Pediatric Hematology and Oncology

62 questions

Question 41Question →

Match each pediatric patient's clinical and laboratory presentation to the most likely hematologic or oncologic diagnosis.

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Items

A 3-year-old boy presents with pallor, bone pain, and hepatosplenomegaly. Bone marrow aspirate reveals >20% blasts positive for TdT, CD10, and CD19, with a t(12;21) translocation.
A 7-year-old boy from central Africa presents with a rapidly growing jaw mass. Biopsy reveals a 'starry sky' appearance and a t(8;14) translocation.
A 10-month-old girl of Mediterranean descent presents with severe anemia and hepatosplenomegaly. Hemoglobin electrophoresis shows absent HbA and elevated HbF.
A 5-year-old girl presents with petechiae, bruising, and mucosal bleeding following a recent viral illness. Laboratory testing shows isolated thrombocytopenia with normal coagulation studies.

Matches

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Answer

Properly match the clinical vignettes to B-ALL, Endemic Burkitt Lymphoma, Beta-Thalassemia Major, and Immune Thrombocytopenia (ITP) respectively.
Each vignette provides pathognomonic clues for a specific pediatric hematologic or oncologic diagnosis. TdT and t(12;21) are specific for B-ALL; 'starry sky' histology and t(8;14) are specific for Burkitt Lymphoma; absent HbA identifies Beta-Thalassemia Major; and isolated post-viral thrombocytopenia indicates ITP.

Step-by-Step Solution

1
Analyze the first presentation: 3-year-old with bone pain, hepatosplenomegaly, and TdT+/CD10+ blasts with t(12;21).
Matches B-cell Acute Lymphoblastic Leukemia.
These are classic markers and a favorable prognostic translocation for pediatric B-ALL.
2
Analyze the second presentation: 7-year-old with a jaw mass, 'starry sky' biopsy, and t(8;14).
Matches Endemic Burkitt Lymphoma.
The African origin, jaw involvement, and c-myc translocation strongly point to the endemic form of this high-grade B-cell lymphoma.
3
Analyze the third presentation: 10-month-old with severe anemia and absent HbA on electrophoresis.
Matches Beta-Thalassemia Major.
The timing corresponds with the physiologic decline of fetal hemoglobin, and the absence of HbA confirms a severe beta-globin gene defect.
4
Analyze the fourth presentation: 5-year-old with post-viral petechiae and isolated thrombocytopenia.
Matches Immune Thrombocytopenia (ITP).
The lack of other cytopenias or coagulation abnormalities in a post-viral setting is highly specific for ITP.

Key Concept

Identifying hallmark clinical, genetic, and laboratory features of common pediatric hematologic and oncologic disorders.
Question 42Question →

A 33-year-old boy is brought to the pediatrician's office by his father, who noticed a firm, painless swelling on the right side of the child's abdomen while dressing him. The child has been eating well, is as active as usual, and has had no fever, vomiting, or bone pain. Vital signs are within normal limits for age, except for a blood pressure of 120/78120/78 mmHg (which is >95>95 th percentile for his age). On physical examination, a smooth, firm, non-tender mass is palpated in the right upper and lower quadrants; it does not cross the midline. The remainder of the examination is unremarkable. Urinalysis reveals 1010-1515 red blood cells per high-power field. Which of the following is the most appropriate next step in the evaluation of this patient?

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Answer: Abdominal ultrasonography

Answer

Abdominal ultrasonography
The correct answer is abdominal ultrasonography. This patient's presentation of a unilateral, painless, firm abdominal mass that does not cross the midline, accompanied by hypertension and microscopic hematuria, is highly suspicious for a Wilms tumor (nephroblastoma). The most appropriate initial step in the evaluation of a pediatric abdominal mass is an ultrasound. It is a rapid, non-invasive imaging modality that avoids ionizing radiation. Ultrasonography can confirm the presence of a mass, differentiate between cystic (e.g., hydronephrosis) and solid structures, and identify the organ of origin (e.g., intrinsic renal mass versus an extrinsic mass like neuroblastoma), which effectively guides the next steps in management and staging.

Step-by-Step Solution

1
Identify the most likely diagnosis based on the clinical presentation.
The patient's age, presence of an asymptomatic unilateral abdominal mass, hypertension, and microscopic hematuria strongly suggest a Wilms tumor (nephroblastoma).
Wilms tumor is the most common pediatric renal malignancy and classically presents with an asymptomatic abdominal mass that does not cross the midline, often accompanied by secondary effects of renal involvement like renin-mediated hypertension and hematuria.
2
Determine the most appropriate initial diagnostic test.
Abdominal ultrasonography is the standard first step.
Ultrasound is a rapid, safe, radiation-free imaging modality that can immediately confirm the mass, distinguish between cystic and solid structures, and verify its origin within the kidney.

Key Concept

Wilms tumor presentation and initial diagnostic workup
Estimated Time:1m 0s
Question 43Question →

An 88-year-old boy with a known history of severe hemophilia A is brought to the emergency department by his parents after falling from a tree and striking his head. The parents report a brief loss of consciousness. He is now awake but complains of a severe headache and has vomited twice. His vital signs are temperature 37.1∘C37.1^\circ\text{C}, heart rate 110 /min110\text{ /min}, blood pressure 115/75 mmHg115/75\text{ mmHg}, and respiratory rate 20 /min20\text{ /min}. Physical examination reveals a large boggy hematoma over the right parietal region. Neurologic examination shows a Glasgow Coma Scale score of 1414 (confused conversation). Arrange the following management steps in the most appropriate chronological order for this patient.

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Answer

The correct sequence is to first administer intravenous recombinant factor VIII concentrate, followed by an emergent non-contrast CT scan of the head, then obtain a neurosurgical consultation, and finally admit the patient for serial neurological examinations.
In patients with bleeding disorders such as severe hemophilia, suspected life-threatening bleeding (e.g., intracranial hemorrhage following head trauma) requires immediate factor replacement therapy as the absolute first step in management. Factor activity must be replaced to a target of 100% immediately before any imaging or other diagnostic tests are performed. Delaying factor administration to obtain a CT scan is a classic medical error that can result in fatal expansion of the hemorrhage. Once hemostasis is supported with factor concentrate, an emergent non-contrast head CT should be obtained to confirm the diagnosis. Subsequent steps involve consulting neurosurgery for possible operative intervention and admitting the patient to a closely monitored intensive care setting for serial neurological checks.

Step-by-Step Solution

1
Identify the critical emergency.
The patient has severe hemophilia A with signs of increased intracranial pressure (headache, vomiting, altered mental status) following head trauma.
Intracranial hemorrhage is the leading cause of trauma-related death in hemophilia patients and must be assumed present until proven otherwise.
2
Determine the immediate life-saving intervention.
Factor VIII replacement must be administered immediately.
Hemostasis is the absolute priority. Diagnostic imaging must never delay factor administration, as the bleeding can rapidly expand in the interim.
3
Determine the appropriate diagnostic sequence.
A non-contrast head CT is performed next.
Once the patient is protected with factor replacement, imaging is required to confirm the diagnosis and determine the extent of the intracranial bleed.
4
Determine subsequent definitive management and disposition.
Neurosurgical consultation followed by admission for monitoring.
Surgical intervention may be necessary for large bleeds, and continuous neurological checks in a critical care setting are required due to the high risk of re-bleeding.

