|
Course Sample:
"What can physicians do for these children? We have to look at them and forget that they have autism. Do the workup as you would for any other child." ? Arthur Krigsman, MD, Pediatric Gastroenterologist
I. Introduction
I.1. What Is Autism?
Autism is a developmental disorder characterized by expressive language dyspraxia or aphasia and myriad deficits in socialization, sensory processing, learning, and neuromotor skills. Seizure disorders and mental retardation may or may not be co-morbid. IQ is frequently unaffected and may be higher than normal. Autism spectrum disorders (ASD) include the diagnoses of classic autism, Asperger?s syndrome (AS), and pervasive developmental disorders-not otherwise specified (PDD-NOS). All appear to frequently feature co-morbidities for nutrition and gastrointestinal (GI) problems. Adults with frank autism are often not able lead independent lives and may require custodial or residential care for life. Individuals with Asperger?s syndrome, high functioning autism, or PDD-NOS may achieve varying degrees of independence as adults, and often need support to successfully navigate school, jobs, and life skills. For differential psychological descriptions of autism spectrum diagnoses, see the Diagnostic and Statistical Manual of Mental Disorders IV (2000).
I.2. Autism On The Rise?
Autism was not described until the mid-20th century, but appears to have risen dramatically in the US in recent years. For 1990, prior to CDC scrutiny of autism, prevalence was estimated at 1.8 per thousand (Newschaffer et all 2005). This shifted to 6.7 per thousand ("1 in 150") in 2002 (CDC 2007). The CDC?s effort to clarify prevalence compared number of ASDs in eight year old children (born in 1992) from six states in 2000, to number of ASDs in eight year old children (born in 1994) from fourteen states in 2002, to see if an increase occurred. It found prevalence to be roughly stable in most sites assessed, with pockets of increase. The report is challenged by using different denominators to obtain prevalence in years compared, and by variation in reporting by state. State by state variation may reflect access to screening resources, or parents? socio-economic status. When data from the same six states are compared for 2000 and 2002, a nearly 10% increase in prevalence is visible1:
|
Site |
2000 Survey
(1992 Births) |
2002 Survey
(1994 Births) |
|
# Children in
Study Area |
# Cases ASD |
# Children in
Study Area |
# Cases ASD |
|
Arizona |
45,322 |
295 |
45,113 |
280 |
|
Georgia |
43,593 |
285 |
44,299 |
337 |
|
Maryland |
21,532 |
118 |
29,722 |
199 |
|
New Jersey |
29,714 |
295 |
29,748 |
316 |
|
South Carolina |
24,535 |
155 |
23,191 |
140 |
|
West Virginia |
23,065 |
104 |
21,472 |
153 |
|
Total |
187,761 |
1,252 |
193,545 |
1,425 |
|
Prevalence rate |
6.7 per thousand |
7.4 per thousand |
Another way to view autism trends is to observe its burden on education resources, as affected children require special accommodations in school. Children receiving special supports or services for autism are not free to obtain them on request, but must pass through a lengthy team review that permits or denies the school district?s choice to assign a disability designation of autism. Another process follows to define the child?s accommodations in an Individual Education Plan (IEP). A typical IEP team for an affected child includes parents, classroom teacher, special education teacher, district staff for speech/language, psychology, and occupational therapy, school principal, and district liaison or head for special education. This rigorous process preserves resources for the neediest children.
Through the Individuals with Disabilities Act (IDEA), the US Department of Education (USDOE) maintains statistics for numbers of children served in public schools under a disability designation of autism. For the 2006-07 school year, nearly 225,000 children ages 6-21 years were served in public schools nationwide under a diagnosis of autism. Excluded from these data are children attending private or home school, children under 6 who may have an ASD diagnosis but who have not yet entered school programs, and 3-5 year olds in public schools who are accommodated via an autism diagnosis:
Children with Autism / ASD age 6?21 in U.S. Schools, 1991-2007 2
1.3. Etiology
Debate continues over ASD etiology. Some attribute the rise in cases to heightened screening, earlier diagnosis, or better discernment between other developmental diagnoses and autism. Contradicting this is an absence of tens of thousands of autistic adults in the population today, who would have been undiagnosed as children 20, 30, or 40 years ago. A hidden bubble of affected adults has not been identified. Autism is a life long disability; while its functional ability features may shift with age, children are not known to outgrow it.
