NMS Q&A Family Medicine

218 NMS Q&A Family MedicineExamination Answers1. The answer is E. Familial short stature is most likelycause of the boy’s height unsatisfactory as it may be tohim. The issue is whether his height falls within about1 SD from the midparental height (MPH) or about at 25%of the distance from the 3rd percentile on the standardpediatric height chart to the MPH [from tables such as32–2 from Current Medical Diagnosis and Treatment Pediatrics, 19th edition, 2009]. The MPH is calculated by adding13 cm (5 in.) to the mother’s height for boys(subtracting 5 in. from the father for girls) and averagingthe result with the father’s height – in this case, the MPHis 5 ft 8 in. and 1 SD below the MPH would be 3.3 in.below the MPH, encompassing the boy’s height. Constitutionalgrowth delay does not fit the case because sexualmaturation had been on schedule. By the same token,Prader–Willi syndrome is characterized by hypogonadismas is hypopituitarism. The normal U:L segment ratiorules out achondroplasia.2. The answer is C. Lower than normal IQ is not a characteristicof Turner syndrome. However, there may belearning difficulties with Turner syndrome patients.Turner syndrome, of course, is defined as the presence ofa single sex chromosome, an X, so that patients are phenotypicallyfemales and lack of development of secondarysex characteristics. The web neck is common; bicuspidaortic valve occurs at greater than normal frequency, andwide-set nipples are common. Other anomalies includeaortic dissection and coarctation of the aorta.3. The answer is D. Reassure the parents and the boy thatthe boy’s level of sexual maturation is within normal limits.Delayed puberty is defined as the onset of puberty atan age later than the age onset of puberty for the sex type.For boys that is 13.5 4 years. For girls, the mean age SD is 13 years 7. Thus, although the 15-year-old boy isin an age above average for the time of clear progress indevelopment of puberty, he does not warrant expensiveand anxious measures of diagnosis at this time.4. The answer is E. Thyroid function studies. That hypothyroidismwas ruled out before embarkation on growthhormone therapy notwithstanding, growth hormonesometimes induces hypothyroidism, and this is a significantpossible etiology of poor growth of patients on therapy. Even patients who are growing normally should havethyroid function testing every year. Stopping growth hormonetreatment would be self-defeating because the girl’sgrowth rate remains an issue. Cortisol levels would be relevantonly if she exhibited signs or symptoms of adrenalinsufficiency or excess, as would the dexamethasone sup-pression test. The karyotype (XO karyotype) was alreadytested and found to be normal.5. The answer is B. Tanner II. Sparse pubic hair can alsobe noticed just on the labia during this stage. Tanner III isbest defined as breast enlargement without separation ofthe contours of the areola and the papilla, in formation ofa single mound. Stage IV features contour development,with the nipple being the only projection of the breast butwithout the full adult pattern (i.e., triangular form). StageV thus is defined by full pubic hair development.6. The answer is B. Tanner II. In keeping with the themethat Tanner I is prepubertal, Tanner II is the first identifiablestage of pubertal development. Stages III and IV inthe case of males are definable only by degree of testicular,penile, and pubic hair growth (i.e., without clear-cutboundaries). Tanner V in males, as in females, is defined bythe full adult pattern of public hair (i.e., for males, spreadof the hair onto the thighs). Arbitrary as the Tanner stagedefinitions may be, they provide the language necessaryfor communication among physicians when questions ofsexual development must be discussed.7. The answer is C. The increased LH and FSH levelsindicate primary ovarian failure; in other words, the factthat gonadotropins were in the stimulatory range, yet thegonads failed to respond, shows that gonadal failure wasthe basis for the abnormality. Turner syndrome is onelikely cause of primary ovarian failure. Weight loss, prolactinoma,and Prader–Willi syndrome can all cause adelay in puberty, but through insufficient hypothalamicrelease of LH and FSH (and thus low levels are detected).Constitutional growth delay also results in low FSH andLH levels (i.e., the cause of delays being a hypothalamic–pituitary cause as opposed to ovarian failure).8. The answer is A. PCOS is a potential etiology of infertility,but not of ovarian failure. FSH and LH have not failed.Other aspects of PCOS include amenorrhea, androgenization,and insulin resistance, leading to type 2 diabetes.Weight loss is the single best therapy for PCOS. Radiationto the ovaries, autoimmune gonadal failure, alkylating chemotherapy,and Turner syndrome can each account forovarian failure. Viral infections (such as mumps or coxsackieB virus) also can produce acute gonadal failure.9. The answer is A. Reassure the parents that this cansometimes be seen at this age and have them contact you ifany other secondary sex characteristics develop. This casedemonstrates premature thelarche, which is most commonly