Makindo Medical Notes

Note: Being NBM (nil by mouth) does not mean no oral fluid intake is allowed, as saliva is still produced and swallowed.

Anatomy

• Parotid Gland: Releases a watery serous fluid.
• Submandibular Gland: Produces a mixed secretion, predominantly seromucinous (a combination of serous and mucus fluid).
• Sublingual Gland: Also releases seromucinous fluid. There are also numerous minor salivary glands scattered throughout the oral cavity.

Saliva Production

• Approximately 1-2 liters of saliva are produced per day.
• Salivation Stimulation: Controlled by the salivary nuclei in the brainstem, through signals from the facial (VII) and glossopharyngeal (IX) nerves.
• Salivation Inhibition: Sympathetic stimulation and anticholinergic drugs (e.g., atropine) can reduce salivation, leading to dry mouth (xerostomia).

Saliva Function

• Taste and Lubrication: Helps in dissolving food for taste sensation and lubricates the food for easier swallowing.
• Speech: Aids in articulation and speech production by moistening the oral cavity.
• Oral Health: Maintains oral hygiene by preventing drying of mucosa and has antimicrobial properties.
• pH Balance: Slightly alkaline, maintaining oral pH and protecting teeth from decay.
• Prevents Tooth Decay: By washing away food particles and neutralizing acids produced by bacteria.
• Other Functions: Saliva plays a role in human interactions, such as kissing, which promotes emotional bonding.

Saliva Composition

• 99.5% Water and Mucus
• Amylase (an enzyme that starts the breakdown of starch)
• Lysozymes (antimicrobial enzymes)
• Immunoglobulins (IgA)
• Electrolytes (such as sodium, potassium, calcium, chloride)

Pathology

• Infiltration: Diseases such as Sjögren's syndrome, sarcoidosis, and others can infiltrate salivary glands, leading to dysfunction.
• Salivary Gland Tumors:
  • Pleomorphic Adenoma: The most common benign salivary gland tumor, typically affecting the parotid gland. Presents as a painless mass; treatment is resection.
  • Warthin's Tumor: A benign tumor often affecting the parotid gland, sometimes bilateral. Treatment is resection.
  • Mucoepidermoid Carcinoma: A malignant salivary gland tumor. It can be high or low grade, often presenting with facial nerve (VII) involvement and lymphadenopathy. Resection is the treatment if feasible.
  • Adenocarcinoma: Another malignant type, often with facial nerve involvement and lymphadenopathy. Resection is the treatment of choice.
• Parotid Swelling: May be associated with:
  • Liver disease or alcohol abuse
  • Sarcoidosis (Mikulicz syndrome when both salivary and lacrimal glands are swollen)
  • Sjögren's syndrome
  • Lymphoma
  • Malignancy (worrying signs include facial nerve palsy on the same side)
• Parotitis: Inflammation of the parotid gland.
  • Bacterial: Often due to poor oral hygiene, dehydration, or salivary duct stones. Common organisms include Staphylococcus aureus.
  • Viral: Mumps is a common viral cause, often associated with orchitis (inflammation of the testes).
• Xerostomia (Dry Mouth): Caused by:
  • Medications (e.g., anticholinergics, antidepressants, lithium)
  • Sjögren's syndrome
  • Radiation therapy
  • Dehydration or renal failure
  Complications: Increased risk of dental caries and oral infections such as candidiasis.
• Sialadenitis: Inflammation of the salivary glands.
  • Bacterial: Common pathogens include Staphylococcus aureus and Streptococcus species.
  • Viral: Often seen in viral infections like mumps.
  • Sarcoidosis: Salivary gland involvement may occur in systemic sarcoidosis, known as Heerfordt's syndrome (uveoparotid fever).
• Mikulicz's Syndrome: Enlargement of both salivary and lacrimal glands, often associated with autoimmune conditions like Sjögren's or sarcoidosis.