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Autism and Gastrointestinal Disorders – Pediatrics study pt. 2

January 19, 2010

Part 2 of the discussion of a meta-study published in the January 2010 issue of the journal Pediatrics. I’ve pulled out the 23 consensus statements from the report, grouped them according to topic and provided an explanation below. Once more the disclaimer: this is a discussion of a research report, it is NOT intended as medical advise. If you or a family member have a medical condition, please talk to your doctor about treatment options.

It’s going to be a long post, you may want to top off your coffee before you start reading.

Group 1: Is there a link between ASD and GI disorders?

Statement 1 (Key Statement):
“Individuals with ASDs who present with gastrointestinal symptoms warrant a thorough evaluation, as would be undertaken for individuals without ASDs who have the same symptoms or signs. Evidence-based algorithms for the assessment of abdominal pain, constipation, chronic diarrhea, and gastroesophageal reflux disease (GERD) should be developed.”

These statements are addressing the presence of GI disorders in kids with ASDs as compared to kids with typical development. In their discussion of the first statement, the authors say that kids with ASDs deserve the same treatment as kids without ASDs when it comes to diagnosis and treatment of GI disorders. They also point out that GI disorders in children are difficult to diagnose and treat in general, and can be more so in children with ASDs. More work needs to be done to take into account the special needs of kids with ASDs, especially in terms of their communication limitations and behavioral differences.

Statement 2:
“Gastrointestinal conditions that are reported to be common in individuals without ASDs are also encountered in individuals with ASDs.”

GI disorders cover a wide range of conditions associated with the digestive system, from food allergies and intolerance (think lactose intolerance) to chronic constipation, inflammatory bowel disease (IBD) and gastroesophageal reflux disease (GERD). The authors report that individuals with ASDs and individuals with typical development have the same types of GI disorders. There seems to be nothing unusual about GI disorders in children with ASDs, they are the same types of disorders seen in other children.

Statement 3:
“The prevalence of gastrointestinal abnormalities in individuals with ASDs is incompletely understood.”

However, when we get down to how often GI disorders occur in children with ASDs, it would be good to know if they are more common than in the general population. The committee looked at several studies, six of which they judged to be good quality. Of these six studies, one concluded that 9% of kids with ASDs and 9% of kids without ASDs showed signs of GI disease, so the same rate in both groups. The other five studies all showed a that kids with ASDs were significantly more likely to be diagnosed with GI disorders than their age-matched, developmentally typical siblings or non-related kids. So it is possible that kids with ASDs also suffer from GI disorders more often than other kids, but we do not know why this appears to be true.

There are lots of possibilities: it’s possible that there is a connection between ASDs and GI problems on a developmental level, it’s possible that kids with ASDs are often wrongly diagnosed with GI problems when really something else is causing their distress, so a larger number of kids with ASDs appear to have GI disorders than really do, it’s possible that parents and other caregivers are more alert to behavioral changes in kids with ASDs than in other kids, and so they are more likely to catch them as symptoms of GI disorders. All of these and more are possible reasons why children with ASD are dignosed more often with signs of GI disorders than typically developing children. Investigating these possibilities and figuring out which one(s) are the actual cause is important; it will improve future diagnosis and treatment of GI disorders in children with ASDs.

Statement 4:

“The existence of a gastrointestinal disturbance specific to persons with ASDs (eg, “autistic enterocolitis”) has not been established.”

The committee looked at the study that coined the term “autistic enterocolitis.” This was the only study referenced by the committee looking at the link between ASDs and inflammation in the gut, and the committee wisely repeated the position that one study does not make something true, there needs to be more and larger studies done before the existence of such a disorder can be ruled true or not true.  Edit 02.10.10 — This study, by Wakefield et al, has been fully retracted by The Lancet (the British medical journal that originally published the data).  This study was questioned before, and has now been essentially struck from the scientific record. The journal commented that it appears the study was not approved by an ethics committee and that Dr. Wakefield, the first author of the study, acted irresponsibly and unethically in doing the study. To read the journal’s comments on the retraction, click here (subscription required).  To read my blog post summarizing the retraction, click here.