Key Concept

Prioritization of Factor Replacement in Hemophilia Trauma
Estimated Time:1m 15s
Question 44Question →

The parents of a 6-month-old boy of Mediterranean descent bring him to the clinic for a routine evaluation. They report that he has been increasingly fussy, easily fatigued, and feeding poorly over the past month. The parents also express two additional concerns: they are worried because he cannot sit up independently, and they request he receive his measles, mumps, and rubella (MMR) vaccine today to finish his immunizations early. He was born at full term, and his growth has consistently tracked along the 50th percentile. His temperature is 37.0∘C37.0^\circ\text{C} (98.6∘F98.6^\circ\text{F}), heart rate is 155/min155/\text{min}, and respiratory rate is 36/min36/\text{min}. On physical examination, the infant appears notably pale. A grade 2/6 systolic ejection murmur is auscultated at the left lower sternal border. The liver edge is palpated 3 cm3\text{ cm} below the right costal margin, and the spleen is palpable 4 cm4\text{ cm} below the left costal margin. Neurologic examination reveals normal symmetric tone; he sits with truncal support and successfully rolls from front to back.

Laboratory testing reveals:
Hemoglobin: 6.2 g/dL6.2\text{ g/dL}
Mean corpuscular volume (MCV): 62 fL62\text{ fL}
Reticulocyte count: 7%7\%
Thyroid-stimulating hormone (TSH): 2.5 \muU/mL2.5\text{ \mu U/mL} (normal: 0.5−5.0 \muU/mL0.5-5.0\text{ \mu U/mL})
Free T4: 1.4 ng/dL1.4\text{ ng/dL} (normal: 0.9−2.3 ng/dL0.9-2.3\text{ ng/dL})

A peripheral blood smear shows microcytic, hypochromic red blood cells with numerous target cells.

Which of the following is the most appropriate next step in the management of this patient?

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Answer: Quantitative hemoglobin analysis

Answer

Quantitative hemoglobin analysis
The most appropriate next step in the management of this patient is quantitative hemoglobin analysis. This infant's presentation of severe microcytic anemia, target cells, an elevated reticulocyte count, and hepatosplenomegaly at 6 months of age is classic for beta-thalassemia major. The onset of symptoms coincides precisely with the physiologic decline in fetal hemoglobin (HbF) around 4 to 6 months of life. Quantitative hemoglobin analysis (via electrophoresis or chromatography) is the definitive test to confirm the diagnosis by demonstrating an absence or severe decrease of adult hemoglobin (HbA) alongside compensatory elevations in HbF and HbA2.

Step-by-Step Solution

1
Identify the primary pathological process based on the clinical presentation and laboratory data.
The 6-month-old infant presents with severe microcytic anemia, an elevated reticulocyte count, hepatosplenomegaly, and target cells on the peripheral smear.
Recognizing the combination of microcytic anemia with extramedullary hematopoiesis (hepatosplenomegaly) and target cells is essential for narrowing the differential diagnosis to hemoglobinopathies.
2
Synthesize the demographic context and symptom timeline with the physical findings.
The patient is of Mediterranean descent, and symptoms appeared at 5 to 6 months of age, which perfectly aligns with the physiologic decline in fetal hemoglobin (HbF) and the unmasking of a beta-globin chain synthesis defect.
This timeline and demographic profile strongly point to beta-thalassemia major as the underlying diagnosis.
3
Determine the diagnostic gold standard for the suspected condition.
Quantitative hemoglobin analysis (via electrophoresis or high-performance liquid chromatography) is required to evaluate the relative percentages of HbA, HbA2, and HbF.
Identifying abnormal hemoglobin fractions definitively diagnoses beta-thalassemia and guides long-term management, including chronic transfusion therapy.
4
Evaluate and confidently dismiss distracting clinical findings.
The infant has normal milestones for a 6-month-old, normal thyroid function, and tachycardia/murmur secondary to high-output cardiac states from anemia. Administering the MMR vaccine early is contraindicated.
A physician must prioritize the acute, life-threatening hematologic abnormality over parental concerns regarding normal milestones or inappropriate early vaccine requests.

Key Concept

Diagnosis and management of beta-thalassemia major, characterized by severe microcytic anemia, target cells, and extramedullary hematopoiesis presenting after 4 to 6 months of age as fetal hemoglobin declines.
Question 45Question →

Evaluate the following histologic, cytogenetic, and clinical descriptions. Pair each specific finding with its corresponding pediatric hematologic or oncologic diagnosis.

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Items

Bone marrow aspirate reveals greater than 20% lymphoblasts that express terminal deoxynucleotidyl transferase (TdT) and CD10, with a t(12;21) translocation.
Biopsy of a rapidly enlarging facial mass demonstrates sheets of medium-sized lymphocytes, a high mitotic index, scattered macrophages, and a t(8;14) translocation.
Bone marrow evaluation shows greater than 20% myeloblasts containing needle-like, eosinophilic cytoplasmic inclusions; cytogenetic testing reveals a t(15;17) translocation.
Abdominal imaging reveals a large, calcified suprarenal mass crossing the midline; biopsy demonstrates small round blue cells with N-myc gene amplification.

Matches

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Answer

The findings match as follows: B-cell Acute Lymphoblastic Leukemia pairs with TdT, CD10, and t(12;21). Burkitt Lymphoma pairs with starry sky histology and t(8;14). Acute Promyelocytic Leukemia pairs with Auer rods and t(15;17). Neuroblastoma pairs with a midline-crossing calcified mass and N-myc amplification.
Each specific diagnosis has highly conserved and tested cytogenetic or histologic markers. Mapping the t(12;21) to B-ALL, t(8;14) to Burkitt Lymphoma, t(15;17) to APL, and N-myc amplification to Neuroblastoma accurately links the pathophysiology to the disease state.

Step-by-Step Solution

1
Analyze the first description focusing on TdT/CD10 positivity and the t(12;21) translocation.
Identified as B-cell Acute Lymphoblastic Leukemia.
These are the classic immunophenotypic and cytogenetic markers for the most common pediatric leukemia.
2
Analyze the second description focusing on the facial mass, 'starry sky' macrophage pattern, and t(8;14).
Identified as Burkitt Lymphoma.
The 'starry sky' appearance and c-myc translocation t(8;14) are pathognomonic for this highly aggressive B-cell non-Hodgkin lymphoma.
3
Analyze the third description focusing on myeloblasts, Auer rods, and the t(15;17) translocation.
Identified as Acute Promyelocytic Leukemia.
Auer rods and the PML-RARA gene fusion caused by t(15;17) define APL, which is treated with all-trans retinoic acid (ATRA).
4
Analyze the fourth description focusing on the calcified midline abdominal mass and N-myc amplification.
Identified as Neuroblastoma.
Unlike Wilms tumor, Neuroblastoma frequently crosses the midline, is calcified, and its prognosis correlates strongly with N-myc gene amplification.

