A 30-year-old woman comes to the emergency department due to worsening, bilateral lower extremity weakness and numbness for the past 4 days. She has had no fever, headache, or back pain, but she had an incident of urinary incontinence today. The patient has no other medical conditions and takes no medications. She does not use tobacco, alcohol, or illicit drugs. Temperature is 37 C (98.6 F), blood pressure is 110/60 mm Hg, pulse is 72/min, and respirations are 16/min. On physical examination, the patient is alert and oriented with normal comprehension and speech. The pupils are equal and reactive, and there is no facial weakness. Upper extremity muscle strength is normal with normal reflexes, but both legs are diffusely weak. Bilateral lower extremity deep tendon reflexes are increased with extensor plantar response. Sensation to pinprick is decreased below the level of the umbilicus, and vibratory sensation is absent in the toes. Which of the following is the most likely cause of this patient's current symptoms?

Question

A 30-year-old woman comes to the emergency department due to worsening, bilateral lower extremity weakness and numbness for the past 4 days.  She has had no fever, headache, or back pain, but she had an incident of urinary incontinence today.  The patient has no other medical conditions and takes no medications.  She does not use tobacco, alcohol, or illicit drugs.  Temperature is 37 C (98.6 F), blood pressure is 110/60 mm Hg, pulse is 72/min, and respirations are 16/min.  On physical examination, the patient is alert and oriented with normal comprehension and speech.  The pupils are equal and reactive, and there is no facial weakness.  Upper extremity muscle strength is normal with normal reflexes, but both legs are diffusely weak.  Bilateral lower extremity deep tendon reflexes are increased with extensor plantar response.  Sensation to pinprick is decreased below the level of the umbilicus, and vibratory sensation is absent in the toes.  Which of the following is the most likely cause of this patient's current symptoms?

Quizplus · Accepted Answer

Explanation: This patient with bilateral lower extremity weakness associated with upper motor neuron signs (UMNS) (ie, increased deep tendon reflexes, extensor plantar response), urinary incontinence, and sensory deficit below the umbilicus likely has acute transverse myelitis. Transverse myelitis is an immune-mediated disorder characterized by the infiltration of inflammatory cells into a segment of the spinal cord, leading to neuron and oligodendrocyte cell death and demyelination. Most cases follow a recent infection (eg, gastroenteritis, upper respiratory infection), although the condition is also associated with multiple sclerosis and systemic disease (eg, sarcoidosis). The incidence of transverse myelitis has a bimodal peak, with most cases occurring in teens and in those age 30-40. Inflammation localizes to ≥1 contiguous spinal cord segments (usually in the thoracic cord) leading to a rapidly progressive myelopathy characterized by: motor weakness that progresses from flaccid to spastic paraparesis with UMNS. autonomic dysfunction including bowel/bladder incontinence or retention and sexual dysfunction. sensory dysfunction including pain, paresthesia, or numbness with a distinct sensory level (ie, lowest spinal cord level with intact sensation). MRI demonstrates enhancement of the affected cord segments without evidence of compression, whereas lumbar puncture typically reveals cerebrospinal fluid pleocytosis and elevated IgG. Management includes high-dose intravenous glucocorticoids, often with plasmapheresis. (Choice A) Guillain-Barré syndrome causes rapidly progressive, ascending weakness. Upper extremity and respiratory muscle involvement is expected to develop, and a distinct sensory level would be atypical. In addition, patients develop flaccid (rather than spastic) paralysis. (Choice B) Spinal cord compression would cause similar myelopathic symptoms; however, cauda equina syndrome is usually associated with severe back pain and sensory loss that involves the thighs and buttocks. This patient has sensory loss below the umbilicus (provided by the T10 spinal nerve), indicating involvement of the thoracic cord. (Choice C) Anterior spinal artery syndrome is characterized by motor weakness and loss of pain and temperature sensation below the lesion; however, proprioception and vibratory sensation are spared (unlike in this patient). (Choice E) Subacute combined degeneration (due to vitamin B₁₂ deficiency) causes sensory ataxia with progressive spastic paraparesis and incontinence. However, it occurs over a prolonged period (years) and is often associated with neuropsychiatric changes. ₁₂ Educational objective: Transverse myelitis is an immune-mediated disorder characterized by the infiltration of inflammatory cells into a segment of the spinal cord. Inflammation localizes to ≥1 contiguous spinal cord segments, leading to a rapidly progressive myelopathy characterized by motor weakness, autonomic dysfunction (eg, bowel/bladder dysfunction), and sensory deficits with a distinct sensory level.

A 30-Year-Old Woman Comes to the Emergency Department Due to Worsening