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The patient is a 2-month-old boy who presented with a skin abscess and is febrile. On exam, he is noted to have silvery hair and hypopigmented skin. A CBC shows a leukocyte count of 3.4 K/mcL with 10% neutrophils. What does the abnormality on the peripheral smear suggest?
- A. Abnormal lysosomal biogenesis
- B. Abnormal ribosome function
- C. Abnormal phagocytosis of opsonized particles
- D. Abnormal mitochondrial activity
Correct Answer: A
Rationale: The correct answer is A: Abnormal lysosomal biogenesis. The patient's presentation of silvery hair and hypopigmented skin suggests a lysosomal storage disorder like Chediak-Higashi syndrome. The peripheral smear showing 10% neutrophils with a low leukocyte count indicates impaired neutrophil function due to abnormal lysosomal biogenesis. This affects phagocytosis and intracellular killing of pathogens, leading to recurrent infections and abscess formation.
Incorrect choices:
B: Abnormal ribosome function - not related to the patient's presentation.
C: Abnormal phagocytosis of opsonized particles - the primary issue is with lysosomal biogenesis, not phagocytosis.
D: Abnormal mitochondrial activity - does not explain the silvery hair and hypopigmented skin seen in Chediak-Higashi syndrome.
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The nurse notes that a patient's gaping wound is developing a blood clot. Which body substance is responsible for this clot formation?
- A. Plasma
- B. Platelets
- C. Red blood cells
- D. White blood cells
Correct Answer: B
Rationale: Platelets are responsible for clot formation in the body. When a wound occurs, platelets adhere to the site and release chemicals to initiate clotting. They then aggregate to form a plug, stopping bleeding. Plasma carries platelets but is not directly involved in clot formation. Red blood cells transport oxygen but do not participate in clotting. White blood cells are part of the immune system and do not play a role in clot formation. Therefore, platelets are the correct choice for clot formation in this scenario.
Which of the following is false regarding heparin?
- A. Subcutaneous injection of heparin is avoided because of hematomas formation.
- B. Heparin is usually stored in the mast cells.
- C. Heparin binds to plasma anti thrombin III and inhibits activated thrombin.
- D. Protamine sulfate can be used to counteract heparin overdose.
Correct Answer: A
Rationale: Step-by-step rationale:
1. Subcutaneous injection of heparin is avoided due to the risk of hematoma formation at the injection site.
2. This statement is false because heparin is commonly administered subcutaneously for prophylaxis of thromboembolic events.
3. The preferred route for heparin administration is subcutaneous or intravenous.
4. Therefore, choice A is the false statement.
Summary:
- Choice A is incorrect as heparin is commonly given subcutaneously.
- Choice B is incorrect as heparin is not stored in mast cells but in specialized granules in mast cells.
- Choice C is correct as heparin binds to plasma antithrombin III to inhibit thrombin.
- Choice D is correct as protamine sulfate can reverse heparin's anticoagulant effects in case of overdose.
A 12-year-old patient with localized osteosarcoma is being treated with cisplatin, doxorubicin, and high-dose methotrexate. The pain at his primary site rapidly resolves after initiation of chemotherapy. After tumor resection, pathology reveals the tumor was greater than 95% necrotic. You want to continue cisplatin, doxorubicin, and high-dose methotrexate. Which of the following is the best answer regarding the evaluations that should be performed to monitor for toxicity in patients receiving cisplatin, doxorubicin, and high-dose methotrexate?
- A. Complete blood count, creatinine, liver function tests
- B. Complete blood count, serum electrolytes (sodium, potassium, BUN, chloride), and EKG to monitor for prolonged QTc
- C. Complete blood count, creatinine, serum magnesium, audiogram, and echocardiogram
- D. Complete blood count, creatinine, serum magnesium, chest x-ray
Correct Answer: C
Rationale: The correct answer is C because it includes essential evaluations to monitor for toxicity associated with cisplatin, doxorubicin, and high-dose methotrexate.
1. Complete blood count: To monitor for potential bone marrow suppression caused by chemotherapy drugs.
2. Creatinine: To assess renal function, as cisplatin can cause nephrotoxicity.
3. Serum magnesium: Monitoring for hypomagnesemia, a common side effect of cisplatin.
4. Audiogram: To screen for hearing loss, a known side effect of cisplatin.
5. Echocardiogram: To evaluate for cardiotoxicity, especially with doxorubicin known to cause cardiomyopathy.
Other choices are incorrect:
A: Does not include serum magnesium, audiogram, and echocardiogram, which are important for monitoring toxicity.
B: While electrolytes and EKG are relevant, it lacks creatinine, serum magnesium, and other crucial tests.
D:
Which of the following is wrong concerning Philadelphia chromosome:
- A. shortening of long arm of chromosome 22
- B. Philadelphia:-ve cases have bad prognosis
- C. diagnostic of CML
- D. found in lymphocytes
Correct Answer: D
Rationale: The correct answer is D, as the Philadelphia chromosome is typically found in myeloid cells, not lymphocytes. This is because the Philadelphia chromosome results from a translocation between chromosomes 9 and 22, leading to the formation of the BCR-ABL fusion gene, which is associated with chronic myeloid leukemia (CML). Choice A is correct as the Philadelphia chromosome results from the shortening of the long arm of chromosome 22. Choice B is incorrect as Philadelphia positivity in CML patients is associated with a worse prognosis. Choice C is correct as the presence of the Philadelphia chromosome is a diagnostic hallmark of CML.
Outstanding feature of ITP:
- A. fever
- B. gum bleeding
- C. moderate splenomegaly
- D. stema tenderness
Correct Answer: B
Rationale: The correct answer is B: gum bleeding. In Immune Thrombocytopenic Purpura (ITP), the hallmark feature is thrombocytopenia leading to mucocutaneous bleeding, including gum bleeding. Fever (choice A) is not a typical feature of ITP. Splenomegaly (choice C) can be present in chronic ITP but is not a defining feature. Sterna tenderness (choice D) is not specific to ITP and is not considered a characteristic feature. Thus, gum bleeding is the outstanding feature of ITP due to the primary pathophysiology of decreased platelet count leading to bleeding manifestations.