A 45-year-old man comes to the physician because of difficulty walking. Over the last several months, he has had increased falls due to feeling off balance. He also has shooting and burning pains in his legs. He does not have a recent history of fevers/chills, trauma, headache, visual changes, slurred speech, or trouble swallowing. The patient also has no history of insect bites, skin rash, or genital lesions. He works as a truck driver in the Mid-Atlantic region of the United States. His temperature is 36.7 C (98 F), blood pressure is 140/90 mm Hg, and pulse is 92/min. His neurologic examination reveals bilateral small pupils that reduce in size with accommodation but not when exposed to bright light. His muscle bulk and strength are normal. He has reduced sensation to pain, temperature, vibration, and proprioception in the lower extremities. Ankle reflexes are absent bilaterally. He is unstable during the Romberg test. Which of the following is most likely to establish the diagnosis?

Question

A 45-year-old man comes to the physician because of difficulty walking.  Over the last several months, he has had increased falls due to feeling off balance.  He also has shooting and burning pains in his legs.  He does not have a recent history of fevers/chills, trauma, headache, visual changes, slurred speech, or trouble swallowing.  The patient also has no history of insect bites, skin rash, or genital lesions.  He works as a truck driver in the Mid-Atlantic region of the United States.  His temperature is 36.7 C (98 F), blood pressure is 140/90 mm Hg, and pulse is 92/min.  His neurologic examination reveals bilateral small pupils that reduce in size with accommodation but not when exposed to bright light.  His muscle bulk and strength are normal.  He has reduced sensation to pain, temperature, vibration, and proprioception in the lower extremities.  Ankle reflexes are absent bilaterally.  He is unstable during the Romberg test.  Which of the following is most likely to establish the diagnosis?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c193_288f_8f63_d5f958c1221b_MD0005_00 This patient is presenting with late neurosyphilis, which typically manifests years after Treponema pallidium infection and can be characterized by tabes dorsalis and Argyll Robertson pupils. Tabes dorsalis is a neurodegenerative condition that involves the posterior spinal columns and nerve roots. Posterior spinal column involvement results in impaired vibration/proprioception, sensory ataxia, and instability during the Romberg test. Nerve root involvement can contribute to diminished pain/temperature sensation and areflexia. Patients might complain of lancinating pains, described as brief shooting or burning pain in the face, back, or extremities. Tabes dorsalis can also be associated with Argyll Robertson pupils, which are characterized by normal pupillary constriction with accommodation but not with light. (Choices A, C, and D) Chronic alcohol use and diabetes mellitus can result in a symmetric sensory peripheral neuropathy that presents similarly to what is seen in this patient. Lyme disease has a high incidence in the Mid-Atlantic region of the United States and can also have variable neurologic manifestations (eg, meningitis, cranial neuritis, and radiculoneuritis). However, Argyll Robertson pupils are not commonly associated with these conditions. (Choice B) Vitamin B₁₂ deficiency can result in peripheral neuropathy and/or subacute combined degeneration (SCD). SCD is a myelopathy characterized by both posterior spinal column disease and lateral corticospinal tract disease, the latter of which causes spastic paresis and hyperreflexia. Folic acid deficiency usually does not cause neurologic symptoms. Deficiencies in these vitamins are not typically associated with Argyll Robertson pupils. ₁₂ Educational objective: Late neurosyphilis can present with tabes dorsalis (sensory ataxia and lancinating pains) and Argyll Robertson pupils (constriction with accommodation but not with light). References: The Argyll Robertson pupil. (http://www.ncbi.nlm.nih.gov/pubmed/20103017) Neurosyphilis. (http://www.ncbi.nlm.nih.gov/pubmed/24365430)

A 45-Year-Old Man Comes to the Physician Because of Difficulty