The Treatment of Posterior Drooling by Botulinum Toxin in a Child with Cerebral Palsy

Abstract

Drooling is the unintentional loss of saliva from the mouth, known as anterior drooling (1). However, anterior drooling has to be distinguished from posterior drooling which refers to saliva that is spilled over the tongue through the faucial isthmus. Under physiological conditions this initiates the pharyngeal phase of swallowing, during which the larynx closes to protect the airways followed by relaxation of the upper esophageal sphincter. Whenever the trigger to swallow is impaired or missing, pooled saliva may lead to posterior drooling mostly apparent from an alarming congested breathing, coughing, gagging, vomiting, and at times aspiration into the trachea. Unrecognized and silent pneumonia can occur (2). The risk of posterior drooling can be enhanced by the fact that many disabled children are taken care of in a supine position for a substantial part of the day. Many children with cerebral palsy (CP) suffer from gastroesophageal reflux (3). In healthy subjects, exposure of the distal esophagus to acid results in an immediate increase of saliva secretion. The possible function of this is that swallowed saliva plays a role in the defense of esophageal mucosa to acid–induced injuries. Reflux in children with CP causes stimulation of pH-sensitive receptors in the mucosa of the distal esophagus which activates the esophageal-salivary reflex leading to an increase of salivary flow rate (3,4). This may exacerbate anterior and posterior drooling. Botulinum neurotoxin (BoNT) injections in the salivary glands in the treatment of anterior drooling demonstrate promising efficacy (5–8). This case report summarizes the results of repeated bilateral single-dose BoNT injections into the submandibular glands in a patient with CP with severe drooling, aspiration, and recurrent pneumonia. The primary treatment intention was to decrease salivary flow in an effort to reduce anterior as well as posterior drooling.