Long-term survivor follow-up US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Long-term survivor follow-up. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Long-term survivor follow-up US Medical PG Question 1: Researchers are investigating oncogenes, specifically the KRAS gene that is associated with colon, lung, and pancreatic cancer. They have established that the gain-of-function mutation in this gene increases the chance of cancer development. They are also working to advance the research further to study tumor suppressor genes. Which of the genes below is considered a tumor suppressor gene?
- A. Her2/neu
- B. BRAF
- C. BCL-2
- D. JAK2
- E. Rb (Correct Answer)
Long-term survivor follow-up Explanation: ***Rb***
- The **retinoblastoma (Rb)** gene is a classic example of a **tumor suppressor gene**. Its protein product, Rb, plays a critical role in regulating the **cell cycle** by preventing uncontrolled cell division.
- When **Rb is mutated or inactivated**, cells can divide without proper checks, leading to tumor formation, particularly in cases like retinoblastoma.
*Her2/neu*
- **Her2/neu** (also known as ERBB2) is an **oncogene** that encodes a receptor tyrosine kinase involved in cell growth and differentiation.
- Its overexpression or amplification is associated with certain cancers, notably **breast cancer**, but it is not a tumor suppressor.
*BRAF*
- **BRAF** is an **oncogene** that codes for a serine/threonine kinase involved in the RAS/MAPK signaling pathway, which regulates cell growth.
- **Gain-of-function mutations** in BRAF are frequently found in melanoma, thyroid cancer, and colorectal cancer, promoting uncontrolled cell proliferation.
*BCL-2*
- **BCL-2** is an **anti-apoptotic gene**, meaning it prevents programmed cell death. While its overexpression can contribute to cancer by allowing abnormal cells to survive, it is not classified as a tumor suppressor gene.
- Instead, BCL-2 is considered an **oncogene** because mutations or overexpression promote cell survival and inhibit apoptosis.
*JAK2*
- **JAK2** (Janus Kinase 2) is a **proto-oncogene** encoding a tyrosine kinase involved in cytokine receptor signaling, which regulates hematopoiesis.
- **Gain-of-function mutations**, such as JAK2 V617F, are frequently found in **myeloproliferative neoplasms** (e.g., polycythemia vera, essential thrombocythemia, myelofibrosis), leading to uncontrolled blood cell production.
Long-term survivor follow-up US Medical PG Question 2: A 71-year-old woman presents to her hematologist-oncologist for follow up after having begun doxorubicin and cyclophosphamide in addition to radiation therapy for the treatment of her stage 3 breast cancer. Her past medical history is significant for preeclampsia, hypertension, polycystic ovarian syndrome, and hypercholesterolemia. She currently smokes 1 pack of cigarettes per day, drinks a glass of wine per day, and denies any illicit drug use. The vital signs include: temperature 36.7°C (98.0°F), blood pressure 126/74 mm Hg, heart rate 111/min, and respiratory rate 23/min. On physical examination, the pulses are strong and irregular, she has a grade 3/6 holosystolic murmur heard best at the left upper sternal border, clear bilateral breath sounds, and erythema over her site of radiation. Which of the following statements regarding doxorubicin is true?
- A. Doxorubicin has a maximum lifetime dose, due to the risk of cardiac toxicity (Correct Answer)
- B. Doxorubicin has a maximum lifetime dose, due to the risk of pulmonary toxicity
- C. Doxorubicin will increase her risk for deep vein thrombosis (DVT) and pulmonary embolism (PE)
- D. Doxorubicin frequently causes an acneiform rash
- E. Doxorubicin frequently causes cystitis
Long-term survivor follow-up Explanation: ***Doxorubicin has a maximum lifetime dose, due to the risk of cardiac toxicity***
- **Doxorubicin** is a potent chemotherapy agent (anthracycline) with a well-known risk of **cardiotoxicity**, which can lead to **dilated cardiomyopathy** and heart failure.
- To mitigate this severe side effect, a **cumulative lifetime dose limit** (usually 450-550 mg/m²) is established for doxorubicin.
*Doxorubicin has a maximum lifetime dose, due to the risk of pulmonary toxicity*
- While some chemotherapy agents can cause pulmonary toxicity, **doxorubicin** is not primarily associated with this as its main dose-limiting toxicity.