Key Concept

Molecular, cytogenetic, and histologic hallmarks of pediatric hematologic and solid malignancies.
Estimated Time:1m 30s
Question 46Question →

During a routine well-child visit, the mother of a 44-year-old girl expresses concern about multiple new bruises on her daughter's legs over the past few days. The mother notes the child had a self-resolving upper respiratory tract infection approximately three weeks prior. The patient is otherwise active and has no history of excessive bleeding, epistaxis, or melena. Physical examination reveals a well-appearing, playful child. Vital signs are within normal limits for age. Skin examination shows scattered petechiae and small ecchymoses confined to the bilateral lower extremities. There is no jaundice, lymphadenopathy, or hepatosplenomegaly.

Laboratory evaluation demonstrates:
Hemoglobin: 12.8 g/dL12.8 \text{ g/dL}
Leukocyte count: 8,200/mm38,200/\text{mm}^3 (normal differential)
Platelet count: 16,000/mm316,000/\text{mm}^3

Which of the following is the most appropriate next step in management for this patient?

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Answer: Observation without pharmacological intervention

Answer

Observation without pharmacological intervention
This patient's presentation of isolated thrombocytopenia, antecedent viral illness, and a normal physical examination (aside from cutaneous bleeding) is highly characteristic of primary immune thrombocytopenia (ITP). In children, ITP is typically a self-limited condition. Current guidelines recommend observation alone for children with newly diagnosed ITP who have purely cutaneous symptoms (e.g., petechiae, bruising), regardless of the absolute platelet count. Pharmacological treatment is reserved for those with mucosal bleeding or severe, life-threatening hemorrhage.

Step-by-Step Solution

1
Analyze the clinical presentation and laboratory findings.
The patient is a well-appearing child with an isolated thrombocytopenia (platelets 16,000/mm316,000/\text{mm}^3) following a recent viral illness, normal white blood cell count, normal hemoglobin, and an unremarkable physical examination (no organomegaly).
This establishes the classic diagnosis of primary immune thrombocytopenia (ITP).
2
Assess the severity of bleeding.
The patient has only cutaneous manifestations (petechiae and ecchymoses on the legs) with no evidence of mucosal bleeding (no epistaxis, melena, or hematuria).
Management of pediatric ITP is dictated by the severity of clinical bleeding, not by the absolute platelet count.
3
Determine the appropriate management step based on bleeding severity.
Observation is indicated.
Current pediatric guidelines recommend observation alone for children with ITP who have purely cutaneous symptoms.

Key Concept

Management of pediatric immune thrombocytopenia (ITP) with purely cutaneous manifestations
Question 47Question →

A 66-year-old boy is brought to the clinic by his parents due to fatigue and yellowish discoloration of his eyes for the past 33 days. He had a mild upper respiratory tract infection one week ago. His past medical history is unremarkable, and his immunizations are up to date. Family history is notable for a paternal aunt who underwent an unexplained splenectomy in her twenties. Vital signs are within normal limits. Physical examination reveals scleral icterus, pale conjunctivae, and a palpable spleen edge 4 cm4 \text{ cm} below the left costal margin. Laboratory studies show the following:

TestResult
Hemoglobin7.8 g/dL7.8 \text{ g/dL}
Mean corpuscular volume80 fL80 \text{ fL}
Mean corpuscular hemoglobin concentration37.5 g/dL37.5 \text{ g/dL}
Reticulocyte count9%9\%
Platelet count240,000/mm3240,000/\text{mm}^3
Leukocyte count8,500/mm38,500/\text{mm}^3
Total bilirubin4.2 mg/dL4.2 \text{ mg/dL}
Direct bilirubin0.4 mg/dL0.4 \text{ mg/dL}

Direct antiglobulin (Coombs) testing is negative.

Which of the following is the most appropriate next step in diagnostic evaluation?

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Answer: Eosin-5-maleimide binding test

Answer

Eosin-5-maleimide binding test
The correct answer identifies the eosin-5-maleimide binding test. The patient's presentation of normocytic anemia, elevated mean corpuscular hemoglobin concentration (MCHC), reticulocytosis, indirect hyperbilirubinemia, splenomegaly, and a family history of splenectomy strongly suggests hereditary spherocytosis (HS). The elevated MCHC (>36 g/dL>36 \text{ g/dL}) is particularly characteristic, resulting from cellular dehydration and membrane loss. Following a negative direct Coombs test (which rules out autoimmune hemolytic anemia), the diagnosis of HS is confirmed using the eosin-5-maleimide (EMA) binding test or an osmotic fragility test.

Step-by-Step Solution

1
Analyze the patient's clinical presentation and family history.
The patient has jaundice, symptomatic anemia, splenomegaly, and a family history of splenectomy following a viral infection, suggesting a hereditary hemolytic anemia.
Identifying the pattern of inheritance and physical findings narrows the differential diagnosis to congenital causes of hemolysis.
2
Evaluate the laboratory data.
Labs show a normocytic anemia, elevated MCHC (37.5 g/dL37.5 \text{ g/dL}), and an appropriate reticulocyte response (9%9\%) with a negative direct Coombs test.
The MCHC is classically elevated in hereditary spherocytosis due to cellular dehydration, while the negative Coombs test rules out an autoimmune etiology.
3
Determine the appropriate confirmatory test.
The eosin-5-maleimide (EMA) binding test is selected to confirm the diagnosis.
EMA binding testing is highly sensitive and specific for detecting the decreased membrane proteins characteristic of hereditary spherocytosis.

Key Concept

Hereditary spherocytosis typically presents with hemolytic anemia, jaundice, splenomegaly, and an elevated MCHC; diagnosis is confirmed with an eosin-5-maleimide binding test or osmotic fragility test.
Question 48Question →

A 99-year-old boy is diagnosed with Burkitt lymphoma after presenting with a rapidly enlarging abdominal mass and abdominal pain. Laboratory studies reveal a white blood cell count of 14,000/mm314,000/\text{mm}^3, a uric acid level of 11.2 mg/dL11.2 \text{ mg/dL}, potassium of 5.1 mEq/L5.1 \text{ mEq/L}, phosphorus of 6.5 mg/dL6.5 \text{ mg/dL}, and calcium of 7.2 mg/dL7.2 \text{ mg/dL}. His serum creatinine is 0.8 mg/dL0.8 \text{ mg/dL}. He is admitted to the pediatric intensive care unit for management. Arrange the following steps in the most appropriate chronological order for the prevention and management of tumor lysis syndrome (TLS) and its potential complications in this patient, starting from the initial intervention upon admission.

