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Your next patient is a 16-year-old female cross-country runner who you are seeing in follow-up for right shin pain. She was diagnosed in the local emergency department 1 week ago with "shin splints" and told to limit her activities. In your office, she tells you that the pain has been worsening over the last 3 months, and she has progressively decreased the distance and time of her runs (but, of course she's a runner, so she hasn't quit). She denies fever, swollen joints, or other systemic symptoms. She normally has regular menses but notes that she has irregular menses during cross-country season. The patient's past medical history is significant for a stress fracture in her left foot 18 months ago. Your examination reveals tenderness at the middle one-third of the right tibia. In addition, she has pain on a single-leg hop. You are able to review her x-rays from the emergency department, which do not reveal any fractures or other abnormalities.
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Question 14.2.1 What is the most appropriate next step to diagnose your patient's leg pain?
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A) Ultrasound of the lower extremity.
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B) MRI of the lower extremity.
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C) Dual-energy x-ray absorptiometry (DEXA) scan.
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D) Thyroid-stimulating hormone (TSH) level.
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Answer 14.2.1 The correct answer is "B." MRI is sensitive and specific for stress fractures and has become the preferred study. The patient's history and examination are concerning for the presence of a tibial stress fracture. Stress fractures often present insidiously and cause gradual progression in symptoms over time until a critical point is reached in terms of sports participation. Half of stress fractures are not visible on plain radiographs. Ultrasound can help in evaluating soft tissue masses, but it does not play a role in evaluating stress fractures. DEXA scan can provide whole-body and site-specific measurement of bone mineral density, which may be related to the pathophysiology of stress fractures, but does not help diagnose a site of injury. Radionuclide bone scans are often less expensive than CT or MRI, and they demonstrate sites of injury based on increased uptake of the radionuclide material. However, bone scans are not specific for stress fractures and are often falsely positive. Of note, plain radiographs may take months to become positive after a stress fracture and, while radiographs may be done, they will not be of use if the result is negative. Given the patient's other complaints, TSH and urine pregnancy test may be warranted but will not assist in the diagnosis of her leg pain.
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An MRI is obtained and confirms the presence of a stress fracture in the middle one-third of the right tibia. Because of your patient's history, especially that of multiple stress fractures, you are concerned she may be suffering from the female athlete triad.
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Question 14.2.2 What are the components of the female athlete triad?
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A) Disordered eating, menstrual dysfunction, altered bone mineral density.
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B) Depression, weight loss, sports-related injury.
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C) Poor sports performance, low self-esteem, injury.
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D) Weight gain, bony injury, mood changes.
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E) Fanatical attachment to sports, testosterone abuse, anger management issues.
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Answer 14.2.2 The correct answer is "A." The female athlete triad was first identified in the early 1990s and originally characterized as anorexia, amenorrhea, and osteoporosis. As more has been learned about the triad, the realization has been made that the triad likely represents a broader spectrum disorder within each category. Many young women with the triad will exhibit disordered eating behaviors, such as caloric restriction or use of diuretics and diet pills, but would not meet the criteria for anorexia or bulimia nervosa. Menstrual dysfunction may include oligomenorrhea or irregular, intermittent menses, as well as amenorrhea. These young women may also have abnormal bone mineral density, with predisposition to bony injury, without having reached the strict criteria of osteoporosis.
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The patient comes back to the office to receive her test results, and you take the opportunity to obtain more history. The patient admits that she is very concerned about her diet during her cross-country season, and she is very careful to choose foods that have very little fat but are often high in protein. She will occasionally "go overboard" and eat a lot, for which she compensates by taking part in extra workouts. She has also used laxatives in the past "to not gain weight when I eat too much."
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Question 14.2.3 Which of the following findings is NOT classically found in bulimia nervosa?
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A) Loss of dental enamel.
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B) Enlarged parotid glands.
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D) Skin changes over the dorsum of the hands.
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E) Maintenance of a significantly low body weight.
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Answer 14.2.3 The correct answer is "E." Loss of dental enamel, skin changes over the dorsum of the hands, and enlarged parotid glands may be seen as a result of repetitive self-induced vomiting. While self-induced vomiting would cause a metabolic alkalosis through loss of stomach acid, repetitive use of laxatives can cause gastrointestinal losses of bicarbonate, resulting in a metabolic acidosis. Individuals with bulimia nervosa often maintain a normal weight, while anorexia nervosa has strict diagnostic criteria requiring maintenance of significantly low body weight, often less than 85% of the ideal body weight.
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Your patient also relates that she began having her periods around age 12. While they were initially irregular, they seemed to become more regular prior to starting high school. However, as she became more involved in high school sports, her periods became more irregular. During her off-season, her menses are "more regular," though she cannot predict when they will occur. She recalls that her last period was about 7 weeks ago.
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Question 14.2.4 In evaluating your patient's menstrual dysfunction, what would be your next course of action?
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A) Obtain serum LH, follicle-stimulating hormone (FSH), and estradiol levels.
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B) Order an abdominal and pelvic ultrasound.
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C) Perform a speculum-assisted pelvic examination with Pap smear.
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D) Obtain a urine beta-hCG.
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E) Prescribe an oral progestin-only pill (progestin challenge).
