The Prevalence of Lymphoid Nodular Hyperplasia in Children and Adolescents with Autism Spectrum Disorder

Lymphoid nodular hyperplasia (LNH) is characterized by diffuse hyperplasia of lymphoid follicles in the gastrointestinal tract, commonly observed in children with abdominal pain, food allergies, and autism. Clinical evaluation, colonoscopy, and anatomopathology are key tools in diagnosing LNH in the terminal ileum, notably associated with autism, inflammatory changes, and eosinophil influx. This study examines the clinical-endoscopic correlation with anatomopathological findings in autistic children and adolescents undergoing ileocolonoscopy to investigate nodosity in the terminal ileum. A total of 100 cases were retrospectively analyzed, including 50 patients with autism spectrum disorder (ASD) and 50 controls without ASD, all under 16 and subjected to ileocolonoscopy at HUAP over the last 20 years. There was a predominance of males in the ASD group (χ2 = 10.18, p < 0.001), aged between three and 16 years. The control group showed a balanced gender distribution. No significant age difference was found between the groups. The incidence of LNH was significantly higher in ASD patients (χ2 = 36.99, p < 0.001), with moderate LNH more frequent in ASD (χ2 = 37.44, p < 0.001) and mild LNH more common in controls (χ2 = 39.60, p = 0.001). Clinical complaints did not differ significantly between groups except for abdominal distension, which was more frequent in ASD (χ2 = 4.17, p = 0.041), while blood in stool and diarrhea were more common in controls (χ2 = 16.88, p < 0.001 and χ2 = 5.88, p = 0.015, respectively). Endoscopic features of nodosity in the terminal ileum were reliably diagnosed through biopsy and confirmed by anatomopathological analysis. The study suggests a correlation between digestive and neurological symptoms, indicating a link between the Enteric Nervous System (ENS) and the Central Nervous System (CNS), supporting the "second brain" concept of the gut, and justifying gastrointestinal investigation in autistic patients with digestive symptoms.