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CPHON practice questions

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Question 1Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 3-year-old is admitted with a large, smooth, firm abdominal mass that imaging suggests is a Wilms tumor. Which nursing instruction is most important to include in the plan of care?

  1. Apply warm compresses to the abdomen.
  2. Measure abdominal girth every shift.
  3. Avoid repeated palpation of the abdomen. Correct answer.
  4. Encourage frequent oral fluids.

Explanation

Wilms tumors are fragile and can rupture with handling, seeding the tumor and causing hemorrhage, so the abdomen is marked and palpated only when essential. Gentle assessment and documentation of the mass are appropriate, but repetitive deep palpation is avoided.

Question 2Care of the Pediatric Patient with Hematologic and Oncologic Disorders

Which finding in a lymph node biopsy is characteristic of Hodgkin lymphoma?

  1. Smudge cells
  2. Reed-Sternberg cells Correct answer.
  3. Auer rods
  4. Philadelphia chromosome

Explanation

Hodgkin lymphoma is defined histologically by Reed-Sternberg cells, large binucleate cells often described as owl-eye cells, within an inflammatory background. The other listed findings belong to different hematologic disorders.

Question 3Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 14-year-old with osteosarcoma of the distal femur is undergoing staging. Which site is the most common location for metastasis at diagnosis?

  1. Liver
  2. Brain
  3. Bone marrow
  4. Lungs Correct answer.

Explanation

Osteosarcoma spreads hematogenously, and the lungs are by far the most common site of metastasis at presentation, so chest imaging is part of routine staging. Metastatic disease to bone also occurs but is less frequent than pulmonary involvement.

Question 4Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A child is beginning therapy that includes doxorubicin. Which baseline and follow-up monitoring is required?

  1. Serial echocardiography Correct answer.
  2. Annual whole-body bone scan
  3. Monthly chest radiography
  4. Biweekly liver function panels

Explanation

Anthracyclines cause cumulative, dose-related myocardial injury, so cardiac function is assessed before therapy and periodically with echocardiography or multigated acquisition scanning. The risk rises with higher cumulative doses and with chest radiation.

Question 5Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A previously healthy 5-year-old has new petechiae and bruising, a platelet count of 12,000/microliter, and no other cytopenias. He is active and has only minor skin bleeding. What is the most appropriate initial management?

  1. Platelet transfusion to raise the count above 100,000
  2. Observation, with IVIG if bleeding is significant Correct answer.
  3. Oral corticosteroids continued for six months
  4. Splenectomy within 24 hours

Explanation

Childhood immune thrombocytopenia is usually self-limited, and treatment is guided by bleeding rather than by the platelet number. Observation alone or a short course of IVIG or corticosteroids is appropriate; platelet transfusions are reserved for life-threatening hemorrhage because transfused platelets are rapidly destroyed.

Question 6Care of the Pediatric Patient with Hematologic and Oncologic Disorders

Hydroxyurea is prescribed for a child with sickle cell disease. What is the primary therapeutic mechanism of this drug?

  1. It reduces the neutrophil count
  2. It chelates excess iron stores
  3. It increases fetal hemoglobin production Correct answer.
  4. It increases red cell 2,3-DPG content

Explanation

Hydroxyurea raises fetal hemoglobin, which inhibits polymerization of sickle hemoglobin, reduces sickling and hemolysis, and decreases vaso-occlusive events. Myelosuppression occurs but is a monitored side effect rather than the therapeutic goal.

Question 7Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 7-year-old is positioned for a lumbar puncture with intrathecal chemotherapy. Which position is correct?

  1. Prone with the head extended
  2. Side-lying with knees drawn to chest Correct answer.
  3. Sitting with the neck flexed
  4. Supine with the hips flexed

Explanation

A lateral decubitus position with the back at the edge of the bed and knees drawn toward the chest widens the spaces between lumbar vertebrae and aligns the spine for safe needle placement. Neck flexion should be avoided because it can compromise the airway.

