Lesch-Nyhan syndrome: a treatment planning dilemma.

The characteristic self-mutilation behaviors of patients with Lescl~Nyhan syndrome are detailed. The behavorial manifestations and dental management of five cases are discussed with emphasis on the lack of viable treatment choices other than extraction. Some suggestions for categorizing the mutilative behaviors have been presented together with possible treatment choices of each group. Lesch-Nyhan syndrome results from an inheritable error of purine metabolism, in which characteristic self-mutilative behavior presents a major problem for the dentist. ’.~ The disorder affects only males and results in overproduction and accumulation of large amounts of uric acid in body fluids, which if untreated, usually leads to renal failure and death in early childhood. Recently, it has been found that treatment of this disorder with allopurinol returns uric acid levels to normal concentrations, dramatically increasing the life expectancy of the patient. Even with normal uric acid levels, the self-mutilative and other associated behaviors of these children remain unchanged. These behaviors and the dilemma they present to the clinical dentist in planning treatment will be the main thrust of this discussion. Clinical Manifestations A major characteristic of the syndrome is severe mental retardation, although most of these patients appear more capable than test scores indicate. These children usually relate well to people, and seem to understand what is said to them. Most communicate adequately through affirmative or negative responses to questions, although speech is severely dysarthric. All of the patients have cerebral palsy with severe spasticity. The characteristic extensor spasms of the trunk are increased by tension or excitement. The self-mutilative behavior is thought to begin with the eruption of teeth; patients then begin to bite themselves. This behavior continues, resulting in partial or total destruction of the perioral tissues, especially the lower lip and to a lesser extent, the upper lip. Partial or complete amputation of the fingers, nose and tongue are also common. The characteristics of the self-mutilative behavior in Lesch-Nyhan syndrome appear to be phenotypical and differ from similar behaviors in other patients. For example, mutilation of the lips occurs in Conelia DeLange syndrome but is much less severe. Loss of tissue is rare, apparently accidental, and the behavior is easily extinguished, using aversive techniques which are not effective in Lesch-Nyhan syndrome. The pattern of mutilative behaviors seen in children with sensory neuropathies such as congenital insensitivity to pain is also quite different. The damage is definitely accidental and these patients have been described as looking like pugalists. In addition, many autistic children and some other mentally retarded children occasionally display selfmutilative behaviors which likewise differ from those observed in Lesch-Nyhan patients. Head banging and hitting are common, with biting rarely observed; therefore, hypertrophy and callous production, not loss of tissue, usually appears in the area of trauma. The dramatic and extremely rapid loss of tissue is a hallmark of Lesch-Nyhan syndrome. Unquestionably, these patients do perceive pain. They usually cry out when biting themselves as if against their will. They are usually relaxed when restrained and when restraints are removed they become very agitated and often scream until restraints are replaced. Biting is not the only source of mutilation: many other actions create perioral damage. Most common is the rubbing of soft tissue between a tooth and some hard surface, a bed sheet, or even the fingers. The PEDIATRIC DENTISTRY: Volume 4, Number 2 127 damage due to trauma together with superimposed infections produces rapid tissue loss. Extension thrusts of the body, causing the head to bang against a hard surface may also cause injury to the patient, but more commonly cause injury to others. This aggression towards other people is a secondary but important facet of behavior in this syndrome. Behavior modification measures have been disappointing in coping: with the self-mutilative behaviors observed in this syndrome. Mild aversive techniques have proven generally ineffective, and more severe aversive techniques have actually increased the frequency of these maladaptive behaviors.3Extinction techniques have :produced mixed results although several programs show some promise and reinforce the concept that the self-mutilative behaviors have some conscious component along with their compulsive aspects. There are, however, serious attendant risks of severe mutilation associated with some extinction programs2 Chemical approaches to modification of mutilative behavior have likewise experienced mixed results. Allopurinol will lower uric acid levels to normal but does not affect the neurological or behavioral aspects of the disease. The use of hydroxytryptophan together with decaboxylase inhibitor has proven effective in reducing or eliminating the self-mutilative behavior for short periods of time with certain patients. Results with this and other drugs thus far have been promising but preliminary. Physical restraints have been the sole reliable resource for preventing self-mutilative behavior. Cloth body restraints, cloth mittens, and plastic arm splints have all been useful in reducing the frequency of injury. However, even with restraints, selfmutilation can and often does occur. Dental Literature Review Although Nyhan says that next to phenylketonuria, Lesch-Nyhan syndrome is the second most common inborn metabolic disorderJ very little has appeared in the literature concerning the dental managemelat of these cases. Budnick~ describes two cases; the first required no dental treatment because an extreme anterior open bite prevented lip hiring, and, the second utilized selfcuring acrylic splints on both upper and lower arches which were successful in preventing lip biting after a splint for the lower arch only was found to be unsuccessful in this regard. These splints required modification and recementation during the mixed dentition period. Eudnick also suggested that covering only the posterior teeth, creating an anterior open bite, might also be helpful. Cudzinowski and Perreault ~ described one case in which all primary teeth were extracted in serial fashion with local anesthestic. This approach apparently eliminated further mutilation, although no follow-up concerning the permanent dentition was described. Shoptow and Reznik ~ described three cases, all having anterior and posterior primary and permanent teeth serially extracted to prevent mutilation. The success of this approach can be described as mixed, since significant mutilation occurred prior to extraction.