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Answer

The correct sequence is: (1) Initiation of aggressive intravenous fluid hydration without potassium, (2) Administration of rasburicase, (3) Initiation of systemic cytotoxic chemotherapy, and (4) Initiation of renal replacement therapy.
In a patient with a highly proliferative malignancy such as Burkitt lymphoma and established laboratory tumor lysis syndrome (TLS), the immediate priority is protecting renal function. Aggressive intravenous hydration without potassium is the critical first step to promote diuresis and prevent crystal precipitation. This is closely followed by rasburicase, which rapidly degrades existing uric acid into the highly soluble compound allantoin. Once prophylactic measures have mitigated the risk of catastrophic cell breakdown, systemic cytotoxic chemotherapy can be safely initiated to treat the underlying malignancy. Finally, if the patient develops refractory oliguria, volume overload, or intractable hyperkalemia despite optimal medical management, renal replacement therapy (hemodialysis) serves as a last-resort rescue intervention.

Step-by-Step Solution

1
Identify the clinical scenario
The patient has a highly proliferative malignancy (Burkitt lymphoma) and presents with laboratory evidence of spontaneous tumor lysis syndrome (TLS) prior to chemotherapy.
Understanding the patient's risk profile dictates the urgency and aggressiveness of medical prophylaxis.
2
Determine the first priority in management
Aggressive intravenous hydration is selected as the initial intervention.
Hyperhydration improves renal perfusion and increases urine output, which is critical for flushing uric acid and phosphate crystals from the renal tubules.
3
Select the appropriate pharmacologic intervention
Rasburicase is administered to rapidly lower uric acid levels.
Given the already elevated uric acid (11.2 mg/dL11.2 \text{ mg/dL}), rasburicase is indicated over allopurinol because it enzymatically degrades existing uric acid into highly soluble allantoin.
4
Determine the timing of tumor-directed therapy
Systemic cytotoxic chemotherapy is initiated only after TLS prophylaxis is established.
Chemotherapy will cause rapid tumor cell lysis; if given before prophylaxis, it would precipitate catastrophic metabolic derangements and acute renal failure.
5
Identify the indication for rescue therapy
Renal replacement therapy is positioned as the final, conditional step.
Hemodialysis is reserved for severe cases where medical management fails to prevent oliguric acute kidney injury, severe hyperkalemia, or volume overload.

Key Concept

The chronological management of tumor lysis syndrome prioritizes aggressive intravenous hydration and hypouricemic agents before initiating cytotoxic chemotherapy, with renal replacement therapy reserved for refractory acute kidney injury.
Question 49Question →

Match each pediatric patient's clinical and laboratory presentation to the most likely underlying diagnosis and its associated pathophysiologic mechanism.

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Items

A 4-year-old boy presents with sudden onset of petechiae and purpura two weeks after a mild viral upper respiratory infection. Labs: Platelets 18,000/mm³, normal PT, normal aPTT.
A 14-year-old girl presents with heavy menstrual bleeding and a lifelong history of epistaxis. Labs: Normal platelets, normal PT, normal or slightly prolonged aPTT, prolonged bleeding time.
A 3-year-old boy is evaluated for recurrent swelling, warmth, and pain in his right knee after minor trauma. Labs: Normal platelets, normal PT, prolonged aPTT, normal bleeding time.
A 6-year-old girl in the intensive care unit with meningococcemia develops oozing from her intravenous catheter sites. Labs: Platelets 45,000/mm³, prolonged PT, prolonged aPTT, decreased fibrinogen.

Matches

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Answer

The clinical presentations correctly match their respective bleeding disorders based on the specific combination of coagulation study abnormalities and physical exam findings.
Each matching pair aligns a classic pediatric clinical vignette with its specific underlying hemostatic defect. ITP involves isolated platelet destruction; von Willebrand disease involves primary hemostasis defects with mucosal bleeding; Hemophilia causes deep tissue bleeding with intrinsic pathway defects; and DIC presents as a consumptive coagulopathy in a critically ill child.

Step-by-Step Solution

1
Analyze the coagulation profile for each patient to determine the affected hemostatic pathway.
Identify if the defect involves primary hemostasis (platelets/vWF), secondary hemostasis (coagulation factors), or a mixed consumptive process.
Differentiating primary from secondary hemostatic defects narrows down the differential diagnosis systematically.
2
Correlate the coagulation profile with the clinical vignette and mucocutaneous vs. deep tissue bleeding patterns.
Match isolated thrombocytopenia to ITP, isolated aPTT prolongation to hemophilia, primary hemostasis defects (prolonged bleeding time) to von Willebrand disease, and global factor consumption to DIC.
Specific pediatric bleeding disorders have highly distinct clinical phenotypes and laboratory signatures.

Key Concept

Diagnosis and Classification of Pediatric Bleeding Disorders
Question 50Question →

A 22-year-old boy with sickle cell disease (HbSS) is brought to the emergency department by his parents due to profound weakness and a rapidly enlarging abdomen over the past 66 hours. He has been unusually sleepy and difficult to arouse. His temperature is 37.0∘C37.0^\circ\text{C} (98.6∘F98.6^\circ\text{F}), heart rate is 168/min168/\text{min}, blood pressure is 70/40 mm Hg70/40\text{ mm Hg}, and respiratory rate is 32/min32/\text{min}. Physical examination reveals marked conjunctival pallor. His abdomen is distended, firm, and diffusely tender. The spleen edge is palpable 6 cm6\text{ cm} below the left costal margin, which is a new finding compared to his baseline. Capillary refill time is 44 seconds. Laboratory studies reveal:

Hemoglobin: 4.2 g/dL4.2\text{ g/dL} (baseline 8.5 g/dL8.5\text{ g/dL})
Reticulocytes: 14%14\%
Platelets: 75,000/mm375,000/\text{mm}^3
Leukocytes: 12,500/mm312,500/\text{mm}^3

Which of the following is the most appropriate next step in management?

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Answer: Intravenous isotonic fluid resuscitation and packed red blood cell transfusion

Answer

The most appropriate next step is immediate intravenous isotonic fluid resuscitation and packed red blood cell transfusion to treat hypovolemic shock.
The correct answer addresses the immediate life-threatening issue: hypovolemic shock secondary to acute splenic sequestration. In this condition, sickled red blood cells obstruct the splenic venous outflow, causing rapid, massive pooling of blood within the spleen. This depletes the systemic circulation of volume and red blood cells, resulting in the classic triad of an acutely enlarging spleen, a sharp drop in hemoglobin (with compensatory reticulocytosis), and hypovolemic shock. The immediate life-saving intervention is rapid administration of intravenous isotonic fluids and packed red blood cell (pRBC) transfusion to restore intravascular volume and prevent cardiovascular collapse.

Step-by-Step Solution

1
Analyze the patient's clinical presentation and vital signs.
The patient has marked tachycardia (168/min168/\text{min}), hypotension (70/40 mm Hg70/40\text{ mm Hg}), and prolonged capillary refill, indicating acute hypovolemic shock.
Recognizing shock is the first step in prioritizing emergency management.
2
Evaluate the physical exam and laboratory findings in the context of sickle cell disease.
The acute drop in hemoglobin, compensatory high reticulocyte count, thrombocytopenia, and newly massive spleen strongly point to acute splenic sequestration crisis.
Differentiating splenic sequestration from other sickle cell emergencies (like aplastic crisis, which would have low reticulocytes) determines the specific pathophysiology.
3
Determine the most appropriate immediate intervention.
The acute pooling of blood in the spleen has caused severe intravascular volume depletion. This requires immediate restoration of volume and oxygen-carrying capacity.
Medical stabilization with isotonic fluids and packed red blood cells is the life-saving priority before any surgical or diagnostic considerations.