Question 8Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A child receiving chemotherapy has painful oral mucositis. Which intervention should the nurse include in the plan of care?

  1. Saline or bicarbonate rinses with topical analgesia Correct answer.
  2. Firm toothbrush use after every meal
  3. Alcohol-based mouthwash every two hours
  4. Lemon-glycerin swabs to keep the mouth moist

Explanation

Gentle saline or sodium bicarbonate rinses remove debris and maintain moisture, and topical anesthetics or systemic analgesics control pain so the child can eat and drink. Irritants such as alcohol, glycerin, and harsh mechanical cleaning are avoided.

Question 9Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 6-year-old receiving chemotherapy has a temperature of 38.5 degrees Celsius and an absolute neutrophil count of 200/microliter. What is the priority action?

  1. Give empiric IV antibiotics within 60 minutes Correct answer.
  2. Begin antifungal therapy as initial treatment
  3. Wait for blood culture results before treating
  4. Give acetaminophen and reassess in four hours

Explanation

Fever with severe neutropenia is an oncologic emergency because bacterial sepsis can progress rapidly; blood cultures are drawn and broad-spectrum IV antibiotics started promptly, generally within one hour. Delay for culture results or antipyretics alone increases mortality.

Question 10Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A child with newly diagnosed Burkitt lymphoma has these laboratory values: potassium 6.4 mEq/L, phosphorus 7.8 mg/dL, calcium 7.1 mg/dL, and uric acid 11 mg/dL. Which pattern do these values represent?

  1. Hyperkalemia, hyperphosphatemia, hypocalcemia, hyperuricemia Correct answer.
  2. Hypokalemia, hypophosphatemia, hypercalcemia, hypouricemia
  3. Hypokalemia, hyperphosphatemia, hypocalcemia, hypouricemia
  4. Hyperkalemia, hyperphosphatemia, hypercalcemia, hyperuricemia

Explanation

Tumor lysis releases intracellular potassium and phosphate while nucleic acid breakdown raises uric acid; the excess phosphate binds calcium, producing hypocalcemia. This combination can cause seizures, tetany, arrhythmias, and acute kidney injury.

Question 11Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A child receives high-dose methotrexate followed by leucovorin. What is the purpose of the leucovorin?

  1. To increase methotrexate uptake by tumor cells
  2. To alkalinize the urine
  3. To rescue normal cells from folate antagonism Correct answer.
  4. To enhance renal excretion of methotrexate

Explanation

Leucovorin is a reduced folate that bypasses the dihydrofolate reductase block in normal tissues, limiting toxicity to bone marrow and mucosa while tumor cells retain high intracellular methotrexate. Urine alkalinization and hydration are separate measures used to prevent renal injury.

Question 12Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A nurse receives a written order to administer vincristine intrathecally. What is the priority action?

  1. Proceed because the order is written
  2. Dilute the drug in preservative-free saline
  3. Stop and clarify the order with the prescriber Correct answer.
  4. Give it in the lateral decubitus position

Explanation

Vincristine is fatal if given by the intrathecal route; it is intended for IV administration only. Any intrathecal order for a drug not formulated for that route must be halted and verified with the prescriber and pharmacy before administration.

Question 13Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 6-year-old has had morning headaches and vomiting for several weeks and now has truncal ataxia and a widened stance. Which diagnosis best fits this presentation?

  1. Osteosarcoma of the distal femur
  2. Medulloblastoma of the posterior fossa Correct answer.
  3. Wilms tumor of the left kidney
  4. Neuroblastoma of the adrenal gland

Explanation

Posterior fossa tumors such as medulloblastoma obstruct cerebrospinal fluid flow and cause morning headache and vomiting along with cerebellar signs like ataxia and wide-based gait. Symptoms often worsen over weeks before diagnosis.

Question 14Care of the Pediatric Patient with Hematologic and Oncologic Disorders

An infant has rapid, irregular eye movements, myoclonic jerks, and irritability, and imaging reveals an abdominal mass. Which tumor is most likely?

