Parents bring their 24-month-old daughter to the emergency department because she has been… — USMLE Step 2 CK

Parents bring their 24-month-old daughter to the emergency department because she has been refusing to stand or walk for the past 48 hours. They also report that she developed new-onset urinary incontinence this morning. The patient appears irritable but is consolable. Temperature is $37.2^\circ\text{C}$ ( $99.0^\circ\text{F}$ ), blood pressure is $115/70\text{ mmHg}$ , and heart rate is $120\text{/min}$ . Physical examination reveals a firm, irregular, palpable abdominal mass crossing the midline. Neurologic examination of the lower extremities shows $2/5$ motor strength bilaterally, $3+$ patellar and Achilles deep tendon reflexes, and a positive Babinski sign bilaterally. Anal sphincter tone is decreased.

Based on the most likely diagnosis, arrange the following management steps in the most appropriate chronological order of execution.

1Administer high-dose intravenous dexamethasone
2Perform urgent magnetic resonance imaging (MRI) of the spine
3Consult neurosurgery or radiation oncology for definitive local decompression
4Perform an image-guided biopsy of the abdominal mass

Answer

The correct chronological order is: 1) Administer high-dose intravenous dexamethasone, 2) Perform urgent magnetic resonance imaging (MRI) of the spine, 3) Consult neurosurgery or radiation oncology for definitive local decompression, 4) Perform an image-guided biopsy of the abdominal mass.

In the setting of suspected malignant spinal cord compression (suggested by the new-onset upper motor neuron signs, paraparesis, and bowel/bladder dysfunction in a patient with a probable neuroblastoma), the immediate priority is protecting the spinal cord. High-dose corticosteroids (dexamethasone) reduce peritumoral edema and must be given as the absolute first step. Once steroids are on board, MRI is performed to confirm and map the compression. This is followed by definitive local therapy (surgery or radiation). Finally, after the neurological emergency is stabilized, a biopsy of the primary mass is performed to guide long-term systemic chemotherapy.

Step-by-Step Solution

Identify the clinical syndrome and underlying etiology.

The patient exhibits upper motor neuron signs (hyperreflexia, positive Babinski), weakness, and autonomic dysfunction (incontinence) combined with an abdominal mass crossing the midline.

These findings are highly indicative of neuroblastoma with paraspinal extension causing malignant spinal cord compression, which is an oncologic emergency.

Determine the most critical, immediate intervention.

Intravenous dexamethasone is administered first.

Corticosteroids rapidly reduce vasogenic edema surrounding the compressed spinal cord, preserving neurologic function. This must precede any diagnostic imaging to prevent permanent paraplegia.

Establish the sequence for diagnostic imaging and structural intervention.

MRI of the spine is ordered next, followed by neurosurgical or radiation oncology consultation.

Imaging is required to localize the exact site of compression. Once localized, mechanical decompression (via surgery or radiation) is needed to treat the structural emergency.

Determine the timing for establishing a definitive tissue diagnosis.

Biopsy of the abdominal mass is placed last.

While essential for dictating systemic chemotherapy, obtaining a tissue diagnosis is not immediately limb- or life-saving and must wait until the acute neurological threat is neutralized.

Key Concept

Management sequence for malignant spinal cord compression in pediatric oncology.

Estimated Time:1m 30s

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