- The most significant and common dose-limiting toxicity of doxorubicin is **cardiotoxicity**, not pulmonary.
*Doxorubicin will increase her risk for deep vein thrombosis (DVT) and pulmonary embolism (PE)*
- Chemotherapy in general can increase the risk of **thromboembolic events**, but this is not a specific dose-limiting toxicity of **doxorubicin** that dictates a lifetime maximum dose.
- The concern for DVT/PE is a broader complication of cancer and its treatment, distinct from doxorubicin's specific cardiac risk.
*Doxorubicin frequently causes an acneiform rash*
- **Acneiform rash** is a common side effect of epidermal growth factor receptor (EGFR) inhibitors (e.g., cetuximab, erlotinib), not typically associated with **doxorubicin**.
- Doxorubicin's dermatologic side effects usually involve **alopecia**, hand-foot syndrome, and radiation recall, but not a predominant acneiform rash.
*Doxorubicin frequently causes cystitis*
- **Cystitis**, particularly hemorrhagic cystitis, is a well-known side effect of **cyclophosphamide** (another drug the patient is receiving), not **doxorubicin**.
- **Mesna** is often administered with cyclophosphamide to prevent this urological toxicity.
Long-term survivor follow-up US Medical PG Question 3: A 38-year-old female presents to her primary care physician with complaints of several episodes of palpitations accompanied by panic attacks over the last month. She also is concerned about many instances over the past few weeks where food has been getting stuck in her throat and she has had trouble swallowing. She denies any prior medical problems and reports a family history of cancer in her mother and maternal grandfather but cannot recall any details regarding the type of cancer(s) or age of diagnosis. Her vital signs at today's visit are as follows: T 37.6 deg C, HR 106, BP 158/104, RR 16, SpO2 97%. Physical examination is significant for a nodule on the anterior portion of the neck that moves with swallowing, accompanied by mild lymphadenopathy. A preliminary work-up is initiated, which shows hypercalcemia, elevated baseline calcitonin, and an inappropriately elevated PTH level. Diagnostic imaging shows bilateral adrenal lesions on an MRI of the abdomen/pelvis. Which of the following is the most likely diagnosis in this patient?
- A. Familial medullary thyroid cancer (FMTC)
- B. Li-Fraumeni syndrome
- C. Multiple endocrine neoplasia (MEN) IIa (Correct Answer)
- D. Multiple endocrine neoplasia (MEN) I
- E. Multiple endocrine neoplasia (MEN) IIb
Long-term survivor follow-up Explanation: ***Multiple endocrine neoplasia (MEN) IIa***
- This patient presents with **medullary thyroid cancer** (due to the thyroid nodule, elevated calcitonin, and family history of cancer), **pheochromocytoma** (indicated by palpitations, panic attacks, hypertension, and adrenal lesions), and **primary hyperparathyroidism** (evidenced by hypercalcemia and inappropriately elevated PTH). These three conditions are the classic triad of MEN IIa.
- The symptoms of food getting stuck in her throat are also consistent with the presence of a **thyroid nodule**.
*Familial medullary thyroid cancer (FMTC)*
- While the patient has **medullary thyroid cancer**, FMTC is typically characterized solely by medullary thyroid carcinoma without the associated pheochromocytoma or primary hyperparathyroidism seen in this case.
- This patient's presentation includes **adrenal lesions** and **hyperparathyroidism**, which are not features of isolated FMTC.
*Li-Fraumeni syndrome*
- This syndrome is associated with a high risk of various cancers, including sarcomas, breast cancer, brain tumors, and adrenocortical carcinoma, but it is not typically associated with **medullary thyroid cancer, pheochromocytoma, or primary hyperparathyroidism** as a primary presentation.
- The genetic basis is a mutation in the **TP53 gene**, and the clinical picture does not match the specific endocrine tumors observed here.
*Multiple endocrine neoplasia (MEN) I*
- MEN I is characterized by tumors of the **parathyroid, pituitary, and pancreas** (the 3 Ps).