  1. Rhabdomyosarcoma
  2. Retinoblastoma
  3. Neuroblastoma Correct answer.
  4. Hepatoblastoma

Explanation

Opsoclonus-myoclonus syndrome in an infant is strongly associated with neuroblastoma, often a small thoracic or abdominal primary. The neurologic findings are thought to be immune-mediated and may persist after tumor resection.

Question 15Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 9-year-old with sickle cell disease develops fever, chest pain, and a new pulmonary infiltrate. Which set of interventions is the priority?

  1. Platelet transfusion to keep count above 50,000/microliter
  2. Hypotonic fluids at twice maintenance rate
  3. Oxygen, antibiotics, and transfusion support Correct answer.
  4. Meperidine for pain control and reassessment

Explanation

Acute chest syndrome is treated with supplemental oxygen to prevent hypoxemia, prompt broad-spectrum antibiotics because infection often triggers it, adequate but not excessive hydration, analgesia, and simple or exchange transfusion for severe disease. It is a leading cause of death in sickle cell disease.

Question 16Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A boy with mild hemophilia A has a small joint bleed after a minor injury. Which treatment is most appropriate?

  1. Fresh frozen plasma infusion
  2. Cryoprecipitate infusion
  3. Desmopressin (DDAVP) Correct answer.
  4. Platelet transfusion

Explanation

Desmopressin releases stored factor VIII from endothelial cells and raises plasma levels enough to treat minor bleeding in mild hemophilia A. It is ineffective in severe hemophilia A because no stored factor is available to release.

Question 17Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A child with beta-thalassemia major has received chronic transfusions for years and now has a serum ferritin of 3,000 ng/mL. Which therapy is indicated?

  1. Oral iron supplementation with vitamin C
  2. More frequent transfusions to suppress erythropoiesis
  3. Chelation with deferoxamine or deferasirox Correct answer.
  4. Splenic irradiation to reduce destruction

Explanation

Chronic transfusion causes iron overload that damages the heart, liver, and endocrine organs, so chelation is started once iron stores rise. Chelation is typically begun after a defined number of transfusions or when ferritin exceeds the threshold set by the treatment protocol.

Question 18Care of the Pediatric Patient with Hematologic and Oncologic Disorders

Thirty minutes into a packed red blood cell transfusion, a child's temperature rises 1.5 degrees Celsius with no other symptoms. What is the nurse's next action?

  1. Stop the transfusion and notify the provider Correct answer.
  2. Document the finding as an expected effect
  3. Continue the transfusion at a slower rate
  4. Give the next scheduled premedication and restart

Explanation

Any new fever during transfusion requires stopping the infusion and evaluating for a hemolytic or septic reaction while notifying the provider and blood bank. The remaining tubing and bag are returned per policy for investigation.

Question 19Care of the Pediatric Patient with Hematologic and Oncologic Disorders

Which chemotherapy agent requires mesna and vigorous hydration to prevent hemorrhagic cystitis?

  1. Vincristine
  2. Cyclophosphamide Correct answer.
  3. Cisplatin
  4. Doxorubicin

Explanation

Cyclophosphamide and ifosfamide produce acrolein, a urotoxic metabolite that inflames the bladder mucosa; mesna binds acrolein in the urine and hydration promotes frequent voiding. Nurses also monitor for hematuria and encourage voiding frequently.

Question 20Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A child receiving induction therapy develops severe epigastric pain and repeated vomiting several days after PEG-asparaginase. Which cause should be suspected first?

  1. Post-lumbar puncture cerebrospinal fluid leak
  2. Asparaginase-induced pancreatitis Correct answer.
  3. Steroid-induced hyperglycemia with ketoacidosis
  4. Vincristine-induced severe constipation

Explanation

Asparaginase is a well-recognized cause of acute pancreatitis, which presents with severe abdominal pain and vomiting and is confirmed by elevated amylase and lipase. The drug is held and the child is managed with bowel rest, fluids, and analgesia.

