Orchitis (Inflammation of the Testicle) in Dogs

Orchitis is an inflammatory condition of the testes or testicles that can occur in dogs. It may involve one (unilateral) or both (bilateral) testicles and is often associated with epididymitis, which is inflammation of the epididymis, since the two structures are so closely related.

In dogs, orchitis is commonly caused by a bacterial infection where the bacteria enter the testes via the urine, prostatic secretions, blood, mucus membranes or trauma like a puncture wound. Other infectious agents that have been reported to cause orchitis include canine distemper virus, fungal infections (blastomycosis and coccidiomycosis) and tick borne diseases (ehrlichiosis and Rocky Mountain spotted fever).

Trauma to the testicles can also cause an immune mediated orchitis, lymphocytic orchitis, where the body’s own immune system causes the inflammation, and testicular damage.

Orchitis may occur rapidly (acute) or may develop slowly with time (chronic). Intact male breeding dogs or intact male dogs that are allowed to roam free are at increased risk for developing orchitis. Older intact male dogs with a history of chronic prostatic or urinary tract infections are also at risk, as infection can spread into the testicles.

What to Watch For

Symptoms of Orchitis in Dogs may include:

• Swelling of one or both of the testicles
• Testes that feel warm and firm to the touch
• Excessive licking sometimes with associated skin abrasions
• Reluctant to move or walking stiffly
• Loss of appetite
• Fever
• Infertility

Diagnosis of Orchitis in Dogs

A complete physical examination including the palpation of the testicles and prostate is essential. Additional tests may include:

• Complete blood count (CBC)
• Biochemical profile
• Urinalysis with culture and sensitivity
• Brucella canis serum titers
• Blood cultures
• Fungal serology titers
• Cytology (microscopic analysis) and culture of semen
• Testicular aspirate (inserting a needle into the testes and withdrawing a sample of cells via suction with a syringe) with cytology and culture
• Scrotal ultrasound
• Biopsy or castration with histopathology (the microscopic evaluation of a tissue sample)

Treatment of Orchitis in Dogs

• Antibiotic therapy
• Intravenous fluids
• Anti-inflammatory medication or analgesics (medication for pain relief)
• For immune mediated disease, immunosuppressive drugs (drugs that suppress the immune response), such as prednisone are indicated
• Cold compresses
• Castration
• Anti-fungal medication

Home Care and Prevention

If your dog was neutered, the incision should be checked daily for any sign of swelling or discharge. The scrotal sack may be slightly swollen post-operatively, but the swelling should slowly resolve within a week or two. If skin sutures are used, they should be removed in 7 to 10 days. If your dog begins to lick the area excessively, an Elizabethan collar (a collar designed to prevent licking) may be required.

The best prevention for orchitis is castration at an early age. Animals that are not neutered should have recheck evaluations.

More Information on Orchitis in Dogs

Dogs with orchitis present with different clinical signs depending on whether it is an acute (sudden) or chronic (developing slowly over time) condition. Dogs with acute orchitis are usually very painful and act ill. If the orchitis is caused by a bacterial infection, it can lead to septicemia, which is the spread of bacteria into the blood, and which can be life threatening. Testicular abscesses can also form with severe orchitis. Abscesses can become very large and may even break through the skin of the scrotum.

In dogs the most common cause of acute orchitis is infection caused by the bacteria Brucella canis. Other bacteria that can cause orchitis include Staphylococcus, Streptococcus, Escherichia coli, Proteus and Mycoplasma. Sometimes, the bacterial infection occurs slowly, but it is progressive and leads to a scarring of the testicles and infertility. This chronic orchitis is more difficult to diagnose since many animals feel fine, are not painful and have no clinical signs.

Immune-mediated orchitis is also a chronic condition that may occur after trauma, or infection. It occurs once the barrier between the blood and testicular tissue is disrupted. An immune response to the testicle (specifically the animals sperm cells) then causes inflammation and subsequent tissue damage.