- This patient's presentation of medullary thyroid cancer, pheochromocytoma, and primary hyperparathyroidism does not include pituitary or pancreatic tumors, and medullary thyroid cancer and pheochromocytoma are not part of the MEN I spectrum.
*Multiple endocrine neoplasia (MEN) IIb*
- MEN IIb includes **medullary thyroid cancer** and **pheochromocytoma**, which are present in this patient.
- However, MEN IIb also classically presents with characteristic **mucosal neuromas** and a **marfanoid habitus**, and *lacks* primary hyperparathyroidism, which this patient clearly exhibits.
Long-term survivor follow-up US Medical PG Question 4: A 7-year-old girl is brought to the physician because of scant painless bleeding from the vagina 6 hours ago. She has no history of serious illness or trauma. Her older sister had her first period at age 11. The patient is at the 80th percentile for height and 95th percentile for weight and BMI. Examination shows greasy facial skin and sparse axillary hair. Breast development is at Tanner stage 3 and pubic hair development is at Tanner stage 2. The external genitalia appear normal. Serum glucose is 189 mg/dL. Intravenous administration of leuprolide causes an increase in serum luteinizing hormone. Which of the following is the most likely underlying cause of this patient's findings?
- A. Overproduction of adrenal cortisol
- B. Ectopic hormone production
- C. Pulsatile GnRH release (Correct Answer)
- D. Compensatory hyperinsulinemia
- E. Deficiency of thyroid hormones
Long-term survivor follow-up Explanation: ***Pulsatile GnRH release***
- The combination of **precocious puberty** (Tanner stage 3 breasts, sparse axillary hair, vaginal bleeding at age 7), **insulin resistance** (serum glucose 189 mg/dL in a 7-year-old, high BMI), and a **positive leuprolide stimulation test** (increase in LH) points to central precocious puberty driven by pulsatile GnRH release.
- **Obesity** can contribute to earlier onset of puberty, and the elevated LH response to leuprolide confirms a gonadotropin-dependent (central) cause.
*Overproduction of adrenal cortisol*
- **Adrenal cortisol overproduction** (Cushing's syndrome) would typically present with central obesity, moon facies, striae, and possibly virilization, rather than the specific pubertal signs and GnRH-dependent LH response seen here.
- While it can cause some metabolic derangements, it does not directly lead to **gonadotropin-dependent precocious puberty**.
*Ectopic hormone production*
- **Ectopic hormone production** (e.g., from an ovarian tumor or adrenal tumor) would typically cause gonadotropin-independent precocious puberty, meaning the leuprolide test would likely show no or minimal LH response.
- Given the patient's **positive leuprolide test**, ectopic production is less likely as the primary cause of her puberty.
*Compensatory hyperinsulinemia*
- While the patient's elevated glucose and high BMI suggest **insulin resistance** leading to compensatory hyperinsulinemia, this is a metabolic consequence often associated with obesity and earlier puberty, not the primary underlying cause of the precocious puberty itself.
- It would not explain the **pulsatile GnRH release** or the positive leuprolide test.
*Deficiency of thyroid hormones*
- **Hypothyroidism** can cause delayed puberty, not precocious puberty. In rare cases, severe, long-standing hypothyroidism can lead to precocious puberty (Van Wyk-Grumbach syndrome), but this is typically associated with very high TSH and enlarged pituitary, and not the primary symptoms presented.
- The patient's clinical picture and the **positive leuprolide test** do not align with thyroid deficiency as the underlying cause.
Long-term survivor follow-up US Medical PG Question 5: A 7-year-old boy is brought to the physician because his parents are concerned about his early sexual development. He has no history of serious illness and takes no medications. His brother was diagnosed with testicular cancer 5 years ago and underwent a radical orchiectomy. The patient is at the 85th percentile for height and 70th percentile for weight. Examination shows greasy facial skin. There is coarse axillary hair. Pubic hair development is at Tanner stage 3 and testicular development is at Tanner stage 2. The remainder of the examination shows no abnormalities. An x-ray of the wrist shows a bone age of 10 years. Basal serum luteinizing hormone and follicle-stimulating hormone are elevated. An MRI of the brain shows no abnormalities. Which of the following is the most appropriate next step in management?