Question 21Care of the Pediatric Patient with Hematologic and Oncologic Disorders

An anthracycline extravasation is suspected at a peripheral IV site. Which agent is the specific antidote?

  1. Dimethyl sulfoxide
  2. Hyaluronidase
  3. Dexrazoxane Correct answer.
  4. Sodium thiosulfate

Explanation

Dexrazoxane is the specific antidote for anthracycline extravasation and is most effective when given within six hours, so the infusion is stopped immediately and the pharmacy is contacted. Cold compresses are also applied for anthracyclines.

Question 22Care of the Pediatric Patient with Hematologic and Oncologic Disorders

An infant with newly diagnosed acute myeloid leukemia has a white blood cell count of 350,000/microliter and increasing respiratory distress. What is the priority of care?

  1. Begin cytoreduction and supportive care for leukostasis Correct answer.
  2. Transfuse packed red cells immediately
  3. Administer granulocyte colony-stimulating factor
  4. Start prophylactic antibiotics and observe

Explanation

Extreme leukocytosis causes sludging in the pulmonary and cerebral microvasculature, producing hypoxia, altered mental status, and respiratory failure. Urgent cytoreduction with hydration and careful monitoring is required, and red cell transfusion is delayed until the white count is lowered because it increases blood viscosity.

Question 23Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A child is 30 days post allogeneic hematopoietic stem cell transplant and develops a maculopapular rash, profuse watery diarrhea, and a rising bilirubin. Which complication is most likely?

  1. Hemophagocytic lymphohistiocytosis
  2. Engraftment syndrome
  3. Veno-occlusive disease
  4. Acute graft-versus-host disease Correct answer.

Explanation

Acute graft-versus-host disease classically involves skin, gastrointestinal tract, and liver, usually presenting within the first 100 days after transplant. First-line treatment is high-dose systemic corticosteroids, plus prophylaxis with calcineurin inhibitors and methotrexate.

Question 24Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A child with high-risk leukemia and known glucose-6-phosphate dehydrogenase deficiency needs urate-lowering therapy during induction. Which plan is appropriate?

  1. Rasburicase, since it acts most rapidly
  2. Allopurinol with hydration and close monitoring Correct answer.
  3. Half-dose rasburicase with aggressive hydration
  4. Rasburicase with glucose-6-phosphate dehydrogenase monitoring every six hours

Explanation

Rasburicase is contraindicated in glucose-6-phosphate dehydrogenase deficiency because the hydrogen peroxide it generates causes severe oxidative hemolysis. Allopurinol blocks xanthine oxidase and is used instead, along with hydration and monitoring of electrolytes and renal function.

Question 25Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A complete blood count shows a white blood cell count of 800/microliter with 40 percent segmented neutrophils and 10 percent bands. What is the absolute neutrophil count?

  1. 480/microliter
  2. 400/microliter Correct answer.
  3. 80/microliter
  4. 320/microliter

Explanation

The absolute neutrophil count equals the white blood cell count multiplied by the combined percentage of segmented neutrophils and bands, so 800 times 0.50 equals 400/microliter. A value below 500/microliter defines severe neutropenia and warrants fever precautions.

Question 26Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A parent reports that in photographs of her 18-month-old child, one pupil appears white rather than red. The child otherwise appears well. Which finding does the nurse anticipate on examination?

  1. A cherry-red macular spot with vision loss
  2. Leukocoria on red reflex testing Correct answer.
  3. Rotary nystagmus with head tilting
  4. Bilateral proptosis with eyelid swelling

Explanation

An absent red reflex with a white pupillary appearance (leukocoria) is the most common presenting sign of retinoblastoma and is often first noticed on photographs. Any child with an abnormal red reflex requires urgent ophthalmologic evaluation because early treatment preserves vision and improves survival.