Further countering better diagnosis as primary cause for the increase are existing disincentives to obtaining autism diagnoses and services. A costly and lengthy process, autism diagnosis is given to a child who has missed sufficient developmental milestones, per assessment of many providers. The pediatrician refers this child for review with several specialists, eg, neurologist, developmental pediatrician, geneticist, speech and language pathologist, occupational therapist, behavior therapist, psychiatrist, and/or psychologist, before a diagnosis is made. Procedures that are challenging for toddlers and young children are often required, eg, MRI, blood tests, speech and language evaluations, and cognitive testing. As an expensive, time consuming, and emotionally wrenching experience for families, little incentive exists for pursuing this diagnosis. Once a diagnosis is confirmed, families often face shouldering the costs of therapies and education out of pocket: Treatments other than psychiatric medications or applied behavior analysis are poorly covered by insurance, and many public school systems are ill-equipped to provide adequate learning supports for children with ASD due to budget constraints.. This too is a cumbersome, costly, slow, and often contentious process for schools and families.
I.3.A. Mercury and Autism
Controversy exists regarding mercury toxicity as an environmental trigger for autism. Genetic susceptibility to environmental triggers has emerged as a plausible etiology (Risch et al 1999). Children with autism may have larger body burdens of mercury, a neurotoxin, than typical peers. Adams et al (2007) found higher levels of mercury in baby teeth of children with ASD compared to controls, while levels of zinc and lead in teeth did not differ significantly. Holmes (2003) and Kern (2007) demonstrated that children with ASD did not excrete mercury while control peers did, suggesting that mercury may be sequestered in children with ASD. Bradstreet et al (2003) found in a case control study that oral dimercaptosuccinic acid (DMSA, aka "Chemet", an established treatment for lead poisoning) provoked significantly higher urinary excretion of mercury in children with autism compared to typical controls. An association has been shown between urine porphyrin excretion indicative of mercury poisoning and autism (Morita, 2005; Nataf, 2006); Geier (2006) showed a linear correlation between coproporphyrin level in urine and severity of autism.
If not expediently excreted, mercury sequesters to fatty tissue, eg, brain, nerve tissue, liver, and kidney. Mercury is encountered today from several sources, and in several species (ethyl, methyl, di-methyl, metallic, mercuric, mercurous). Sources include coal burning power plant emissions, food, agricultural chemicals, dental amalgams, industrial processes, and vaccines. US children born between 1990 and 2003 set a precedent by receiving unusually high per kilogram doses of mercury by adhering to the recommended vaccination schedule, which was expanded at that time. Mercury in vaccines occurs as thimerosal, an organic mercury preservative used in many medications for decades. It is nearly 50% mercury by weight and is metabolized to ethylmercury, which crosses the blood brain barrier (Magos, 1985). In addition to receiving more mercury per kg than previous generations did via vaccination, children born since 1990 received vaccine doses earlier, including during the neonatal period. Mercury from thimerosol containing vaccines may represent 50% of total mercury exposure of infants in this cohort (Ball et al 2001). Data from Vaccine Safety DataLink (Verstraeten 2000) found a relative risk of autism of 2.48 in infants receiving 62.5 mcg or more of ethylmercury by three months of age.
In 2001, the National Institute of Medicine stated that a causal connection between thimerosal and autism is "biologically plausible". This triggered efforts to diminish it in pediatric vaccines, though it persists in flu vaccines, DTaP vaccines, vaccines for children over age one year, and in trace amounts in some others. In 2004, the IOM reversed its position, and rejected thimerosal in vaccines as a plausible trigger for autism. Geier and Geier (2006) reviewed trends in neurodevelopmental disorders relative to thimerosal exposures and found a positive linear relationship that reversed with withdrawal of thimerosal from vaccines. Another study (Thompson 2007) showing lack of causal relationship between thimerosal exposure and neurodevelopmental disorders excluded children with autism diagnoses, but did find a correlation between early mercury exposure and speech and motor impediments.
