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  Do not delay bedside glucose determination, administration of glucose, and naloxone, if indicated. These interventions may prevent the need for endotracheal intubation.

  
  
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  Talk to the paramedics and family; they can often identify the cause of altered mental status (AMS).

  
  
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  Identify level of AMS, systemic conditions, and any focal deficits with the physical examination.

  
  
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  Re-examine your patients frequently and note any changes in condition and response to therapy.

Altered mental status (AMS) may have an organic (ie, structural, biochemical, pharmacologic) or functional (ie, psychiatric)cause. AMS accounts for 5% of emergency department (ED) visits. About 80% of patients with AMS have a systemic or metabolic cause, and about 15% have a structural lesion.

Consciousness has 2 main components: arousal and cognition. Arousal is controlled by the ascending reticular activating system (ARAS) in the brainstem. Cognition is controlled by the cerebral cortex. Lethargy, stupor, obtundation, and coma are imprecise terms used to describe alterations of arousal. A description of the patient’s arousal level (eg, opens eyes to voice) is preferable. Delirium is an alteration of both arousal and cognition. Patients exhibit restlessness, agitation, and disorientation. Dementia is an alteration of cognition, not arousal.

ARAS is a complex system of nuclei in the brainstem. It may be impaired by small structural lesions in the brainstem such as ischemic or hemorrhagic stroke, shear forces from head trauma, or external compression from brain herniation. Severe toxic and/or metabolic derangements (eg, hypoxia, hypothermia, drugs) can also cause impairment. Bilateral cerebral cortex dysfunction must occur to cause decreased levels of arousal or profound AMS. This is usually caused by toxic/metabolic derangements, infection, seizures, subarachnoid hemorrhage (SAH), or increased intracranial pressure (ICP). Unilateral lesions such as stroke do not by themselves cause profound AMS.

History

AMS represents a spectrum of disease presentations from profoundly depressed arousal requiring emergent intubation to severe agitation and confusion requiring restraint and sedation. Initial stabilizing measures are often needed before a complete history and physical examination can be performed.

If the patient is unable to give a coherent history, alternate sources of history should be sought. Prehospital providers should be questioned about the patient’s condition in the field, therapies given and the response, and the condition of the home environment (eg, pill bottles, suicide note). Family members should be contacted to ascertain past history of similar episodes, medical history, trauma, substance abuse, and the last time the patient was seen in a normal state. The patient’s belongings should be searched for medical identification bracelets, pill bottles, phone numbers, or other potential sources of information.

Patients presenting to the ED with AMS often include the elderly, who are more prone to infection, have comorbid illnesses, and take multiple medications; substance abusers (eg, heroin, cocaine, alcohol withdrawal, and liver failure); and psychiatric patients who may be on mood-stabilizing drugs, which, when taken in excess, have toxic effects that cause abnormal arousal or cognition.

Physical Examination

Vital signs; airway, breathing, and circulation (ABCs); pulse oximetry; and bedside glucose should be assessed, looking for immediate life threats and treatable causes of AMS (ie, hypoglycemia, hypoxia or abnormal respiratory pattern, hyper- or hypotension, hyper- or hypothermia). Naloxone (Narcan), glucose, and thiamine should be administered, as dictated by history and examination.

A “head-to-toe” examination should follow, looking for systemic causes of AMS and focal neurologic deficits. The head should be examined for any signs of trauma. Pupil size, symmetry, and reactivity should be assessed. Pinpoint pupils are a sign of opiate overdose or pontine hemorrhage. An asymmetrically dilated “blown” pupil is a sign of uncal herniation. Fundi should be assessed for the presence of papilledema or subhyaloid hemorrhage associated with SAH. Neck stiffness indicates meningeal irritation caused by either SAH or infection. Cardiovascular exam should assess for dysrhythmias (atrial fibrillation), murmurs (endocarditis), or rubs (pericarditis). Lung exam should assess for symmetric breath sounds, respiratory rate, wheezes, rhonchi, and rales. Abdominal exam should assess for masses and organomegaly (alcoholic liver disease, splenic sequestration in sickle cell disease). Skin exam should assess for color, turgor (dehydration), rashes (petechiae, purpura suggesting thrombotic thrombocytopenic purpura or meningococcemia), and infection (cellulitis, fasciitis). If the neurologic examination cannot be completed because of the patient’s mental status, document what you are able to do and how the patient appears. Mental status assessment should include AVPU (alert, responds to voice, responds to pain, unresponsive). If the patient responds to voice, the appropriateness and coherence of the response should be documented. The cranial nerves, motor, deep tendon reflexes (including Babinski or plantar reflex), cerebellar, and sensory examinations should be included if possible.