- A. Leuprolide therapy (Correct Answer)
- B. Testicular ultrasound
- C. Cortisol supplementation
- D. Radiation therapy
- E. Observation
Long-term survivor follow-up Explanation: ***Leuprolide therapy***
- This patient presents with **central precocious puberty** (CPP), indicated by elevated **basal LH and FSH levels** in the context of advanced bone age, Tanner stage 3 pubic hair, and Tanner stage 2 testicular development at a young age.
- **Leuprolide** is a GnRH analog that, when given continuously, downregulates the pituitary's GnRH receptors, suppressing gonadotropin release and halting pubertal progression. This is the appropriate treatment for CPP.
*Testicular ultrasound*
- While useful for evaluating testicular size and consistency, it is typically performed when there is suspicion of **peripheral precocious puberty** (e.g., Leydig cell tumor) with low LH/FSH or significant testicular asymmetry, which is not the primary presentation here.
- The elevated basal LH and FSH values indicate a **central origin** of puberty, making a testicular ultrasound less immediately relevant as a *next step* compared to directly addressing the central hormonal drive.
*Cortisol supplementation*
- This would be indicated for conditions causing **adrenal insufficiency**, such as **congenital adrenal hyperplasia (CAH)** with salt-wasting or Addison's disease.
- CAH typically presents with virilization and advanced bone age but would show **low LH/FSH** (due to peripheral androgen excess) and elevated adrenal androgens (e.g., DHEA-S, 17-hydroxyprogesterone), which are not described.
*Radiation therapy*
- This is a treatment for **malignant tumors**, often used in cases of brain tumors.
- The MRI of the brain showed **no abnormalities**, ruling out a pituitary or hypothalamic tumor as the cause of CPP in this case, thus making radiation therapy inappropriate.
*Observation*
- **Observation** alone is inappropriate given the significant **advancement of bone age** (10 years in a 7-year-old) and clear signs of central precocious puberty.
- Untreated CPP can lead to **compromised adult height potential** due to premature epiphyseal fusion and psychosocial issues, necessitating intervention.
Long-term survivor follow-up US Medical PG Question 6: A 62-year-old woman presents to her oncologist to discuss the chemotherapy options for her newly diagnosed breast cancer. During the meeting, they discuss a drug that inhibits the breakdown of mitotic spindles in cells. Her oncologist explains that this will be more toxic to cancer cells because those cells are dividing more rapidly. Which of the following side effects is closely associated with the use of this chemotherapeutic agent?
- A. Photosensitivity
- B. Peripheral neuropathy (Correct Answer)
- C. Paralytic ileus
- D. Hemorrhagic cystitis
- E. Pulmonary fibrosis
Long-term survivor follow-up Explanation: ***Peripheral neuropathy***
- Drugs that inhibit the breakdown of **mitotic spindles** are **microtubule-targeting agents** (e.g., **taxanes** like paclitaxel/docetaxel, **vinca alkaloids** like vincristine/vinblastine).
- These agents interfere with **microtubule function** in neurons, leading to **axonal damage** and **peripheral neuropathy**.
- This is the **most characteristic and common dose-limiting toxicity** of microtubule inhibitors, affecting sensory and motor nerves (numbness, tingling, weakness in extremities).
*Photosensitivity*
- **Photosensitivity** is a common adverse effect associated with certain chemotherapeutic agents like **fluorouracil** (5-FU) or **methotrexate**, but is not linked to microtubule inhibitors.
- It involves an increased sensitivity to UV light, often manifesting as a rash or exaggerated sunburn.
*Paralytic ileus*
- **Paralytic ileus** can occur with **vinca alkaloids** (especially vincristine) due to autonomic neuropathy affecting the **enteric nervous system**.
- However, this is **less common** than peripheral neuropathy and occurs more specifically with vincristine rather than taxanes.
- **Peripheral neuropathy** is the more pervasive, dose-limiting, and universally characteristic side effect across all microtubule inhibitors.
*Hemorrhagic cystitis*
- **Hemorrhagic cystitis** is a classic side effect of **alkylating agents** like **cyclophosphamide** and **ifosfamide**, which produce the toxic metabolite **acrolein**.
- It is prevented/managed with **mesna**, which inactivates acrolein.