Key Concept

Acute splenic sequestration crisis is a life-threatening complication of sickle cell disease characterized by rapid pooling of blood in the spleen, leading to acute severe anemia, reticulocytosis, thrombocytopenia, rapidly enlarging spleen, and hypovolemic shock. The immediate treatment is intravascular volume expansion and blood transfusion.
Question 51Question →

A 66-year-old boy is brought to the emergency department by his parents due to a new-onset fever and a mild cough that started earlier today. The patient was diagnosed with acute lymphoblastic leukemia (ALL) 44 months ago and is currently receiving maintenance chemotherapy. His last chemotherapy cycle was 1010 days ago. His temperature is 39.4∘C39.4^\circ\text{C} (102.9∘F102.9^\circ\text{F}), pulse is 125/min125/\text{min}, respirations are 24/min24/\text{min}, and blood pressure is 95/60 mmHg95/60 \text{ mmHg}. On physical examination, the child appears pale and mildly lethargic but is easily rousable. Lung auscultation is clear bilaterally without wheezing or crackles. There is a central venous port in the right upper chest with no surrounding erythema or induration.

Laboratory studies show:
Leukocyte count: 800/μL800/\mu\text{L}
- Neutrophils: 15%15\%
- Lymphocytes: 80%80\%
- Monocytes: 5%5\%
Hemoglobin: 9.2 g/dL9.2 \text{ g/dL}
Platelet count: 85,000/μL85,000/\mu\text{L}

Which of the following is the most appropriate next step in the management of this patient?

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Answer: Obtain blood cultures and immediately initiate empiric broad-spectrum intravenous antibiotics

Answer

Obtain blood cultures and immediately initiate empiric broad-spectrum intravenous antibiotics.
The correct step is to immediately obtain blood cultures and start empiric broad-spectrum intravenous antibiotics. This patient has febrile neutropenia, defined as a single oral temperature ≥38.3∘C\ge 38.3^\circ\text{C} (101.0∘F101.0^\circ\text{F}) or a sustained temperature ≥38.0∘C\ge 38.0^\circ\text{C} (100.4∘F100.4^\circ\text{F}) for over 11 hour, accompanied by an absolute neutrophil count (ANC) <500/μL< 500/\mu\text{L}. This patient's ANC is calculated as total WBC multiplied by the percentage of neutrophils (800/μL×0.15=120/μL800/\mu\text{L} \times 0.15 = 120/\mu\text{L}). Because neutropenic patients lack an adequate cellular immune response, typical signs of localized infection (like abscess formation or pulmonary infiltrates) are often absent, and bacterial infections (especially Gram-negative pathogens like *Pseudomonas aeruginosa*) can rapidly progress to fatal septic shock. Therefore, prompt blood cultures followed by immediate anti-pseudomonal beta-lactam therapy (e.g., cefepime, piperacillin-tazobactam, or meropenem) is mandatory.

Step-by-Step Solution

1
Calculate the Absolute Neutrophil Count (ANC).
ANC = Total WBC ×\times (% Neutrophils + % Bands) = 800×0.15=120/μL800 \times 0.15 = 120/\mu\text{L}.
Determining the ANC is required to identify if the patient has severe neutropenia (defined as ANC <500/μL< 500/\mu\text{L}).
2
Combine the ANC calculation with the patient's vital signs.
The patient has a fever of 39.4∘C39.4^\circ\text{C} (102.9∘F102.9^\circ\text{F}) and an ANC of 120/μL120/\mu\text{L}.
Fever in the presence of severe neutropenia meets the criteria for febrile neutropenia, which is a life-threatening oncologic emergency.
3
Determine the initial management for febrile neutropenia.
Immediate acquisition of blood cultures followed by the administration of empiric broad-spectrum intravenous antibiotics (e.g., cefepime, meropenem, or piperacillin-tazobactam).
Patients with severe neutropenia lack the inflammatory cells to localize infection, making them highly susceptible to rapid progression to septic shock, particularly from Gram-negative organisms like Pseudomonas aeruginosa.

Key Concept

Febrile Neutropenia Management
Question 52Question →

A pediatric oncology team is reviewing pathology, laboratory, and imaging reports for several newly admitted patients. Match each patient's characteristic diagnostic profile to the most accurate underlying solid tumor diagnosis.

Click a left item, then click its matching right item

Items

Elevated urine catecholamine metabolites (VMA and HVA); histology demonstrates small round blue cells forming Homer-Wright pseudorosettes.
Normal urine catecholamines in a patient with an asymptomatic unilateral abdominal mass; histology reveals a triphasic pattern of blastemal, stromal, and epithelial elements.
Radiographic evidence of a 'sunburst' periosteal reaction and Codman triangle; histology shows malignant spindle cells producing unmineralized osteoid.
Radiographic evidence of a lamellated ('onion-skin') periosteal reaction in the diaphysis; cytogenetics confirm a t(11;22) translocation.

Matches

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Answer

The diagnostic profiles match as follows: Elevated catecholamines and Homer-Wright pseudorosettes indicate Neuroblastoma. Triphasic histology and normal catecholamines indicate Wilms tumor. Osteoid production with a sunburst pattern indicates Osteosarcoma. A diaphyseal lesion with an onion-skin pattern and t(11;22) indicates Ewing sarcoma.
Each specific set of clinical, biochemical, and histological findings serves as the pathognomonic triad for a specific pediatric solid tumor, directly guiding diagnosis and treatment staging.

Step-by-Step Solution

1
Differentiate the two common pediatric abdominal tumors based on catecholamine secretion and histology.
Identify that Neuroblastoma secretes catecholamines (elevated VMA/HVA) and has Homer-Wright rosettes, whereas Wilms tumor has normal catecholamines and triphasic histology.
Both present as abdominal masses, but their cellular origins and biochemical markers are distinct.
2
Differentiate the two common pediatric bone tumors based on radiographic appearance, location, and cytogenetics.
Identify that Osteosarcoma is characterized by osteoid production and a sunburst pattern, whereas Ewing sarcoma is characterized by the t(11;22) translocation and an onion-skin periosteal reaction.
Bone tumors have highly specific radiographic and genetic signatures that dictate management.

Key Concept

Pathologic, radiographic, and biochemical hallmarks of common pediatric solid tumors.
Question 53Question →

An adolescent girl, aged 1010, is evaluated in the outpatient hematology clinic due to recurrent epistaxis and progressive fatigue over the past three months. Her adoptive parents report she has always been significantly smaller than her peers. Vital signs are within normal limits for her age. Physical examination reveals short stature (below the 33 rd percentile), microcephaly, an absent right thumb, and several flat, hyperpigmented macules across her abdomen and back. Laboratory testing shows a hemoglobin of 7.2 g/dL7.2 \text{ g/dL}, a mean corpuscular volume of 112 fL112 \text{ fL}, a leukocyte count of 1,800/mm31,800/\text{mm}^3, and a platelet count of 22,000/mm322,000/\text{mm}^3. Which of the following is the most likely underlying mechanism for this patient's clinical and laboratory findings?

