12-year-old (Female) with Absent Breast Development

00:01 Okay guys. We have a fantastic USMLE question here.

00:05 This is going to be very similar to what you'll see on exam day so let's dive right in.

00:10 A 12-year-old girl presents to a pediatrician because she fails to show signs of breast development so far.

00:19 On physical examination, the pediatrician notes that her stature is shorter than expected for her age and sex.

00:27 She has a webbed neck, a low posterior hairline, and a broad chest with widely spaced nipples.

00:36 Non-pitting bilateral pedal edema is present.

00:40 The pediatrician orders a karyotype analysis.

00:43 The results of which are shown below.

00:46 Which of the following findings is most likely to be present on auscultation of her chest? Answer choice A: Short systolic murmur along the left sternal border in the 3rd and 4th, intercostal spaces which radiate to the left infrascapular area; Answer choice B: Systolic ejection murmur best heard over pulmonic area, radiating to lung fields bilaterally with inaudible pulmonic component to second heart sound; Answer choice C: Continuous machine-like murmur over second left intercostal space which radiates to the left clavicle; Answer choice D: High-pitched holosystolic murmur over the apical area which radiates to the left axilla; or Answer choice E: Low and harsh holosystolic murmur best heard over the left lower sternal border Now, take a moment to come to the answer by yourself before we go through it together.

02:03 Okay guys, like I said, this is a complex question.

02:06 This is what modern-day USMLE looks like. Multiple questions involving multiple layers to come to an answer.

02:13 So, let's dive right in.

02:15 Now, looking at the question characteristics, this is a pediatric question.

02:18 We have a 12-year-old girl coming into the pediatrician with a concern for her development.

02:23 Now it's a three-step question and this is what USMLE is like now, there are three steps.

02:29 First step, we gotta get to the diagnosis.

02:31 Second step, we gotta see how the diagnosis is related to cardiovascular or heart defects and then lastly, we have to pair those possible defects with an appropriate auscultation finding in the answer choices.

02:46 And of course, the stem here is required because we have to pull a lot of information from the question stem to be able to pull enough basis to go through this thinking.

02:55 So, let's walk right through it. Now the first thing we have to do is determine the diagnosis.

03:00 Now, we have a female patient coming to us of prepubescent age.

03:04 Now the chief complaint here is delayed puberty.

03:09 Now recall that the onset of puberty in girls is between 10 to 12 years old and this patient shows no sign of breast development at the age of 12.

03:19 Now, delayed puberty has a wide differential diagnosis and it includes the following: you can have what's called constitutional delay of puberty.

03:31 Now, this is the most common diagnosis of patients who are presenting for evaluation of delayed puberty.

03:38 Here, there's no underlying pathology.

03:40 Normal development occurs at a later than average onset and it's often associated with the family history of delayed puberty.

03:48 Also, on the differential are CNS disorders such as hypogonadotropic hypogonadism, which is obviously due to a pathology of the pituitary gland.

04:00 Chronic disease can delay puberty such as diabetes mellitus.

04:03 Chromosomal anomalies can delay puberty, such as Turner syndrome in females and Klinefelter syndrome in males.

04:12 Excessive exercise can cause delayed puberty, especially in girls and this can lead to amenorrhea.

04:19 Now, let's go through the exam findings here.

04:23 We're told that the patient has a stature shorter than average and this really supports various diagnoses here that we've been thinking of so far including constitutional delay of puberty.

04:33 But we're then told the patient has a webbed neck, now that's suggestive of Turner syndrome.

04:40 We're told the patient has a low posterior hairline, now that's suggestive of Turner syndrome.

04:45 We're told the patient has a broad chest with widely spaced nipples, now that's suggestive of Turner syndrome and we're also told that the patient has bilateral non-pitting pedal edema and that's suggestive of Turner syndrome.

04:59 Then we'll lastly will look at our karyotype and we see that it's a 45,X0.

05:05 We don't see a Y nor do we see a second X chromosome and since we have only one X chromosome, that is consistent with the diagnosis of Turner syndrome.

05:14 Now, we have to think, well, patients with Turner syndrome actually often have cardiovascular or heart defects and there's two common ones that you absolutely need to know.

05:25 One of them is what's called a bicuspid aortic valve, in which you have fusion of two aortic valve leaflets rendering the valve bicuspid instead of normally tricuspid.

05:38 Another common condition in turner is what's called coarctation of the aorta, which is a narrowing of the aorta and it most commonly will occur in the aortic arch.

05:49 So, the second step is thinking, okay, so we know it's turner syndrome or what cardiac abnormalities are associated with Turner syndrome and it's going to be the bicuspid aortic valve and also the coarctation of the aorta.

06:04 Now the third part of our thinking here is determining which murmur in the answer choices matches one of these two conditions.

06:13 Now a murmur of the bicuspid aortic valve would present with a systolic ejection sound radiating to the apex.

06:22 Now no provided answer choice matches that so we know the heart defect that the patient's most likely going to have in the answer choice is coarctation of the aorta.

06:32 So now we're on the hunt for that now.

06:34 Now, a murmur of the coarctation of the aorta is a systolic murmur along the left sternal border in the 3rd and 4th intercostal spaces, in which you have radiation to the left infrascapular area and this can actually be accompanied by a diastolic murmur due to regurgitant flow.

06:53 Now if you find that, you'll see that the answer choice A is correct here, which is a short systolic murmur along the left sternal border and a 3rd and 4th intercostal spaces with radiation to the left infrascapular area.