Orchitis may also occur due to urinary tract infections. Infections of the prostate gland (prostatitis) or urinary bladder (cystitis) are common routes of transmission due to their close association with the testes (they are connected via the vas deferens). This can lead to either acute or chronic disease. Other diseases that cause similar symptoms as orchitis include:

• Testicular torsion: A testicular torsion is a twisting of the testicle around the spermatic cord, the structure that leads from the abdomen to the testicle and supplies blood to the testicle. This causes the obstruction of blood flow and subsequent testicular enlargement. Testicular necrosis (death of tissue) may even occur. The entire scrotum may be very swollen and firm. A torsion happens very quickly and is extremely painful.
• Testicular tumors: Tumors of the testicle are very common and may be confused with either acute or chronic orchitis. Large painful tumors may seem like the acute disease. Smaller multiple, non-painful masses might be mistaken for the chronic disease.
• Testicular trauma: Blunt trauma to the testicle may cause bleeding within the scrotum leading to an acute swelling. Many times the swelling will resolve on its own, without any therapy.
• Scrotal hernia: A scrotal hernia occurs when abdominal organs or fat slide through the abdominal wall and enter the scrotum. This causes a scrotal swelling. These hernias may be congenital or traumatic.

More Information on Diagnosing Orchitis in Dogs

The diagnosis of acute orchitis is usually strongly suspected on the basis of a good physical examination. Chronic orchitis is usually more difficult to diagnose and may require further testing.

• The complete blood count (CBC) evaluates the red and white blood cell lines. Elevations in the white blood cell are often present with inflammatory or infectious conditions. Many animals with acute orchitis have high white cell counts. A low red cell count indicates anemia and possibly a secondary condition.
• The biochemical profile evaluates the metabolic status of a variety of organ systems. Since orchitis is a more common occurrence on older animals, it is a useful screening test to rule out other problems and or associated disease. Liver and kidney function are evaluated. Blood sugar and electrolytes are also checked to provide a good overall assessment of the general condition of the patient. In dogs with severe acute orchitis and sepsis, hypoglycemia (a low blood sugar) and elevated liver enzymes may be seen.
• Animals with orchitis commonly have urinary tract infections. These infections can be the cause of the testicular infection or a result of the infection. Your veterinarian will check the urine for signs of infection and prescribe an antibiotic for long-term care.
• All dogs with orchitis, either acute or chronic, should be tested for Brucella. The serology blood tests are an easy screening test. The rapid slide agglutination test identifies negative animals with accuracy (but positives need to be rechecked). The tube agglutination test is more specific for Brucellosis, but is still not definitive. Test results should be interpreted with the help of your veterinarian and may need to be repeated.
• Blood cultures are occasionally submitted if a bacterial infection appears to have spread into the blood. Brucellosis is occasionally diagnosed on blood cultures.
• Fungal serology is a blood test that is occasionally useful if a fungal infection is suspected. This is a rare condition, and generally limited to certain geographic locations. Animal with these infections usually have systemic fungal disease (affecting multiple organ systems), and clinical signs relating to more generalized illness.
• Cytologic examination of the semen is useful in confirming a diagnosis of orchitis. The sample is obtained via an ejaculate. Unfortunately, even though this is a good diagnostic test, it is rarely done. Affected dogs with acute disease are generally painful and uncooperative, and dogs with the chronic disease usually have significantly decreased libidos.
• Testicular aspiration will usually show signs of infection, with white blood cells and bacteria seen on cytology. An animal may need to be sedated for the procedure. Testicular abscesses that are aspirated may yield a large amount of purulent (pus filled) fluid.
• An ultrasound may occasionally be useful diagnosing orchitis. It is especially useful for ruling out a scrotal torsion. Animals with a scrotal torsion may be very painful and have a swollen scrotum, thus appearing as if it is orchitis. The ultrasound is a non-invasive test that allows your veterinarian to visualize the structures with in the scrotum. An ultrasound is also used to distinguish between testicular tumors, abscesses and hernias.
• The definitive method of diagnosing orchitis is by biopsy of the affected testicle, and submitting the tissue for histopathic analysis. Almost always, if a biopsy is done it is combined with a castration. This allows for both diagnosis and treatment in a single procedure.