Question 27Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A previously healthy 4-year-old has scattered petechiae and bruising after a viral illness. The platelet count is 12,000/microliter, hemoglobin is 12 g/dL, the white cell count is 7,000/microliter, and the peripheral smear shows no blasts. The child is playful and has no mucosal bleeding. Which management does the nurse anticipate?

  1. Emergent splenectomy before hospital discharge
  2. Induction chemotherapy with vincristine and steroids
  3. Immediate platelet transfusion to raise the count above 50,000
  4. Observation with restriction of contact activities Correct answer.

Explanation

Childhood immune thrombocytopenia is usually self-limited and follows a viral illness, with isolated thrombocytopenia and a normal-appearing child. Treatment is reserved for clinically significant bleeding, and observation with avoidance of trauma is appropriate when only skin manifestations are present.

Question 28Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 6-month-old is diagnosed with sickle cell anemia after newborn screening. Which prophylactic measure does the nurse include in family teaching?

  1. Oral penicillin twice daily to age 5 years Correct answer.
  2. Weekly hydroxyurea injections started during infancy
  3. Monthly intramuscular vitamin B12 injections for life
  4. Daily iron supplementation beginning now and continuing indefinitely

Explanation

Infants with sickle cell anemia are functionally asplenic and have a high risk of overwhelming pneumococcal sepsis, so twice-daily oral penicillin prophylaxis is started early and continued until at least age 5 years. Prophylaxis is paired with the full pneumococcal immunization series.

Question 29Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A child who is severely immunocompromised requires a packed red blood cell transfusion. Which product modification does the nurse verify to prevent transfusion-associated graft-versus-host disease?

  1. Leukoreduction by filtration at the bedside
  2. Gamma irradiation of the unit before transfusion Correct answer.
  3. Use of fresh whole blood rather than packed cells
  4. Washing the units with normal saline before infusion

Explanation

Donor lymphocytes that survive in an immunocompromised recipient can engraft and attack host tissues, causing transfusion-associated graft-versus-host disease, which is almost always fatal. Gamma irradiation inactivates those lymphocytes and is required for immunocompromised and hematopoietic stem cell transplant recipients.

Question 30Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 2-year-old with sickle cell anemia has a sudden onset of pallor and abdominal fullness. The spleen is 6 cm below the costal margin and firm. Hemoglobin has fallen from 8.5 to 4.0 g/dL, reticulocytes are 9%, and the platelet and white cell counts are normal. Which complication does the nurse suspect?

  1. Parvovirus-induced aplastic crisis
  2. Acute splenic sequestration crisis Correct answer.
  3. Acute chest syndrome with hypoxia
  4. Splenic infarction from vaso-occlusion

Explanation

Splenic sequestration is marked by a rapidly enlarging spleen, a sharp fall in hemoglobin, and a reticulocyte response as the marrow attempts to compensate. It is most common in young children with sickle cell anemia and is treated with volume support and red cell transfusion.

Question 31Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 7-year-old with sickle cell disease has a fever, a mild facial rash, and increasing fatigue. Hemoglobin is 4.8 g/dL and the reticulocyte count is 0.2%, near zero. Which action should the nurse anticipate?

  1. Administering hydroxyurea to raise fetal hemoglobin
  2. Encouraging oral iron therapy to correct the anemia
  3. Packed red cell transfusion with supportive care Correct answer.
  4. Beginning broad-spectrum antibiotics for sepsis

Explanation

Parvovirus B19 infects erythroid precursors and causes a transient red cell aplasia, producing severe anemia with an inappropriately low reticulocyte count. The marrow recovers on its own, but transfusion is needed to support oxygen delivery until red cell production resumes.

Question 32Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 5-year-old with sickle cell anemia is scheduled for a yearly screening test that estimates stroke risk. Which test does the nurse anticipate?

  1. Transcranial Doppler ultrasonography Correct answer.
  2. Electroencephalography during quiet wakefulness
  3. Magnetic resonance angiography of the intracranial vessels
  4. Carotid duplex scanning of the neck vessels

Explanation

Annual transcranial Doppler screening is recommended for young children with sickle cell anemia because elevated flow velocities in the major intracranial arteries predict stroke risk. Children with abnormal velocities are offered chronic transfusion therapy to prevent stroke.