I.4. Nutrition, Biomedical Interventions, and Autism
Regardless of the mercury controversy, therapeutic nutrition measures for autism have been in use since the 1960s. These have been largely administered by parents seeking resolution for developmental concerns, and chronic GI symptoms that are often co-morbid with autism. Nearly half of parents of affected children implement special diets or supplements for autism (Green 2006). Clinical curiosity has triggered exploration into altered nutritional biochemistry and gut status in ASD. Many findings regarding toxicity, gut inflammation, gastrointestinal symptoms, pancreatic insufficiency, altered immune status, oxidative stress, and nutrient deficiencies frequently seen in ASD have emerged; these in turn have yielded several protocols known as biomedical interventions for autism. These interventions represent a shift away from a paradigm that autism is an inherited brain disorder only treatable with behavior therapy and psychiatric medication, and toward another that autism is a systemic illness triggered in utero, early infancy, or toddlerhood by external factors in genetically susceptible individuals. Biomedical treatments are anecdotally successful for many children, permitting varying degrees of recovery away from the autism spectrum. Results vary as widely as the protocols. Without standardized assessment, treatment, monitoring, or adequate research, it is difficult for families and providers to know what to do. A sizeable challenge for families is choosing a protocol and a competent provider suited to their child?s condition, and paying out of pocket for what are, thus far, non-reimbursable and novel treatments.
Also problematic is that biomedical protocols tend to place the nutrition care process in parents? hands. The MD provider using a biomedical treatment model may run many biochemistries on a child with ASD, but standards of child nutrition assessment and growth monitoring are generally not applied. Thus many children who are receiving biomedical treatment for ASD may languish on inadequate diets injurious to growth and development, while attempting several well-intended, MD-directed measures to eliminate toxicity, oxidative stress, immune dysregulation, or bowel symptoms.
Child nutrition assessment and monitoring is an existing piece of standardized care that can support children with ASD, while enhancing novel biomedical treatments. It addresses growth and macronutrient needs of children as well as micronutrient needs, while biomedical treatments tend to focus on metabolic stress and toxicity issues. Using the latter alone is costly for children regardless of developmental diagnosis. When ongoing in young children, even mild malnutrition can cause cognitive delays, growth problems, attention issues, insomnia, frequent infection, more complications with infection, and behavioral problems. A baseline nutrition assessment can thus separate effects of the child?s developmental diagnosis from effects of marginal nutrition status, toxicity, or metabolic stress.
II. Medical Nutrition Therapy for ASD
II.1. Do Children With Autism Eat Differently?
Children in the US do not suffer from malnutrition as a general rule. High-risk groups are children in homeless shelters and remote rural areas. Children with autism, however, may comprise a largely unstudied, at-risk population for malnutrition. As early as 1986, Raiten and Massaro described a "nutritional ecology" of children with autism. Children with ASD showed more food cravings, pica, and eating problems than typical controls. They also had lower intakes of vitamins A and C than controls. Concern for calcium intake and absorption in children with ASD have emerged as well, with a small study that showed thinner bones in boys with ASD versus controls (Hediger et al 2007). Some data on diets of children with ASD have not shown significant differences compared to typical peers; others show more rigidity and pickiness in food choices. Mixed results exist to date for efficacy of special diets. Few if any studies have used standardized food intake assessment instruments to review diets of children with ASD. None have included clinically valid nutrition status assessment tools. Most have used survey instruments that rely on remote reporting from parents for the child?s weight, height, and food intake. Levy et al (2007) compared food intakes of children with ASD to recommended dietary allowance standards for macronutrients but not to control children; findings showed higher than "average" intake of protein and frequent unexplained gastrointestinal abnormalities. Test subjects are often not well matched, eg, a mix of autism spectrum diagnoses will be grouped. These design variations create wide variability in the data (Millward 2004). In any case, the child with ASD who presents for nutrition care deserves individual assessment with existing standards for methodology.
