Keywords: Stress fracture, amenorrhea (PubMed Search)
Energy availability considers the amount of remaining energy for metabolic processes based on calories takin in with eating and calories burned through exercise or both.
Menstrual dysfunction occurs as a result of low energy availability causing decreased GnRH inhibition and ovarian suppression and decreased estrogen.
Low bone mineral density occurs due to amenorrhea and decreased energy availability. Estrogen limits bone resorption (stimulates calcitonin and renal calcium retention).
This is very important for young girls as by age 12 they have 83% of their total BMD & 95% two years after menarche.
If you see an athlete in the ED with one component of the triad, inquire about the other two. A 15yo athlete with a stress fracture may not realize that her disordered eating, excessive exercise or amenorrhea may by contributing factors and may benefit from follow up with PCP, dietitian, Gyn, etc.