A 34-year-old man comes to the office after several days of difficulty walking. He also has had some "funny" sensations in his feet. He has no recent skin rash, diarrhea, or joint pain. He has had lower back pain for the last week due to a lifting injury while he was moving. He visited friends in Connecticut 1 month ago and while there developed an upper respiratory infection that lasted 4 days. The patient smokes 1 pack of cigarettes a day and admits to occasional IV drug use. He has not been sexually active for 3 months. Temperature is 36.7 C (98 F), blood pressure is 120/80 mm Hg, pulse is 90/min, and respirations are 16/min. Chest examination is unremarkable. The abdomen is soft and nontender. The liver span is 8 cm and the spleen is not palpable. Cranial nerves II-XII are intact. Muscle strength is reduced in the lower extremities but well preserved in the upper extremities. Lower-extremity sensation is decreased. Mild hyperreflexia is noted bilaterally in the lower extremities. Stroking the soles of the feet elicits extension of the great toe. Which of the following is most likely to diagnose this patient's condition?

Question

A 34-year-old man comes to the office after several days of difficulty walking.  He also has had some "funny" sensations in his feet.  He has no recent skin rash, diarrhea, or joint pain.  He has had lower back pain for the last week due to a lifting injury while he was moving.  He visited friends in Connecticut 1 month ago and while there developed an upper respiratory infection that lasted 4 days.  The patient smokes 1 pack of cigarettes a day and admits to occasional IV drug use.  He has not been sexually active for 3 months.  Temperature is 36.7 C (98 F), blood pressure is 120/80 mm Hg, pulse is 90/min, and respirations are 16/min.  Chest examination is unremarkable.  The abdomen is soft and nontender.  The liver span is 8 cm and the spleen is not palpable.  Cranial nerves II-XII are intact.  Muscle strength is reduced in the lower extremities but well preserved in the upper extremities.  Lower-extremity sensation is decreased.  Mild hyperreflexia is noted bilaterally in the lower extremities.  Stroking the soles of the feet elicits extension of the great toe.  Which of the following is most likely to diagnose this patient's condition?

Quizplus · Accepted Answer

This patient has signs and symptoms of spinal cord compression. He has isolated, symmetric lower-extremity symptoms, including loss of sensation, and signs of upper motor neuron disease (eg, hyperreflexia, Babinski sign, weakness without fasciculations). The presence of upper motor neuron symptoms indicates involvement of the central nervous system. Because the symptoms are bilateral and present only in the lower extremities, the lesion can be localized to the spinal cord. Possible etiologies for this patient's spinal cord compression are disk herniation, abscess, and malignancy. An epidural abscess (even without fever) is of particular concern in this patient with IV drug use. Spinal cord compression is a medical emergency and must be evaluated immediately with an MRI of the spine. (Choice A) Electromyography can be helpful in distinguishing between nerve and muscle disease. It would show upper motor neuron disease in this patient but would be unable to localize the site of the lesion. (Choice B) Head CT is the diagnostic modality of choice for evaluating intracranial pathology such as acute CNS bleeds and rapidly assessing for elevated intracranial pressure. This patient's abnormality is in the spinal cord, and obtaining a head CT would not aid in diagnosis. (Choice D) This patient's recent travel to Connecticut is a risk factor for Lyme disease. However, acute Lyme disease typically presents as erythema migrans, headache, arthralgias, and myalgias. Late disseminated disease that occurs months to years after infection can manifest as subacute encephalopathy (meningitis/encephalitis) and axonal polyneuropathy. These symptoms are not consistent with those of the patient. (Choice E) Lumbar puncture is indicated to evaluate for CNS infection and Guillain-Barré syndrome. It is unlikely that meningitis will result in symmetric lower-extremity weakness. Lumbar puncture is not recommended when there may be an epidural abscess as bacteria can be introduced into the spinal fluid. Guillain-Barré syndrome would present with symptoms similar to those in this patient. However, it is NOT characterized by upper motor neuron signs such as extensor plantar response (Babinski sign) or significant sensory findings (except in rare sensory forms). (Choice F) The edrophonium test is used to diagnose myasthenia gravis. This disease is characterized by easy muscle fatigability due to autoantibodies against the acetylcholine receptor. Diplopia is common, but upper motor neuron signs would not be present. Educational objective: Spinal cord compression is characterized by signs and symptoms of upper motor neuron dysfunction distal to the site of compression. These include weakness, hyperreflexia, and an extensor plantar response. Cord compression is a medical emergency requiring prompt diagnosis by spinal MRI. References: Spinal epidural abscess (http://www.ncbi.nlm.nih.gov/pubmed/20060254)

A 34-Year-Old Man Comes to the Office After Several Days