Andrew R. Peterson

Sporadic ALS Astrocytes Induce Neuronal Degeneration In Vivo

Summary Astrocytes from familial amyotrophic lateral sclerosis (ALS) patients or transgenic mice are toxic specifically to motor neurons (MNs). It is not known if astrocytes from sporadic ALS (sALS) patients cause MN degeneration in vivo and whether the effect is specific to MNs. By transplanting spinal neural progenitors, derived from sALS and healthy induced pluripotent stem cells (iPSCs), into the cervical spinal cord of adult SCID mice for 9 months, we found that differentiated human astrocytes were present in large areas of the spinal cord, replaced endogenous astrocytes, and contacted neurons to a similar extent. Mice with sALS but not non-ALS cells showed reduced non-MNs numbers followed by MNs in the host spinal cord. The surviving MNs showed reduced inputs from inhibitory neurons and exhibited disorganized neurofilaments and aggregated ubiquitin. Correspondingly, mice with sALS but not non-ALS cells showed declined movement deficits. Thus, sALS iPSC-derived astrocytes cause ALS-like degeneration in both MNs and non-MNs.

Lactate: Friend or Foe

Lactic acid has played an important role in the traditional theory of muscle fatigue and limitation of endurance exercise performance. It has been called a waste product of anaerobic metabolism and has been believed to be responsible for the uncomfortable “burn” of intense exercise and directly responsible for the metabolic acidosis of exercise, leading to decreased muscle contractility and ultimately cessation of exercise. Although this premise has been commonly taught, it is not supported by the scientific literature and has led to a great deal of confusion among the sports medicine and exercise science communities. This review will provide the sports medicine clinician with an understanding of contemporary lactate theories, including lactates role in energy production, its contributions to metabolic acidosis, and its function as an energy substrate for a variety of tissues. Lactate threshold concepts will also be discussed, including a practical approach to understanding prediction of performance and monitoring of training progress based on these parameters.

Utilization of a text-messaging robot to assess intraday variation in concussion symptom severity scores.

Objective:To determine the amount of within-day variation of Concussion Symptom Severity Scores (CSSSs) in athletes with a clinically diagnosed concussion. Design:This prospective cohort study used a text-messaging robot to survey concussed athletes using the CSSS 5-times daily while they remained symptomatic. Setting:Academic sports concussion clinic at a large tertiary care medical center. Participants:Fourteen 14- to 22-year-old athletes with clinically diagnosed concussions were enrolled. All were injured in sport, still in season, English speaking, and used a cellular telephone to text message on a regular basis. Assessment of Risk Factors:This study did not collect any demographic or other information about the subjects. The only data collected were the individual responses to the questions in the Post Concussion Symptom Score (PCSS). The only aim of this study was to evaluate the variability in responses to the CSSS, which is calculated from the PCSS. Main Outcome Measurements:The primary outcome measure was a repeatability coefficient from a random-effects model. Concussion Symptom Severity Score, mean daily CSSS, and standard deviation of CSSS differences from the mean were also calculated. Results:Mean follow-up was 23.9 days. A total of 24 180 text messages were received from subjects. Eight hundred four complete surveys were analyzed. Repeatability coefficient was ±23.1. Conclusions:When surveyed frequently by a text-messaging robot, concussed athletes report poorly repeatable Sport Concussion Assessment Tool 2 (SCAT2) Symptom Severity Scores. Clinical Relevance:The SCAT2 Symptom Severity Score may be an invalid method of tracking concussion severity and resolution over time.

The Preparticipation Sports Evaluation

1. Andrew R. Peterson, MD, MSPH* 2. David T. Bernhardt, MD† 1. *Department of Pediatrics, University of Iowa, Iowa City, IA. 2. †Departments of Pediatrics and Orthopedics and Rehabilitation, University of Wisconsin, Madison, WI. After completing this article, readers should be able to: 1. Perform a preparticipation history and physical examination and identify children and adolescents who may be at increased risk of morbidity or mortality from sports participation. 2. Recognize that many adolescents make infrequent contact with the medical system and that the mandatory preparticipation evaluation serves as an opportunity to address medical issues not necessarily associated with sports participation. 3. Know the conditions that should be evaluated by a cardiologist before sports participation. 4. Discuss the importance of assessing and documenting neurocognitive function in a preparticipation sports examination. 5. Understand that disqualification from one sport does not imply disqualification from all sports. Sports participation among people of all ages has increased steadily over the past 4 decades. This trend generally has been considered to be a positive development, with conventional wisdom asserting that sports participation teaches leadership and cooperative skills that have a lifelong impact. In addition, as the obesity pandemic worsens, organized sports participation and unstructured play or physical exercise can be a source of needed physical activity for children and adolescents. The pediatrician often is asked to evaluate a childs or adolescents suitability for sports participation. The purpose of this evaluation has remained constant since it was first described in 1978. (1)(2) The goals are to fulfill the institutions legal and liability requirements, provide some assurance to coaches that athletes will start the season at an acceptable level of health and fitness, provide an opportunity to discover treatable conditions, and aid in predicting and preventing future injuries. The evaluation should be practical and applicable to all sports. The specific objectives of the evaluation …