Question 33Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 12-year-old with sickle cell disease reports a painful erection that has lasted 45 minutes. Which initial action should the nurse take?

  1. Preparing the child for immediate surgical shunt placement
  2. Administering an opioid and reassessing in 2 hours
  3. Applying ice to the perineum and restricting fluids
  4. Hydration, analgesia, and prompt provider notification Correct answer.

Explanation

Priapism in sickle cell disease is caused by venous stasis and sickling, and initial management includes hydration, analgesia, and urgent provider notification. Episodes lasting more than 4 hours require urologic intervention such as aspiration or irrigation to prevent permanent erectile dysfunction.

Question 34Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 14-year-old with newly diagnosed Hodgkin lymphoma has a large anterior mediastinal mass and mild orthopnea. Which nursing action is most important?

  1. Encourage hallway ambulation several times per shift to prevent clots
  2. Position the child flat in bed to promote full lung expansion
  3. Permit a position of comfort and avoid sedating the child Correct answer.
  4. Administer a sedative before transport to radiology for imaging

Explanation

A large anterior mediastinal mass can compress the trachea, great vessels, and heart, and both supine positioning and sedation can precipitate sudden airway obstruction or cardiovascular collapse. The child should remain upright in a position of comfort and sedation should be avoided unless conducted with airway precautions in place.

Question 35Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 3-year-old is admitted with a large, firm, unilateral abdominal mass suspected to be a Wilms tumor. Which nursing intervention is priority?

  1. Measure abdominal girth every shift to track growth
  2. Encourage the child to eat a high-fiber diet to prevent constipation
  3. Palpate the mass gently to determine its exact size and mobility
  4. Mark the abdomen "no palpation" and handle gently Correct answer.

Explanation

A Wilms tumor is a fragile, encapsulated mass, and deep or repeated palpation can rupture it and spill tumor cells, upstaging the disease. The abdomen is protected with gentle handling and clear signage restricting palpation until resection.

Question 36Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A child is receiving cisplatin. Which assessment should the nurse perform to detect a characteristic dose-limiting adverse effect?

  1. Audiometry before and during therapy Correct answer.
  2. Daily weights and urine specific gravity
  3. Serial echocardiograms for ejection fraction
  4. Weekly liver enzyme panels

Explanation

Cisplatin causes cumulative, often irreversible sensorineural hearing loss, particularly in the high frequencies, so baseline and serial audiometry are standard. Hearing loss is dose limiting and can impair speech and language development in young children.

Question 37Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 5-year-old has mild jaundice, an enlarged spleen, and a family history of gallstones in young adulthood. The CBC shows anemia with an elevated MCHC, and the direct antiglobulin test is negative. Which diagnosis does the nurse anticipate?

  1. Iron deficiency anemia from poor intake
  2. Glucose-6-phosphate dehydrogenase deficiency
  3. Warm autoimmune hemolytic anemia
  4. Hereditary spherocytosis Correct answer.

Explanation

Hereditary spherocytosis is an inherited membrane disorder causing spherocytes, an elevated MCHC, splenomegaly, jaundice, and pigment gallstones, with a negative direct antiglobulin test. It is confirmed by osmotic fragility or eosin-5-maleimide binding testing.

Question 38Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 6-year-old with acute lymphoblastic leukemia receiving maintenance mercaptopurine develops a platelet count of 40,000/microliter and a neutrophil count of 600/microliter, with no other cause identified. Which explanation should the nurse consider?

  1. Antibody-mediated destruction of circulating platelets and neutrophils
  2. Cumulative marrow suppression from prior cranial radiation
  3. Poor adherence to the prescribed oral chemotherapy regimen
  4. Genetically reduced thiopurine methyltransferase activity Correct answer.

