Differential Diagnosis for 41 Year Old Female with Weakness and Kidney Pain After Running a 50 Mile Marathon

• Single Most Likely Diagnosis
  • Rhabdomyolysis: This condition is characterized by the breakdown of muscle tissue, leading to the release of myoglobin into the bloodstream, which can cause kidney damage. The intense physical exertion of running a 50-mile marathon increases the risk of rhabdomyolysis, especially if the individual is not adequately hydrated or has underlying muscle or metabolic conditions. The symptoms of weakness and kidney pain are consistent with this diagnosis.
• Other Likely Diagnoses
  • Dehydration: Running long distances without adequate fluid intake can lead to dehydration, which may cause weakness, dizziness, and kidney pain due to decreased blood volume and renal perfusion.
  • Electrolyte Imbalance: Prolonged physical activity can disrupt the body's electrolyte balance, particularly sodium, potassium, and calcium levels. This imbalance can lead to muscle weakness, cramps, and potentially affect kidney function.
  • Muscle Strain or Injury: The physical stress of running a marathon can cause direct muscle injury, leading to pain and weakness. While this might not directly cause kidney pain, it could contribute to overall discomfort and decreased mobility.
• Do Not Miss Diagnoses
  • Kidney Stone: Although less likely, a kidney stone could cause severe pain and might be exacerbated by dehydration from running. Missing this diagnosis could lead to severe complications if the stone obstructs the urinary tract.
  • Acute Kidney Injury (AKI) from Other Causes: Besides rhabdomyolysis, other causes of AKI, such as severe dehydration, medications (e.g., NSAIDs), or pre-existing kidney disease, need to be considered. AKI can be asymptomatic in its early stages but can progress to severe illness if not addressed.
• Rare Diagnoses
  • Exertional Heat Stroke: This is a life-threatening condition that occurs when the body's heat-regulation system is overloaded, causing the body temperature to rise rapidly. Symptoms can include weakness, confusion, and in severe cases, organ failure, including kidney damage.
  • Hyponatremia: Although more commonly associated with endurance activities involving excessive water intake, hyponatremia (low sodium levels in the blood) can occur and lead to weakness, confusion, and in severe cases, seizures or coma.