A case report: Glycopyrrolate for treatment of exercise-induced hyperhidrosis

Objective: Hyperhidrosis can cause dehydration and exercise intolerance. There are several case reports of extremely high sweat rates in athletes. We present as case report of a 17-year-old male with the highest sweat rate recorded in the literature (5.8 L/h). Our goal was to determine if glycopyrrolate, an anticholinergic medication with primarily anti-muscarinic effects that is known to decrease sweat production, would reduce the sweat rate of our subject in a controlled exercise setting. Methods: Our patient and a control subject were subjected to an exercise protocol consisting of running on a treadmill (5.4–6.7 mile/h at 1° of incline) in a warm climate-controlled chamber after receiving 0, 2, or 4 mg of glycopyrrolate. Core temperature, heart rate, rater of perceived exertion, and sweat rate were monitored in both subjects. Results: Glycopyrrolate dose was not significantly correlated with decreased sweat rate and maximal core temperature. However, the clinical effect of reducing the sweat rate was very strong. The improvement of the subject’s sweat rate allowed him to successfully return to sport. Conclusion: Our findings suggest that low-dose glycopyrrolate may be a safe and effective method of controlling exertional hyperhidrosis.

Youth Football Injuries: A Prospective Cohort

Background: There are approximately 2.8 million youth football players between the ages of 7 and 14 years in the United States. Rates of injury in this population are poorly described. Recent studies have reported injury rates between 2.3% and 30.4% per season and between 8.5 and 43 per 1000 exposures. Hypothesis: Youth flag football has a lower injury rate than youth tackle football. The concussion rates in flag football are lower than in tackle football. Study Design: Cohort study; Level of evidence, 3. Methods: Three large youth (grades 2-7) football leagues with a total of 3794 players were enrolled. Research personnel partnered with the leagues to provide electronic attendance and injury reporting systems. Researchers had access to deidentified player data and injury information. Injury rates for both the tackle and flag leagues were calculated and compared using Poisson regression with a log link. The probability an injury was severe and an injury resulted in a concussion were modeled using logistic regression. For these 2 responses, best subset model selection was performed, and the model with the minimum Akaike information criterion value was chosen as best. Kaplan-Meier curves were examined to compare time loss due to injury for various subgroups of the population. Finally, time loss was modeled using Cox proportional hazards regression models. Results: A total of 46,416 exposures and 128 injuries were reported. The mean age at injury was 10.64 years. The hazard ratio for tackle football (compared with flag football) was 0.45 (95% CI, 0.25-0.80; P = .0065). The rate of severe injuries per exposure for tackle football was 1.1 (95% CI, 0.33-3.4; P = .93) times that of the flag league. The rate for concussions in tackle football per exposure was 0.51 (95% CI, 0.16-1.7; P = .27) times that of the flag league. Conclusion: Injury is more likely to occur in youth flag football than in youth tackle football. Severe injuries and concussions were not significantly different between leagues. Concussion was more likely to occur during games than during practice. Players in the sixth or seventh grade were more likely to suffer a concussion than were younger players.

Basic recovery aids: what's the evidence?

This review summarizes the evidence base for using compression, massage, caloric replacement, cold, and heat as exercise recovery aids in sport.

Using sideline concussion tests in the emergency department

Purpose Traumatic brain injury (TBI) is a significant cause of death and disability in the United States. Many patients with TBI are initially treated in the emergency department (ED), but there is no evidence-based method of detecting or grading TBI in patients who have normal structural neuroimaging. This study aims to evaluate the validity of two common sideline concussion tests. The Concussion Symptom Severity Score (CSSS) and modified Balance Error Scoring System (mBESS) tests are well-validated sideline tests for concussion, but have not been validated in the setting of non-sport-related concussion, in settings other than the sideline or athletic training room or in moderate or severe TBI. Patients and methods One hundred forty-eight subjects who had sustained a TBI within the previous 72 hours and 53 healthy control subjects were enrolled. CSSS and mBESS were administered. Clinical outcomes were followed up prospectively. Results The CSSS was collected in 147 TBI subjects but only 51 TBI subjects were able to complete the mBESS. The CSSS was collected for all 53 control subjects, and the mBESS was completed for 51 control subjects. The mean CSSS for TBI and control subjects was 32.25 and 2.70, respectively (P < 0.001). The average mBESS for TBI and control subjects was 7.43 and 7.20, respectively (P = 0.82). CSSS greater than 5.17 was 93.43% sensitive and 69.84% specific for TBI. Conclusion The mBESS is poorly tolerated and, among those who can complete the test, not sensitive to TBI in the ED. The CSSS is both sensitive to TBI and well tolerated.

Weight Management Counseling for Wrestling Athletes

Helping a wrestler manage body weight can be a daunting process for a pediatric health care provider. Each high school wrestling program has been mandated by the National Federation of State High School Associations to determine an appropriate weight classification for each individual wrestler. This article discusses how an appropriate weight class is determined, the methods for ascertaining a persons hydration status and body density, and the importance of a fully hydrated and normally nourished state that will allow for optimal athletic performance for a wrestler.

Symptomatic Overlap and Therapeutic Opportunities in Primary Headache

Headache, a nearly universal experience, remains costly, disabling, and often suboptimally managed. The most common presentations in the United States are migraine, tension-type headache (TTH) and “sinus” headache, but their extensive symptomatic overlap suggests that these conditions can be approached as variations in the same underlying pathology and managed accordingly. We use case studies of patients with varying prior diagnoses (none, migraine, TTH, and sinus headache), as well as a 4-question diagnostic screening tool, to illustrate how pharmacists can use this conceptual framework to simplify identification, management, and referral of patients with primary headache conditions of uncertain etiology.