II.2. Untreated Bowel Disease in Children with ASD
Emerging data have shown that children with autism suffer reflux, malabsoprtion, maldigestion, gut inflammation, and growth problems more frequently than typical peers (Horvath 2002). Still, gastroenterology referral with a new autism diagnosis is rare, unless parents press for review of signs and symptoms in this regard. Often these are hidden until endoscopy or nutrition assessment reveals them. More specifically, children with ASD show pancreatic insufficiency, nutrient deficiencies, altered gut tissue histology, gut tissue injury, marginal intakes, and inflammation from foods more often than typical peers. There is an urgent need for standardized assessment and care for these co-morbidities for two reasons: First, as is true for any child, corrections for nutritional compromise are critical to optimal development, growth, and learning. Second, children with autism frequently lack expressive language, leaving them unable to verbalize painful gastrointestinal symptoms. Many have been found to have gut disease undetected prior to endoscopy, and to resort to self-injurious behavior when in pain (Krigsman 2007). Compromised status for even one of the dozens of nutrients recognized as essential by the Institute of Medicine?s Food and Nutrition Board (IOM/FNB) can cause cognitive delay, growth regression, behavior problems, or developmental compromise in children (Kapil 2002). Growth can be permanently retarded in failure to thrive (FTT) infants, due to the interaction of protracted illness and undernutrition (Eid 1971). Growth impairment in infancy is a reliable predictor of diminished motor and cognitive function at age 7 years (Cooke 2003). Chronic inflammation from foods can impair growth (Isolauri 1996; Christie et al 2002). For decades, long-term effects of early malnutrition on cognition have been recognized (Trahams & Pipes, 1997; Galler 1983). Chronic marginal status for protein, energy, and micronutrient intakes or absorption will also trigger immune function shifts that correlate with poor outcomes in children. Changes noted include fewer T lymphocytes, impaired lymphocyte response, impaired phagocytosis secondary to decreased complement and certain cytokines, and decreased secretory immunoglobulin A (IgA) (Grigsby 2006). These predispose children to more severe, more frequent infections.
II.3. Need For Early Nutrition Referral
Children with autism will suffer the same insults from chronic marginal nutrition status as any other child. As has been known for decades, ages 0-3 are critical years for developmental intervention; this drives federal nutrition programs nationwide. Regardless of developmental status, infants and toddlers should be referred for nutrition assessment as soon as problems with feeding, eliminating, growth, food allergy, food intolerance, gastrointestinal symptoms, or frequent illnesses persist. Since children with ASD often have these co-morbidities, early nutrition referral is appropriate. Mitigating these problems as early as possible will mitigate developmental impact.
By 2010, the first wave of tens of thousands of "autism bubble" children will turn 21. Many will require custodial care and services ? a circumstance some have called the biggest public health crisis in the US (Goldberg 2007). In Massachusetts alone, it is reported that from 2006 through 2013, an estimated 600 to 750 children per year will be turning 22 and thus losing state educational entitlements. There are currently 1.5 million individuals diagnosed with ASD in the US, with an expected rise to 4 million in the next decade. As a chronic condition with consistent nutritional co-morbidities, therapeutic nutrition for ASD can be standardized and tapped to lessen autism?s burden on affected persons, their families, schools, and communities.
III. Nutrition Assessment Of The Child With Autism
1. Autism and Components of Pediatric Nutrition Assessment
As clinical experience and research have begun to shed light on the special nutrition needs of children with ASD, providers and parents have been eager to implement findings. Because findings have emerged sporadically and from several disciplines, a cohesive path for the nutrition care process for these children has not been created. The American Dietetic Association describes four steps in the nutrition care process (ADA 2007):
- Nutrition Assessment: A means to obtain, verify, interpret, and document data needed to identify a nutrition-related problem.
- Nutrition Diagnosis: Identification and labeling of a nutrition problem that a dietetics professional is independently responsible for treating.
- Nutrition Intervention: Actions to change aspects of nutritional health.
- Nutrition Monitoring and Evaluation: Review of a patient?s status at follow-up, with comparison to previous status, reference standards, or intervention goals.
Children with ASD pose several challenges to the ADA?s effort toward a standardized nutrition care process across all settings. First, due to the peculiarities of autism?s physiological features, nutrition status and needs of children with ASD may be inadequately described, if existing child nutrition assessment tools are used without regard for markers of inflammation, oxidative stress, or toxicity. Second, the ADA classifies nutrition diagnoses as "temporary and resolved with nutrition interventions", while it classifies medical diagnoses as pertaining to "diseases or pathologies of organs or body systems". Children with ASD fall somewhere in-between; see Appendix 1 for diagnosis codes relevant to findings common in children with ASD. Third, while it may be reasonable to recommend that nutrition problems be assessed, treated, and monitored by dietetics professionals, families of affected children generally do not seek out this group for care. Dietetics professionals are not as accessible in the health care landscape as MDs, naturopathic doctors, or osteopaths, many of which have become active in biomedical treatments for autism. Referrals for care with a licensed nutrition professional may be unsupported on a family?s insurance plan; training and experience with autism is currently scant within this profession; and confounding medical co-morbidities often necessitate close involvement with an MD provider. Thus, families have generally not turned to dietetics professionals for this piece, and have thus not had access to child nutrition monitoring skills beneficial to this intervention.
