by Jamie Martin, Children’s National

The Case
4 year old previously healthy female presents via EMS with altered mental status, weakness, and abnormal eye movements for a few hours.  One of the challenges of this case was determining what could be the cause of AMS, nystagmus, and ataxia/abnormal gait.

Here’s How You Answered Our Questions

Other = comprehensive tox screen; assess time of day, observe for longer time to determine severity/urgency; utox; 1. Better Neuro exam. 2. Better history (toxic exposure). 3. Neuroblastoma w/u

With initial labs that were reassuring (normal glucose, lactate, etc.), providers felt that a CT-Head was a priority. Most providers felt that with a continued abnormal exam, an LP would likely be indicated prior to admission.  Several providers would give prophylactic ceftriaxone given the unclear etiology.

Denouement
The doctors in this case thought about giving a benzo for an atypical seizure, but deferred given that she was interacting/following commands. They also did not give Narcan, as her VS and exam (no pinpoint pupils) were not indicative of that.  Given the acute onset, they were thinking about tox, but the mom was fairly adamant that the child hadn’t gotten into any meds/household products.

Labs were reassuring. CT head negative. ECG normal. Urine tox was pending. In the meantime, she continued to improve. She was less altered, and the nystagmus less noticeable. Neurology and Poison Control were involved.

It was only after multiple iterations of the question that mom realized/admitted that the “Tylenol” she gave was actually OTC fever and cold medication.

Ultimately, this patient had a positive urine drug screen for PCP. The fever/cold medication mother gave contained Dextromethorphan and the patient had an acute reaction to the medication. Dextromethorphan is one agent that can cause false positive urine drug screen for PCP as well as AMS and nystagmus. She was observed in ED, discharged home once improved MS, normal gait, tolerating PO. Poison Control agreed and planned to follow up with the patient the next morning.

Teaching Points
Ddx AMS, nystagmus, and ataxia/abnormal gait:
ICH (eg: subdural), space-occupying lesion (abscess/tumor), other malignancy like neuroblastoma, encephalitis/meningitis/labyrinthitis, medications (eg: Lithium, AED’s, Baclofen, Amitriptyline, etc.), and tox (ethanol, PCP, dextromethorphan, and benzo’s)

Things not to miss:
– Intracranial hemorrhage/SDH, though no history of trauma and no findings on exam
– Brain abscess, encephalitis, though no fever
– Neoplasm, exam and onset were not consistent with opsoclonus myoclonus (click here for video)

According to UpToDate, if concerns about neuroblastoma, obtain urine or serum catecholamine metabolite levels, vanillylmandelic acid (VMA) and homovanillic acid (HVA).
Ferritin and LDH concentrations may be elevated initially in neuroblastoma patients.
Ultrasonography can usually be obtained quickly and may confirm the presence and location of a mass. However, it should be followed by either CT or MRI.