A 13-year-old boy presents to the emergency department with complaints of headache and visual changes. History reveals progressive dyspnea on exertion, generalized fatigue, and increased bruising. His labs are significant for a WBC of 350,000/mcL, of which 80% are reported to be blasts and appear to be myeloblasts without the presence of Auer rods. His hemoglobin is 7.2 g/dL, and his platelets are 18,000/mcL. A CT scan of the head shows a small intracerebral hemorrhage. His coags are normal. Which of the following is the most appropriate therapy?

Correct Answer: C

Rationale: The most appropriate therapy in this scenario is emergent leukapheresis plus hydroxyurea (Choice C). Leukapheresis is needed to rapidly reduce the high white blood cell count, preventing further complications such as leukostasis and hyperviscosity syndrome. Hydroxyurea can help further control the rapid proliferation of blasts. Induction chemotherapy (Choice A) may lead to tumor lysis syndrome due to the high tumor burden. Performing leukapheresis alone without a subsequent therapy (Choice B) may not adequately address the underlying disease. Providing cranial radiation (Choice D) is not the initial management for acute myeloid leukemia.

Correct Answer: C

Rationale: The most likely diagnosis for this 13-year-old boy presenting with fatigue, weight loss, night sweats, splenomegaly, anemia, thrombocytosis, leukocytosis (300,000/mm3) is Chronic Myeloid Leukemia (CML). 1. Presence of anemia, thrombocytosis, and leukocytosis is characteristic of CML. 2. CML typically presents with splenomegaly. 3. Age of onset (13 years) is within the typical range for CML. 4. The Philadelphia chromosome (t(9;22)) is present in most cases of CML, aiding in diagnosis. 5. Leukemoid reaction (A) is a reactive increase in white blood cells, not a primary neoplastic disorder. 6. Acute lymphoblastic leukemia (ALL) (B) typically presents with bone pain, lymphadenopathy, and CNS symptoms in children. 7

Correct Answer: D

Rationale: The correct answer is D: Obtain labs, including a CBC with platelet count and fibrinogen. This is the most appropriate next step because the infant's presentation with an indurated and purpuric lesion raises concern for a possible bleeding disorder or coagulopathy. By obtaining labs, including a CBC with platelet count and fibrinogen, we can assess the infant's hemostatic profile and rule out any underlying hematologic abnormalities. This step is crucial in ensuring the infant's well-being and guiding further management if any abnormalities are detected. Why the other choices are incorrect: A: Doing nothing is not appropriate as the presentation warrants further investigation. B: An ultrasound may not provide useful information in this scenario as the lesion is concerning for a systemic issue. C: An MRI is not the initial diagnostic test of choice for evaluating a possible bleeding disorder or coagulopathy.

Correct Answer: D

Rationale: The correct answer is D: Kruskal-Wallis test. This non-parametric test is used to compare the medians of three or more independent groups when the data is not normally distributed, as in this case with LOS. It is an extension of the Wilcoxon-Mann-Whitney test, which compares two groups. The Kruskal-Wallis test assesses whether the medians of the groups are equal or different by ranking all observations, calculating the sum of ranks for each group, and then comparing these sums. It is appropriate here because it allows for comparison of central line types without assuming normality. The other choices (A: Student's t test and B: ANOVA) require the data to be normally distributed, which is not the case in this scenario. Choice C: Wilcoxon-Mann-Whitney test is for comparing two groups, not three or more.

Correct Answer: B

Rationale: The correct answer is B because autologous hematopoietic stem cell transplantation should be used when it can provide a survival benefit over chemotherapy. This approach is particularly beneficial for certain cancers such as neuroblastoma and relapsed lymphoma. - Choice A is incorrect because the indication for autologous transplantation is not solely based on the need for high-dose therapy, but rather on providing a meaningful survival benefit over chemotherapy. The listed cancers are not the most common ones treated with this approach. - Choice C is incorrect because the graft-versus-tumor effect is actually desired in some cases of autologous transplantation, and the listed cancers are not the most common ones treated with this approach. - Choice D is incorrect because the purpose of autologous transplantation is not to avoid extensive chemotherapy but to provide a survival benefit. The listed cancers are not the most common ones treated with this approach.