Prostatitis is a bacterial infection of the prostate gland. Infection of the prostate may be caused by disease of the urethra (the small tube where urine flows from the bladder through the penis), other urinary tract infections, or may be secondary to a more serious prostatic disease. This disease occurs more commonly in male dogs who have not been neutered. Older dogs are at greater risk than younger dogs. Prostatitis can occur in an acute (sudden) and chronic (long standing) form; however, animals with the acute form are generally more debilitated than with the chronic form.

Sign and Symptoms

Clinical signs of prostatitis vary with the severity of the infection and whether the disease is acute or chronic. The following symptoms could indicate the presence of this condition:

  • fever
  • cloudy or bloody discharge from the penis
  • blood in the urine
  • abdominal discomfort
  • stiff gait
  • weakness
  • lethargy
  • straining to urinate or defecate
  • anorexia
  • vomiting
  • weight loss
  • chronic intermittent urinary tract infections
  • infertility in a breeding male

Diagnosis

If your dog exhibits any of the above symptoms, take him to your veterinarian. Your vet will check your dog's history and most likely perform a physical examination including the following:

  • digital rectal exam
  • urinalysis
  • check the culture and sensitivity of the urine
  • cytological (microscopic) evaluation of seminal or prostatic fluid
  • prostatic massage and wash for cytology, culture and sensitivity
  • abdominal radiographs (x-rays)
  • abdominal ultrasound with or without prostatic aspiration
  • clotting profile
  • complete blood count
  • biochemical profile

Possible Causes

The most common cause of prostatitis is believed to be ascending infection from the urethra. The prostate can also become infected from infections in the bladder, kidneys or blood. If other forms of prostatic disease are present, such as cysts, neoplasia or squamous metaplasia, the prostate may be predisposed to developing a secondary infection. E. coli is the most common bacterium that causes infection.

There are actually two different clinical presentations of prostatitis in the dog: acute and chronic. These two forms of the disease often present very differently, and require a different clinical work-up and different therapy. In acute prostatitis, animals are usually quite ill and may even require emergency care. Animals are usually feverish and may have significant abdominal pain. Some dogs may even shows signs of a critical blood infection (septicemia). On the other hand, dogs with the chronic disease are generally much more stable or sometimes exhibit no clinical symptoms.

Other diseases that may cause similar clinical signs as prostatitis

Urinary Tract Infections - bacterial infections of the urinary bladder or kidneys may cause blood in the urine, fever and abdominal pain. It is not uncommon for an animal to have a urinary tract infection together with prostatitis.

Prostatic Abscess- an abscess is a walled off pocket of infection containing white blood cells, bacteria and cellular debris. Abscesses occasionally form within the prostate gland in cases of chronic prostatic infections. They may get to be quite large and cause compression of both the colon and urethra. Animals may be straining when they defecate or urinate, and most animals will feel ill.

Benign Prostatic Hyperplasia (BPH) - BPH is the most common form of prostatomegaly (increased prostate size), with virtually all intact (not neutered) male dogs; who generally acquire the condition as they age. BPH is caused by an increase in the number and size of the prostate cells as the intact dog ages and is exposed to normal hormonal influences. This is a benign condition that usually does not cause any clinical signs. Occasionally a urethra discharge is present, which can be bloody. The majority of the time this condition is found incidentally on routine physical examinations. Dogs with chronic prostatitis sometimes have very similar signs.

Prostatic Neoplasia (cancer) - may closely mimic chronic prostatitis. Animals with prostatic neoplasia tend to be systemically ill, and have a history of weight loss. Tumors of the prostate are almost always malignant. The most common tumors involving the prostate are adenocarcinoma and transitional cell carcinoma. Most other types of prostatic disease, and prostatic cancer occur with the same frequency in both intact and neutered dogs.

Squamous Metaplasia - is a change in the prostate gland due to elevated blood estrogen levels. The main cause of this is an estrogen-producing tumor, such as a Sertoli cell tumor. Long-term oral estrogen supplementation can also cause these changes. Sertoli cell tumors can also cause a chronic debilitating disease due to the suppressive effects of estrogen on the bone marrow.

A complete history and physical examination is the first step in obtaining an accurate diagnosis. An intact male dog with a fever, pain in the area of the prostate, and blood or pus in the urine has a high percentage of having acute pancreatitis. Dogs with acute prostatitis are usually quite ill and their prostate is generally painful. The diagnosis is usually more apparent in the acute condition and may require fewer diagnostics than in the chronic disease.

Achieving a diagnosis of chronic prostatitis is more difficult as there are less consistent clinical signs. In chronic prostatitis, it is even typical that there is no prostatic pain. The diagnostic evaluation and potential results vary significantly depending on whether or not the disease is acute or chronic.

Treatment

The treatment for prostatitis varies depending on whether the disease is acute or chronic. Acute prostatitis is a much more critical condition than chronic prostatitis and requires more immediate and aggressive care. When evaluating a dog for chronic prostatitis, it is generally appropriate to wait until a definitive diagnosis has been established prior to beginning therapy. In this way, appropriate antibiotic therapy may be started based on culture and sensitivity results. This may not be an option in some of the acute cases since the animal may require emergency treatment before the diagnostic test results are back.

The decision as to when to begin therapy depends on the clinical assessment of the patient. In general, a more rapid treatment is required for the acute disease, and a longer treatment course is needed for the chronic condition. Although animals are sicker with the acute disease, it is generally easier to achieve a complete cure than with the chronic disease. Dogs with chronic prostatitis are more likely to have a continued intermittent problem despite therapy. Chronic prostatitis is a difficult disease to cure.

Antibiotics are typically given for a minimum of four weeks. Intravenous fluids may be required in acute prostatitis cases, along with analgesic or pain medications, and in some instances neutering may also be recommended. Antibiotics that are effective include: erythromycin, clindamycin, chloramphenicol, trimethoprim/sulfonamide and the quinolones.

Home Care and Prevention

Recheck examinations 7 to 14 days later are strongly suggested, as follow-up prostatic palpation is recommended. Abnormal blood tests should also be re-evaluated. The urine or a sample of the prostatic fluid may also need to be re-cultured at this time.

Make sure the urine color is becoming more clear if it was an abnormal color when your pet was ill. Your pet should continue to improve on therapy at home, but relapses may occur, especially with chronic disease. If there is any deterioration in condition, or recurrence of clinical signs, notify your veterinarian immediately.

Your veterinarian may also recommend that cultures of the urine and or prostatic fluid might be recommended after finishing the antibiotics to be certain the abnormal condition no longer exists. Neutering a dog before reaching sexual maturity may help decrease the incidence of prostatitis.