During a routine examination of a 10-mo-old male infant, you find a white pupillary reflex of the right eye; the eye movements are normal. You suspect retinoblastoma. Of the following, the BEST confirmatory diagnostic evaluation of this infant is

Correct Answer: B

Rationale: In this scenario, the best confirmatory diagnostic evaluation for a suspected case of retinoblastoma in a 10-month-old infant is option B: examination under general anesthesia by an experienced ophthalmologist. Retinoblastoma is a serious eye cancer that primarily affects young children. An examination under anesthesia allows for a thorough evaluation of the eye, including detailed visualization of the retina and assessment of the extent of the tumor. This method is crucial in confirming the diagnosis of retinoblastoma as it provides a comprehensive view of the affected eye and allows for necessary interventions to be planned. Option A, indirect ophthalmoscopy with slit-lamp examination, may not provide an adequate view of the entire retina, especially in a young child who may not cooperate fully during the examination. Orbital ultrasonography (option C) may be helpful in some cases but is not as definitive as an examination under anesthesia. Brain MRI (option D) is not the most appropriate test for diagnosing retinoblastoma as it focuses on the brain rather than the eye. In an educational context, understanding the importance of selecting the most appropriate diagnostic test for specific conditions is critical in providing optimal patient care. In the case of retinoblastoma, prompt and accurate diagnosis is essential for initiating timely treatment and improving outcomes for the child. Educating healthcare providers on the significance of specialized evaluations, such as examination under anesthesia by an experienced ophthalmologist, can help ensure proper management of pediatric eye conditions.

Correct Answer: D

Rationale: The most effective treatment for a child with ileocecal Burkitt lymphoma presenting with hyperuricemia (serum uric acid 12 mg/dl) is option D, recombinant urate oxidase. This enzyme helps to break down uric acid into a more soluble form, lowering serum levels and preventing complications like tumor lysis syndrome. Option A, excessive hydration, may help prevent renal damage from uric acid crystals but is not as effective in rapidly reducing elevated uric acid levels. Option B, sodium bicarbonate, is used to alkalinize urine and prevent uric acid crystallization in the renal tubules but does not directly lower serum levels. Option C, xanthine oxidase inhibitor, is used in chronic hyperuricemia like gout but is not as effective in acute tumor lysis syndrome. In an educational context, understanding the pathophysiology of tumor lysis syndrome and the role of urate oxidase in lowering uric acid levels is crucial in managing pediatric oncology patients. It highlights the importance of prompt and effective intervention to prevent life-threatening complications.

Correct Answer: A

Rationale: The correct answer is A) nephroblastoma. In a 2-month-old infant with a left renal mass, nephroblastoma, also known as Wilms tumor, is the most likely diagnosis. Nephroblastoma is the most common renal tumor in children and typically presents with an asymptomatic abdominal mass. It is important to consider this diagnosis in pediatric patients with renal masses, especially in the context of the patient's age and presentation. Option B) neuroblastoma is an incorrect choice in this scenario because neuroblastoma is a tumor of the sympathetic nervous system and is not typically associated with renal masses. Option C) mesoblastic nephroma is less common than nephroblastoma and usually presents in the first few months of life, often with a palpable abdominal mass. Option D) clear cell sarcoma is a rare tumor that typically affects older children and adults, making it less likely in a 2-month-old infant. Educationally, understanding the common pediatric renal tumors and their typical presentations is crucial for healthcare providers working with pediatric populations. Recognizing the age at presentation, common signs and symptoms, and typical imaging findings of these tumors can aid in early diagnosis and appropriate management, ultimately improving patient outcomes.

Correct Answer: A

Rationale: In nasopharyngeal carcinoma, elevated lactate dehydrogenase (LDH) level carries the worst outcome because it is a marker of aggressive disease and poor prognosis. LDH is often elevated in conditions associated with tissue damage or cancer progression, indicating a higher tumor burden and disease severity. Advanced disease and extensive cervical lymph node involvement are also poor prognostic factors, but elevated LDH is a more direct indicator of tumor activity and aggressiveness. Evidence of Epstein-Barr virus (EBV) DNA may be present in nasopharyngeal carcinoma due to its association with the disease, but it does not necessarily correlate with a worse outcome compared to elevated LDH. In an educational context, understanding the significance of different prognostic factors in nasopharyngeal carcinoma is crucial for healthcare providers involved in the care of pediatric patients. Recognizing the impact of elevated LDH on prognosis can help guide treatment decisions and management strategies to improve patient outcomes. It is essential for healthcare professionals to be able to differentiate between various prognostic factors to provide optimal care for pediatric patients with nasopharyngeal carcinoma.

Correct Answer: D

Rationale: In this scenario, the correct answer is D) vitamin B12. A strict vegetarian diet, particularly one that excludes all animal products, can lead to a deficiency in vitamin B12 as it is primarily found in animal-based foods. Vitamin B12 is crucial for neurological function, red blood cell production, and overall growth and development, especially in young children. Option A) niacin, Option B) thiamin, and Option C) vitamin B6 are not the most likely deficiencies in a child following a strict vegetarian diet. While these vitamins are also important for overall health, they are more readily available in plant-based foods or can be synthesized by the body in adequate amounts, compared to vitamin B12 which is primarily found in animal products. From an educational perspective, this question highlights the importance of understanding the specific nutritional considerations for pediatric patients with different dietary patterns. It emphasizes the need for healthcare providers to be aware of potential deficiencies in children following strict vegetarian diets and to provide appropriate guidance and supplementation to ensure optimal health and development.