title: Marathon runner's retinopathy.
abstract: OBJECTIVE
  To report a case of an unusual retinopathy in an otherwise healthy 25-year-old marathon runner.
  
  
  METHODS
  Case report.
  
  
  RESULTS
  A 25-year-old female marathon runner developed sudden onset of monocular vision loss during a routine training run. The retinal features included a large, central, subhyaloid hemorrhage, multiple intraretinal hemorrhages, disc edema and venous dilation and tortuosity resembling characteristics of both valsalva retinopathy and nonischemic central retinal vein occlusion. Work up for underlying systemic cause was negative. However, the patient did participate in endurance exercise.
  
  
  CONCLUSIONS
  Strenuous exercise increases activated platelets and other clotting factor elements. During exercise, this increase in clotting factors in the coagulation cascade is usually balanced by activation of key elements in the fibrinolysis cascade as well. However, certain individuals, especially those who already have a predisposition to clotting or other thrombogenic risk factors may disrupt the balance between coagulation and fibrinolysis during strenuous exercise favoring coagulation which places them at risk for thrombus formation.
authors: The Retina Service, Eye and Ear Institute, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
authors: Leanne T
authors: LT
authors: Labriola
authors: Thomas R
authors: TR
authors: Friberg
authors: Alethea
authors: A
authors: Hein
mesh_terms: D000328:Adult; D001778:Blood Coagulation Disorders / Q000150:complications*; D005260:Female; D006801:Humans; D010807:Physical Endurance; D012166:Retinal Hemorrhage / Q000209:etiology*; D012170:Retinal Vein Occlusion / Q000150:complications*; D012420:Running; D014636:Valsalva Maneuver; D015349:Vision, Monocular