Abscesses in Guinea Pigs
An abscess is a localized collection of pus in a cavity formed by the disintegration of cells. Abscesses form when infectious agents (bacteria, fungi, parasites) or foreign bodies (like splinters) lodge in tissue and cause a persistent inflammatory response.
Abscesses are typically filled with a creamy material called pus and can form in any tissue in the body. Clinical changes that may occur vary with the location of the abscess.
What to Watch For
- Signs of focal irritation or pain
- Areas excessively groomed
- Discharge or moistened fur
- Firm or doughy painful mass
- Excessive salivation
- Bad breath
- Facial swellings
- Loss of appetite
- Weight loss
- History and physical examination
- Complete blood count
- Blood chemistries
- Cytology (microscopic evaluation of cells)
- Biopsy and microscopic evaluation of affected tissues
- Culture and antimicrobial sensitivity testing
- Radiographs (X-rays)
Surgical removal of affected tissues or surgically opening the abscess are the most common treatments. Often, the affected area is flushed with sterile saline and/or antimicrobial solutions, which are solutions that kill or suppress the growth of the microorganisms. Additional treatments may include:
- Systemic and local antimicrobial agents
- Fluids and supportive nutrition
Home Care and Prevention
Keep sharp objects away from your guinea pig and keep his living area clean and sanitized. Avoid contact between guinea pigs and other animals that may result in puncture wounds from teeth or nails.
To prevent life-threatening foot infections (pododermatitis), make sure your guinea pig does not become obese, keep the bedding clean and dry and use a soft bedding material.
Prevent your guinea pig from chewing on sharp or fibrous objects that may cut the gums or inside of the mouth or that may splinter and cause penetrating wounds in the mouth.
If your guinea pig is scratched or cut, see your veterinarian as soon as possible, so the wound can be cleaned and treated properly.
Abscesses form when invading infectious agents (bacteria, fungi, parasites) or foreign bodies (like splinters) lodge in tissue and cause a persistent inflammatory response. As part of the body's defense mechanism the immune system stimulates the production of cells and secretions that attempt to "wall off" and destroy invading organisms or foreign bodies. It is a wall of fibrin that creates the borders of an abscess.
Abscesses are typically filled with a creamy material that is usually white, yellow, grey or brown in color. This creamy material is called pus and is formed by the body's attempt to liquefy and remove dead or dying cells. Some abscesses may contain blood or be black in color from degenerating blood cells.
Cysts, tumors, hematomas, fibrous scars and granulomas can cause swellings that appear similar to an abscess. Bot fly larvae may cause swollen areas in guinea pigs housed outdoors.
In guinea pigs, E. coli, Corynebacterium, Pasteurella, Staphylococcus, Actinobacter, Klebsiella, Streptococcus and Mycobacterium avium have all been associated with abscesses. Any foreign body, bacteria, fungus or parasite that can encyst as part of its life cycle could cause an abscess.
Abscesses can form in any tissue in the body like the skin, muscle, walls of blood vessels, liver, lung, heart and brain. The clinical changes that might occur vary with the location of the abscess.
Abscesses in the skin either become encapsulated and slowly resolve, migrate internally, which may lead to septicemia and death, or migrate externally, allowing the pus to be released from the body. The material contained within an encapsulated abscess may be slowly absorbed to a point where only a small knot remains as evidence of the former abscess.
Abscesses in internal tissues either become encapsulated and slowly resolve or rupture. When these internal abscesses rupture, the immune system either cleans up the released debris or this material can cause fatal septicemia. Infections that originate in the middle or internal ear, tooth roots, bone, heart, lungs or nasal sinuses may spread to and cause abscess formation in the brain, which are particularly dangerous.
Abscesses involving the skin, tissue around the eyes or lining of the mouth are recognized by swelling, redness, heat or signs of focal irritation or pain. A deeper abscess should be considered in guinea pigs that excessively groom or constantly scratch at the same area. The sudden moistening of fur with a thick creamy discharge might indicate that a deep abscess has recently ruptured. If this clinical change is noted, seek veterinary attention as soon as possible so that any deep tissue damage can be treated and any infectious material that may still be present in the deeper tissues can be removed.
Abscesses in the lining of the mouth or associated with the teeth may cause excessive salivation and persistent bad breath. Abscesses in the back of the mouth may be associated with difficulty swallowing or difficulty breathing.
