Gastrointestinal Disease in Children with ASD

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Evaluation of patients with ASD and co-morbid chronic gastrointestinal symptoms consists of thorough review of the clinical history (with emphasis on the chronology of presenting gastrointestinal and developmental symptoms), clinical data obtained from the patients existing medical records, select laboratory testing, and a patient/parent interview.

Patients in whom this data suggest the presence of gastroesophageal reflux disease, acid-peptic disorder, food allergy, inflammatory bowel disease, allergic/autoimmune esophago-gastro-enteropathy, or autistic enteritis/enterocolitis are often in need of a comprehensive diagnostic survey of the gastrointestinal tract, including gastrointestinal endoscopy and biopsy. Microscopic examination of biopsy obtained gastrointestinal tissue remains the gold standard in making an accurate diagnosis for purposes of appropriate therapeutic intervention.

During endoscopic procedures, a variety of lesions in the esophagus, stomach, small bowel and colon are typically discovered. The lesions take the form of ulcerations, erosions, erythema, inflammatory polyps and prominent and disease-associated lymphoid nodular hyperplasia. In addition to lesions strongly associated with the co-occurring ASD diagnosis, additional diagnoses such as acid reflux esophagitis are frequently encountered. 

There are three traditionally recognized chronic inflammatory diseases of the gastrointestinal tract that together, fall under the larger category of Inflammatory Bowel Disease: ulcerative colitis, Crohn’s Disease, and indeterminate enterocolitis. 

Patients with ASD's appear to suffer from a fourth form of IBD, autistic enterocolitis. Autistic enterocolitis is defined as inflammation of varying intensity anywhere in the gastrointestinal tract with associated prominent lymphoid nodular hyperplasia, in the setting of autism, and lacking the specific diagnostic features of ulcerative colitis or Crohn’s Disease. Importantly, unique histochemical and molecular features of ASD-associated bowel inflammation distinguish it from both Crohn’s disease and ulcerative colitis. It’s appearance ONLY in children with the diagnostic features of “autism” suggests that the autism and gastrointestinal disease are related (for further information regarding the diagnosis of autism-associated enterocolitis, click here)
 

While the underlying cause of autism-specific intestinal disease is still unknown, it appears to result from an exaggerated, poorly regulated immune response involving the gastrointestinal mucosa, which is the lining of the GI tract. The most common clinical manifestations of these lesions are diarrhea, abdominal pain, constipation, abdominal distention and growth problems. It is thought that behavioral symptoms traditionally attributed to autism may often in fact be symptoms of gastrointestinal disease or gastrointestinal pain.

GI symptoms can precede, coincide with, or appear after the onset of the behavioral, cognitive, or neurological symptoms of autism or autistic regression. A current conceptual model linking the gastrointestinal pathology to cognitive deficits involves a biochemical sequence of events in which luminal contents, which consist primarily of ingested foods and products of microbial degradation, are pathologically absorbed through the highly permeable inflamed intestinal mucosa before they are properly broken down intraluminally into smaller micromolecules. The absorbed macromolecules then undergo metabolic degradation and processing by pathways not normally employed, resulting in the production of byproducts that may be toxic to the developing brain. Included are immunological responses to the these “foreign” absorbed substances. Though ultimately theoretical, this proposed mechanism is supported in its separate steps, both by published scientific data, the observations of clinicians caring for these children, and most importantly, the observations of countless parents.

Identification and treatment of gastrointestinal disease in children with ASD is for the purpose of alleviating the symptoms of gastrointestinal disease, just as in children without ASD.  

Pain, diarrhea, constipation, growth failure etc. needs to be treated in children with ASD just as in any other child. Proper gastrointestinal evaluation, diagnosis, and treatment in this group of children is often hampered by a historic bias favoring psychiatric explanations for ASD behaviors, an over-reliance by health care personnel on psychotropic medications, lack of familiarity or tolerance for alternative treatments often employed by families, reluctance to scientifically embrace the concept of gut-brain interactions, and the realistic time constraints present in meeting the complex medical, behavioral, cognitive, and social needs of these children and their families within the limited time available during typical physician office visits.

Individual patient Intolerance to many commonly used medications and added ingredients (e.g. dyes, preservatives, etc.), feeding difficulties, and the overall poor cooperation of many ASD children impose further difficulties in attempting to treat these children. Our office staff takes great pride in the knowledge and experience in dealing with each and every one of these issues, gained from years of experience interacting with almost 2000 children and their families.

Many of the gastrointestinal diagnoses in these children are curable, as they are in neurotypical children. While other diagnoses, such as IBD's (inflammatory bowel disease), are not curable, IBD's are treatable and most patients respond to some combination of anti-inflammatory medication, antimicrobials, probiotics, digestive enzymes and dietary restriction. These responses are measurable in quantifiable improvement in the presenting gastrointestinal symptoms.    

Proper diagnosis and treatment of gastrointestinal disease in autistic children may result not only in improvement of their gastrointestinal symptoms (normalization of the stool, resolution of pain, weight gain, proper growth, etc.) but also in improvement of behavioral and cognitive symptoms following gastrointestinal symptom resolution. It is thought that the presence of chronic GI symptoms, whatever their source, makes the child less available to the benefits of proven behavioral and functional therapies and that treating them removes this barrier.

Proper diagnosis and treatment of gastrointestinal disease in autistic children not only may lead to improvement in their gastrointestinal symptoms, such as normalized stool, resolution of pain, weight gain and proper growth, but can also lead to improvement in behavioral and cognitive symptoms upon resolution of chronic pain. 

Aside from being intuitive, this conclusion has also been widely disseminated as a consensus opinion in a recent publication in Pediatrics, the flagship journal of the American Academy of Pediatrics.

Treating the gastrointestinal symptoms of children with ASD may not treat autism as such, but relieving these children of chronic physical pain can make them more available for the therapies that are of demonstrated benefit and allow them to better participate in an academic setting.