RED-S Diagnosis Differential

The following differential diagnosis is organized into categories to facilitate a thorough evaluation of the condition.

• Single most likely diagnosis

  • Relative Energy Deficiency in Sport (RED-S): This is the most likely diagnosis given the context of the question. RED-S is a condition characterized by a mismatch between energy intake and energy expenditure, leading to a range of physiological and psychological consequences. The diagnosis is justified by the name of the condition itself, which directly points to RED-S as the primary consideration.

• Other Likely diagnoses

  • Anorexia Nervosa: This eating disorder can present with similar symptoms to RED-S, such as significant weight loss, amenorrhea, and an intense fear of gaining weight. The justification for including anorexia nervosa in the differential is the overlap in clinical presentation, particularly in athletes who may also have body image concerns or disordered eating behaviors.
  • Overtraining Syndrome: Athletes experiencing RED-S may also exhibit signs of overtraining, including persistent fatigue, decreased performance, and mood disturbances. The overlap in symptoms makes overtraining syndrome a plausible alternative diagnosis.

• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)

  • Cardiac Conditions (e.g., Hypertrophic Cardiomyopathy): Certain cardiac conditions can be exacerbated by the physiological stress of intense athletic training and energy deficiency, potentially leading to sudden cardiac death. Although less common, these conditions are critical to rule out due to their high mortality risk.
  • Osteoporosis with Increased Fracture Risk: Severe energy deficiency can lead to significant bone loss, increasing the risk of fractures. This condition, while not immediately life-threatening, can have long-term consequences on an athlete's health and career, making it essential not to miss.

• Rare diagnoses

  • Pituitary Adenoma (e.g., Prolactinoma): In rare cases, hormonal imbalances caused by pituitary adenomas can mimic some symptoms of RED-S, such as amenorrhea or changes in appetite. These conditions are less common but should be considered in the differential diagnosis to ensure comprehensive evaluation.
  • Other Endocrine Disorders (e.g., Thyroid Dysfunction, Adrenal Insufficiency): Various endocrine disorders can present with fatigue, weight changes, and other symptoms that overlap with RED-S. Although rare, these conditions require specific treatment and thus should be included in the differential diagnosis for thoroughness.