Altered Mental Status – Delirium
Cardinal Presentations / Presenting Problems, Neurological, Psychiatric and Behaviour
- Altered mental status is common, representing 5-10% of all patient visits to the emergency department (ED).
- Amongst vulnerable populations (elderly, demented) these rates are even higher.
- When undiagnosed, delirium results in significantly increased mortality rates.
- Delirium is defined by the DSM-5 as an acute, fluctuating change in attention, awareness, and cognition.
- Given the broad differential, it is important to have a concise, evidence-based approach to investigating and diagnosing this common chief complaint.
- While many scoring tools exist to help diagnose delirium (CAM, RASS), the ED environment (loud noises, distractions) and time constraints make delirium a clinical diagnosis. As such, a thorough history from the patient and collateral sources (if possible) is of the highest utility.
- Include a medication review to assess for possible etiologies.
- All patients with altered level of consciousness should receive an initial assessment of vital signs and ABC’s for stability, and a complete physical exam, including a thorough neuro exam.
- A basic workup should include a complete blood count, basic electrolytes panel (sodium, potassium, chloride, bicarbonate, blood urea nitrogen, and creatinine), liver function tests, urinalysis, toxicology panel (EtOH, acetaminophen, salicylates), VBG, and ECG.
- Further investigations should be targeted based on the clinical presentation, in order to narrow down the differential diagnosis.
- Drugs: Urine drug screen, serum osmolality.
- Infection: blood cultures, chest XR, urine culture, line culture, LP.
- Metabolic: extended electrolytes (calcium, magnesium, phosphate), thyroid function.
- Structural: head CT.
- Given the broad differential diagnosis for altered mental status, many clinicians opt for a broad approach to investigative testing. Significant caution should be used with certain investigations.
- CT brain scan should not be used routinely but should be considered in patients with the following indications: (SIGN, 4)
- New focal neurological signs
- Reduced level of consciousness not adequately explained by another cause
- History of recent falls
- Head injury
- Anticoagulation therapy.
- Lumbar puncture should not be performed routinely in patients presenting with delirium.
- Results of urinalysis should be interpreted cautiously. Asymptomatic bacteriuria is common. and delirium should not be attributed to a UTI without accompanying clinical signs and symptoms.
- A simple approach to altered mental status utilizes the DIMS mnemonic:
- Drugs (withdrawal or overdose)
- Medications: benzodiazepines, sleeping medications, anticholinergics, neuroleptics, psychotropics
- Drugs of abuse: Alcohol, narcotics
- Infection: pneumonia, UTI, sepsis, cellulitis, endocarditis, meningitis
- Metabolic: hypo/hyperglycemia, hyponatremia, hypo/hyperkalemia, hypo/hypercalcemia, AKI/renal failure, uremia, hypoxia, hypercarbia, acid/base disorders, hyper/hypothyroidism, Wernicke’s encephalopathy
- Cardiac: Myocardial infarction, arrhythmia, heart failure
- Hepatic encephalopathy
- Neurologic: intracranial hemorrhage, ischemic stroke, subacute mass.
- Other: seizures, psychiatric diagnoses (should be a diagnosis of exclusion).
- Drugs (withdrawal or overdose)
Quality Of Evidence?
We are highly confident that the true effect lies close to that of the estimate of the effect. There is a wide range of studies included in the analyses with no major limitations, there is little variation between studies, and the summary estimate has a narrow confidence interval.
We consider that the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. There are only a few studies and some have limitations but not major flaws, there are some variations between studies, or the confidence interval of the summary estimate is wide.
When the true effect may be substantially different from the estimate of the effect. The studies have major flaws, there is important variations between studies, of the confidence interval of the summary estimate is very wide.
OTHER RELEVANT INFORMATION
Kakuma R, Fort GGD, Arsenault L, et al. Delirium in Older Emergency Department Patients Discharged Home: Effect on Survival. Journal of the American Geriatrics Society. 2003;51(4):443-450. doi:10.1046/j.1532-5415.2003.51151.x
Schulz L, Hoffman RJ, Pothof J, Fox B. Top Ten Myths Regarding the Diagnosis and Treatment of Urinary Tract Infections. The Journal of Emergency Medicine. 2016;51(1):25-30. doi:10.1016/j.jemermed.2016.02.009
The purpose of this document is to provide health care professionals with key facts and recommendations for the diagnosis and treatment of patients in the emergency department. This summary was produced by the BC Emergency Medicine Network and uses the best available knowledge at the time of publication. However, healthcare professionals should continue to use their own judgment and take into consideration context, resources and other relevant factors. The BC Emergency Medicine Network is not liable for any damages, claims, liabilities, costs or obligations arising from the use of this document including loss or damages arising from any claims made by a third party. The BC Emergency Medicine Network also assumes no responsibility or liability for changes made to this document without its consent.
Last Updated Dec 13, 2020
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