More Information on Treating Orchitis in Dogs

The two major factors are important in deciding the best treatment for orchitis. One is whether the animal is being used for breeding. Breeding animals present a problem, since the orchitis often leads to infertility. Despite therapy, these animals often have damage to the germinal cells of the testes (the cells producing sperm), fibrosis (scarring) of the testicle, and secondary immune destruction of the testicular tissue. These changes may not lead to infertility initially, but over several months, significant decreases in fertility are commonly seen. Additionally if breeding animals are diagnosed with Brucella canis, they should not be used for breeding again since they may be a potential source of infection to other dogs (and rarely for people), despite treatment. Effected animals should be neutered or euthanized.

The other factor to consider when treating orchitis is whether it is an acute or chronic problem. Acute orchitis needs to be treated more aggressively, since the patient is usually in discomfort and is feeling ill. Animals are often brought to the veterinarian as an emergency due to the severe pain, lethargy, or weakness. Treatment may include intravenous antibiotics and fluids, and a longer hospitalization is often needed. With the chronic disease, animals are usually not ill and are brought to the veterinarian either for infertility or chronic intermittent infections. It is generally difficult to improve fertility in these animals. Specific treatment plans include:

• In cases of bacterial orchitis, antibiotics are administered at the first stage of treatment. Ideally, the choice of antibiotics should be based on culture results of the infected testicle. Prior to having the culture results, good antibiotic choices include clavulanate-amoxicillin, enrofloxacin, or trimethoprim-sulfonamide. Animals with Brucellosis are treated with minocycline, tetracycline or doxycycline in addition to an aminoglycoside.
• Intraveneous fluids may be needed in animals with acute orchitis that are either dehydrated, in shock, or septic (bacterial blood infection). Fluid therapy maintains tissue perfusion, blood pressure and circulatory status in the critical patient.
• Anti-inflammatory medication and analgesics may be administered to alleviate pain. Steroids may also be used in cases of immune-mediated orchitis, but at higher, or immunosuppressive, doses.
• Cold compresses help reduce swelling, heat, and the pain that accompanies acute orchitis. This is most useful when attempting to preserve fertility in the breeding animal, since prolonged exposure to the increased heat will lead to long term testicular tissue injury.
• If an animal is not a breeding animal the most effective method of achieving a cure is castration. Castration removes the possibility that an animal will have chronic, recurrent episodes, and allows for the fastest cures. Castration is always advised for the non-breeding animal. In an acute problem the animal should be stabilized first with the appropriate antibiotic and fluid therapy. Once stable, neutering is advised.
  If only a single testicle is involved, and the patient is a breeding animal, a unilateral orchiectomy (the removal of only the affected testicle) may be considered. If treated soon enough, and the inflammation in the scrotum is not too severe, fertility might be preserved allowing the animal to be used for breeding again.
• Anti-fungal medication may be used in the rare event of a fungal orchitis. Generally these animals have systemic (affecting other organs) disease.

Ongoing Care for Dogs with Orchitis

Optimal treatment for your dog requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your dog does not improve rapidly:

• Administer all medications as directed. Alert your veterinarian if you are experiencing problems treating your dog.
• Antibiotics are generally given for at least two to three weeks. The antibiotics may need to be changed based on the results of the cultures taken.
• If your pet was castrated the incision and scrotum should be checked daily for any signs of swelling or discharge. Occasionally blood may ooze into the scrotum post-operatively causing a scrotal hematoma (blood clot). Scrotal hematomas may become quite large and can be painful, but they usually resolve on their own. Occasionally they require surgery.
• If your dog is taking prednisone, the dose will need to be adjusted, by your veterinarian, pending the response to therapy.
• Animals with both acute and chronic orchitis are prone to having repeated episodes of infection if they are not neutered. Recheck physical examinations, testicular palpation and good communication are important parts of continued care.