Explanation

Mercaptopurine is inactivated by thiopurine methyltransferase, so patients with low enzyme activity accumulate cytotoxic thioguanine nucleotides and develop profound myelosuppression at standard doses. Genotyping or phenotyping allows dose reduction before severe toxicity occurs.

Question 39Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A child is 16 days after an allogeneic hematopoietic stem cell transplant. Which finding best indicates that engraftment has occurred?

  1. Neutrophils above 500/microliter for 3 consecutive days Correct answer.
  2. A rising white cell count with 90% lymphocytes on the differential
  3. A platelet count above 30,000/microliter without transfusion support
  4. A rising reticulocyte count with a stable hemoglobin level

Explanation

Engraftment is defined by recovery of neutrophils, typically an absolute neutrophil count of at least 500/microliter on 3 consecutive days. Platelet and red cell recovery are tracked separately and generally occur later.

Question 40Care of the Pediatric Patient with Hematologic and Oncologic Disorders

A 4-year-old with severe hemophilia A has been receiving factor VIII concentrate twice weekly. He now has recurrent joint bleeds that no longer respond to usual doses, and a recovery study after infusion shows a low factor level. Which complication should the nurse suspect?

  1. Chronic liver disease with reduced clotting factor synthesis
  2. An allergic reaction to the factor VIII protein
  3. Vitamin K deficiency related to poor oral intake
  4. An inhibitor antibody that neutralizes infused factor VIII Correct answer.

Explanation

Roughly one third of children with severe hemophilia A develop alloantibodies that neutralize infused factor VIII, shown by poor recovery and lack of response to usual doses. Management requires bypassing agents, and inhibitor titers are measured with the Bethesda assay.

Question 41Disease Management and Treatment Modalities

A nurse is preparing chemotherapy for a child and must confirm the route before administration. Which drug is intended for intravenous use only because intrathecal administration causes fatal ascending paralysis?

  1. Methotrexate
  2. Hydrocortisone
  3. Cytarabine
  4. Vincristine Correct answer.

Explanation

Vincristine is a vinca alkaloid that must be given intravenously; accidental intrathecal injection is uniformly fatal because it causes ascending myeloencephalopathy. Only agents specifically prepared and labeled for intrathecal use may be given by that route.

Question 42Disease Management and Treatment Modalities

Which set of laboratory findings is characteristic of tumor lysis syndrome?

  1. Hyperkalemia, hypophosphatemia, hyperuricemia, hypercalcemia
  2. Hypokalemia, hypophosphatemia, hyperuricemia, hypercalcemia
  3. Hyperkalemia, hyperphosphatemia, hyperuricemia, hypocalcemia Correct answer.
  4. Hyperkalemia, hyperphosphatemia, hypouricemia, hypercalcemia

Explanation

Rapid lysis of malignant cells releases intracellular potassium, phosphate, and nucleic acids, producing hyperkalemia, hyperphosphatemia, and hyperuricemia. Excess phosphate binds serum calcium, so hypocalcemia develops and may cause tetany or seizures.

Question 43Disease Management and Treatment Modalities

A child with acute lymphoblastic leukemia has an absolute neutrophil count of 200/mm3 and a single oral temperature of 38.4 degrees C. What is the priority action?

  1. Draw blood cultures and start empiric IV antibiotics now Correct answer.
  2. Wait for culture results before starting any antibiotics
  3. Give oral acetaminophen and recheck the temperature in 4 hours
  4. Send the child home with a prescription for oral antibiotics

Explanation

Fever in a child with severe neutropenia is an oncologic emergency because bacterial sepsis can progress within hours. Cultures are obtained and broad-spectrum intravenous antibiotics begun promptly, generally within 60 minutes of presentation.

Question 44Disease Management and Treatment Modalities

Leucovorin (folinic acid) is administered after high-dose methotrexate to do which of the following?

  1. Alkalinize the urine to prevent drug crystallization
  2. Increase methotrexate uptake by the tumor cells
  3. Reduce nausea and vomiting caused by methotrexate
  4. Rescue normal cells from methotrexate toxicity Correct answer.

