Causes and risk factors
It is caused by bacteria Pasteurella multocida. This bacterium is a normal inhabitant of many animals, especially domestic dogs, cats, and sheep. Most commonly, infection is acquired by bites, scratches, or licks of dogs and cats. Close contact with these animals can also cause the disease. However, in up to 15 per cent of the cases, no known animal contact occurs. In these cases, most commonly respiratory tract is involved. Droplet infection, food water contamination can lead to the disease.
Clinical presentation
After animal bite, infection progresses rapidly causing following symptoms – pain, local redness [erythema], swelling. There is purulent discharge from the wound. Fever may occur. Lymphangitis, local lymph node swelling [lymphadenopathy] may occur. Patients who are not exposed to animals may still get infected. These patients generally have preexisting chronic respiratory disease and are prone to develop conditions like acute pneumonia, tracheobronchitis, and empyema. Lung abscess can occur occasionally. It can also cause eye infection, GI infection, lung abscess, meningitis, septicemia in severe cases.
Investigations
Medical history by the patient and clinical examination by the doctor helps in diagnosis. Usually there will be a history of animal bite. Investigations like bacterial culture of the wound is recommended for detecting the organism. Sample is obtained from wound or respiratory tract.
Treatment
Treatment involves proper wound care. Thorough cleaning and debridement of wounds is crucial. Never suture animal bite wound as it increases chances of infection. Antibiotics are required.
Complications
If ignored, infection may set in. Abscess, sepsis, necrosis of the affected part can occur. Osteomyelitis, septic shock, septic arthritis may occur. Meningitis also can occur.
When to Contact a Doctor
One must consult a doctor as soon as one gets animal bite.
Prevention
People who have been bitten by a cat should be given vaccine to prevent Pasteurella multocida infection. Animal bites, especially cat bites, should not be sutured.
Systems involved
Integumentary system, circulatory system, respiratory system, CNS, lymphatic system
Organs involved
Skin, blood vessels, lymph nodes, brain, lungs.
