Clinical Pearls & Morning Reports
Published October 2, 2019
There has been a resurgence of syphilis in low- and middle-income countries and in certain populations in developed countries, but the diagnosis of neurosyphilis tends to be overlooked because of its rarity. Read the Review Article here.
Q: Describe the different forms of neurosyphilis.
A: Neurosyphilis is the clinical result of infection of the nervous system by Treponema pallidum. The treponeme invades the nervous system within days after primary infection, and subsequent neurosyphilis can be categorized as asymptomatic or symptomatic and as early (1 to 2 years after primary infection) or late. Early neurosyphilis is usually characterized by asymptomatic meningitis, evidenced only by a cellular reaction in the CSF, but it can be symptomatic with headache, meningismus, cranial-nerve palsies, and blindness or deafness. The late form includes general paresis and tabes dorsalis. Meningovascular syphilis is a form of meningitis involving vasculitis of small and medium-size arteries in the central nervous system; it causes strokes and many types of myelopathy. Meningovascular syphilis is usually interposed temporally between early and later forms of neurosyphilis, typically occurring 1 to 10 years after the primary infection.
Q: How does HIV coinfection affect the course of neurosyphilis?
A: Patients with HIV coinfection may have earlier development of neurologic features than people without HIV infection as well as incomplete responses to treatment. Routine CSF testing for syphilis in persons with dementia has not been recommended but may be appropriate if there is a risk of syphilis — for example, because of HIV infection.
A: General paresis and tabes dorsalis have been considered to be the result of a chronic meningeal reaction to spirochetal invasion and destruction of adjacent neural tissue, sometimes coupled with cerebral infarction due to meningovascular disease. General paresis is a frontotemporal dementia. Unusual halting and repetitive speech patterns were, and still are, a feature. General paresis is characterized by psychosis, depression, personality change, or nondescript progressive dementia with — as in the past — flamboyant delusions. Tabes is characterized by gait ataxia with Romberg’s sign (falling or stepping to one side when standing with feet together and eyes closed) and in most cases by Argyll Robertson pupils (constriction of the pupils when the eyes are focused on a nearby object but not when the pupil is illuminated). The gait was identifiable by its “stamp and stick” sound, with the patient landing forcefully and flat-footed on a wide base in order to detect the position of the feet and then striking a cane on the floor for stability. The sound and cadence of the tabetic gait are still characteristic but are now more commonly caused by other forms of sensory ataxia such as diabetic neuropathy or spinal multiple sclerosis. Tabes has become more rare than general paresis for unknown reasons.
A: Parenteral penicillin treats all forms of neurosyphilis. Serial reexamination of the CSF white-cell count has been used to determine the adequacy of treatment, and retreatment has been suggested if pleocytosis has not abated in 6 months or has not been eliminated 2 years after treatment. On the basis of historical experience, penicillin probably does not improve late neurosyphilitic syndromes but usually halts their progression. For patients with penicillin allergy, skin testing and desensitization are recommended. Limited evidence suggests that ceftriaxone, tetracycline, or doxycycline is effective in the treatment of neurosyphilis, but penicillin is still strongly preferred.