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Difficulty: Very hardNeurosurgery

A 68-year-old man is brought to the emergency department due to rapidly progressive weakness in his legs over the past 24 hours. He is now unable to walk unassisted. He also reports lower abdominal discomfort and an inability to urinate since yesterday evening. For the last 3 months, he has had a constant, aching mid-back pain that frequently wakes him from sleep and is unrelieved by over-the-counter analgesics. His medical history includes hypertension, diet-controlled type 2 diabetes mellitus, and a 50-pack-year smoking history. His temperature is 37.2°C (99.0°F), blood pressure is 158/92 mm Hg, pulse is 88/min, and respirations are 16/min. He is awake and fully oriented with a Glasgow Coma Scale score of 15. Neurologic examination shows 2/5 strength in the bilateral lower extremities with flaccid muscle tone. Deep tendon reflexes are 1+ at the patellae and absent at the Achilles tendons bilaterally. Plantar responses are absent. There is a distinct loss of pinprick and temperature sensation below the level of the umbilicus. A urethral catheter is placed, draining 750 mL of clear urine. Which of the following is the most appropriate initial step in the management of this patient?

  1. Administration of intravenous dexamethasoneAnswer
  2. B
    Magnetic resonance imaging of the thoracic spine
  3. C
    Emergency decompressive laminectomy
  4. D
    Administration of intravenous ceftriaxone and vancomycin
  5. E
    Electromyography and nerve conduction studies

Answer

Administration of intravenous dexamethasone
This patient presents with a classic presentation of malignant epidural spinal cord compression (MESCC). His history of nocturnal back pain and heavy smoking suggests a metastatic spinal tumor (likely of lung origin). The acute onset of bilateral leg weakness, urinary retention, and a distinct sensory level at T10 localizes the lesion to the thoracic spinal cord. Although upper motor neuron (UMN) lesions typically present with spasticity and hyperreflexia, acute severe spinal cord injury initially presents with flaccid paralysis and hyporeflexia, a phenomenon known as spinal shock. When MESCC is suspected clinically, the immediate administration of high-dose intravenous glucocorticoids (e.g., dexamethasone) is the most critical next step. Glucocorticoids reduce vasogenic peritumoral edema, rapidly relieving pressure on the spinal cord and preventing irreversible ischemic injury. This medication must be given as soon as the diagnosis is suspected, before sending the patient for confirmatory imaging.

Step-by-Step Solution

1
Analyze the patient's risk factors and chronic symptoms
Older age, heavy smoking history, and nocturnal mid-back pain strongly suggest an underlying malignancy, likely metastatic lung cancer.
Establishing the underlying etiology is crucial for interpreting the acute neurological deterioration.
2
Localize the neurologic lesion based on physical exam findings
Loss of sensation below the umbilicus (T10 dermatome) accompanied by lower extremity weakness localizes the lesion to the thoracic spinal cord.
A distinct sensory level confirms myelopathy (spinal cord lesion) rather than a peripheral nerve, neuromuscular junction, or muscle disorder.
3
Interpret the seemingly contradictory motor findings
The presence of flaccid paralysis, hyporeflexia, and absent plantar responses in the setting of acute cord compression indicates spinal shock.
Acute severe upper motor neuron injury initially presents with lower motor neuron signs (spinal shock) before spasticity and hyperreflexia develop days to weeks later.
4
Determine the most critical initial intervention
High-dose intravenous dexamethasone must be given immediately.
Glucocorticoids reduce peritumoral edema, relieve pressure on the cord, and preserve neurologic function while awaiting definitive diagnosis (MRI) and treatment (surgery or radiation).

Key Concept

Patients with suspected acute malignant epidural spinal cord compression must receive high-dose intravenous glucocorticoids immediately upon clinical suspicion, prior to obtaining confirmatory magnetic resonance imaging.
Estimated Time:1m 30s
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Neurosurgery

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