Explanation

Leucovorin is a reduced folate that bypasses the dihydrofolate reductase block produced by methotrexate, replenishing normal cells while tumor cells remain saturated with polyglutamated methotrexate. Hydration and urinary alkalinization are separate measures used to prevent renal toxicity.

Question 45Disease Management and Treatment Modalities

Which blood product modification prevents transfusion-associated graft-versus-host disease in an immunocompromised child?

  1. Irradiation with 25 Gy Correct answer.
  2. Use of fresh-frozen plasma
  3. Saline washing of the unit
  4. Leukoreduction by filtration

Explanation

Gamma or x-ray irradiation inactivates donor T lymphocytes, which are responsible for transfusion-associated graft-versus-host disease. Irradiation is standard for cellular products given to children with compromised cellular immunity and for all directed-donor units.

Question 46Disease Management and Treatment Modalities

Hydroxyurea benefits children with sickle cell disease primarily by doing which of the following?

  1. Suppressing the marrow to reduce hemolysis
  2. Increasing red cell 2,3-DPG concentration
  3. Decreasing intestinal iron absorption
  4. Increasing fetal hemoglobin production Correct answer.

Explanation

Hydroxyurea raises fetal hemoglobin levels, which interfere with polymerization of sickle hemoglobin and reduce sickling. It also lowers neutrophil and platelet counts and decreases the frequency of vaso-occlusive crises and acute chest syndrome.

Question 47Disease Management and Treatment Modalities

Which medication class is standard first-line prophylaxis for acute chemotherapy-induced nausea and vomiting in children?

  1. Antihistamines such as diphenhydramine
  2. Proton pump inhibitors such as omeprazole
  3. 5-HT3 antagonists such as ondansetron Correct answer.
  4. Corticosteroids used alone such as prednisone

Explanation

5-HT3 receptor antagonists block serotonin released from enterochromaffin cells after chemotherapy and are the backbone of antiemetic regimens in pediatrics. They are frequently combined with dexamethasone and, for highly emetogenic regimens, an NK1 antagonist.

Question 48Disease Management and Treatment Modalities

Daily penicillin prophylaxis is begun in infancy for a child with sickle cell disease primarily to prevent which of the following?

  1. Painful vaso-occlusive episodes
  2. Pneumococcal sepsis Correct answer.
  3. Acute chest syndrome
  4. Splenic sequestration crisis

Explanation

Functional asplenia develops early in sickle cell disease, leaving young children vulnerable to rapidly fatal encapsulated organism sepsis, particularly pneumococcal disease. Prophylactic penicillin is started by 2 months of age and continued until at least age 5 years, along with appropriate immunizations.

Question 49Disease Management and Treatment Modalities

A child is receiving doxorubicin and the cumulative dose is approaching the recommended limit. Which monitoring is most appropriate?

  1. Liver function tests before every dose
  2. Weekly serum troponin levels during therapy
  3. Echocardiogram to measure ejection fraction Correct answer.
  4. Monthly chest radiographs to detect enlargement

Explanation

Anthracyclines cause dose-related cardiomyopathy through free radical injury to myocytes, so cardiac function is assessed at baseline and periodically with echocardiography or MUGA scanning. Dexrazoxane may be used as a cardioprotectant when higher cumulative doses are required.

Question 50Disease Management and Treatment Modalities

Which intervention is most important in preventing hemorrhagic cystitis in a child receiving high-dose cyclophosphamide?

  1. Urinary alkalinization with sodium bicarbonate
  2. Prophylactic antibiotics throughout the infusion
  3. Strict bed rest for 24 hours after the dose
  4. Hydration and mesna with frequent voiding Correct answer.

Explanation

Cyclophosphamide is metabolized to acrolein, a urotoxin that inflames the bladder mucosa. Mesna binds acrolein in the urine, and vigorous hydration with frequent emptying keeps urinary concentration and contact time low.