Successful treatment of self-inflicted oral mutilation using an acrylic splint retained by a head gear.

S elf-injurious behavior (SIB) is defined as deliberate harm to one's own body without suicidal intent. It usually occurs as head banging or hitting, body hitting, skin cutting, or finger biting' and includes ocular, genital, and oral self mutilation. SIB can occur with mental retardation, coma, psychotic problems, poisoning, or character disorders. In pediatric patients, SIB usually is related to: 1) genetic syndromes such as Lesch-Nyhan, Cornelia de Lange, and Gilles de la Tourette syndromes;" 2) mental retardation; 3) congenital malformation; and 4) infectious disease such as encephalitis.The etiology of SIB remains unclear. Psychologic explanations attempt to address an individual's motivation and emotional status during SIB, leading to psychodynamically based psychotherapy and behavior modification.' Animal models and treatment studies suggest the involvement of neurotransmitter dysregulation, including opiatergic, dopaminergic, and serotonergic systems in SIB patients. Precursors or antagonists of these neurotransmitters have been applied as pharmacological therapy in numerous cases. Naltrexone (opiate antagonist)" and L-tryptophan (precursor of serotonin), for example, have been utilized with variable success. Lip and cheek biting have been reported with LeschNyhan syndrome, viral encephalitis, cerebral palsy, and other neurological impairments.--~ Special attention is paid to Lesch-Nyhan syndrome due to its unique destructive pattern. This syndrome arises from deficiency of purine metabolism enzyme hypoxanthine guanine phosphoribosyl transferase (HGPRT). This leads to excessive uric acid production and delayed neurologic development. Patients with Lesch-Nyhan syndrome compulsively bite themselves, but do perceive pain, and feel relieved when restrained. In severe cases, partial or total amputation of the lip and tongue is common. Constant physical restraint and tooth extraction have been recommended to reduce SIB.-' Orthognathic surgery to create an openbite also has been described. Recently, appliances'have been