Approach to altered mental status: Clinical sciences

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Introduction0:00–0:35

Altered mental status refers to the abnormal change in consciousness, cognition, behavior, or mood, which can range from mild confusion to coma.
It can occur suddenly, like following acute intoxication, or gradually, as in hepatic encephalopathy. Altered mental status can arise from various causes, including abnormal glucose levels, toxins and medications, central nervous system conditions, infections, and metabolic disorders.
If your patient presents with altered mental status, perform an ABCDE assessment and start acute management. Stabilize the patient’s airway, breathing, and circulation.

ABCDE assessment/Acute management0:35–1:38

Next, assess their level of consciousness by checking the Glasgow Coma Scale or GCS, which measures eye-opening, verbal, and motor response to stimuli on a scale from 3 to 15.
A GCS score of 3 represents a comatose state, while a score of 15 represents a normal level of consciousness. Moreover, individuals with a GCS of 8 or less might require intubation.
After that, obtain IV access and check a fingerstick glucose. If it is low, give IV glucose.
If you suspect opioid intoxication, administer naloxone. Lastly, don’t forget to start continuous vital sign monitoring, including blood pressure, heart rate, and pulse oximetry.

H&P1:38–2:10

Once you stabilize your patient, obtain a focused history and physical examination. Since these patients are often unable to provide a history, you may need to gather information from family members, caretakers, or witnesses.
History usually reveals a change in the patient’s level of consciousness, behavior, or mood, which can be persistent or fluctuate in severity with time.
Additionally, the physical exam reveals a decreased level of consciousness, as well as confusion and memory loss. As you are dealing with altered mental status, your next step is to assess the underlying cause.

Abnormal glucose levels2:10–3:55

Start by obtaining serum glucose levels. If glucose levels are above 250 mg/dL, consider hyperglycemic hyperosmolar syndrome or HHS or diabetic ketoacidosis or DKA, and order labs including arterial blood gas, known as ABG, or venous blood gas analysis, also known as VBG; serum osmolality; CMP; and serum and urine ketones like beta-hydroxybutyrate.
If labs reveal glucose levels above 600 mg/dL; pH above 7.3; bicarbonate levels greater than 18 with variable anion gap; serum osmolality above 320 mOsm/kg; with minimal to no serum and urine ketones, you are dealing with hyperosmolar hyperglycemic syndrome or HHS.
Alternatively, if labs reveal glucose levels above 250 mg/dL; pH less than 7.3; bicarbonate levels less than 15; increased anion gap, variable serum osmolality; and high serum and urine ketone levels, your patient has diabetic ketoacidosis or DKA.
Going back a step, if the serum glucose is below 55 to 70 mg/dL, the cause of altered mental status is hypoglycemia. Let’s switch gears and talk about normal glucose levels.

Hypoxia and Hypercapnia3:55–4:32

First, you should rule out hypoxia or hypercapnia. If your patient presents with shortness of breath, and their physical exam reveals an abnormal respiratory rate, abnormal lung sounds, and possibly cyanosis, consider hypoxia or hypercapnia and obtain ABG.
If the ABG reveals decreased partial pressure of oxygen, your patient has hypoxia, but if it shows an elevated partial pressure of carbon dioxide, that’s hypercapnia.

Toxins/medications4:32–6:51

Next, you should look for toxin- and medication-induced altered mental status. Some individuals might have a history of recent substance use, which may include CNS stimulants like amphetamines or depressants like opioids.
Physical exam findings can vary based on the substance involved. For example, CNS stimulants might result in diaphoresis, an increased respiratory rate, and dilated pupils.
On the other hand, CNS depressants are typically associated with a decreased respiratory rate, and constricted pupils. In this case, consider intoxication, and order a urine toxicology screen and serum alcohol level.
If either comes back positive diagnose intoxication as the cause of the altered mental status. Next up is withdrawal syndrome.
These patients present with a history of a recent reduction or cessation of alcohol or substance use. The physical exam shows agitation, increased heart rate, and blood pressure; or depression and fatigue if they are experiencing withdrawal from stimulants.
With these findings, consider withdrawal syndrome, and again, order a urine toxicology screen and serum alcohol levels. If the results are negative, the substance has been metabolized and eliminated from the body, so the cause of altered mental status is probably withdrawal syndrome.
Here’s a clinical pearl! A positive serum alcohol level does not necessarily rule out alcohol withdrawal.
Sometimes, individuals with prolonged, heavy alcohol use can experience withdrawal even when they still have detectable serum alcohol levels.
They are at high risk of severe withdrawal, which can be life-threatening. Moving on to medication adverse effects.
History reveals the use of medications with known CNS side effects, such as antiepileptics, antipsychotics, and sedatives.
If the suspected medication was recently started, your patient’s altered mental status is probably due to that medication’s adverse effects.
Now let’s take a look at the most important CNS-related causes of altered mental status, which include traumatic brain injury or TBI, cerebrovascular accidents, and CNS infections.