- Not associated with microtubule inhibitors.
*Pulmonary fibrosis*
- **Pulmonary fibrosis** is a known side effect of certain chemotherapeutic drugs, most notably **bleomycin** and **busulfan**.
- This adverse effect is not associated with agents that target **mitotic spindle breakdown**.
Long-term survivor follow-up US Medical PG Question 7: A previously healthy 46-year-old woman comes to the physician because of a 3-month history of fatigue and progressive shortness of breath. She does not take any medications. Her pulse is 93/min and blood pressure is 112/80 mm Hg. Examination shows no abnormalities. Her hemoglobin concentration is 8 g/dL, leukocyte count is 22,000/mm3, and platelet count is 80,000/mm3. A peripheral blood smear shows increased numbers of circulating myeloblasts. Bone marrow biopsy confirms the diagnosis of acute myeloid leukemia. ECG, x-ray of the chest, and echocardiogram show no abnormalities. The patient is scheduled to start induction chemotherapy with cytarabine and daunorubicin. This patient is at increased risk for which of the following long-term complications?
- A. Left ventricular dysfunction (Correct Answer)
- B. Gross hematuria
- C. Bilateral tinnitus
- D. Endometrial hyperplasia
- E. Decreased diffusing capacity of the lung for carbon monoxide
Long-term survivor follow-up Explanation: ***Left ventricular dysfunction***
- **Daunorubicin** is an **anthracycline antibiotic** frequently used in AML chemotherapy; it is known to cause **dose-dependent cardiotoxicity**, leading to **left ventricular dysfunction** and congestive heart failure.
- The risk of cardiotoxicity is cumulative and can manifest years after treatment, making it a significant long-term complication.
*Gross hematuria*
- **Gross hematuria** is typically associated with hemorrhagic cystitis, a common side effect of **cyclophosphamide** or **ifosfamide** due to their metabolite **acrolein**.
- These agents are not part of the standard induction regimen mentioned (cytarabine and daunorubicin) for AML, thus making this complication less likely in this specific context.
*Bilateral tinnitus*
- **Bilateral tinnitus** is a common adverse effect of **cisplatin** and other **platinum-based chemotherapy agents**, which cause ototoxicity.
- These drugs are not part of the standard induction chemotherapy for AML described in the scenario.
*Endometrial hyperplasia*
- **Endometrial hyperplasia** is primarily associated with **unopposed estrogen stimulation** and is not a direct long-term complication of cytarabine and daunorubicin chemotherapy.
- While some chemotherapy can induce premature menopause, endometrial hyperplasia is not a specific or common drug-related long-term complication of this AML regimen.
*Decreased diffusing capacity of the lung for carbon dioxide*
- A **decreased diffusing capacity of the lung for carbon monoxide (DLCO)** is typically associated with **bleomycin-induced pulmonary fibrosis** or other interstitial lung diseases.
- **Bleomycin** is not used in the standard AML induction regimen of cytarabine and daunorubicin, making this an unlikely long-term complication in this patient.
Long-term survivor follow-up US Medical PG Question 8: An 18-month-old boy is brought to the doctor’s office for evaluation of abdominal pain. The boy looks emaciated and he is now significantly below his growth chart predicted weight. The family history is non-contributory. The vital signs are unremarkable. On physical examination, a non-tender mass is felt in the upper part of the abdomen. A magnetic resonance image (MRI) scan of his abdomen demonstrates a mass in his right adrenal gland. Biopsy of the mass demonstrates an abundance of small round blue cells. With this biopsy result, which 1 of the following findings would confirm the diagnosis?
- A. Elevation of vanillylmandelic acid in the urine (Correct Answer)
- B. MRI showing the intrarenal origin of the mass
- C. Increased lactic dehydrogenase
- D. Increased alpha-fetoprotein
- E. Radiograph of the bone showing the presence of lytic bone lesion with periosteal reaction
Long-term survivor follow-up Explanation: ***Elevation of vanillylmandelic acid in the urine***
- The clinical presentation (abdominal mass, emaciation, age) and biopsy finding of **small round blue cells** in the adrenal gland are highly suggestive of **neuroblastoma**.
