19.1 Introduction

Sialorrhea is defined as salivation beyond the lip margin. Sialorrhea is considered normal in infants, and it typically stops in the second year of life. Sialorrhea is considered pathologic when it presents in patients who are 4 years of age or older. Sialorrhea is a common disorder found in adult patients with neurologic deficits (stroke, amyotrophic lateral sclerosis [ALS], Parkinson disease [PD]) and in children and adults who are neurologically impaired (cerebral palsy, mental retardation, etc.). It is predominantly due to poor oral/facial muscular control in combination with hypersecretion, poor posture, and poor occlusion.

In a normal adult, approximately 1.5 L of saliva is produced daily. The six major salivary glands—the bilateral parotid, submandibular, and sublingual glands—produce 90% of the total saliva. Hundreds of minor salivary glands throughout the oral cavity and oropharynx produce the rest. At baseline, approximately 70% of the total production comes from the submandibular and sublingual glands. When fully stimulated, the salivary production can increase five times, with the parotid gland production increasing dramatically. ¹ Saliva is important for oral function and health by lubricating food boluses, providing amylase for initial food breakdown, and preventing local infection through its bacteriostatic and bacteriocidal properties.

The neurologic pathways for salivation arise from the parasympathetic nervous system, which originates its signals in the pons and medulla. The preganglionic fibers synapse in the otic and submandibular ganglions and then travel postganglionically to the parotid gland (via the otic ganglion) and the submandibular and sublingual (via the submandibular ganglion). Sympathetic muscular contraction enhances the expression of saliva when stimulated.

The complications associated with sialorrhea include dehydration, foul odor, and poor oral/perioral hygiene, which can lead to frequent local infections. These complications lead to many psychosocial issues such as isolation, poor social standing, and further dependency of care, and provide barriers to normal socialization (unable to share toys due to excess salivation). As these patients typically have other pressing medical issues as well, sialorrhea is frequently overlooked as a potentially treatable problem. A team approach to sialorrhea, ² including providers from primary care, dentistry, neurology, otolaryngology, and occupational therapy, has been shown to result in improved outcomes.

There are several different etiologies of sialorrhea, often acting in combination: neuromuscular dysfunction, hypersecretion, sensory dysfunction, and motor dysfunction. PD is the most common etiology in adults. Pseudobulbar palsy, bulbar palsy, facial nerve paralysis, and stroke are less common causes. In children, cerebral palsy and mental retardation are the most common etiologies.

Hypersecretion is typically caused by teething, dental caries, or oral infections. Medications, reflux, and toxins are other possible causes of hypersecretion. Poor swallowing function is seen frequently in patients with PD. Anatomic abnormalities such as macroglossia and malocclusion, surgical changes, and neurologic changes such as facial paralysis all can adversely affect oral competence and management of increased secretions.

19.2 Workup

Evaluation of sialorrhea should include a thorough history and physical examination to characterize the severity and frequency as well as measure the degree of detriment to the patient’s quality of life. Noting the characteristics of the drooling—its consistency and flow patterns throughout the daytime on a typical day—is important to help formulate an effective treatment plan.

A comprehensive head and neck examination, with specific emphasis on the neurologic component, is crucial in devising a successful treatment plan. Head position, tongue size, tonsil size, adenoid size, perioral skin condition, dental health, mandibular position, malocclusion, nasal obstruction, and the presence of mouth breathing are important anatomic factors. Neurologic signs such as tongue thrusting, hyposensitive and hypersensitive gag reflex, swallowing inefficiencies, laryngeal hyposensitivity and hypersensitivity, and tongue mobility are very important to note. Flexible nasopharyngeal laryngoscopy is an important component of the examination to fully assess the upper airway for anatomic or neurologic abnormalities.

Sialorrhea can be measured by subjective scales and objective measures (Table 19‑1).

19.3 Anatomy

Sialorrhea predominantly comes from the major salivary glands: the bilateral parotid glands and the bilateral submandibular glands (Fig. 19‑1). The submandibular glands lie superior to the digastric muscles in the anterior neck. There is a superficial and deep lobe associated with each gland, which is separated by the mylohyoid muscle. Typically, the deep lobe contains the majority of the gland. Secretions emanate from the gland and follow Wharton’s duct on the gland’s superior surface, crossing the lingual nerve and traveling anteriorly to drain just lateral to the lingual frenulum in the floor of the mouth.

The parotid glands lie between the zygomatic arch and the angle of the mandible just anterior-inferior to the external ear. It is shaped as a pyramid directed inferiorly. Landmarks near the parotid include the styloid process medially, the posterior belly of the digastrics medially and inferiorly, the mandible anteriorly, and the sternocleidomastoid posteriorly. Three major structures run through the parotid gland: the facial nerve and its associated branches, which separate the superior lobe from the deep lobe of the parotid; the maxillary and superficial temporal artery branches of the external carotid artery; and the retromandibular vein.

Salivary flow from minor ductal structures coalesces in Stensen’s duct and drains medially and anteriorly to the oral mucosal orifice just adjacent to the second upper molar bilaterally.

19.4 Technique

A team approach to the treatment of sialorrhea is typically the most successful. ¹ Occupational therapists and speech pathologists work to improve the swallowing mechanics and help provide posture support through exercises or devices such as the head-back wheelchair. The dentist treats any malocclusion issues as well as oral decay. Orthodontic appliances or customized palate inserts can aid in better oral competence. The primary care and social work team works to improve basic quality-of-life issues that impact the patient. The otolaryngology team works to correct any anatomic abnormalities such as adenotonsillar hypertrophy, nasal obstruction, and macroglossia that may contribute to sialorrhea. Neurologists help identify any neuropathologies associated with sialorrhea to plan appropriate oral medications that would aid in the treatment plan.

When all of the team members have met to discuss the patient’s various problems, an overall plan of treatment is devised with the patient’s input. Treatment options range from conservative (observation, postural changes, biofeedback treatment) to more aggressive measures of medication, radiation, and surgical therapy.

Anticholinergic medications are effective in reducing drooling, but can be limited by side effects. BoNT-A injections into the parotid and submandibular glands are safe and effective, ⁶ but repeat injections are necessary as the effect is temporary. Surgical intervention, including salivary gland excision, salivary duct ligation, and duct rerouting, provides the most effective, permanent treatment of significant sialorrhea to improve the patient’s quality of life. ⁷ Typically, the treatment begins with the least invasive option, and progresses, if necessary, to more aggressive options.

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