Symptom overlap: Challenging diagnoses in pediatric neurology

SEATTLE — Sarah J. Spence, MD, PhD, shared tips on differentiating pediatric neurological conditions with overlapping symptoms, at the 2022 American Academy of Neurology annual meeting.

Among the conditions Spence detailed were infantile spasms, which she noted are one of the most common forms of epilepsy in infancy. Children who have spasms as infants, she said, often have higher rates of intellectual disabilities later in life.

“There is something about social communication that's really specific with infantile spasms,” Spence, co-director of the Autism Spectrum Center at Boston Children's Hospital, said. “If you look at a group of kids with spasms, 10% to 15% will develop autism later. And if you look backwards in a group of people with autism, you find out that a certain percentage had spasms as babies.”

Moreover, nearly 30% of adults with autism or epilepsy had spasms in infancy, she said.

Tuberous sclerosis complex, a hereditary condition that can cause frequent seizures, also can be linked to high rates of epilepsy and autism. Spence said autism rates range from 40% to 50% for those with tuberous sclerosis complex.

Another clinical condition that mimics others is Landau-Kleffner syndrome, which affects speech and can cause seizures.

“There is language regression in autism. There's behavioral regression in autism. There are EEG abnormalities in autism, the same way there are in Landau-Kleffner,” she said. “When we see individuals with a major regression, we do go looking.”

According to Spence, there is no single epilepsy syndrome, so making a diagnosis when someone is presenting with seizures is often difficult.

“It's actually sometimes hard, for even expert epileptologists, to tell the difference between what looks like a focal seizure or an absence seizure in some autistic behaviors,” she said. “If you look at some focal seizure behavior, you are going to see unresponsiveness. How do you find out whether somebody is unresponsive? You call their name. What is one of the diagnostic criteria of autism? Not answering when your name is called. So, this is a little bit of a tricky issue.”

Spence reminded attendees that when speaking with parents who think their child is seizing, it is the clinician’s job to point out the differences in presentation.

“I talk to families about the seizure [being] very involuntary, and autism behavior seems much more voluntary,” she said.