Letters to the editor

A 23-year-old male patient presented to his general dental practice complaining of toothache from the LL6. The patient appeared noticeably pale on entering the surgery, with lips that appeared cyanosed. An examination was carried out, revealing a neglected dentition and generalized bleeding on probing, with the blood taking on an unusual, ‘melted-chocolate’-like appearance. A diagnosis of a peri-apical abscess affecting the unrestorable LL6 was made, and it was agreed with the patient that extraction of this tooth would be required.

The patient completed a standard medical history form on which he stated he had congenital methaemoglobinaemia. When questioned about this condition, the patient stated it was ‘a blood disorder from birth’ and that he knew that this disorder had affected a family member's dental treatment in the past, but did not know more about his condition. After discussion with colleagues, a decision was made to contact the local special care dentistry department, and more light was shed on the situation. They advised that we were right to be concerned about the administration of local anaesthetics in this patient. Administering prilocaine to this patient could potentially have resulted in a serious medical emergency. Further liaison with our special care colleagues has resulted in arrangements to have a ‘local anaesthetic test’ carried out in a secondary care environment. In this setting, standard dental formulations of lidocaine would be administered under anaesthetist supervision, with methylene blue on hand should it be required. Should it be deemed that this can be administered safely, the patient would be discharged back to general dental practice.