Approach to autism spectrum disorder: Using the new DSM-V diagnostic criteria and the CanMEDS-FM framework

Objective

To review the diagnostic criteria for autism spectrum disorder (ASD) from the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-V), and to develop an approach to managing ASD using the CanMEDS– Family Medicine (CanMEDS-FM) framework.

Sources of information

The DSM-V from the American Psychiatric Association, published in May 2013, provides new diagnostic criteria for ASD. The College of Family Physicians of Canada’s CanMEDS-FM framework provides a blueprint that can guide the complex management of ASD. We used data from the Centers for Disease Control and Prevention to determine the prevalence of ASD, and we used the comprehensive systematic review and meta-analysis completed by the UK National Institute for Health and Care Excellence for their guidelines on ASD to assess the evidence for more than 100 interventions.

Main message

The prevalence of ASD was 1 in 88 in 2008 in the United States according to data from the Centers for Disease Control and Prevention. The ASD classification in the fourth edition of the DSM included autism, Asperger syndrome, pervasive developmental disorder, and childhood disintegrative disorder. The new DSM-V revision incorporates all these disorders into one ASD umbrella term with different severity levels. The management of ASD is complex and requires a multidisciplinary team effort and continuity of care. The CanMEDS-FM roles provide a framework for management.

Conclusion

Family physicians are the key leaders of the multidisciplinary care team for ASD, and the CanMEDS-FM framework provides a comprehensive guide to help manage a child with ASD and to help the child’s family.The prevalence of autism spectrum disorder (ASD) in the United States has risen more than 75% in the past decade—from 1 in 150 in 2002 to 1 in 88 in 2008—according to data from the Centers for Disease Control and Prevention (CDC).¹ The CDC suggests that this increase is the result of a combination of better recognition of the disorder, improved diagnosis, and a true increase in prevalence. Only 10% of children with ASD have identifiable genetic or neurologic conditions such as fragile X syndrome, Down syndrome, or tuberous sclerosis. Common comorbidities include attention deficit hyperactivity disorder, obsessive-compulsive disorder, seizure, and anxiety.²Using the new criteria for ASD from the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-V),³ family physicians can make timely diagnoses, and they can play an important role in the management and follow-up of these children using the CanMEDS–Family Medicine (CanMEDS-FM) framework.⁴     

Climatic droplet keratopathy: an old disease in new clothes

Climatic droplet keratopathy (CDK) is an acquired and potentially handicapping cornea degenerative disease that is highly prevalent in certain rural communities around the world. It predominantly affects males over their forties. It has many other names such as Bietti's band‐shaped nodular dystrophy, Labrador keratopathy, spheroidal degeneration, chronic actinic keratopathy, oil droplet degeneration, elastoid degeneration and keratinoid corneal degeneration. CDK is characterized by the haziness and opalescence of the cornea's most anterior layers which go through three stages with increasing severity. Globular deposits of different sizes may be histopathologically observed under the corneal epithelium by means of light and electron microscopy. The coalescence and increased volume of these spherules may cause the disruption of Bowman's membrane and the elevation and thinning of the corneal epithelium. The exact aetiology and pathogenesis of CDK are unknown, but they are possibly multifactorial. The only treatment in CDK advanced cases is a corneal transplantation, which in different impoverished regions of the world is not an available option. Many years ago, the clinical and histological aspects of this disease were described in several articles. This review highlights new scientific evidence of the expanding knowledge on CDK's pathogenesis which will open the prospect for new therapeutic interventions.     

