Week 8 Lesson 64 Common Disorders of the Oral Cavity

Systems 2: Digestion, Metabolism, and Nutrition

Lesson #64: Common Disorders of the Oral Cavity

Instructor: Dr. Muhammad BhaiyatInstitution: St. George's University, School of Veterinary Medicine, Grenada, West Indies

Common Disorders of the Salivary Glands

Learning Objectives

1. Portals of Entry/Pathways of Spread:

   • Describe how pathogens enter and spread in salivary glands and the implications of such infections.

2. Defense Mechanisms:

   • Understand the defense and barrier systems of salivary glands that protect against pathogens.

3. Lesion Identification:

   • Identify and categorize lesion types affecting domestic animals' salivary glands, focusing on their clinical relevance.

4. Responses to Injury:

   • Explain how salivary glands adapt and respond to various types of injuries.

5. Pathogenesis:

   • Describe the different types of disorders in salivary glands, including inflammatory, degenerative/obstructive, and neoplastic conditions.

Dysfunction/Responses to Injury

• Caustic Substances:

  • Can lead to chemical erosions or ulcerations of oral mucosa, significantly affecting the animal's ability to eat and drink. Mucous membranes generally heal quickly, but significant damage may require medical intervention.

• Antibiotic Use:

  • Antibiotics may disrupt the normal flora in the oral cavity, leading to overgrowth of opportunistic pathogens such as yeast, resulting in conditions like oral thrush.

• High Blood Glucose Levels:

  • Conditions like diabetes can lead to colonization by sugar-loving organisms, causing issues like Candida infections and impacting overall health.

Portals of Entry/Pathways of Spread

• Mucosal Impact:

  • Anything in the oral cavity, including food and pathogens, can impact the mucosa, potentially leading to infection or inflammation.

• Oral Infections:

  • Oral infections are rare due to effective oral secretions and epithelial barriers that usually prevent the establishment of pathogens.

• Mechanisms of Spread:

  • Mechanical penetration allows pathogens to spread within submucosal tissues and reach vascular and lymphatic channels, complicating the clinical picture.

• Multiplication Conditions:

  • Some pathogens require specific surfaces or lymphoid tissues to multiply effectively. For example, small lacerations in the oral cavity can introduce bacteria leading to systemic diseases like listeriosis, impacting the overall health of the animal.

Defense Mechanisms/Barrier Systems

• Physical and Chemical Barriers:

  • Stratified Epithelial Surface:

    • Provides resistance to trauma and irritants, protecting underlying tissues.

  • Taste Buds:

    • Serve to reject toxic materials based on taste, preventing ingestion of harmful substances.

  • Microbiota:

    • Occupy attachment sites in the oral cavity, preventing colonization by pathogenic organisms, thereby protecting the host.

  • Saliva:

    • Serves multiple functions, including a flushing action that removes pathogens from the oropharynx and forming protective mucosal coatings. Saliva contains antimicrobial enzymes (e.g., lysozyme, IgA) that play a crucial role in oral hygiene.

Categories of Lesions

Identification of Lesion Types

• Developmental Anomalies:

  • Conditions that occur due to developmental disruptions during embryogenesis.

• Inflammation:

  • Represents the body's response to harmful stimuli and can manifest in various forms.

• Disturbances of Growth:

  • Conditions that disrupt normal cellular proliferation and differentiation.

• Hyperplasia:

  • An increase in the number of cells within a tissue or organ, which can lead to enlarged structures.

• Neoplasia:

  • Abnormal tissue growth that may be benign or malignant.

Developmental Anomalies

Major Conditions

• Palatoschisis (Cleft Palate):

  • A congenital condition characterized by the failure of fusion of lateral palatine processes, resulting in a communication between oral and nasal cavities.

  • Etiology: genetic factors, toxic exposure, teratogenic agents.

  • Potential complications: include failure to suckle, leading to starvation, and aspiration pneumonia due to nasopharyngeal reflux of food and liquids.

• Cheiloschisis (Cleft Lip):

  • Incomplete fusion of the frontonasal process, commonly observed in rabbits as a “hare lip.” This condition can lead to cosmetic and functional issues affecting feeding.

Inflammation

Types of Inflammation

• Stomatitis (pl. Stomatitides):

  • Inflammation of the oral mucosa, which can manifest in several forms including gingivitis, and various vesicular, erosive, ulcerative, necrotizing, eosinophilic, and chronic types.

  • Clinical Impact: constant bombardment by ingested substances can lead to erosions and ulcerations, resulting in pain, difficulty eating, and systemic infections.

  • Etiology: Infectious agents such as viruses, chemicals, trauma, and autoimmune diseases can lead to these conditions.

Inflammation Etiology

• Infectious Agents:

  • Viral infections, chemical injuries, toxic materials, and systemic diseases can all contribute to oral inflammation.

  • Clinical Signs: include anorexia, hypersalivation, and gingivitis, with specific associations noted in feline immunodeficiency virus (FIV) in cats.

Erosive and Ulcerative Stomatitis

Characteristics

• Multiple ulcerated spots on buccal mucosa varying in size, often causing significant pain and discomfort.

Causes

• Predominantly viral infections (e.g., BVD, MCF), uremia, trauma, and chemical damage that may lead to severe clinical outcomes.

Neoplasia

Oral Tumors Identification

• Identification of oral tumors is crucial, particularly in distinguishing malignant from benign growths.

• Common Types:

  • Squamous Cell Carcinoma: characterized by a high malignancy rate in aged cats; aggressive and often metastasizes.

  • Melanoma: most common oral tumor in dogs, usually malignant and can be very aggressive.

  • Papilloma: typically benign and may regress spontaneously in young animals.

  • Fibrosarcoma and Osteosarcoma: both exhibit malignancy with a dire prognosis and require prompt intervention.

Tongue: Another Area of Interest

Dysfunction/Responses to Injury

• The tongue plays a key role in mixing saliva with food and is essential for taste sensation, which is critical for swallowing reflex. Changes in tongue health can drastically affect feeding behavior and overall nutritional intake.

Portals of Entry

• Epitheliotropic Viruses:

  • Infectious agents targeting epithelial tissue can cause damage leading to severe dysphagia (difficulty swallowing) and intense pain, affecting the quality of life.

Defense Mechanisms of the Tongue

• Anatomical Structure:

  • Thick squamous epithelium acts as a robust barrier against xenobiotics and pathogens, though certain infectious agents can compromise its integrity.

Glossitis

Manifestations and Causes

• Glossitis is characterized by inflammation of the tongue and is often associated with systemic diseases and opportunistic infections, such as oral thrush, which may occur due to antibiotic treatment or underlying immunocompromised states.