Paediatric acute-onset neuropsychiatric syndrome (PANS): Age-related symptomatology and comparison with non-PANS...

To characterise the clinical features in children with paediatric acute-onset neuropsychiatric syndrome (PANS), and compare these features to non-PANS neurodevelopmental disorders (NDDs).

Using a standardised tool (NDD-ECHO), clinical data was prospectively captured from 162 patients referred with tics and/or OCD, some of whom were referred due to a suspicion of PANS, before clinical assessment. The Strengths and Difficulties Questionnaire (SDQ) compared behaviour in all children, and 58 healthy controls were used for reference. At clinical review, the patients were classified into PANS (n = 56, median age 12 years, [range 4-21], 59% male) and non-PANS NDDs (n = 106, median age 10 years, [range 4-18], 72% male).

The median age at first neuropsychiatric flare in PANS was 5 years, with males presenting earlier (4 years vs 6.5 years, p < 0.05). In addition to core symptoms of obsessive-compulsive disorder (OCD, 98%) and eating restriction (62%), younger children with PANS were more likely to have new onset speech dysfunction during flares whereas older children had depression. OCD symptoms were present in 98% of children with PANS and 27% of children with non-PANS NDDs, tics were less common in PANS compared to non-PANS NDDs (66% vs 84%, p < 0.05), whereas autism (43% vs 31%, ns) and attention deficit hyperactivity disorder (57% vs 58%, ns) did not differ. Severe fluctuations and relapsing-remitting course were more common in PANS than non-PANS NDDs (54.3% vs 28.7%, and 11% vs 1%, both p < 0.05, respectively). However, symptom fluctuations of any kind were common in both PANS and non-PANS NDDs (73.8% and 88.2%, ns, respectively), with stress reported as an exacerbating factor in both groups (84.4% vs 87.2%, p = 0.795), whereas infection was a reported exacerbating factor more frequently in PANS (80.0% vs 50.5%, p = 0.003). Maternal autoimmune disease was more common in PANS than non-PANS NDDs (49% vs 17%, p < 0.001), particularly autoimmune thyroid disease (26% vs 2%, p < 0.0001). SDQ scores were significantly higher in PANS compared to non-PANS NDDs in emotional, internalising, and impact domains (all p < 0.01).

PANS demonstrates age-related symptomatology, familial autoimmunity, and significant behavioural impact in emotional domains. Clinical fluctuations provoked by environmental factors are common to both PANS and non-PANS NDDs, suggesting that gene-environment interactions are common to many NDDs, with PANS being a severe phenotype.