Altered mental status resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Moises Romo, M.D.

Overview

Altered mental status can result from a variety of factors, including alterations in the chemical environment of the brain, insufficient oxygen or blood flow in the brain, and excessive pressure within the skull. The level of consciousness may decline abruptly or slowly, or it may increase and decrease intermittently. Life threatening causes of altered mental status include malignant hypertension, myocardial infarction, rabies and sepsis. Other common causes of altered mental status include alcohol withdrawal, dehydration, electrolyte disturbance and hypoglycemia.

Causes

Life Threatening Causes

Life-threatening causes include conditions that may result in death or permanent disability within 24 hours if left untreated

• Carbon monoxide toxicity
• Heat stroke
• Hypothermia
• Malignant hypertension
• Myocardial infarction
• Rabies
• Sepsis

Common Causes

• Alcohol withdrawal
• Drug withdrawal
• Dehydration
• Electrolyte disturbance
• Encephalitis
• Epileptic seizures
• Hyperglycemia
• Hypoglycemia
• Meningitis
• Sepsis

Diagnosis

Shown below is an algorithm summarizing the diagnosis of altered mental status according to the the American Academy of Neurology guidelines.

Patient with altered mental status (Amnesia, confusion, loss of alertness, disorientation, disruption of judgement, behavior and perception)

Evaluate ABCDEF • Airway • Breathing • Circulation • Disability (Glasgow coma scale) • Exposure (Rapid head to toe revision) • Fingerstick blood glucose

Check vital signs

Unstable?

Yes

Stabilize

No

Combative?

Yes

Apply physical or chemical restrain

No

Alcoholism and thiamine deficiency suspected?

Yes

Administer thiamine

Improvement

Yes

End

No

Hypoglicemic?

Yes

Administer dextrose

Improvement?

Yes

End

No

Opioid intoxication suspected?

Yes

Administer naloxone

Improvement?

Yes

End

No

Take history

Perform physical examination with full neurologic evaluation

Order CBC, electrolyte panel, liver and kidney function tests (including albumin), urinalysis, urine culture, urine toxicology screen, chest x-ray, EKG

Suspected neurodegenerative disease?

Yes

Perform minimental exam

No

Positive for neurodegenerative electrolyte imbalance, hepatic encephalopathy, urinary infection, pneumonia, drug intoxication?

Yes

End

No

Perform non-contrasted CT scan of the brain

Positive for stroke or structural causes (hidrocephalus, neoplasms)?

Yes

End

No

Perform lumbar puncture

Yes

End

Positive for neuro infection or subarachnoid hemorrhage?

Yes

End

No

Suspicious for status epilepticus?

Yes

Perform EEG

Positive for status epilepticus?

Yes

End

No

Order the following tests guided by findings of the evaluation: Serum ammonia, thyroid function tests, morning cortisol, vitamin B12, arterial blood gas, sedimentation rate, autoimmune serologies including antinuclear antibodies, thyroperoxidase and thyroglobulin antibodies, blood cultures, extended toxicology screen, blood gas analysis

Positive for sepsis, intoxication, overdose, withdrawal, concusion, Hashimoto encephalopathy, hypothyroidism, uremic encephalopathy, porphyria, B12 deficiency, autoimmune encephalitis, carbon monoxide intoxication?

Yes

End

No

Perform a thorough psychiatric evaluation to rule out psychiatric conditions

Do's

• Perform an ABCDEF evaluation as a first step.
• If combative, use physical or chemical restraining.
• Take a non-contrasted CT scan of the head before contrasted when head trauma is suspected.
• Sodium imbalances should be slowly corrected to avoid a central pontine myelinolysis or a brain herniation.

Don'ts

• Do not administer glucose before thiamine, when alcoholism and thiamine deficiency is suspected. Administration of glucose before thiamine may lead to Wernicke encephalopathy.
• Do not assume psychiatric causes of altered mental status until the level of extent from other physical or chemical triggers is ruled out.