The study itself sampled only 12 children, and all the children had been previously diagnosed with developmental regression on the autism spectrum. The study found an association between gut inflammation (ileocolitis) and developmental regression. The study did not look at developmentally typical siblings or unrelated children, so we cannot say for certain that the connection is true, because there was no chance for gut inflammation to be found in a child without developmental regression. The committee pointed out that the same type of gut inflammation is often found in developmentally typical children with food allergies and in children with no other health concerns.

So, gut inflammation could be associated with ASDs, but there needs to be larger studies with better controls before we can say for sure. Also, even if a correlation is found, it does not mean that one causes the other. Without studies that look at children at risk for ASDs before they show signs of either gut inflammation or ASDs, we cannot say that gut inflammation is a cause of ASDs. There are studies like this going on now, so hopefully there will be good, reliable information on this issue within the next few years.

Statement 5:
“The evidence for abnormal gastrointestinal permeability in individuals with ASDs is limited. Prospective studies should be performed to determine the role of abnormal permeability in neuropsychiatric manifestations of ASDs.”

In addition to autistic enterocolitis, the committee also looked into the “leaky gut” hypothesis, that kids with ASDs have altered gut permeability. The committee found one study which showed that 9 of 21 (43% ) of children with ASDs also had altered gut permeability (no word on how this was measured) compared to 0 of 40 (0%, obviously) of typically developing children of the same age group. This study is better than the autistic enterocolitis study by virtue of inclusion of typically developing children, however, the committee pointed out that a larger number of children would make the conclusions firmer.

It’s also important to say that no correlation was shown between altered gut permeability and underlying GI disorders. Is a leaky gut a sign of a GI problem, or something that is atypical but not harmful? We do not know. The study also failed to show a correlation between amount of altered gut permeability and the severity of developmental regression (do more permeable intestines = more severe regression? We do not know).

This study is a start, but there is lots more work to be done to determine if a connection between leaky gut and ASDs even exists, and if so, is this a correlation (they happen to go together) or a causal relationship (one leads to the other). The committee recommended more studies like the one described above for enterocolitis, where kids at risk for ASDs are followed before they show signs of either GI problems or regression.

Group 2: ASD can complicate the diagnosis and treatment of GI disorders.

Statement 6:
“Individuals with ASDs and gastrointestinal symptoms are at risk for problem behaviors. When patients with gastrointestinal disorders present with behavioral manifestations, the diagnostic evaluation can be complex.”

The committee cited several studies that suggest that children with ASDs and GI disorders (or other health problems) are at significantly greater risk for problem behaviors (i.e. aggression, self-injury) than children with ASDs in good physical health. Including the possibility of a medical condition as a reason for problem behaviors could lead to new ways to help a child an decrease problem behaviors, or it could lead to unnecessary tests and procedures for a child that may not understand what is happening and may not need a medical intervention. Every child is different and every situation is different. Doctors will have to use their expertise and experience with each patient and their family to plan the best course of evaluation and treatment for an individual child. This plan could include medical evaluation and/or treatment as well as behavioral treatment (such as teaching the child how to cope with or communicate discomfort).

Statement 7:
“For a person with an ASD who presents for treatment of a problem behavior, the care provider should consider the possibility that a gastrointestinal symptom, particularly pain, is a setting event, that is, a factor that increases the likelihood that serious problem behavior (eg, self-injury, aggression) may be exhibited. Sudden and unexplained behavioral change can be the hallmark of underlying pain or discomfort. Behavioral treatment may be initiated as the possible concurrent medical illness is being investigated, diagnosed (or excluded), and treated, but the behavioral treatment should not substitute for medical investigation. The behavioral treatment plan should be developed, implemented, and changed as needed in collaboration with the medical caregivers who are leading the medical investigation.”

Statement 8:
“Education of caregivers and health care providers is necessary to impart knowledge of how to recognize typical and atypical signs and symptoms of gastrointestinal disorders in individuals with ASDs.”

Children with ASDs often present GI symptoms differently than other children. For example, a child with typical developmental skills might say that his tummy hurts, or that eating certain foods makes him feel funny or bad. Because of their difficulties with communication, kids with ASDs can find it difficult or impossible to express GI troubles (or other physical discomfort) in this way. The committee pointed out that behavioral changes (increased irritability, sleep problems, aggression, self-injury, etc.) are quite often the only signs of GI disorders in kids with ASDs. Unfortunately, these behavioral changes are not often attributed to GI symptoms or other physical pain/discomfort, leading to delays in medical treatment. Doctors should be made aware that a GI disorder or other physical problem could be the source of a new problem behavior. Then the doctor, the family and other caregivers can decide on a treatment plan and whether or not it should include a physical evaluation. The committee said they felt that an integrated plan of care, including medical, psychological and behavioral treatments was likely the best way to treat kids with ASDs and GI disorders, but that again, primary care doctors should use their experience with the patient and his/her family and take the lead in forming a plan that works best for each individual child.

