What is the relationship between swallowing and the parotid (parotid gland)?

From the Guidelines

The parotid gland plays a crucial role in the swallowing process by producing saliva that moistens food and initiates digestion, and its dysfunction can lead to difficulty swallowing, highlighting the importance of optimal parotid gland function for comfortable swallowing. When you swallow, the parotid glands, which are the largest of the salivary glands located in front of each ear, secrete saliva containing amylase enzyme through Stensen's duct into the oral cavity. This saliva helps form food into a bolus, making it easier to swallow. The parotid glands are stimulated both by the physical act of chewing and by the parasympathetic nervous system through the glossopharyngeal nerve (cranial nerve IX).

Disorders affecting the parotid gland, such as sialadenitis (inflammation), sialolithiasis (stones), or Sjögren's syndrome, can reduce saliva production and cause difficulty swallowing (dysphagia) 1. Treatment for these conditions may include increasing fluid intake, using sialagogues like lemon drops to stimulate saliva flow, medications such as pilocarpine for severe dry mouth, or surgical intervention for stones or tumors. Maintaining good oral hygiene and staying hydrated are essential for optimal parotid gland function and comfortable swallowing.

Some key points to consider in the context of parotid gland function and swallowing include:

• The importance of saliva production for moistening food and initiating digestion
• The role of the parotid gland in producing saliva containing amylase enzyme
• The potential consequences of parotid gland dysfunction, including difficulty swallowing and dysphagia
• The need for optimal parotid gland function for comfortable swallowing, as highlighted by the potential consequences of dysfunction, including aspiration pneumonia, dehydration, and malnutrition 1. It is also worth noting that, according to a recent study, passive drooling is the most commonly used method for collecting saliva, and it provides whole, “mixed,” resting-state saliva comprising saliva from all of the major salivary glands, including the parotid gland 1.

From the FDA Drug Label

In a 12 week randomized, double-blind, placebo-controlled study in 207 patients (placebo, N=65; 5 mg, N=73; 10 mg, N=69), increases from baseline (means 0.072 and 0.112 mL/min, ranges -0.690 to 0.728 and -0.380 to 1. 689) of whole saliva flow for the 5 mg (63%) and 10 mg (90%) tablet, respectively, were seen 1 hour after the first dose of pilocarpine hydrochloride tablets. Increases in unstimulated parotid flow were seen following the first dose (means 0.025 and 0.046 mL/min, ranges 0 to 0.414 and -0.070 to 1. 002 mL/min for the 5 mg and 10 mg dose, respectively).

• Pilocarpine can increase salivary flow and parotid gland secretion.
• The effect of pilocarpine on parotid gland secretion is dose-related, with higher doses resulting in greater increases in unstimulated parotid flow.
• Pilocarpine can stimulate saliva production in patients with Sjogren's Syndrome and head and neck cancer.
• When swallowing, patients taking pilocarpine may experience increased salivary flow and parotid gland secretion, which can help with dry mouth symptoms 2.

From the Research

Parotid Gland and Swallowing

• The parotid gland is the salivary gland most commonly affected by inflammation 3, 4.
• Infections of the parotid gland can range from acute to severe and can be caused by various factors, including bacterial, viral, and obstructive etiologies 4, 5.
• The most common bacteria associated with acute bacterial parotitis are Staphylococcus aureus and anaerobic bacteria 3, 4.

Diagnosis and Management

• Diagnosis of parotitis should differentiate local primary parotid infection from systemic infection 4.
• Assessment of the disease process should include history, clinical examination, salivary volume and chemistry, and imaging studies such as computerized tomographic scan and sialography 6.
• Treatment of parotitis can include conservative measures such as antibiotics, warm compresses, massage, sialogogues, and adequate hydration 7, 5.
• Sialendoscopy is a minimally invasive option for the diagnosis and management of chronic inflammatory disorders of the salivary glands and offers the option of gland and function preservation 7, 5.

Complications and Prevention

• Predisposing factors to suppurative infections include dehydration, malnutrition, oral neoplasms, immunosuppuration, sialolithiasis, and medications that diminish salivation 4.
• Early and proper antimicrobial therapy may prevent suppuration 4.
• Maintenance of good oral hygiene, adequate hydration, and early and proper therapy of bacterial infection of the oropharynx may reduce the occurrence of suppurative parotitis 3.