Nokea
An 18-month-old boy, whose parents are first cousins, is referred to you because of a significant episode of epistaxis. The parents report that the child had bleeding after circumcision and large hematomas with immunizations. Platelet aggregation studies show the following: This child's platelets are unable to interact with which of the following?
- A. ADP
- B. Fibrinogen
- C. von Willebrand factor
- D. Platelet factor 4
Correct Answer: B
Rationale: The correct answer is B: Fibrinogen. In this scenario, the child likely has Glanzmann thrombasthenia, a rare inherited platelet disorder where platelets lack functional integrin αIIbβ3, preventing binding to fibrinogen. This results in impaired platelet aggregation and clot formation, leading to bleeding issues. Choices A, C, and D are incorrect because platelet aggregation studies would typically show normal interactions with ADP, von Willebrand factor, and Platelet factor 4 in Glanzmann thrombasthenia.
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A 3-year-old boy is referred to you for evaluation of right leukocoria. Funduscopic examination under anesthesia reveals a large amelanotic mass occupying more than two-thirds of the vitreous space in his right eye, with massive retinal detachment, consistent with group E retinoblastoma. The left eye is normal. An MRI confirms the funduscopic findings and shows no extraocular disease. What is the most appropriate next step in the management of this child's disease?
- A. Enucleation
- B. Systemic chemotherapy
- C. Brachytherapy
- D. Needle biopsy
Correct Answer: A
Rationale: The most appropriate next step in the management of the child's retinoblastoma is enucleation (choice A). Enucleation, the surgical removal of the affected eye, is indicated when there is a large intraocular tumor with extensive retinal detachment, as in this case. Enucleation can provide local control of the disease and prevent systemic spread. It is considered the standard treatment for advanced retinoblastoma to prevent metastasis.
Systemic chemotherapy (choice B) is not the first-line treatment for advanced retinoblastoma with massive intraocular involvement. Brachytherapy (choice C) involves the placement of a radioactive source near the tumor, which may not be effective in this case of extensive intraocular disease. Needle biopsy (choice D) is not recommended as the primary management strategy due to the risk of seeding tumor cells outside the eye. Therefore, enucleation is the most appropriate next step in this scenario.
In a study to investigate the rates of central line–acquired bacterial infections, it is discovered that patient length of stay (LOS) is not normally distributed but is highly right-skewed. What is the correct relationship between the mean, median, and mode of LOS?
- A. The mean is less than the median but greater than the mode.
- B. The mean is equal to the median and the mode.
- C. The mean is greater than the median and mode.
- D. The mean and median will both be less than the mode.
Correct Answer: C
Rationale: The correct answer is C: The mean is greater than the median and mode. In a highly right-skewed distribution, the mean is pulled towards the higher end by the extreme values, making it greater than the median, which is the middle value. The mode is the most frequent value, which is typically lower than the mean in a right-skewed distribution. In summary, the mean is influenced by extreme values, causing it to be greater than both the median and the mode in a highly right-skewed distribution.
NADPH is a product of the hexose monophosphate pathway (HMP) in the red blood cell. The NADPH is used for the
- A. Synthesis of fatty acids
- B. Reduction of glutathione
- C. Formation of ATP
- D. Removal of oxygen radicals
Correct Answer: B
Rationale: The correct answer is B: Reduction of glutathione. In the HMP pathway, glucose-6-phosphate is converted to ribulose-5-phosphate, generating NADPH. NADPH is essential for the reduction of glutathione, which helps in detoxifying reactive oxygen species and protecting red blood cells from oxidative damage. Fatty acid synthesis (choice A) primarily requires NADPH from the pentose phosphate pathway. ATP formation (choice C) is not a direct function of NADPH production in the HMP pathway. NADPH is not directly involved in the removal of oxygen radicals (choice D), as it is the reduced form of NADP+ that participates in antioxidant defense mechanisms.
Busulfan therapy lead to all except:
- A. hyperpigmentation
- B. pulm .Fibrosis
- C. optic neuritis
- D. BM suppression
Correct Answer: C
Rationale: The correct answer is C: Optic neuritis. Busulfan therapy is known to cause adverse effects like hyperpigmentation, pulmonary fibrosis, and bone marrow suppression due to its cytotoxic nature. However, optic neuritis is not a common side effect associated with busulfan. Optic neuritis typically occurs due to inflammation of the optic nerve and is more commonly linked to conditions like multiple sclerosis. Therefore, in the context of busulfan therapy, optic neuritis is not a expected side effect, making it the correct answer.
A 17-year-old female presents with cervical adenopathy and a history of daily fevers and drenching night sweats. A biopsy is performed and reveals classic Hodgkin lymphoma. Which of the following is least appropriate as part of the staging workup?
- A. Chest x-ray
- B. CT scan of chest, abdomen, and pelvis
- C. Functional imaging (PET scan)
- D. Lumbar puncture and cerebrospinal fluid (CSF) analysis
Correct Answer: D
Rationale: The correct answer is D, Lumbar puncture and cerebrospinal fluid (CSF) analysis. In Hodgkin lymphoma, central nervous system involvement is rare at presentation, making routine CSF analysis unnecessary. Staging workup typically includes imaging studies (A, B, C) to assess disease extent and involvement of distant organs. CSF analysis is reserved for cases with neurological symptoms or signs suggestive of CNS involvement. Therefore, in this case, the least appropriate option for staging workup is D.