Veterinary Clinical Medicine-I (General and Systemic)

Mucous membrane and its clinical significance

MUCOUS MEMBRANES

• Examination of the visible mucous membranes is of great clinical importance as it reflects the general condition of the animal as well as certain disease conditions (e.g. jaundice in case of liver diseases).
• The visible mucous membranes are oral, nasal, conjunctival mucous membranes and vaginal mucous membrane in females.
• Changes in color may result from disturbance in oxidation process of the blood, disturbances in blood circulation or of certain other disease conditions.
• Noticeable changes in mucous membranes include changes in color, presence of exudates and swelling.

Changes in color

• The normal color of the visible mucous membranes varies between species.
• In general, different shades of pink (light pink, pink or rosy red) are considered normal depending on the species (please refer to your practical session tutor for details).
• The following changes occur in various diseases:
  • Anaemic mucous membranes
    • Blood loss anaemia
    • Parasitic infestations leading to haemolysis
    • Tumours or leucosis
    • Iron deficiency anemia
    • Long-standing infectious diseases
    • Exposure to X-rays and some medications
  • Congested mucous membranes
    • High environmental temperatures and exercise
    • Any disease resulting in fever
    • Diseases of the heart, brain and its membranes
  • Yellowish or icteric mucous membranes
    • Icterus of jaundice occurs due to increase of blood bilirubin concentration (blood parasites, leptospirosis, hepatitis, cholangitis, cholecystitis and cholangiohepatitis).
    • Infectious anaemia and contagious pleuropheumonia of horses.
    • Chronic gastric dilatation.
  • Cyanosed mucous membranes
    • Bluish discoloration of visible mucous membranes resulting from presence of reduced haemoglobin in blood capillaries.
    • Myocarditis, pericarditis.
    • Plant and mineral intoxications.

Swelling of mucous membranes

• Inflammation of mucous membranes results in its swelling; in which case the mucous membranes may also be hot and tender (i.e. showing cardinal signs of inflammation).
• Marked swelling of conjunctival mucous membranes is characteristic of equine influenza.
• A slight degree of swelling is noticed in contagious pleuropneumonia of horse and cattle plague, anthrax and fowl diphtheria.

Presence of exudate

• Escape of serous fluid and fibrinogen from blood vessels, which also contains desquamated epithelial cells, leukocytes and erythrocytes.