Approach to altered mental status (pediatrics): Clinical sciences

Altered mental status refers to any change in brain function that significantly impacts behavior, mood, or consciousness. Differential diagnosis for altered mental status includes metabolic disturbances, substance exposure, structural brain lesions, infection, hypoxemia, hypoventilation, shock, and seizures.

If a pediatric patient presents with altered mental status, first perform an ABCDE assessment to determine if they are stable or unstable.

Because altered mental status is a manifestation of many life-threatening conditions, you should consider your patient unstable and start acute management. First, stabilize the airway, breathing, and circulation. Then, 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. For children less than 5 years of age, use the Pediatric Glasgow Coma Scale instead. A GCS score of 3 represents a comatose state, while a score of 15 indicates a normal level of consciousness. In trauma patients, GCS of 8 or less might require intubation, however when dealing with a pediatric patient with altered mental status, you might want to intubate even with higher GCS to protect the airway! Next, obtain IV access, check a bedside glucose, and administer naloxone if you suspect opioid intoxication. Finally, begin continuous vital sign monitoring; and if needed, provide supplemental oxygen.

Once you’ve stabilized your patient, obtain a focused history and physical exam.

Since these patients are often unable to provide a history, you may need to gather information from family members or caregivers. They typically report a significant change in the patient’s level of consciousness, with decreased alertness; confusion; altered mood; or altered behavior, like inconsolable crying. These symptoms may fluctuate in severity.

The exam reveals a decreased level of consciousness, with confusion, disorientation, or irritability. In more severe cases, patients may exhibit lethargy, stupor, or coma.

These findings indicate altered mental status. To find out what’s causing it, you’ll need to use clinical findings to guide the diagnostic evaluation, but before you do, check the bedside glucose result.

If the glucose isbelow the reference range for age, your patient has hypoglycemia. This usually corresponds to glucose less than 55 mg/dL in newborns and less than 60 mg/dL in infants and children. Hypoglycemia is a common cause of altered mental status and can result from various etiologies, including reduced oral intake, ethanol intoxication, excess insulin administration, or in rare cases, an inborn error of metabolism. Regardless of its cause, hypoglycemia is a medical emergency that you can treat with intravenous dextrose.

Alternatively, with a glucose level above 250 mg/dL, consider diabetic ketoacidosis. Next, order arterial blood gas, or ABG; BMP, serum beta-hydroxybutyrate level, and urinalysis.

If arterial pH is less than 7.3 or serum bicarbonate level is less than 15, the serum beta-hydroxybutyrate is above 3 mmol/L, and urinalysis reveals moderate to severe ketonuria, your patient meets diagnostic criteria for diabetic ketoacidosis.

Here’s a clinical pearl! Hyperosmolar hyperglycemic syndrome, or HHS, is another important cause of altered mental status with hyperglycemia. These patients have glucose levels above 600 mg/dL and serum osmolality above 320 mOsm/kg; without ketoacidosis. Keep in mind that HHS is typically seen in older patients, but it can occasionally occur in children with type 2 diabetes.

Moving on, if the bedside glucose is normal, you should look for medication or other substance exposures.

Your patient might use recreational substances, like opioids, alcohol, or sympathomimetics; or take medications, such as salicylates, antihistamines, or tricyclic antidepressants. Younger children might have ingested a household agent, such as antifreeze or an organophosphate pesticide.

If there’s a confirmed or suspected substance exposure, or if your patient shows signs of improvement after naloxone administration, their altered mental status is probably medication- or substance-induced.

However, if there’s no confirmed or suspected substance exposure, be sure to rule out structural brain disease.

Your patient may present after blunt head trauma, but even if there’s no reported injury, remember to think about non-accidental head trauma, especially when evaluating an infant. History may reveal a known CNS condition or a previous neurosurgical procedure, such as ventriculoperitoneal shunt placement. In the case of trauma, the exam may show evidence of a basilar skull fracture, like raccoon eyes or periorbital bruising; Battle sign, which is bruising behind the ear; or hemotympanum, which is blood behind the tympanic membrane. Focal neurological deficits, such as asymmetry in tone, movements, or reflexes, suggest intracranial pathology.

If you see any of these findings, obtain a head CT. It may reveal an intracranial hemorrhage, hydrocephalus, cerebral edema, a space-occupying lesion, or a vascular malformation. Any one of these confirms structural brain disease, which is the likely cause of your patient’s altered mental status.

Keep in mind that patients with concussion may have a normal CT scan, and some intrinsic CNS lesions resulting from vasculitis or multiple sclerosis might not show up on a CT scan, so you may need to consider other imaging modalities, such as MRI.

Now, if your patient has no indications for neuroimaging, proceed with an assessment for nonstructural causes of altered mental status, starting with infection.

Let’s start with CNS infections. These patients typically have fever, headache, photophobia, and occasionally neck stiffness; while the exam may demonstrate nuchal rigidity and a positive Kernig or Brudzinski sign. With these findings, consider CNS infection.