Reducing Ventral Tegmental Dopamine D2 Receptor Expression Selectively Boosts Incentive Motivation

Altered mesolimbic dopamine signaling has been widely implicated in addictive behavior. For the most part, this work has focused on dopamine within the striatum, but there is emerging evidence for a role of the auto-inhibitory, somatodendritic dopamine D2 receptor (D2R) in the ventral tegmental area (VTA) in addiction. Thus, decreased midbrain D2R expression has been implicated in addiction in humans. Moreover, knockout of the gene encoding the D2R receptor (Drd2) in dopamine neurons has been shown to enhance the locomotor response to cocaine in mice. Therefore, we here tested the hypothesis that decreasing D2R expression in the VTA of adult rats, using shRNA knockdown, promotes addiction-like behavior in rats responding for cocaine or palatable food. Rats with decreased VTA D2R expression showed markedly increased motivation for both sucrose and cocaine under a progressive ratio schedule of reinforcement, but the acquisition or maintenance of cocaine self-administration were not affected. They also displayed enhanced cocaine-induced locomotor activity, but no change in basal locomotion. This robust increase in incentive motivation was behaviorally specific, as we did not observe any differences in fixed ratio responding, extinction responding, reinstatement or conditioned suppression of cocaine, and sucrose seeking. We conclude that VTA D2R knockdown results in increased incentive motivation, but does not directly promote other aspects of addiction-like behavior.     

A novel modification of the Thrombelastograph assay, isolating platelet function, correlates with optical platelet aggregation

Flow cytometry, singlet platelet counting, and optical aggregation have been used to monitor clopidogrel and glycoprotein IIb/IIIa (GPIIb/IIIa) platelet antagonists. Optical aggregation is considered the gold standard, but neither it nor flow cytometry is convenient in larger-scale clinical studies or point-of-care systems. Singlet platelet counting, a point-of-care assay correlated with optical platelet aggregation, only provides a measurement of platelet function at a single point in time. The Thrombelastograph is used to assay whole blood for thrombin-generated maximal clot-shear elasticity, referred to as the maximal amplitude (MA). Although platelet dysfunction, thrombocytopenia, and the in vitro effect of strong inhibitors such as IIb/IIIa antagonists can be observed, with thrombin generation milder platelet inhibitors cannot be assessed. We modified the Thromboelastograph assay, using reptilase and factor XIIIa, to form a clot, without thrombin generation, in heparinized whole blood. The resulting clot MA is dependent on added platelet agonists such as ADP or arachidonic acid, is sensitive to platelet antagonists, and provides a continuous measure of platelet function more analogous and better correlated with optical aggregation. This novel modification of the Thromboelastograph assay should prove to be a useful point-of-care whole-blood assay with which to monitor the effects of GPIIb/IIIa, ADP, and thromboxane A(2)-receptor-inhibiting drugs in patients.     

The Addenbrooke’s Cognitive Examination-Revised accurately detects cognitive decline in Huntington’s disease

Cognitive features, which begin before manifestation of the motor features, are an integral part of Huntington’s disease and profoundly affect quality of life. A number of neuropsychological batteries have been used to assess this aspect of the condition, many of which are difficult to administer and time consuming, especially in advanced disease. We, therefore, investigated a simple and practical way to monitor cognition using the Addenbrooke’s Cognitive Examination-Revised (ACE-R) in 126 manifest Huntington’s disease patients, 28 premanifest gene carriers and 21 controls. Using this test, we demonstrated a selective decrease in phonemic, but not semantic, fluency in premanifest participants Cognitive decline in manifest Huntington’s disease varied according to disease severity with extensive cognitive decline observed in early-stage Huntington’s disease patients, indicating that this would be an optimal stage for interventions designed to halt cognitive decline, and lesser changes in the advanced cases. We next examined cognitive performance in patients prescribed antidopaminergic drugs as these drugs are known to decrease cognition when administered to healthy volunteers. We paradoxically found that these drugs may be beneficial, as early-stage Huntington’s disease participants in receipt of them had improved attention and Mini-Mental State Examination scores. In conclusion, this is the first study to test the usefulness of the ACE-R in a Huntington’s disease population and demonstrates that this is a brief, inexpensive and practical way to measure global cognitive performance in clinical practice with potential use in clinical trials.