CNS-related causes6:51–8:50

Patients with TBI typically present with a history of blunt head trauma. Their physical exam might reveal focal neurological deficits, such as hemiparesis.
In this case, consider traumatic brain injury and order a head CT. If it shows an intracranial hemorrhage or evidence of a concussion, like cerebral edema or contusion, diagnose TBI.
Moving on to cerebrovascular accident or CVA. History reveals a sudden onset of neurological symptoms, such as word-finding difficulties or even being obtunded.
Patients might also have risk factors for stroke, like high blood pressure, smoking, or atrial fibrillation. The physical exam may reveal signs of focal neurological deficits, like a speech deficit.
In this case, consider a cerebrovascular accident and order a head CT. If the CT scan reveals a large ischemic or hemorrhagic stroke, diagnose cerebrovascular accident.
Next up are CNS infections. If your patient presents with fever, headache, photophobia, and possibly neck stiffness, while the physical exam possibly reveals nuchal rigidity, consider a CNS infection, like meningitis or encephalitis.
Then, perform a lumbar puncture to collect cerebrospinal fluid and send it for analysis. If it shows any consistent abnormalities, your patient has a CNS infection.

Other infections8:50–10:20

Alright, after addressing CNS causes, let’s consider non-CNS infections, like urinary tract infection or UTI, and pneumonia.
Patients with UTI typically report dysuria, urinary frequency, or urgency. The physical exam might reveal suprapubic or costovertebral angle tenderness.
In this case, consider a UTI and order a urinalysis. If urinalysis is positive for nitrates, leukocyte esterase, white blood cells, or bacteria, you can diagnose UTI.
Next up is pneumonia. These patients typically present with fever and productive cough.
The physical exam usually reveals an elevated body temperature, with or without decreased oxygen saturation and lung crackles.
With these findings, consider pneumonia, and order a chest X-ray to confirm. If it reveals infiltrates, diagnose pneumonia as the cause of altered mental status.
Here’s a high-yield fact! Respiratory and urinary tract infections are common causes of altered mental status, especially in elderly patients.
However, any other infection can also cause altered mental status. So, if your patient has a fever, leukocytosis, and signs of a localized infection, that could be the cause of their altered mental status.

Metabolic disorders10:20–12:24

Finally, let’s go over metabolic disorders that can lead to altered mental status, starting with uremic encephalopathy. These patients typically present with symptoms like confusion, lethargy, muscle cramps, and itching, with a known history of chronic kidney disease.
The physical exam might reveal tremors or asterixis. With these findings, consider uremic encephalopathy, and obtain a CMP.
If the CMP reveals elevated levels of BUN and creatinine, often accompanied by hyperkalemia, you can diagnose uremic encephalopathy.
Next up is hepatic encephalopathy. Patients typically present with a history of liver disease or cirrhosis.
The physical exam might reveal asterixis, as well as other signs of liver disease such as jaundice, ascites, and palmar erythema.
With these findings consider hepatic encephalopathy. Keep in mind that cirrhosis with asterixis is enough to make the diagnosis.
However, if you don’t find both, obtain a CMP. If it shows elevated levels of AST, ALT, ALP, and bilirubin, think of hepatic encephalopathy.
Here is one last clinical pearl! Other metabolic causes of altered mental status include electrolyte abnormalities and acid-base disorders, both of which can disrupt brain function.
Examples include hyponatremia, hypernatremia, hypocalcemia, and hypercalcemia, as well as acid-base disorders like metabolic acidosis and alkalosis.
Additionally, the altered mental status might be caused by endocrinopathies like myxedema coma, delirium, brain tumors, psychiatric disorders, and finally nonconvulsive status epilepticus.

Review12:24–12:56

Alright, as a quick recap… Altered mental status refers to changes in consciousness, cognition, behavior, or mood. Acute management should address easily reversible causes, such as hypoglycemia and opioid intoxication.
Besides abnormal glucose levels, other causes of altered mental status include hypoxia or hypercapnia, toxins and medications, central nervous system disorders, infection, and metabolic disorders.