Marathon MedicineMedical Volunteer Training CourseBen Nelson MDEssentia Health Sports MedicineGrandmas Marathon
IntroductionThank you very much for volunteering to provide medical coverage at Grandmas Marathon.This course is designed to introduce you to the most common and most important conditions youll be treating in the medical tent.These issues include:Exercise Associated CollapseHeat-Related IllnessExertional HyponatremiaCardiac ArrestStress Fracture
Exercise Associated CollapseThis is the most common medical problem encountered after marathons59-85% of all post-marathon medical visitsBr J Sports Med. 2011 Nov;45(14):1157-62. EAC is caused by a postural drop in systolic blood pressureInactivation of the calf muscle pump upon cessation of prolonged exerciseResults in lower extremity venous blood pooling, reduced atrial filling pressure, and subsequent syncope
Exercise Associated CollapsePresentationRunners with EAC will be exhausted, lightheaded, unsteady on their feet or unable to stand
Exercise Associated Collapse TreatmentEvaluate in supine position with legs elevatedOral rehydrationCoolingRestMost patients will recover in 30 minMonitor for MENTAL STATUS CHANGES or failure to progress which might suggestExertional HyponatremiaHyperthermiaCardiac ArrestHypothermiaHypoglycemia
Exertional HyponatremiaDilutional decrease in serum sodium concentration during physical activity caused by:Over hydrationSalt losses in sweatFluid retention enhanced by increased ADH secretion during runningIncidence12.5% of marathon runners.London MarathonBr J Sports Med. 2011 Jan;45(1):14-9. Epub 2009 Jul 20.
Exertional HyponatremiaRisk factorsFinishing time over 4 hoursMarathon running inexperienceSmall statureFemale genderNSAID useUnusually hot conditions
Exertional HyponatremiaMild EHDefined by Na+ less than 135mmol/L with headache, parestesias, nausea, bloated/swollen sensationSevere EHDefined by Na+ less than 135mmol/L with decreased mental status, confusion, disorientation, agitation, delirium, seizures, respiratory distress
Exertional HyponatremiaTreatmentMild EHNo IV fluidsConsider oral fluid restrictionPt may drink salty oral fluids like V8, Coke, or chicken broth (4 bouillon cubes in 4oz water).Monitor until urination.Discharge home with instructions to monitor for EH symptoms and to seek urgent medical attention if any symptoms develop
Severe EHCheck core temp treat hyperthermia if present100mL 3% hypertonic saline bolusUp to two additional 100ml 3% hypertonic saline boluses may be given at 10 min intervals with Na+ recheck and no improvement in symptomsTransfer to ER for ongoing treatment/monitoring/recovery
Heat-Related IllnessOn a cool, dry day well care for around 200 ill runners. On a hot, humid day the race could generate over 600 patients in the medical tent.Heat-Related Illness can cause a mass-casualty event in hot or humid marathonsHeat-Related Illness can be life-threatening and must be identified and treated promptly
Heat-Related IllnessDefinitions Continuum of diseaseHyperthermia core temp > 40C or 104FHeat Cramps cramping assoc with dehydration, muscle fatigue, and electrolyte depletion.Heat Exhaustion Inability to exercise due to heat intoleranceExertional Heat Stroke Hyperthermia with central nervous system changes (Mental Status Changes) and possibly multiple organ system failure
Heat-Related IllnessSymptoms are NonspecificHeadacheDizzinessProfound FatigueChillsNauseaVomitingHeat CrampsSignsCore Temp > 39.4TachycardiaHyperventilationHypotensionSyncopeDisorientationConfusionIrrational/unusual behavior
Treatment of Heat-Related IllnessEarly recognition and treatment is keyRectal Temp is the only accurate measure of core temperatureEmperical treatment if suspicion is highRemove excess clothingPlace in supine position with legs elevatedOral fluid replacementCooling therapyMust be done on-site prior to transferTime is tissue!!!
Treatment of Heat-Related IllnessOn-Site Cooling MethodsIce BagsPlace bags in groin, axilla, and behind neckLeast efficient but most convenient cooling methodAppropriate for low-grade casesIced TowelsCover exposed skin with iced towelsPlace fan on pt for improved convectionProven as a rapid method for core temp reductionLess invasive than Ice Water SubmersionIce Water SubmersionContinuous rectal temperature must be monitoredPt is lowered into ice waterRemove pt when temp is below 40C
Cardiac ArrestIncidence of SCA1 in 57,000 marathon runnersRetrospective survey of marathon medical directorsMed Sci Sports Exerc. 2012 Apr 19. 1 per 100,00 full marathon runnersRace Associated Cardiac Arrest Event RegisteryN Engl J Med. 2012 Jan 12;366(2):130-40 1 per 50,000 marathon runnersTCM and Marine Corp marathons 1976-1994J Am Coll Cardiol. 1996 Aug;28(2):428-31
Location of Cardiac Arrest According to Race Quartile.Cardiac Arrest Can Happen Anywhere on the Course.
Time to defibrillation affects survivalSurvival rate decreases by 10% every 3 minutes in VF
Myocardial InfarctionMost common in middle-aged male runnersMay have vague or atypical presentation mimicking other conditions like GERD or MSK painA normal EKG in the medical tent should not be reassuring as ischemic changes may have not yet developedAll angina should be considered unstable. Emergency cardiac meds and rapid hospital transfer should be initiated.
Stress FracturesAtraumatic bone injury caused by repetitive, excessive stress.Continued stress can progress to complete fractures.Stress fractures comprise 5-10% of sports medicine visits in the US.Running is the most common sport associated with stress fractures.
Stress Fractures: DiagnosisPhysical exam: Reproducible focal point tenderness. Pain with ROM if joint involved (ie femoral neck)Imaging: X-rays could reveal evidence of healing stress fracture or completed stress fracture.MRIs image of choice given high sensitivity/specificity and ability to assess soft tissues. CT and bone scans are slightly inferior alternatives to MRI.
High Risk Stress FracturesHigh Risk Stress Fractures should be made non-wt bearing and sent for urgent imagingIncreased risk complications including:MalunionNonunionAvascular necrosisArthritic changeAccult fractures.
High Risk LocationsFemoral NeckTibial DiaphysisNavicular5th Metatarsal Diaphysis
Figure 1. Location of Cardiac Arrest According to Race Quartile.To account for differences in race distance between the marathon (26.2 mi) and half-marathon (13.1 mi), the point in the race course where the cardiac arrest occurred was examined as a function of the total race-distance quartile. Q1 denotes 0 to 6.5 mi (marathon) and 0 to 3.3 mi (half-marathon), Q2 6.5 to 13.1 mi (marathon) and 3.3 to 6.5 mi (half-marathon), Q3 13.1 to 20 mi (marathon) and 6.5 to 10 mi (half-marathon), and Q4 20 mi to finish (marathon) and 10 mi to finish (half-marathon).Shows that time to defibrillation affects survival. No different in athletes.Survival rate decreases by 10% every 3 minutes in VF.Avg 1st response unit 3.5 min, Avg paramedic response 6.5 minRecommend early recognition of SCA, immediate CPR, and Defibrillation in less than 3-5 min.