment

Treatment for confusion will depend on the underlying cause. If the confusion is due to a CNS ADR, the offending medication may need to be discontinued 2, 3. For status epilepticus, treatment with antiseizure medications such as benzodiazepines, fosphenytoin, or valproate may be necessary 4. In some cases, general anesthesia or immunotherapy may be required 4.

Legal and Ethical Considerations

When treating a confused patient, clinicians must also consider legal and ethical challenges, such as assessing the patient's capacity and obtaining informed consent 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Serious Neurological Adverse Events of Ceftriaxone.

Antibiotics (Basel, Switzerland), 2021

Research

Diagnosis and Treatment of Status Epilepticus.

Journal of epilepsy research, 2020

Research

The confused patient in the acute hospital: legal and ethical challenges for clinicians in Scotland.

The journal of the Royal College of Physicians of Edinburgh, 2013

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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