A Tale Of Too Many Bone Stress Injuries

HISTORY: 28-year-old woman with a history of anorexia (in recovery), osteopenia, and multiple stress fractures (bilateral tibias, femoral neck) presented with recurrent shin pain. Six months ago, she ran a half marathon and had significant difficulty walking afterward, leading to treatment with bilateral boots and physical therapy. She now experiences anterior shin pain, worsened by running. Previously running 15 miles per week, she now tolerates only 2 miles. A DEXA scan 6 years ago showed low bone mineral density (BMD). Her menstrual cycles are now regular, though they were previously irregular, and she uses NuvaRing for contraception. She takes vitamin D (1000 IU) and calcium (500 mg) inconsistently.Due to her history of bone stress injuries and low BMD, she was referred to endocrinology. She reported irregular cycles since menarche, with infrequent periods during college athletics. Withdrawal bleeding from NuvaRing ceased in the past year. PHYSICAL EXAM: 5/5 strength in both lower extremitiesTenderness over bilateral tibial bodies and medial tibial bordersNo pain with weight bearing DIFFERENTIAL DIAGNOSIS: Bilateral tibial stress reactions/stress fracturesBilateral medial tibial stress syndromeFemale athlete triad (low energy availability, menstrual dysfunction, osteoporosis)Endocrinopathy (hyperparathyroidism, Cushing’s, hyperthyroidism) TEST AND RESULTS: X-ray: No tibial cortical abnormalitiesMRI: Bilateral grade 1 stress responsesDEXA: L-spine Z-score -1.8 (osteopenia)Labs: Low estradiol (during NuvaRing withdrawal), Low vitamin D, Normal calcium, PTH, TSH, cortisolEstradiol increased after stopping NuvaRing (46 and 50.7 after 1 and 6 months) FINAL WORKING DIAGNOSIS: Bilateral tibial stress injuries due to low estrogen from NuvaRing use TREATMENT AND OUTCOMES: Reduce activity to 5,000 steps per day; stop running until symptoms improve. Consider cycling or swimmingPhysical therapy focusing on weight-bearing activities, gradually increasing stepsVitamin D (2000 IU) and calcium (600 mg twice daily); repeat DEXA in 2-3 years.Discontinue NuvaRing, leading to improved estrogen levels and return of regular menses.Consult gynecology for alternative contraception options.Continue monitoring nutrition; the patient, a nutritionist, remains in eating disorder remission.