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Answer: Inherited defect in cellular DNA cross-link repair mechanisms

Answer

Inherited defect in cellular DNA cross-link repair mechanisms
The correct answer accurately identifies the pathophysiology of Fanconi anemia. This patient's presentation of macrocytic anemia, thrombocytopenia, and leukopenia (pancytopenia) combined with classic congenital anomalies (short stature, absent thumb/radial hypoplasia, microcephaly, and café-au-lait spots) is highly characteristic of Fanconi anemia. This condition is an autosomal recessive disorder caused by mutations in genes responsible for the repair of DNA interstrand cross-links. Patients typically present with bone marrow failure in the first decade of life and are at a significantly increased risk of developing acute myeloid leukemia (AML) and solid tumors later in life.

Step-by-Step Solution

1
Analyze the patient's laboratory findings.
The patient has macrocytic anemia, leukopenia, and thrombocytopenia, indicating bone marrow failure (pancytopenia).
Identifying the hematologic disturbance is the first step in formulating a differential diagnosis.
2
Evaluate the physical examination findings.
The patient exhibits short stature, microcephaly, an absent right thumb (radial hypoplasia), and café-au-lait spots.
Correlating lab results with physical anomalies helps differentiate between acquired and inherited causes of bone marrow failure.
3
Synthesize findings to determine the most likely diagnosis.
The combination of pancytopenia and this specific pattern of congenital anomalies is the classic presentation of Fanconi anemia.
Recognizing the pathognomonic physical signs prevents misdiagnosing the condition as an acquired nutritional or infectious aplasia.
4
Identify the underlying pathophysiology of the diagnosed condition.
Fanconi anemia is caused by a genetic defect in the repair of DNA interstrand cross-links.
The question specifically asks for the mechanism causing the patient's presentation.

Key Concept

Fanconi anemia presentation and pathophysiology
Question 54Question →

A 5-year-old boy with a known history of severe hemophilia A is brought to the pediatric emergency department after falling from a playground structure and striking his head. His parents report that he has vomited twice since the fall and appears unusually lethargic. On primary survey, his airway is patent, breathing is unlabored, and perfusion is adequate. His Glasgow Coma Scale score is 13. Arrange the following management steps in the most appropriate chronological order.

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Answer

The correct sequence is to first administer factor VIII concentrate, followed by a non-contrast head CT, then obtain a neurosurgery consultation, and finally admit to the PICU.
In any patient with severe hemophilia presenting with significant head trauma or signs of increased intracranial pressure (such as vomiting and lethargy), an intracranial hemorrhage must be assumed. The most critical, life-saving step is the immediate administration of factor VIII concentrate to achieve 100% factor activity. This must be done before the patient is sent to radiology for a CT scan, as the time taken for imaging can allow catastrophic, unchecked bleeding. Once factor is administered and hemostasis is initiated, a non-contrast head CT is performed to confirm the diagnosis. Following imaging, a neurosurgery consultation is obtained to assess the need for operative intervention. Finally, the patient is admitted to the PICU for serial neurologic examinations and continued factor replacement therapy.

Step-by-Step Solution

1
Administer intravenous recombinant factor VIII concentrate.
Hemostasis is immediately supported, raising factor VIII levels to 100%.
Intracranial hemorrhage is the leading cause of mortality in patients with hemophilia. Factor replacement must never be delayed for imaging.
2
Obtain a non-contrast CT scan of the head.
Identifies the presence, size, and location of intracranial bleeding.
Imaging is necessary for definitive diagnosis, but only after life-threatening coagulopathy is initially managed.
3
Request pediatric neurosurgery consultation.
Provides surgical expertise for potential operative intervention.
Surgical management or intracranial pressure monitoring may be necessary based on the CT findings.
4
Admit to the pediatric intensive care unit.
Ensures continuous specialized care.
The patient requires frequent neurologic checks, ongoing factor replacement, and intensive monitoring regardless of immediate surgical intervention.

Key Concept

In patients with severe bleeding disorders presenting with significant head trauma, factor replacement therapy must precede diagnostic neuroimaging.
Estimated Time:1m 15s
Question 55Question →

A 24-month-old toddler is brought to the pediatric clinic by her parents, who noticed an unusual lump in her abdomen while dressing her. Over the past month, the child has been increasingly fussy, has experienced intermittent bone pain, and has lost a noticeable amount of weight. Vital signs show a temperature of 37.2°C (99.0°F), a heart rate of 115/min, and a blood pressure of 138/88 mmHg. Physical examination reveals a firm, irregular, nodular abdominal mass that extends across the anatomic midline. Additional findings include bilateral periorbital ecchymoses and a right-sided mild ptosis with miosis. Which of the following laboratory studies is most appropriate to help confirm this patient's most likely diagnosis?

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Answer: Measurement of urinary homovanillic acid and vanillylmandelic acid

Answer

The correct answer is the measurement of urinary homovanillic acid and vanillylmandelic acid, which confirms the diagnosis of neuroblastoma.
The correct answer identifies the measurement of urinary homovanillic acid (HVA) and vanillylmandelic acid (VMA). The patient's presentation—a firm, nodular abdominal mass crossing the midline, elevated blood pressure, periorbital ecchymoses ('raccoon eyes'), and Horner syndrome (ptosis and miosis)—is classic for neuroblastoma. This embryonal tumor of neural crest origin frequently secretes catecholamines. Detecting elevated levels of their urinary metabolites, HVA and VMA, is highly specific and represents the most appropriate initial biochemical test to confirm the diagnosis.

Step-by-Step Solution

1
Identify the clinical syndrome based on the physical exam findings.
The firm, nodular abdominal mass crossing the midline, combined with periorbital ecchymoses and Horner syndrome, strongly suggests neuroblastoma.
Wilms tumor typically does not cross the midline and lacks these specific metastatic and sympathetic chain signs.
2
Determine the biochemical signature of the suspected tumor.
Neuroblastomas are derived from primitive sympathetic ganglion cells and actively secrete catecholamines.
Identifying the metabolic byproducts of these catecholamines is the standard biochemical diagnostic step.
3
Select the appropriate laboratory test from the given options.
Measuring urinary homovanillic acid (HVA) and vanillylmandelic acid (VMA) is the best choice.
HVA and VMA are the primary breakdown products of dopamine and norepinephrine, respectively, which are secreted by neuroblastomas.