- **Neuroblastomas** arise from neural crest cells and characteristically produce **catecholamines**, leading to elevated urinary levels of their metabolites like **vanillylmandelic acid (VMA)** and **homovanillic acid (HVA)**.
*MRI showing the intrarenal origin of the mass*
- An **intrarenal origin** of the mass would suggest a **Wilms tumor** (nephroblastoma), which is another common pediatric abdominal malignancy.
- However, the mass is described as being in the **adrenal gland**, and the biopsy shows small round blue cells, which are characteristic of neuroblastoma rather than Wilms tumor.
*Increased lactic dehydrogenase*
- Elevated **lactic dehydrogenase (LDH)** is a non-specific tumor marker often associated with a high tumor burden and rapid cell turnover in various malignancies, including neuroblastoma.
- While it can be elevated in neuroblastoma, it is not a specific diagnostic marker and would not confirm the diagnosis over other pediatric cancers.
*Increased alpha-fetoprotein*
- Elevated **alpha-fetoprotein (AFP)** is primarily associated with **hepatoblastoma** and **germ cell tumors**.
- It is not typically elevated in neuroblastoma and would therefore not confirm this diagnosis.
*Radiograph of the bone showing the presence of lytic bone lesion with periosteal reaction*
- While **neuroblastoma** can metastasize to bones, causing **lytic bone lesions** and a periosteal reaction, these findings indicate metastatic disease rather than confirming the primary diagnosis.
- A bone radiograph showing such lesions points to advanced disease but doesn't specifically confirm neuroblastoma as the primary tumor type.
Long-term survivor follow-up US Medical PG Question 9: A 3-year-old girl is brought to the physician by her parents for complaints of breast development and pubic hair growth for the past 6 months. She has no significant birth or medical history. The temperature is 37.0°C (98.6°F), the pulse is 88/min, and the respirations are 20/min. Physical examination shows enlarged breasts at Tanner stage 3 and pubic hair at stage 2. Height and weight are in the normal range. On GnRH stimulation testing, a luteinizing hormone (LH) response of < 5 IU/L is detected. What is the most appropriate next step in diagnosis?
- A. Perform leuprolide stimulation test to measure testosterone
- B. Measure baseline estradiol levels and perform pelvic ultrasound (Correct Answer)
- C. Measure FSH levels to evaluate pituitary function
- D. Calculate LH:FSH ratio from previous GnRH test
- E. Repeat GnRH stimulation test to confirm LH response
Long-term survivor follow-up Explanation: ***Measure baseline estradiol levels and perform pelvic ultrasound***
- This patient presents with **precocious puberty** (breast development and pubic hair at age 3). The **low LH response** (<5 IU/L) to GnRH stimulation confirms **peripheral (gonadotropin-independent) precocious puberty**.
- In peripheral precocious puberty, sex hormones are produced **autonomously** (independent of pituitary control), which **suppresses** the hypothalamic-pituitary-gonadal axis through negative feedback.
- The next step is to **identify the source** of autonomous sex hormone production. **Measuring estradiol levels** confirms elevated estrogen, and **pelvic ultrasound** evaluates for ovarian causes such as **ovarian cysts** or **tumors** (e.g., granulosa cell tumor), which are common causes of peripheral precocious puberty in girls.
- Other causes to consider include **McCune-Albright syndrome** (café-au-lait spots, polyostotic fibrous dysplasia) or exogenous estrogen exposure.
*Measure FSH levels to evaluate pituitary function*
- Measuring FSH is **not helpful** in this clinical context because the low LH response to GnRH stimulation **already indicates** that the pituitary is suppressed.
- In peripheral precocious puberty, both LH and FSH are **suppressed** due to negative feedback from peripherally produced sex hormones. Measuring FSH would simply confirm what we already know - that the pituitary axis is not activated.
- The priority is to find the **source** of the sex hormones, not to further characterize pituitary suppression.
*Perform leuprolide stimulation test to measure testosterone*
- Leuprolide is a **GnRH agonist** used to evaluate **central precocious puberty**, where the HPG axis is prematurely activated.
- This test is **not indicated** for peripheral precocious puberty, which has already been confirmed by the low LH response.
