A 68-year-old hospitalized man is evaluated for new-onset leg weakness. Six days ago, he was admitted to the hospital due to fever, right leg pain, and swelling. Physical examination showed right lower extremity edema, erythema, warmth, and tenderness from the foot to the midcalf. Leukocyte count was 16,000/mm³, and venous Doppler ultrasonography revealed patent leg veins without thrombosis. Blood cultures grew Staphylococcus aureus. The patient was treated with intravenous antibiotics, and his leg symptoms improved. However, this morning he had trouble getting out of bed due to significant leg weakness. The patient has a history of hypertension, type 2 diabetes mellitus, coronary artery disease, and systolic heart failure. He also has chronic low back pain from a work-related injury. The patient has had worsening mid-back pain over the last 2 days. Temperature is 38 C (100.4 F), blood pressure is 130/80 mm Hg, and pulse is 88/min. Physical examination shows normal mental status and cranial nerves. Abdominal examination reveals a suprapubic mass. There is midline tenderness over the lower thoracic vertebral area. Upper extremity strength is normal, but he is not able to lift either lower extremity against gravity. Which of the following is the best next step in management of this patient?

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11ec25c8_d147_4afd_bc81_694e33bd3de2_MD0003_00 Spinal epidural abscess (SEA) is a rare infection of the epidural space that may threaten the spinal cord and result in paralysis. Most cases are due to hematologic spread from a distant infection (eg, cellulitis, bone/joint), intravenous drug use, or direct inoculation during a spinal procedure. Staphylococcus aureus is the most common (65%) causative organism. SEA classically results in the triad of fever, back pain, and neurologic deficits; however, all 3 symptoms are present in a minority of cases. Most patients initially develop severe, focal back pain that progresses over days to nerve root pain ("shooting/electric") and more severe neurologic manifestations (motor weakness, sensory changes, bowel/bladder dysfunction, paralysis). The diagnostic test of choice is MRI of the spine due to high sensitivity early in the course of illness and excellent localization of infection extent. Treatment with broad- spectrum antibiotics and aspiration/surgical decompression is usually required. MRI of the spine (Choice A) Brain lesions usually manifest with unilateral neurologic findings. This patient with isolated, bilateral lower extremity weakness, S aureus bacteremia, and point tenderness over his thoracic spine is much more likely to have a spinal cord process. (Choice B) The suprapubic mass is likely a distended bladder due to urine retention from spinal cord injury. Abdominal imaging is not required at this time. (Choice C) S aureus bacteremia can cause infective endocarditis, which may manifest with systemic (eg, fever, myalgia, malaise), skin (eg, splinter hemorrhages), and pulmonary symptoms (eg, dyspnea, chest pain). This patient likely developed SEA from S aureus cellulitis and has significant bilateral lower extremity weakness; urgent MRI of the spine is needed. (Choice D) Lumbar puncture is required for suspected meningitis (fever, headache, altered mental status, meningeal symptoms) but is not typically performed in patients with suspected SEA due to low diagnostic sensitivity and risk of central nervous system inoculation. (Choice F) Nerve conduction studies are useful in peripheral nervous system dysfunction (eg, entrapment syndrome, polyneuropathies); however, this patient has bilateral weakness, fever, focal spine tenderness, and known S aureus bacteremia. Due to high risk of SEA, MRI of the spine should not be delayed. (Choice G) A tagged leukocyte scan is sometimes used to diagnose osteomyelitis, especially in the setting of metal implants (which may preclude MRI); however, MRI is more sensitive for SEA and should be performed in most patients. Educational objective: Spinal epidural abscess may present with fever, focal back pain, and neurologic dysfunction. Evaluation includes urgent MRI of the spine. Most patients require treatment with broad-spectrum intravenous antibiotics and prompt drainage/surgery.

A 68-Year-Old Hospitalized Man Is Evaluated for New-Onset Leg Weakness