Infection and Inflammation

Infection and Inflammation

• Infection: invasion of the body by harmful microorganisms (viral, bacterial, parasitic, or fungal)
• Inflammation: complex response to harmful stimuli, characterized by five cardinal signs:
  • Pain
  • Heat
  • Redness
  • Swelling
  • Loss of function

Inflammatory Cells

• Part of the body's natural defense response to injury or disease
• Part of the immune system
• Examples:
  • Macrophages
  • Lymphocytes
  • Neutrophils
  • Eosinophils
  • Basophils
  • Mast cells

Bacterial Infections of the Oral Mucosa

• Can be divided into two categories:
  • Oral Granulomatous Diseases
  • Non-Oral Granulomatous Diseases

Oral Granulomatous Diseases

• Examples:
  • ANUG (Acute Necrotizing Ulcerative Gingivitis)
  • Noma (Cancrum oris)
  • Gonorrhea
  • Tuberculosis of the Oral Cavity
  • Actinomycosis
  • Syphilis
  • Leprosy

ANUG (Acute Necrotizing Ulcerative Gingivitis)

• Definition: acute inflammatory process of the gingiva characterized by ulceration and necrosis of the gingival margin
• Causative organism: fusiform bacilli, Bacteroides, and spirochetes (Vincent's organisms)
• Predisposing factors:
  • Local factors: alcohol, tobacco, poor oral hygiene, pre-existing gingivitis
  • Systemic factors: psychological stress, poor diet, immunocompromised status
• Clinical features:
  • Necrotic punched-out or crater-like ulcerations on interdental papilla and marginal gingiva
  • Grayish pseudo-membrane covering the ulcers
  • Halitosis, gingival bleeding, pain, and foal odor
  • Excessive salivation and bad metallic taste
• Treatment:
  • Removal of local irritating factors
  • Antiseptic mouth rinse (Chlorhexidine Gluconate)
  • Antibiotic regimen (Penicillin and Metronidazole)

Noma (Cancrum oris)

• Definition: destructive, disfiguring, necrotizing disease affecting the orofacial tissues
• Affects children, particularly in developing countries, who are malnourished or debilitated
• Preceded by ANUG, followed by rapid spread of necrosis
• Histopathological and bacteriological features similar to ANUG
• Early diagnosis and treatment of ANUG can prevent the development of Noma

Gonorrhea

• Definition: venereal disease transmitted by sexual intercourse
• Causative organism: Neisseria gonorrhea
• Oral manifestations: asymptomatic to painful, including generalized erythematous stomatitis, ulceration, burning sensation, and difficulty swallowing

Tuberculosis of the Oral Cavity

• Definition: chronic specific granulomatous bacterial infection
• Causative organism: Mycobacterium tuberculosis (Acid-fast bacteria)
• Clinical features:
  • Primary lesion rare, usually associated with coughing-up of infected sputum from pulmonary tuberculosis
  • Chronic, irregular, indurated, painful ulcer affecting tongue, buccal mucosa, palate, and lips
  • Mucosa shows fissuring and swelling
• Histopathological features:
  • Microscopic examination reveals granulomatous inflammation (tubercle)
  • Central caseous necrosis
  • Collections of epithelioid histiocytes, lymphocytes, and multinucleated Langhans giant cells

Actinomycosis

• Definition: chronic suppurative granulomatous bacterial infection
• Causative organism: endogenous bacteria, especially Actinomyces israeli and/or Actinomyces bovis
• Predisposing factors:
  • Local factors: poor oral hygiene, periodontal pocket, or after tooth extraction or jaw surgery
  • Systemic factors: immunocompromised patients with malignancies, HIV, diabetes, or steroid use
• Clinical features:
  • Two types: Peripheral Actinomycosis (solitary, firm, indurated swelling) and Central Actinomycosis (chronic actinomycosis osteomyelitis)
  • Lesion begins as asymptomatic firm swelling, and later breaks down forming sinuses and discharging pus containing sulfur granules
• Treatment:
  • Incision and drainage
  • Long-term penicillin-based antibiotics

Syphilis

• Definition: chronic, specific granulomatous bacterial infection
• Causative organism: spirochete Treponema pallidum
• Classification:
  • Acquired syphilis (3 stages: primary, secondary, and tertiary)
  • Congenital syphilis
• Primary stage:
  • Incubation period: 2-3 weeks
  • Characterized by the formation of Chancre
  • Regional lymphadenopathy, unilateral, rubbery, and discrete
• Secondary stage:
  • Highly contagious
  • Appears 6-8 weeks after disappearance of Chancre
  • Characterized by the formation of mucous patches and condyloma latum
  • Systemic manifestations: skin rash, fever, enlarged lymph nodes, fatigue, weight loss, hair loss, and headaches
• Tertiary stage:
  • Appears 2-3 years after infection
  • Oral manifestations: gumma, diffuse syphilitic glossitis, and diffuse syphilitic osteitis
• Histopathological features:
  • Central coagulation necrosis
  • Surrounded by chronic inflammatory cells (lymphocytes, macrophages, and plasma cells)
  • Fibroblasts for the synthesis of fibrous tissue

Leprosy

• Definition: chronic infectious disease produced by Mycobacterium leprae (Acid-fast bacilli)
• Classification:
  • Two forms: tuberculoid leprosy (limited form with low-virulence bacilli) and lepromatous leprosy (generalized form with high-virulence bacilli)
• Clinical features:
  • Oral lesions: multiple necrotic and ulcerated nodules with slow healing and atrophic scarring
  • Cutaneous lesions: erythematous plaques or nodules
  • Severe maxillofacial deformities
  • Damage to peripheral nerves
• Histopathological features:
  • Granulomatous inflammatory response
  • Epithelioid histiocytes and multinucleated giant cells
  • Infiltration of nerves by mononuclear inflammatory cells
  • Well-formed granuloma in tuberculoid leprosy, similar to that of TB
  • Poorly formed granuloma with sheets of macrophages in lepromatous leprosy