Abscesses associated with bacteria and fungi can be life threatening if not treated appropriately and in a timely manner. If the body is not successful in walling off an infectious agent, then the site of a persistent bacterial or fungal infection can be a center for producing millions of infectious organisms (or large quantities of toxins from the infectious organism) that can enter the blood stream and seed infections in other organs or cause system failure and death. Seek veterinary care immediately if a mass is noted, the mass suddenly disappears and the animal becomes acutely depressed or lethargic. These changes could indicate that an abscess has ruptured with the toxic material contained in its center being released into the blood stream.
In well walled-off abscesses, the guinea pig may be clinically normal with no recognizable changes in attitude or blood values. If an abscess is discharging a portion of degenerated cells to the blood stream, then the patient is likely to be feverish, depressed and have an elevated white blood cell count. These clinical changes are similar to those associated with many bacterial, fungal or viral infections.
Infections are most common in crowded conditions where numerous guinea pigs are congregated.
Your veterinarian may do routine diagnostic tests to evaluate the overall health status of a sick guinea pig.
- Radiographs. The most common radiographic change associated with an abscess is a soft tissue mass in the affected tissue. Radiographs may be used to determine if the abscess is associated with an underlying bone, joint or internal organ or if the abscess is undergoing calcification. Radiographs may also be helpful in determining if a foreign body is the cause of an abscess. On an X-ray, cysts, tumors, hematomas, fibrous scars and granulomas can appear similar to an abscess. Ultrasound may be used to determine if a mass is fluid-filled or solid and to determine if a foreign body is present in the mass.
- Complete blood count (CBC). If the abscess is completely walled-off by the immune response, then there may be no changes in the white blood cell count. If the abscess has recently formed or is leaking infectious agents to the general circulation, then there may be a substantial increase in the number of white blood cells (neutrophilia) with or without toxic changes in these cells. In animals that are septic, the white blood cell may be decreased (neutropenia) with a high proportion of immature cells and/or toxic changes. This finding is associated with a poorer prognosis.
- Cytology and culture tests. Confirming the cause of an abscess is best achieved by combining tests: cytology or biopsy, which demonstrates the morphologic characteristics of an organism, and culture and antimicrobial sensitivity. Culture is usually necessary to identify the specific type of bacteria or fungus present in the organism, but cultures from abscesses are frequently negative. Cytology is important in helping to identify the presence of organisms that may be difficult to grow in the laboratory. Cytology and culture of fluid collected from the spinal canal (CSF tap), may be used in patients with suspected infections in the brain or nervous system.
Complete surgical excision of an abscess is best if all of the affected tissue can be removed without causing problems in the animal. If excision is not possible, then as much affected tissue as possible is surgically removed and the wound is left open to facilitate flushing and healing. Depending on the location of the abscess, your veterinarian may or may not place a piece of tubing (called a drain) in your guinea pig.
Additional treatments may include:
- Both local and systemic antimicrobial agents will probably be prescribed for your guinea pig. Depending on ease of administration, your veterinarian may suggest an injectable or oral antimicrobial agent. Long term antimicrobial therapy may be necessary, particularly with fungal infections or when bone is involved.
- Local abscesses are usually treated on an outpatient basis. Guinea pigs with septicemia or with abscesses involving internal organs will probably be hospitalized for the initial treatment period.
- Spaying is recommended in a female with an abscess of the uterus. Castration is recommended if a testicle is abscessed. Abscessed teeth are removed. Amputation of a limb may be necessary when abscesses associated with the feet and legs progress to involve bones or joints.
- Other therapies may include fluids to correct dehydration, vitamin C supplementation, and supportive nutrition if the guinea pig has not eaten for several days or has lost considerable weight.
- Treatment is considered successful when a guinea pig is removed from antibiotics and remains clinically normal.
Optimal treatment for your guinea pig requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your animal does not rapidly improve.
Make certain you administer all prescribed medications at the appropriate time intervals. Contact your veterinarian immediately if you are having difficulties treating your guinea pig as prescribed. If you are having problems, it may be best to hospitalize your guinea pig to assure that a proper course of treatment is administered.
Guinea pigs that are being treated for abscesses should be isolated from other animals to prevent transmission of infectious agents. Caretakers should wear a dust mask when handling the waste of guinea pigs. To reduce dust, use a misting bottle filled with disinfectant to moisten excrement before handling.
For skin abscesses, make certain that the abscess stays open so it will heal from the inside to the outside. If a surgically opened abscess closes over, contact your veterinarian immediately.
Clinical changes associated with an abscess should begin to improve within 24 to 48 hours after the abscess has been surgically opened, and antimicrobial therapy has been initiated. If your guinea pig does not respond within this time period, you should contact your veterinarian. As the abscess heals, it should begin to decrease in size, drainage should decrease, inflammation should decrease and the guinea pig's general condition should improve.