Neurosyphilis

In early neurosyphilis, more commonly the meninges are affected (and this is not technically Tertiary Syphilis).  Later, the brain and spinal cord parenchyma are affected (this is now Tertiary Syphilis), leading to the two major syndromes below:

1. General Paresis (of the Insane) – brain cortex is affected many years after infection, leading to progressive dementia, followed by depression, mania, psychosis.  Summarized by the mnemonic PARESIS:

P = Personality changes
A = Affect
R = Reflexes (hyperreflexia)
E = Eye (Argyll Robertson Pupil – reacts to accommodation, not light – aka “Prostitute’s Pupil”)
S = Sensorium – hallucinations, delusions
I = Intellect decreased – memory, orientation, judgement
S = Speech

2. Tabes Dorsalis – due to syphilis affecting the posterior columns of the spinal cord and also the dorsal roots.  Get ataxia, gait abnormalities, absent LE reflexes, bladder incontinence, loss of sexual function, and sharp and sudden pains in the limbs or abdomen.  Argyll Robertson pupil occurs here as well.
Of course, the two syndromes above can coexist.

Diagnosis of Neurosyphilis:

• CSF Findings – pleocytosis (other that is usually lymphocyte predominant, elevated protein.
• CSF VDRL – only ~30% sensitive, but highly specific.
• CSF FTA-Abs – surprisingly, this is highly sensitive but not very specific.
• CSF RPR is not done.

Since VDRL is not sensitive, the diagnosis of neurosyphilis can sometimes be challenging, but other clues of course include positive serum nontreponemal or treponemal tests in conjunction with abnormal CSF parameters and clinical signs of neurosyphilis.

(Chanu Rhee MD, 2/1/11)