Group 3: Nutrition for people with ASD and GI disorders. — these are just the committee statements, I will add explanations as soon as I can.

Statement 9:
“Pediatricians and other primary care providers should be alert to potential nutritional problems in patients with ASDs. Evaluation by a nutritionist who is familiar with nutrition support for individuals with ASDs is recommended if caregivers raise concern about the patient’s diet or if the patient exhibits selectivity of intake or is on a restricted diet.”

Since GI discomfort is often caused by a food allergy or intolerance, people with GI discomfort often avoid certain types of food. Children with ASDs are often picky eaters anyway, and if that sort of selective eating gets extreme or is combined with a restrictive diet, nutrition suffers. All kids need a certain amount of protein, calcium, iron, etc. to grow and develop properly. They also don’t need a lot of junk food and empty calories in their diet. The committee recognizes that it can be difficult for kids to get proper nutrition if their diet is limited for any reason, and so they recommend that parents seek advise from a qualified nutritionist. A nutritionist can take into account a child’s dietary restrictions and help parents design meals and snacks to allow their child to get the right amount of calories and nutrients each day.

Statement 10:
“Primary care nutritional assessment for each person with an ASD should include (1) weight for height or BMI, (2) weight for age, (3) height for age, and (3) any marked changes in growth rate (percentiles over time).”

All children should be tracked by a doctor to make sure they are growing normally. Kids with ASDs are not immune to problems with physical development, including obesity and poor nutrition (this includes taking in too many calories but not enough nutrients as well as too few calories).

Statement 11:
“Anecdotal reports have suggested that there may be a subgroup of individuals with ASDs who respond to dietary intervention. Additional data are needed before pediatricians and other professionals can recommend specific dietary modifications.”

Statement 12:
“Available research data do not support the use of a casein-free diet, a gluten-free diet, or combined gluten free, casein-free (GFCF) diet as a primary treatment for individuals with ASDs.”

Statement 13:
“For patients with ASDs, a detailed history should be obtained to identify potential associations between allergen exposure and gastrointestinal and/or behavioral symptoms.”

Statement 14:
“Standardized definitions of adverse reactions to foods would be helpful in discussions with patients/providers. These definitions also should be used in studies of adverse food reactions in individuals with ASDs.”

Statement 15:
“For patients with ASDs, a detailed history (including personal history of allergic disease, dietary history, and family history) and physical examination should be performed to accurately identify potential co-morbid allergic disease.”

Statement 16:
“Involvement of specialists (allergists, gastroenterologists, dietitians, and feeding therapists) for the management of individuals with ASDs may be beneficial.”

Group 4: Could gut inflammation be the cause of GI disorders in people with ASDs, or even ASDs themselves?

Statement 17:
“Immunologic aberrations have been reported in individuals with ASDs. However, a direct cause-and-effect relationship between immune dysfunction and ASDs has yet to be proven.”

Statement 18:
“The role of immune responses in the pathogenesis of gastrointestinal disorders in individuals with ASDs warrants additional investigation.”

Statement 19:
“The role of gut microflora in the pathogenesis of gastrointestinal disorders in individuals with ASDs is not well understood.”

Statement 20:
“Given the heterogeneity of persons with ASDs and the many inconsistent research findings regarding ASDs, it is imperative that the phenotype (biological, clinical, and behavioral features) of future study subjects be well defined. This will help to clarify the underlying pathophysiology and the clinical aspects of the disorder and guide focused evaluations and treatments.”

Statement 21:
“Studies of gastrointestinal disorders in ASDs should include genetic testing for all participants.”

Statement 22:
“Prevalence and characterization of specific gastrointestinal symptoms should be examined in well-defined genetic syndromes with high rates of ASDs.”

Statement 23:
“Clinical trials of treatment of gastrointestinal symptoms should include banking of DNA samples.”

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