Polysomnographic studies of Lesch-Nyhan syndrome

Severe Respiratory Acidosis in Status Epilepticus as a Possible Etiology of Sudden Death in Lesch-Nyhan Disease: A Case Report and Review of the Literature

INTRODUCTION

Lesch-Nyhan disease (LND) is an X-linked disorder of purine metabolism, associated with self-mutilation, dystonia, and chorea. Seizures are uncommon in LND. Patients with LND are at risk for sudden and unexpected death. The etiology of this is unknown, but appears to occur from a respiratory process. We propose that respiratory failure secondary to subclinical seizure may lead to sudden death in these patients.

CASE

We report a case of an 11-year-old boy with LND who had two episodes of nocturnal gasping. The second event was immediately followed by a 10 min generalized seizure. Upon arrival at the hospital, an arterial blood gas test revealed a severe respiratory acidosis. Following aggressive treatment of his seizures, this patient did well, and was discharged home on oxcarbazepine with rectal diazepam. No further seizures have been noted in 1 year of follow-up.

CONCLUSIONS

In this case report and review, we hypothesize that sudden death from respiratory failure in Lesch-Nyhan disease may in some cases be due to seizure-induced respiratory failure, akin to sudden unexpected death in epilepsy (SUDEP). We suggest screening for paroxysmal respiratory events; consideration of electroencephalography for patients with LND presenting in respiratory distress or failure; and consideration of more aggressive treatment of seizures in these patients. Brief Summary:We present an 11-year-old boy with Lesch-Nyhan disease (LND) who developed respiratory failure and severe respiratory acidosis from his first known seizure, which evolved to subclinical status epilepticus. We propose that patients with LND have a predisposition to respiratory failure and sudden death, which in some cases may be provoked by seizure (sudden unexpected death in epilepsy, or SUDEP).

Sudden death in Lesch-Nyhan disease

To increase awareness of sudden and unexpected death in Lesch-Nyhan disease (LND) and to explore its potential causes, we report the anteceding clinical features and laboratory evaluations of five males with LND who ultimately experienced sudden and unexpected death, along with three additional males who suffered serious respiratory events during life. The ages of patients ranged from 2 to 45 years. The cause of sudden death in LND appears to have a respiratory rather than a cardiogenic basis. All cases cannot be linked readily with a single respiratory process. Instead, different respiratory processes appear to operate in different cases. These may include aspiration, laryngospasm, central apnea, cyanotic breath-holding spells, and high cervical spine damage. Better recognition of these processes will help to guide appropriate workup and management that could include chest imaging, endoscopy of the airways, polysomnography, electroencephalogram, and brain and/or spine imaging.

Neurotransmitter changes in the pathophysiology of Lesch-Nyhan syndrome

The neurological symptoms of Lesch-Nyhan syndrome (LNS) are assumed to result from the neurotransmitter changes in this disorder. Among them, the dopaminergic system is believed to play a role in the self-injurious behavior through receptor supersensitivity. However, the precise mechanism underlying the dopamine supersensitivity remains unclear. An increased serotonergic action in the striatum may be crucial for the appearance of self-injurious behavior, and pharmacological evidence suggests the efficacy of serotonin agonists/antagonists for the treatment of the self-mutilation in LNS.