Key Concept

Diagnosis of pediatric neuroblastoma relies on identifying its unique clinical presentation (a firm abdominal mass often crossing the midline, sympathetic chain involvement, and orbital metastases) and confirming via elevated urinary catecholamine metabolites (HVA and VMA).
Estimated Time:1m 30s
Question 56Question →

Parents bring their 33-year-old son to the clinic after noticing he has been uncharacteristically lethargic and refusing to walk for the past two weeks. The child has also experienced intermittent subjective fevers. Vital signs show a temperature of 38.2∘C38.2^\circ\text{C} (100.8∘F100.8^\circ\text{F}), heart rate of 115115/min, blood pressure of 92/6092/60 mmHg, and respiratory rate of 2222/min. On examination, the patient appears pale and tired. There are widespread petechiae on his shins and forearms. Palpation of the abdomen reveals the liver edge 44 cm below the right costal margin and the spleen tip 55 cm below the left costal margin. Cervical lymph nodes are enlarged, firm, and non-tender. The physician suspects a primary hematologic malignancy and initiates a comprehensive evaluation. Arrange the following diagnostic and staging steps in the most appropriate chronological sequence.

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Answer

The correct sequence begins with basic blood work (CBC), followed by morphological review (peripheral smear), definitive tissue diagnosis (bone marrow aspiration), molecular characterization (flow cytometry/cytogenetics), and finally CNS staging (lumbar puncture).
The evaluation of suspected acute lymphoblastic leukemia begins with non-invasive baseline tests: a complete blood count to identify cytopenias, followed immediately by a peripheral blood smear to look for circulating blasts. Once leukemia is suspected based on peripheral blood, a bone marrow aspiration and biopsy is the definitive next step to confirm the diagnosis (≥20%\geq 20\% blasts). The marrow sample is then sent for flow cytometry and cytogenetics to characterize the exact subtype and molecular profile. Finally, after the systemic diagnosis is established, a lumbar puncture is performed for CNS staging and simultaneous prophylactic intrathecal chemotherapy administration.

Step-by-Step Solution

1
Complete blood count (CBC) with differential
Identifies broad hematologic derangements like anemia, thrombocytopenia, and leukocytosis or leukopenia.
This is the most appropriate initial, non-invasive screening test for suspected hematologic malignancies.
2
Peripheral blood smear evaluation
Detects the presence of circulating lymphoblasts.
Once the CBC shows cytopenias, a manual smear is critical to visually identify malignant cells before progressing to invasive procedures.
3
Bone marrow aspiration and biopsy
Confirms the diagnosis of acute leukemia by demonstrating ≥20%\geq 20\% blasts in the bone marrow.
Definitive tissue diagnosis is required prior to initiating any treatment or staging.
4
Flow cytometry and cytogenetic analysis of marrow aspirate
Classifies the leukemia lineage and identifies prognostic translocations.
Requires the bone marrow sample obtained in the previous step and is essential for risk stratification and targeted treatment planning.
5
Lumbar puncture with cerebrospinal fluid (CSF) analysis
Evaluates for central nervous system involvement.
Staging of the CNS is performed after the diagnosis is confirmed; it is not part of the initial diagnostic workup due to the risk of introducing peripheral blasts into the CSF space during the procedure if circulating blasts are present.

Key Concept

The diagnostic and staging sequence for pediatric acute lymphoblastic leukemia (ALL) progresses from least invasive screening to definitive marrow biopsy, molecular characterization, and finally CNS staging.
Question 57Question →

A 5-year-old girl with acute lymphoblastic leukemia (ALL) comes to the hematology-oncology clinic with her father for a routine visit. She is currently in the maintenance phase of her treatment regimen, taking daily oral mercaptopurine and weekly methotrexate. Her father reports that she developed a mild cough and runny nose two days ago but has remained afebrile and active. He also expresses concern that she is unable to ride a two-wheeled bicycle without training wheels, although she effortlessly pedals her tricycle.

Vital signs show a temperature of 36.9∘C36.9^\circ\text{C} (98.4∘F98.4^\circ\text{F}), a heart rate of 98/min98/\text{min}, a blood pressure of 95/60 mmHg95/60\text{ mmHg}, and a respiratory rate of 18/min18/\text{min}. Physical examination reveals clear rhinorrhea and clear lung fields bilaterally.

The father notes that she is due for her kindergarten immunizations, having last received vaccines at 1818 months of age.

Which of the following is the most appropriate next step in the management of this patient?

Show answer & explanation

Answer: Administer indicated inactivated vaccines and defer live-attenuated preparations

Answer

Administer indicated inactivated vaccines and defer live-attenuated preparations.
This patient is receiving active maintenance chemotherapy for acute lymphoblastic leukemia (ALL), which causes significant immunosuppression. In severely immunocompromised patients, live-attenuated vaccines (such as measles, mumps, and rubella [MMR]; varicella; and intranasal influenza) are strictly contraindicated because the attenuated viruses can replicate unchecked and cause severe, potentially fatal vaccine-strain infections. However, inactivated vaccines (such as intramuscular influenza, DTaP, and IPV) are safe. They should be administered according to the standard schedule to provide whatever protection the patient's immune system can mount, even if the immunologic response is somewhat blunted. Therefore, the appropriate action is to give the indicated inactivated vaccines and defer the live preparations until the patient has been off chemotherapy for an adequate recovery period (typically at least 3 to 6 months).

Step-by-Step Solution

1
Assess the patient's immune status based on her medical history.
The patient is on maintenance chemotherapy (mercaptopurine and methotrexate) for ALL, meaning she is severely immunocompromised.
Immune status directly dictates which immunizations can be safely administered.
2
Evaluate the presenting symptoms and developmental concerns.
Her viral URI symptoms are mild and require no antibiotics. Her ability to ride a tricycle is developmentally appropriate for a 5-year-old.
This rules out the need for acute infectious interventions or developmental referrals.
3
Determine the appropriate immunization strategy for a severely immunocompromised host.
Inactivated vaccines should be given, but all live-attenuated vaccines must be strictly deferred.
Live vaccines can cause fatal disseminated infections in patients lacking cell-mediated immunity.

Key Concept

Live-attenuated vaccines are contraindicated in patients with severe immunosuppression, such as those receiving active chemotherapy for pediatric malignancies, whereas inactivated vaccines remain safe and recommended.
Estimated Time:1m 0s
Question 58Question →

A medical student is reviewing pathologic specimens during a pediatric hematology and oncology rotation. Match each described histologic or peripheral blood smear finding with the most appropriate diagnosis.

Click a left item, then click its matching right item

Items

Bone marrow aspirate reveals atypical promyelocytes with deeply lobated nuclei and multiple, needle-like cytoplasmic inclusions.
Lymph node biopsy displays large, binucleated cells with prominent eosinophilic nucleoli within a mixed inflammatory background.
Tissue biopsy shows a high-grade proliferation of medium-sized lymphoid cells interspersed with numerous tingible body macrophages.
Peripheral blood smear demonstrates normochromic, normocytic red blood cells with small, round, basophilic nuclear remnants.