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Answer 14.2.4 The correct answer is "D." The most common cause of secondary amenorrhea in women of childbearing age remains pregnancy. If pregnancy has been excluded, and the history and physical are reassuring, a progestin challenge can be helpful to determine if adequate estrogen is present; the progestin challenge should induce menses if adequate estrogen exists (see Chapter 15 for details on the evaluation of amenorrhea). Imaging studies and hormonal levels may help in excluding other diagnoses or may be warranted based on physical examination. A pelvic examination may be warranted based on history, but is often not necessary in the initial evaluation of menstrual dysfunction. Pap smears are no longer recommended for women under the age of 21, regardless of sexual activity status.
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Your patient's pregnancy test is negative and a progestin challenge induced menses, indicating adequate circulating estrogen. A comprehensive plan is developed that includes psychological counseling, dietary modification, physical therapy, consultation with a nutritionist, and frequent follow-up. Over the next several months, the patient recovers from her injury, and returns to running on a modified schedule. However, she now complains of heavy, painful menses and wants to go on the "shot" to stop them.
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Question 14.2.5 In your counseling about birth control options, which of the statements below is FALSE?
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A) The birth control pill can be used to treat irregular menses of the female athlete triad and will also increase bone deposition.
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B) The effect of Depo-Provera (medroxyprogesterone) is to suppress the hypothalamic—pituitary—ovarian axis, creating a low estrogen state akin to peri-menopause.
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C) The FDA issued a "Black Box" warning on Depo-Provera that states "prolonged use…may result in loss of bone density that may not be completely reversible after discontinuation of the drug."
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D) The risk of future fracture using Depo-Provera is unknown, as bone density is an incomplete measure of bone strength, and remodeling and recovery are significant.
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E) Use of a Long Acting Reversible Contraceptive (LARC) should be offered as first line contraceptive choice.
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Answer 14.2.5 The correct (and "false") answer is "A." The other statements are all true. Starting a combined estrogen/progesterone contraceptive pill will restart a menstrual cycle but may not increase bone density. As to "E," an American Academy of Pediatrics (AAP) policy statement from September 2014 recommends that a LARC be considered as a first line contraceptive option in adolescents, including intrauterine device (IUD) or subdermal implant. These can provide 3 to 10 years of contraception and are effective and safe forms of birth control. Concerns about an increase in pelvic inflammatory disease (PID) with the IUD have been found to be unwarranted.
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In your routine anticipatory guidance, you discover that she avoids most dairy products due to a combination of prior concerns about fat content and lactose intolerance.
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Question 14.2.6 What do you recommend for her daily intake of elementary calcium?
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Answer 14.2.6 The correct answer is "C." While the absolute best intake of calcium for individuals is unknown, studies have shown positive calcium balance for adolescents with an intake of 1,200 to 1,500 mg daily. In its 2010 report, the Institute of Medicine (IOM) set 1,300 mg/day as the "adequate" dietary intake for boys and girls 9 to 18 years of age. This guideline was set to meet the needs of 95% of healthy children, with the upper limit of calcium intake set at 2,500 mg/day.
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For most persons, 1,300 mg/day of calcium intake can be accomplished with four servings of dairy products (8 oz of milk = 8 oz of yogurt or cottage cheese = 1 inch cube of cheese) plus a varied diet that includes other calcium-rich foods (e.g., broccoli, collard greens, and turnip greens). It is generally preferable to achieve intake of calcium via diet, including fortified foods, because foods provide multiple nutrients that are important for bone health, such as phosphorus and magnesium. Despite widespread non- and low-fat dairy options and numerous supplements, concern over fat intake has resulted in an average adolescent intake of only 700 to 800 mg/day for girls and about 1,000 mg/day for boys—and yet, we have an obesity epidemic. Ironic but not funny.
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Question 14.2.7 On average, what percentage of total body mineral content has a young woman deposited by the time she reaches 12 years of age?
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Answer 14.2.7 The correct answer is "D." Research suggests that by age 12, a young woman has reached approximately 83% of her peak bone mineral content, with 50% deposition happening from the time of "peak height velocity," which is premenarchal through 1 year post-menarche. The ability to absorb calcium from the diet is also enhanced during this period. Rates of deposition begin to decline approximately 2 years post-menarche and no significant gains are seen after the age of 17. These statistics emphasize that osteoporosis, while manifesting in older adults, is truly an issue of adolescent preventive medicine.
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Your patient returns from a high-powered sports medicine clinic in Palm Springs (or Laguna Beach…or anywhere more likely to make TV than Iowa). She brings you her DEXA scan results that are consistent with osteopenia. She looks up from her Instagram feed and asks, "So, what are we gonna do about that, Doc?"
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Question 14.2.8 You scour the literature and recommend:
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B) Calcium and vitamin D.
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C) Vigorous weight-bearing exercise.
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D) Dehydroepiandrosterone (DHEA).
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Answer 14.2.8 The correct answer is "B." Alendronate has no proven benefit in adolescent osteopenic females. Recommending exercise is the usual course for older patients with osteopenia, but you need to be careful in the adolescent with weight concerns who may exercise excessively at baseline. DHEA is investigational and has not been shown to increase bone mineral density. Stick with the standard of care: calcium in the daily doses as recommended above and vitamin D 600 IU daily (note that this recommendation is a change in the 2010 IOM guideline).
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Objectives: Did you learn to…
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Evaluate leg pain in a runner?
Identify the "female athlete triad?"
Recognize the importance of calcium and vitamin D intake and osteoporosis prevention in adolescence?