Pediatric EM Morsels is, for me, the best pediatric education resource on the internet because the format of each post allows me to review the subject and also to review quickly other topics because of the outstanding format of the posts – the beginning of each post contains links to Dr. Fox’s posts on related topics. For an example of how Dr. Fox does this see his post on Hyperammonemia [I’ve excerpted the beginning of that post below]:
The child with altered mental status certainly grabs our attention (rightfully so) and we have discussed several related topics. We often consider the infectious concerns (ex, Encephalitis, Meningitis, Sepsis) and traumatic etiologies (ex, head injury, hemorrhagic shock). We are always very vigilant for possible Hypoglycemia! Unquestionable, toxicologic issues also leap to our minds (ex, Loperamide Overdose, Ethanol Ingestion, Huffing Hydrocarbons, Iron toxicity, and Carbon Monoxide Poisoning), but let us not overlook the potential for that “poison” coming from the patient’s own body (ex, Inborn Errors of Metabolism). Let us take a minute to digest a morsel on the management of Hyperammonemia: . . .
And below are excerpts from Dr Fox’s post, Non-Convulsive Status Epilepticus:
Most chief complaints generate a clear Differential Diagnosis (Ddx) list in your mind. There are the well-known, “big ticket” issues that need to be considered (Abdominal Pain -> Appendicitis; Chest Pain -> Pericarditis; Headache -> Meningitis) as well as the more common causes (Abdominal Pain -> CRAP; Chest Pain -> Asthma; Headache -> Benign Headaches). The challenge with children, as we have stated numerous times, is that the significant problems can masquerade as benign ones. Additionally, their non-specific presentations overlap greatly, requiring us to be ever vigilant. One presentation that requires a very broad Ddx list is Altered Mental Status. Let us take a minute to highlight one item on that Ddx list that may be overlooked – Non-Convulsive Status Epilepticus in Children:
Non-Convulsive Status Epilepticus
- My simple definition: Non-Convulsive Status Epilepticus (SE) = an electrical storm in the brain, but there is no shaking on the outside.
- It is like the Pulseless Electrical Activity of the brain… there is electrical activity, but no muscular movement.
- Both are bad!
It is NOT Rare! [Abend, 2009]
- It is common in ALL inpatient settings, not just the PICU. [Greiner, 2012]
- Estimates vary (based on the definition used).
- Incidence as high as 46% of critically ill children.
- In children with clinical suspicion for non-convulsive SE, 14% found to have it. [Greiner, 2012]
Continuous EEG is required to make the diagnosis! [Wilson, 2015]
- The lack of external seizure activity makes this challenging to detect.
- There may be subtle “twitching” or “abnormal eye movement.”
- May also present as: [Yamaguchi, 2019]
- Abnormal Movements
- Prolonged Altered Consciousness
- Ultimately, the diagnosis is dependent upon the EEG findings.
- Prompt recognition is important to be able to improve outcomes. [Yamaguchi, 2019; Greiner, 2012; Tay, 2006]
- Initiation of EEG is often delayed…
- Hard to recognize need.
- Hard to coordinate STAT EEG.
- Reduced-lead (4 channel) EEG or EEG “cap” has been successful at detecting seizure activity within 1 hour! [Yamaguchi, 2019; Jafarpour, 2015; Greiner, 2012; Abend, 2009]
- Early EEG (even in the ED) can help pick up on the diagnosis early and affect therapy.
- ~50% of non-convulsive SE can be seen in first hour.
- 80-87% detected within 24 hours of continuous EEG monitoring.
Non-Convulsive Status Epilepticus: When To Consider
- High Risk for Non-Convulsive SE [Wilson, 2015; Jafarpour, 2015; Greiner, 2012]
- Acute Encephalopathy
- Status Epilepticus or Refractory Status Epilepticus [Tay, 2006]
- Just because you successfully resolved the external shaking, doesn’t mean the brain is still not in a chaotic electrical storm.
- Certainly, if you intubated the patient, then the paralytic will create “non-convulsive SE.”
- Other considerations for Non-Convulsive SE [Wilson, 2015; Greiner, 2012]
- Underlying Epilepsy Diagnosis
- Younger Age (< 24 months of age)
- Underlying Congenital Heart Disease
- Use of a Reduced-Lead EEG (only 4 electrodes) has been shown to help expedite detection of non-convulsive SE while patient is still in the ED. [Yamaguchi, 2019]