There is no additional risk with general anaesthesia. There is a single report of a 73-year-old woman with late congenital pharyngo-laryngeal syphilis, who presented with a potentially difficult intubation during the induction of general anaesthesia. Syphilis poses no specific problems for regional blockade. The three main manifestations of late syphilis (neuro-, cardiovascular, and gummatous syphilis) can have a wide range of presentation. It is prudent to assess and document all existing signs and symptoms (including neurological examination) in the anaesthetic record. There is no evidence to suggest that regional blockade can affect the extent or likelihood of neurosyphilis. The lesion in tabes dorsalis is concentrated on the dorsal spinal roots and dorsal columns of the spinal cord, most often at the lumbosacral and the lower thoracic region. There have been reports that spinal anaesthesia induces severe lightning pain in the lower limbs of patients with phantom limb pain, tabes dorsalis, or causalgia. The exact mechanism of this phenomenon is controversial. Some hypothesize that complete loss of sensory input after spinal anaesthesia may decrease the level of inhibition and increase the self-sustained neural activity.
