Some people are resistant to local anaesthetic, meaning they must endure dental and medical procedures without pain relief. The condition is poorly understood, but a new genetic study of one family may provide answers.
Lori Lemon, from Florida, recalls being unable to go numb at the dentist as a child. Despite multiple injections, the anaesthetic had no effect. “I just screamed and was in tears the whole time,” she says. The same problem recurred during a later procedure to remove a lipoma from her elbow, leaving doctors flabbergasted.
Steven Clendenen, an anaesthesiologist at the Mayo Clinic in Jacksonville, confirms that standard medications did not work for Lemon. He began investigating after witnessing her distress. The medical literature contains scattered reports of similar cases, but the underlying mechanisms remain unknown.
Alan Hakim and colleagues at University College Hospital in London first linked the condition to Ehlers-Danlos Syndrome (EDS), a group of rare genetic disorders affecting connective tissue. Some EDS patients report resistance to local anaesthesia. Theories include differences in tissue absorption of the drug or variations in nerve location, but no formal investigation has been conducted since a 2005 report.
Hard data on the condition are scarce. Joel Weaver, a dentist anaesthesiologist at Ohio State University, notes that existing studies have not detailed whether infiltration or nerve block techniques fail. The new genetic study of Lemon and her family may shed light on the causes.