Standard methods from pediatric nutrition assessment, when blended with novel tools that have sprung from the biomedical movement, add a critical piece to treating nutrition problems of children with autism. Children with ASD exist under the same absolutes for nutritional demands and growth kinetics as any other child. The difference for the child with autism is that these demands may be unmet or marginally met, and no one has noticed. Corrections for these improve growth and development for all children. Lessons from treatments for children with cystic fibrosis, growth regression/failure, micronutrient deficiencies, Crohn?s disease, or celiac disease can inform for children affected by ASD, as there is some overlap with the nutrition challenges of these diagnoses.
Pediatric nutrition assessment includes anthropometrics, food intake data, clinical signs and symptoms, medical history, and biochemical/medical testing data.
III.2. Anthropometrics: Understanding Growth Parameters
The single most important parameter for defining nutrition status in infants, children, or teens is growth (Leonberg 2008), yet this piece is largely overlooked in biomedical treatment models currently used for ASD. Across the world, clinical standards for defining nutritional failure in children begin with growth data. Growth pattern is the direct expression of a child?s food intake and gut function: Diets must be both adequate, and adequately digested and absorbed, for children to grow. Reviewing growth charts from birth will reveal when a child?s diet and/or gut function became impaired. The growth history can also reveal what the impairment may be because
- Adequate intake and/or absorption of protein drive progress for stature or height/age.
- Adequate intake and/or absorption of energy (carbohydrates, fats) drive progress for weight/age.
- Malnutrition will affect weight first, then stature, then head circumference (HC).
- Weight/age is a barometer of recent health and nutrition status.
- Length/age (infants, toddlers) or stature/age (children able to stand for measure) reflect long-term status.
For example:
- A child with flattening trajectories for head circumference, weight, and length/stature is in entrenched malnutrition, and may not achieve genetic potential for stature or cognitive ability with re-feeding.
- A child with a recently flattening trajectory for weight/age and other parameters normal is either not getting adequate total calories, has carbohydrate/fats malabsorption, or both.
- A child who has a flattening trajectory for stature but remains in channel for weight/age does not eat enough total protein, has protein malabsorption, or both.
- A child with flattening weight/age and height/age trajectories, with head circumference unaffected, is showing entrenched, mild to moderate malnutrition. Intervention is needed to prevent permanent stunting and cognitive deficits.
Growth patterns are trackable on Centers for Disease Control (CDC) growth charts, complete sets for which are available on the CDC?s website. For correct use of growth charts, see ADA Pocket Guide to Pediatric Nutrition Assessment (Leonberg 2008) or view the CDC?s online learning modules on this topic. Charts are age, sex, and condition specific and should be used accordingly. Parameters to follow include head circumference (HC) to age three; weight for age, length (for infants and toddlers) or stature (for children able to stand for measure) for age, weight to height ratio, and body mass index (BMI).
Weight for age can compare a child with others of the same age and sex, but it is not in itself a valid measure of a child?s weight status, eg, underweight or overweight. This is only achievable by relating a child?s age and weight to current height; hence the need for tools like weight to height ratio (ages 0-3 years) and BMI for children between 2 and 20 years.
According to the World Health Organization,
- Wt for ht ratio <80% of median = moderate malnutrition
- Wt for ht ratio <70% of median = severe malnutrition (wasting)
- 85-89% of ideal wt for ht = early malnutrition and underweight
Another means of defining wasting in children is to calculate the child?s weight as a percentage of ideal body weight (IBW). IBW is the 50th percentile weight for the child?s current measured length or height, calculated thus:
%IBW = Current measured weight x 100
50th percentile for wt for length
A child is in normal nutrition status when at or above 90% of the ideal weight for his height. Once a child drops below this point, malnutrition is in place:
- 80-90% of IBW = mild wasting
- 70-80% of IBW = moderate wasting
- <70% of IBW = severe wasting
Likewise, stunting, or slower than expected growth for stature, can be used as an assessment tool. Stunting of linear growth reflects chronic undernutrition, particularly for protein. Children that are at or above 95% of 50th percentile height for their age are achieving expected gains in stature. Further (Waterlow 1972),
|