Matches

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Answer

Atypical promyelocytes with Auer rods matches Acute Promyelocytic Leukemia. Binucleated cells with prominent nucleoli matches Classical Hodgkin Lymphoma. Medium-sized cells with tingible body macrophages matches Burkitt Lymphoma. Basophilic nuclear remnants (Howell-Jolly bodies) matches Sickle Cell Disease.
Each pediatric hematology/oncology diagnosis listed has a highly specific morphologic finding. Acute promyelocytic leukemia presents with numerous Auer rods; Classical Hodgkin lymphoma features Reed-Sternberg cells; Burkitt lymphoma demonstrates a 'starry sky' pattern due to macrophages clearing apoptotic debris; and Sickle Cell disease causes early functional asplenia, preventing the removal of Howell-Jolly bodies from red blood cells.

Step-by-Step Solution

1
Analyze the specific microscopic cellular features and inclusions described in each left item.
Identified pathognomonic hallmarks: Auer rods, Reed-Sternberg cells, 'starry sky' pattern, and Howell-Jolly bodies.
Recognizing key morphologic features is the primary diagnostic step in hematopathology.
2
Correlate each identified hallmark with its corresponding pediatric hematologic or oncologic disease process.
Matched each finding to Acute Promyelocytic Leukemia, Classical Hodgkin Lymphoma, Burkitt Lymphoma, and Sickle Cell Disease, respectively.
Each condition has a distinct pathophysiology that directly produces these specific microscopic findings.

Key Concept

Pathognomonic histologic and peripheral smear findings in pediatric hematology and oncology.
Question 59Question →

A 1212-year-old boy with a known history of Ewing sarcoma is brought to the emergency department due to worsening, severe back pain for the past 4848 hours. This morning, he developed weakness in both legs and has been unable to urinate. His temperature is 37.2∘C37.2^\circ\text{C} (99.0∘F99.0^\circ\text{F}), blood pressure is 112/70 mmHg112/70\text{ mmHg}, pulse is 98/min98\text{/min}, and respirations are 20/min20\text{/min}. Physical examination reveals 2/52/5 motor strength in the bilateral lower extremities, exaggerated deep tendon reflexes at the knees and ankles, and a loss of sensation to pinprick below the level of the umbilicus. Anal sphincter tone is markedly decreased. Arrange the following steps in the most appropriate chronological order for the management of this patient's current condition.

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Answer

The correct sequence is to first administer high-dose intravenous dexamethasone, then obtain an urgent MRI of the entire spine, followed by consulting neurosurgery and radiation oncology specialists, and finally performing definitive surgical decompression or emergent radiation therapy.
The correct sequence prioritizes the immediate preservation of neurologic function over diagnostic confirmation. In malignant spinal cord compression, irreversible ischemia can occur rapidly. Therefore, corticosteroids must be given first to decrease edema. Only after this acute intervention is initiated should the patient be sent for an MRI to confirm the anatomy, followed by multidisciplinary specialist consultation and definitive decompression therapy.

Step-by-Step Solution

1
Recognize malignant spinal cord compression (MSCC).
The patient's back pain, lower extremity weakness, sensory level, and bowel/bladder dysfunction in the setting of a known solid tumor (Ewing sarcoma) strongly indicate MSCC.
Establishing the clinical diagnosis dictates the immediate urgency of medical intervention.
2
Prioritize initial pharmacologic intervention.
Intravenous dexamethasone is administered first, prior to any imaging.
Glucocorticoids reduce vasogenic edema around the tumor, rapidly relieving pressure on the spinal cord and preventing irreversible neurologic damage. This critical step must be taken before the patient goes to the imaging suite.
3
Obtain confirmatory imaging.
An urgent MRI of the entire spine is performed.
MRI is required to anatomically confirm the diagnosis, identify the exact level of compression, and rule out multiple asymptomatic epidural metastases across the neuroaxis.
4
Plan and execute definitive therapy.
Specialists are consulted to proceed with surgery or targeted radiation.
Once the anatomy is visualized, multidisciplinary input ensures the correct modality is chosen to definitively relieve the compression based on tumor radiosensitivity and spinal stability.

Key Concept

In patients presenting with signs of malignant spinal cord compression and neurologic deficits, immediate administration of high-dose corticosteroids (e.g., dexamethasone) is the most critical first step to preserve neurologic function, and it must precede confirmatory imaging with an MRI.
Question 60Question →

An 88-year-old girl with a history of homozygous sickle cell anemia (HbSS) is brought to the pediatric emergency department due to a two-day history of progressive shortness of breath, right-sided chest pain, and fever. Her temperature is 38.9∘C38.9^\circ \text{C} (102.0∘F102.0^\circ \text{F}), blood pressure is 100/60 mmHg100/60\text{ mmHg}, heart rate is 128/min128/\text{min}, and respiratory rate is 34/min34/\text{min}. Oxygen saturation is 89%89\% on room air. Physical examination reveals shallow breathing and crackles over the right lower posterior lung fields. Laboratory studies show:

* Hemoglobin: 7.1 g/dL7.1\text{ g/dL}
* Leukocyte count: 19,500/μL19,500/\mu \text{L}
* Reticulocytes: 11%11\%

Chest radiography demonstrates a new alveolar infiltrate in the right lower lobe. The patient is immediately started on supplemental oxygen, pain control, and intravenous normal saline. Which of the following is the most appropriate additional pharmacologic therapy for this patient?

Show answer & explanation

Answer: Intravenous ceftriaxone and oral azithromycin

Answer

Intravenous ceftriaxone and oral azithromycin
The correct answer provides the standard empiric antibiotic therapy for Acute Chest Syndrome (ACS). ACS is characterized by fever, chest pain, tachypnea, hypoxemia, and a new pulmonary infiltrate on chest radiography in a patient with sickle cell disease. Because atypical pathogens (e.g., Mycoplasma pneumoniae, Chlamydia pneumoniae) and encapsulated organisms (e.g., Streptococcus pneumoniae) frequently trigger or complicate ACS, patients require broad-spectrum coverage. Intravenous ceftriaxone provides excellent coverage for typical encapsulated organisms, while azithromycin covers the atypical pathogens.

Step-by-Step Solution

1
Identify the patient's acute complication based on her underlying disease and clinical presentation.
The patient has sickle cell anemia and presents with fever, chest pain, hypoxemia, and a new pulmonary infiltrate, which defines Acute Chest Syndrome (ACS).
Recognizing ACS is critical because it is a life-threatening emergency in sickle cell patients requiring immediate, specific interventions.
2
Determine the standard medical management for Acute Chest Syndrome.
Standard management includes supplemental oxygen, cautious intravenous fluids, pain control, and empiric broad-spectrum antibiotics.
Infection is a major trigger for ACS, and distinguishing between pulmonary infarction and pneumonia is clinically difficult. Coverage for both encapsulated organisms and atypical bacteria is required.
3
Select the appropriate antibiotic regimen from the given options.
A third-generation cephalosporin (ceftriaxone) covers encapsulated organisms (e.g., Streptococcus pneumoniae), and a macrolide (azithromycin) covers atypical pathogens (e.g., Mycoplasma pneumoniae).
This dual-therapy approach ensures comprehensive coverage for the most common bacterial triggers of ACS in the pediatric population.

Key Concept

Management of Acute Chest Syndrome in Sickle Cell Disease
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