07:07 Now that is challenging. I'm not going to expect any of you to be able to fly right through this question.

07:13 The way you solve this question is by going through all the answer choices and eliminating them one by one.

07:19 So let's do that together in a little bit more detailed fashion so that you can see how I quickly got rid of bicuspid aortic valve and so comfortably knew I was searching for coarctation of the aorta.

07:31 Now, let's look at our answers.

07:32 Well, answer choice A, which is the correct answer here.

07:35 Now, our patient has Turner syndrome and with Turner syndrome like we said, we expect a short systolic murmur along the left sternal border and a 3rd and 4th intercostal spaces with radiation to the left infrascapular area and that's suggestive of coarctation of the aorta, which is one of the common heart diseases that we see in Turner syndrome along with bicuspid aortic valve.

07:58 Now there were important signs in the patient's questions stem that told us that she had Turner syndrome.

08:05 Of course, we had the karyotype but you don't always get that.

08:08 Now the patient had a short stature, webbing of the neck, and low posterior hairline.

08:13 You can also have protruding ears.

08:16 She had lymphedema of the hands and feet.

08:18 You can also have cubitus valgus which is an increased carrying angle of the elbow.

08:24 You can have shield chest and wide-spaced nipples.

08:28 Now, patients may also present with primary amenorrhea and have an absence of secondary sex characteristics and infertility.

08:38 Interestingly, approximately 40% of patients with Turner syndrome actually have a congenital heart disease and now you see why this question is so high-yield.

08:49 It's common for patients with Turner's to have a heart problem so we need to be aware of it.

08:55 Now like we said, the most common congenital heart disease associated with Turner's is bicuspid aortic valve and coarctation of the aorta.

09:04 However, you can also have more rare conditions with this Turner syndrome, such as aortic stenosis, hypoplastic left heart syndrome, and cardiac conduction abnormalities.

09:14 Now, the coarctation of the aorta like we said has the auscultation characteristic of a short systolic murmur along the left sternal border in the left 3rd and 4th intercostal spaces with radiation to the left infrascapular area or the neck.

09:32 Now, what we would have expected if they were trying to show us bicuspid aortic valve would've been a systolic ejection click may be present in the super sternal notch and that would have been suggestive of bicuspid aortic valve.

09:46 Now let's go through the other answer choices, say what those auscultations would be and what conditions we could expect those in cus those might be other questions you will see on exam day.

09:57 Now looking at answer choice B, we have a systolic ejection murmur heard best over the pulmonic area radiating to both pulmonic lung fields with an inaudible pulmonic component to the second heart sound.

10:12 Now, this finding is consistent with pulmonic stenosis. Now, pulmonic stenosis is not common in Turner syndrome but what are some conditions in which you would expect pulmonic stenosis.

10:24 That would be Alagille Syndrome, Noonan syndrome, Williams-Beuren Syndrome, and Costello syndrome.

10:31 All important to know.

10:33 Now looking at answer choice C, you have a continuous machine-like murmur over the second left intercostal space which radiates to the left clavicle.

10:43 Now, this auscultation is suggestive of a patent ductus arteriosus.

10:48 Now a PDA is not, again, common in Turner syndrome but conditions in which your PDA is related or Holt-Oram syndrome, Noonan's syndrome, Char syndrome, Patella syndrome also called trisomy 13, Edwards syndrome also called trisomy 18, and cri Du Chat syndrome.

11:09 Now looking at answer choice D, you have a high pitched holosystolic murmur over the apical area which radiates to the left axilla.

11:19 Now, this is mitral regurgitation and this can actually be seen with Marfan syndrome, very high-yield, Marfan syndrome not seen the Turner.

11:28 Answer choice E, you have a loud harsh holosystolic murmur best heard over the lower left sternal border, now that's suggestive of a ventricular septal defect.

11:40 Now, you don't see this with Turner but other conditions that you can see it with are DiGeorge syndrome, Holt-Oram syndrome, Noonan syndrome, Down syndrome also called trisomy 21, Patella syndrome also called trisomy 13, Edwards syndrome also called trisomy 18, Cri Du Chat syndrome, Char syndrome, and Kabuki syndrome.

12:04 Now let's review some high-yield facts. Now, starting with Turner syndrome, this will be seen in females who have the karyotype of 45,X0, so only one X chromosome.

12:17 This is not a hereditary condition if thought to be due to a sporadic event such as an error during meiosis.

12:25 Now here you actually have variable of expression in patients with Turner syndrome and this depends on whether the second X chromosome is completely or partially missing.

12:36 And the diagnosis really is ultimately gonna come down to karyotyping and the treatment is directed at managing the signs and symptoms for the patient such as reproductive technology for fertility.

12:50 Now let's discussed coarctation of the aorta, a very high-yield topic on USMLE.

12:56 They, for some reason, love this. Now, coarctation of the aorta is really narrowing of the aorta.

13:01 Look at the image below.

13:03 When you have coarctation of the aorta, really, the wall of the aorta really narrows that passageway so it's really narrowing of the aorta. That's how I want you to think about it.

13:14 This most commonly occurs in the aortic arch near or at the site of the ductus arteriosus insertion.

13:21 Now, mild cases are typically asymptomatic but in severe cases, symptoms are associated with insufficient blood supply and patients can present with dyspnea, failure to thrive, feeding difficulties, and cyanosis.

13:36 And you can also have hypertension due to poor outflow.

13:40 Now the diagnosis is made via ultrasound and MRI and treatment for symptomatic patients is surgical repair.