August 1981

Congenital Absence of Pain

Author Affiliations

From the Quinta Clinica Neurologica dell'Università di Roma (Prof Manfredi and Drs Bini, Cruccu, Accornero, and Berardelli) and the Istituto di Biologia Generale dell'Università di Roma (Dr Medolago).

Arch Neurol. 1981;38(8):507-511. doi:10.1001/archneur.1981.00510080069010

• A 16-year-old boy had congen ital absence of pain sensitivity and no impairment of other sensory modalities. Routine electrophysiologic investigation showed no abnormalities. The threshold and latency of electrically elicited corneal reflex and cortical potentials evoked by tooth pulp stimulation were normal, but suprathreshold electric stimulation of corneal mucosa and dental pulp, as well as electric stimulation of dorsal roots, did not elicit pain. The total CSF opioid activity was raised. However, naloxone hydrochloride administration failed to reverse the analgesia. The axon reflex to intradermal injection of histamine dihydrochloride was absent. Cutaneous nerve branches showed unspecific changes affecting part of unmyelinated axons. Most of the unmyelinated as well as the myelinated axons were normal. We consider the case an example of congenital indifference to pain.