Current Case: Summer 2022

Contributed by:
Aristides Hadjinicolaou, MD
Division of Epilepsy and Clinical Neurophysiology, Boston Children's Hospital, Boston, MA, USA

Case Presentation

Not your regular old Valsalva

An 8-year-old girl with autism, left frontal grey matter heterotopia and drug-resistant epilepsy, with prior EEGs demonstrating abundant sleep-activated multifocal, as well as generalized spikes and polyspike and wave discharges, as well as prior generalized seizures (myoclonic and tonic), presented for evaluation of new spells. In the ED, the events were characterized by head turn followed by falling backwards with eye fluttering for 2 seconds before self-resolving. These events continued at a rate of up to 30 per hour despite valproic acid increase and lorazepam initiation. Video-EEG monitoring captured multiple episodes that began with disordered breathing with grunting and bearing down, after which she became limp, fell and became unresponsive, occasionally followed by jerks of the extremities.

 

 

Question 1: Given the above EEG, what is the most likely diagnosis? ?

  1. Generalized seizure
  2. Focal seizure
  3. Non-epileptic event
  4. Syncope
Answer: (click here)

Correct answer: C. Non-epileptic event.

There were no time-locked ictal EEG changes, however following initial loss of waveform in the chest leads, along with EKG showing a sudden reduction in amplitude suggestive of a Valsalva-like maneuver, EEG noted generalized low amplitude theta slowing which later became high amplitude delta slowing lasting 3-4 seconds before returning to baseline. These sequential changes in respiratory plethysmography channel, EKG channel, followed by EEG changes, correlating with stereotyped clinical changes, confirmed the non-epileptic nature of the events related to breath holding. Considering the repeated nature of the events, as well as the patient’s diagnosis of autism spectrum disorder, a diagnosis of compulsive respiratory stereotypy was established.

Discussion of event physiology: Valsalva with forced expiration against a closed glottis may resemble simple apneas on the respiratory belt. The sequence of events is as follows: (a) sudden rise in intrathoracic pressure result in EKG amplitude reduction due to cardiac axis deviation; (b) reduced cardiac output with a reflex acceleration of heart rate (c) fall in arterial pressure. When maintained over several seconds, cerebral hypoxia ensues, causing diffuse EEG slowing and loss of consciousness with marked pallor. The episodes may be volitional and compulsive, and occur often during idle periods, on arousal, or with strong emotions. This case highlights the importance of concomitant use of cardiac and respiratory channels when evaluating atypical events, especially in at risk patient populations.

Question 2: Which feature does NOT help distinguish respiratory stereotypy from a seizure?

  1. EEG findings
  2. Video
  3. History of epilepsy
  4. Respiratory plethysmography and EKG belts
Answer: (click here)

Correct answer: C. History of epilepsy.

Stereotypies can be present in children both with and without epilepsy. A broad differential should be maintained for new paroxysmal events in patients with a known diagnosis of epilepsy. Video-EEG, including respiratory belt and EKG channels can be useful in monitoring such patients, especially the order in which changes occur. Respiratory belt and/or EKG changes preceding EEG changes, along with the non-ictal EEG findings (e.g. non-evolving slowing with absence of epileptiform discharges), are suggestive of a non-epileptic event. Video review is also essential, as it aids in correlating changes noted on the aforementioned channels to behavioral events or stereotypies.

Question 3: During Valsalva, a change in which monitor is seen first?

  1. Respiratory plethysmography
  2. EKG
  3. EEG
  4. Video
Answer: (click here)

Correct answer: A. Respiratory belt.

The first documented change in Valsalva is a loss of waveform in the respiratory channel (plethysmography), which is then followed by EKG amplitude change.

 

 

Acknowledgments:

Dr. Chellamani Harini and Dr. Jeffrey Bolton for their support and supervision in the preparation of this case.

References

  1. Kuiper A, van Egmond ME, Harms MP, Oosterhoff MD, van Harten B, Sival DA, de Koning TJ, Tijssen MA. Clinical Pearls - how my patients taught me: The fainting lark symptom. J Clin Mov Disord. 2016 Nov 2;3:16. doi: 10.1186/s40734-016-0045-8. PMID: 27822381; PMCID: PMC5090888.
  2. Gastaut H, Zifkin B, Rufo M. Compulsive respiratory stereotypies in children with autistic features: polygraphic recording and treatment with fenfluramine. J Autism Dev Disord. 1987 Sep;17(3):391-406. doi: 10.1007/BF01487068. PMID: 3654490.

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