- Additionally, measuring testosterone would not be useful in a female patient presenting with estrogenic signs (breast development).
*Calculate LH:FSH ratio from previous GnRH test*
- The **LH:FSH ratio** is useful in diagnosing **central precocious puberty**, where an LH-predominant response (LH:FSH ratio >0.6-1.0) is characteristic.
- Since the LH response is already **low** (<5 IU/L), confirming peripheral precocious puberty, this ratio would not provide diagnostic value.
- The focus should be on investigating the **peripheral source** of sex hormones.
*Repeat GnRH stimulation test to confirm LH response*
- Repeating the GnRH stimulation test is **unnecessary** when the initial test provides clear results.
- The low LH response (<5 IU/L) definitively indicates peripheral precocious puberty, and repeating the test would only delay appropriate diagnostic workup for the underlying cause.
Long-term survivor follow-up US Medical PG Question 10: A 6-year-old girl is brought to the pediatrician by her father for an annual physical examination. The father reports that the patient is a happy and healthy child, but he sometimes worries about her weight. He says that she is a “picky” eater and only wants chicken nuggets and French fries. He also notes some mild acne on her cheeks and forehead but thinks it’s because she “doesn’t like baths.” The father says she has met all her pediatric milestones. She has recently started kindergarten, can tell time, and is beginning to read. Her teacher says she gets along with her classmates well. The patient was born at 38 weeks gestation. She has no chronic medical conditions and takes only a multivitamin. Height and weight are above the 95th percentile. Physical examination reveals scattered comedones on the patient’s forehead and bilateral cheeks. There is palpable breast tissue bilaterally with raised and enlarged areolae. Scant axillary hair and coarse pubic hair are also noted. A radiograph of the left hand shows a bone age of 9 years. Serum follicular stimulating hormone (FSH) level is 9.6 mU/mL (normal range 0.7-5.3 mU/mL) and luteinizing hormone (LH) level is 6.4 mU/mL (normal range < 0.26 mU/mL). Which of the following is the most appropriate diagnostic test?
- A. Pelvic ultrasound
- B. Estrogen levels
- C. 17-hydroxyprogesterone levels
- D. Dehydroepiandrosterone sulfate levels
- E. Brain magnetic resonance imaging (MRI) (Correct Answer)
Long-term survivor follow-up Explanation: ***Brain magnetic resonance imaging (MRI)***
- The constellation of **precocious puberty** (breast development, pubic and axillary hair, advanced bone age) and **elevated FSH and LH levels** in a 6-year-old girl indicates central precocious puberty, which is often caused by a CNS lesion.
- **Brain MRI is the gold standard imaging** to rule out **hypothalamic hamartomas**, **gliomas**, **craniopharyngiomas**, or other structural abnormalities of the **hypothalamic-pituitary axis**.
- MRI provides superior soft tissue resolution without radiation exposure, making it the preferred modality in children.
*Pelvic ultrasound*
- A pelvic ultrasound is primarily used to evaluate **gonadal tumors** or cysts in cases of **peripheral precocious puberty**, where FSH and LH levels would be suppressed.
- Given the elevated FSH and LH, the puberty is central (gonadotropin-dependent), making CNS imaging more appropriate than ovarian imaging.
*Estrogen levels*
- While estrogen levels would certainly be elevated in this patient, measuring them would confirm sexual precocity but would not differentiate between **central** and **peripheral precocious puberty**.
- The **elevated FSH and LH levels** already indicate active gonadal stimulation, making direct estrogen measurement less informative for pinpointing the etiology.
*17-hydroxyprogesterone levels*
- Elevated 17-hydroxyprogesterone levels are indicative of **congenital adrenal hyperplasia (CAH)**, particularly the 21-hydroxylase deficiency.
- CAH typically causes signs of **virilization** (e.g., clitoromegaly) but not breast development, and would not cause elevated FSH and LH levels.
*Dehydroepiandrosterone sulfate levels*
- Elevated DHEAS levels suggest an **adrenal source of androgens**, which could contribute to **pubic and axillary hair growth** (adrenarche).
- However, DHEAS elevation alone would not explain the **breast development** and **elevated gonadotropins**, which point towards central precocious puberty.
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