Tongue - Pathology

()Map ALIMENTARY SYSTEM (Map)

Introduction

See anatomy and physiology of the tongue

Erosive & Ulcerative Pathology

Ulcerative glossitis

• Cat
• Relatively common.
• Youngish to middle age (mainly - although can be any age).
• Unable to eat although wants to. Hurts to open mouth.
• Whole of back of mouth covered in ulcerative granulation tissue.
• Chronic, tends to start at angle of jaw (bilateral), progression quite slow but over weeks affects whole of back of mouth.
• May also affect anatomy and physiology of the tongue.

Pathology

Epithelium lost over whole of mucosa, lots of macrophages, lymphocytes and proliferating fibrous response at base.

Pathogenesis

• Probably viral.
• Calicivirus found in 7-80%, also often find picorna virus and Feline Immunodeficiency Virus (FIV)
• Probably calici virus that starts it.
• Also owners often claim develops after 'having cold' prior to it.
• Calici virus infection may be followed by autoimmune / exaggerated immune response which produces lesions.
• Will heal eventually, but takes time and cat loses lots of condition.

Neutrophilic Inflammation

Liquefactive necrosis

• Introduction of pyogenic bacteria through the protective epithelium can lead to the development of localised liquefactive necrosis (abscesses) anywhere in the soft tissues of the oropharynx.
• These usually follow local trauma, e.g. penetrating foreign bodies.
• The bacteria involved are usually Staphylococci, Streptococci or Arcanobacterium pyogenes.

Granulomatous and pyogranulomatous Inflammation

Actinobacillosis

• "Wooden tongue"
• In cattle - very widespread in world, but rather sporadic, less common now than it was.

Clinical

• Seen in youngish animals in beef breed, especially sucklers on poor forage.
• Starts like foot and mouth disease - dull, salivating (if only one animal is unlikely to foot and mouth). - nearly always sporadic.
• ongue feels like a big lump of wood especially dorsal part of posterior 2/3rds.
• Small areas of ulceration are often found on side of tongue.

Pathogenesis

'Sulpher body' of Actinobacillosis (Courtesy of Alun Williams (RVC))

• Very similar to Mandibular Osteomyelitis ("lumpy jaw").

• Causal agent: Actinobacillus lignieresii (small gram -ve) gets into tongue via small abrasions.
  • Pathogen is very widespread in environment.
• Progressive disease - low virulence but high persistence so animal may stop eating and eventually die but can be treated.

Pathology

Fibrous Stroma - Cut Surface of actinobacillosis affected tongue (Courtesy of Alun Williams (RVC))

• If cut into tongue, substance of tongue changed to fibrous stroma with raised red nodules. (2-3mm across).
• This lesion is a pyogenic granuloma with central sulphur body.
• Can spread from tongue to other tissues e.g. retropharyngeal lymph nodes and palate.
• This type of lesion is caused by the host response to the pathogen, rather than directly a pathogen effect.

Other sites

• Occasionally can see generalised infections but more commonly spreads to local lymph nodes of alimentary tract.
• Organism can be inhaled causing actinobacillus pneumonia.
• Can affect rumen wall.
• In skin forms a neoplastic like mass in dermis.

Fibrinous/Diptheritic Inflammation

• Severe damage to epithelium produces exudation of fibrin -with formation of dry white fibrinous deposit - diptheritic membrane.
• Usually associated with organism fusobacterium necrophorum found everywhere in environment (but strict anaerobe).
• Produces lesions that damage epithelium due to toxin that damages vessels.
• Often a secondary invader but can be a primary pathogen.

Calf diptheria

• Caused by Fusiformis.

Clinical

• Seen in animals kept in cold, damp, muddy conditions.
• Usually associated with poor general health.

• Animals usually less than 6 months old, in groups and poorly kept.
• Lesions affect tongue, inside of mouth and larynx.
• Usually die fairly acutely as exudate blocks airway.

• May occur in young lambs secondary to orf (parapox) virus infection that can spread from lips to the inside of the mouth.

(These lesions then become secondarily infected with Fusiformis.)

• Involvement of the pharynx and larynx may result in dyspnoea and the development of pneumonia.
• May lead to death.

Macroscopically

• Grossly, there is a firm swelling visible on the outer aspect of the cheek
• On the mucosal surface there is a deep, irregular ulcer, covered by a thick diphtheritic membrane.

Microscopically

• There is complete loss of the surface epithelium:
  • a mass of necrotic debris
  • polymorphs and fibrin is found overlying severely inflamed subepithelial tissues in which bacterial colonies may be seen and around which there may be marked fibrosis in an attempt to “wall off” the lesion.

Haemorrhagic Inflammation

• Complete loss of integrity of epithelium. Uncommon.
• Characteristic of “Blue Tongue”, a Reovirus infection of sheep - (v. rare – doesn’t occur in UK !).
• Epithelium lost and haemorrhage produces blue / black discoloration of the tongue, hence the name.

Immune Mediated Pathology

Proliferative Pathology

Neoplastic

Tongue Lymphoma

Tongue Lymphoma - a recognised entity (Courtesy of Alun Williams (RVC))

Traumatic Pathology

Ulcers Following Trauma

• Any animal that is exposed to coarse feed or sharp things in food can suffer from ulcers in mouth.
• They often become secondarily infected with production of metastatic infection that may result in large abscess on point of jaw.
  • i.e. trauma on tongue may lead to secondary infection that may lead to abscess in drainage lymph node.

• Deep ulcers may occur as a result of trauma in any species.
• These readily become secondarily infected by Fusiformis.
• Produces a fibrin-covered ulcer.
• Responds to antibiotics, but may leave a defect or scar in mucosa.

See also Tongue Trauma Clinical Page

(Other)

Fungal

• Fungal infections are relatively rare but do occur.
• The best known is infection with the yeast Candida albicans which causes thrush.

Learning Tools

Tongue Flashcards