Review Question - QID 214328

This patient, with an extensive sexual history, presents with loss of balance, absence of vibratory sensation in bilateral lower extremities, ataxia, and absence of pupillary constriction to light with preservation of accommodation (Argyll Robertson pupil). This combination of symptoms is most consistent with neurosyphilis, which affects the dorsal column and dorsal root ganglia of the spinal cord.

Neurosyphilis is a manifestation of tertiary Treponema pallidum infection of the central nervous system that typically occurs 30+ years after exposure to the spirochete. Early signs of neurosyphilis include meningeal symptoms (neck stiffness and headache). Later in the disease course, patients classically present with tabes dorsalis (ataxia, loss of vibratory sensation, and proprioception). Other symptoms of tertiary syphilis include cardiac syphilis (aortitis and subsequent aortic aneurysm), gummas (destructive granulomatous lesions with a necrotic center affecting any organ), and pupils that accommodate but do not constrict to direct or indirect light (Argyll Robertson pupils). Initial tests for neurosyphilis include rapid plasma reagin (PRP) or Venereal Disease Research Laboratory (VDRL), and the confirmatory test is a fluorescent treponemal antibody absorption (FTA-ABS). Treatment includes IV benzathine penicillin G for 10-14 days.

Incorrect Answers:
Answer 1: Cerebellar pathology can be found in patients with cerebellar infarction, infection or malignancy. Patients with cerebellar pathology may present with ataxia, dysmetria, dysdiadochokinesia, pronator drift, and nystagmus, but patients do not have loss of vibratory sensation of the lower extremities nor Argyll Robertson pupil.

Answer 2: Mammillary body pathology is the site of involvement for patients with Wernicke encephalopathy. Wernicke encephalopathy is a result of long standing alcohol use and is characterized by confusion, oculomotor dysfunction (most commonly nystagmus), and gait ataxia.

Answer 3: Periventricular white matter pathology is most commonly indicative of primary central nervous system lymphoma or multiple sclerosis. Patients with these disease states most often present with focal neurological deficits and would not have Argyll Robertson pupil.

Answer 4: Posterior limb of the internal capsule pathology is consistent with a lacunar infarct secondary to occlusion of the lenticulostriate artery from longstanding hypertension. Patients with infarcts in this location present with pure motor strokes and contralateral hemiparesis of the face, arm, and leg.

Bullet Summary:
Neurosyphilis classically occurs 30+ years after untreated syphilis and presents with tabes dorsalis, aortitis, and/or Argyll Robertson pupils.