Author: Karen L. McGlothlin, DVM, PhD
Veterinarian: Dr. Crawford
Patient: Samson Hardy
Breed: Labrador Retriever
Age: 12.5 years old
Background: In mid-April of this year, Samson Hardy, 12.5 year old intact male Labrador Retriever, was brought in to see Dr. Crawford. Samson had enjoyed a great weekend: eating well, playing with the children in his family, and running all over the farm. By Monday morning, Samson’s appetite was drastically decreased and he was very lethargic. While Samson was able to walk and to move around without assistance, he was reluctant to do so.
Dr. Crawford gave Samson a thorough physical examination and found him to be running a fever of 104.3. His heart rate was higher than usual, but overall his physical appearance was within normal limits for a dog his age. When Dr. Crawford did a rectal exam on Samson, he seemed to be straining as if he needed to defecate and Dr. Crawford could not palpate is prostate gland at all.
The Hardy’s consented to Dr. Crawford’s request for diagnostics in order to determine the source of Samson’s fever, lethargy, and inappetence. His chemistry panel was unremarkable and his heartworm test was negative, but Samson’s complete blood count had some concerning abnormalities, including an slight non-regenerative anemia and a high white blood cell count consistent with an infection. Samson’s urinalysis revealed that he had a large number of white blood cells, red blood cells, and rod-shaped bacteria. Since Samson is an intact male, Dr. Crawford wanted check Samson’s prostate and since he could not palpate it during a rectal exam, he used ultrasound to visualize the gland. He found that Samson’s prostate gland was greatly enlarged and contained a cavitary center, which is not normal (the prostate gland should be solid in appearance on ultrasound). At that point, Dr. Crawford was able to diagnose Samson’s prostatitis.
What is the Prostate? The prostate gland is part of the male reproductive tract, located near the base of the urinary bladder and surrounding the urethra in the male dog. The prostate gland in a male cat is situated further away from the bladder and does not completely encircle the urethra like it does in the dog, so cats rarely have prostate problems. The prostate gland contributes some of the fluid that forms semen in the male dog and can be affected by four major disorders:
- Benign prostatic hyperplasia or hypertrophy – the most common prostate condition seen in intact male dogs. This condition usually develops in older intact male dogs and is a result of the influence of testosterone levels on the growth of the prostate gland. Dogs with benign prostatic hyperplasia may show no clinical signs and this may be an incidental finding on physical exam. If clinical signs do occur, the dog is not sick, but may develop a bloody urethral discharge, blood in the semen, and/or flat, ribbon-like stools due to the compression of the enlarged prostate gland on the colorectal region of the large intestine. Again, these dogs are not sick and do not respond to antibiotics. The most effective treatment for this condition is castration.
- Prostatitis – an infection of the prostate gland, seen relatively commonly in intact male dogs. This can be seen in intact male dogs at any age but tends to be more common in older males with concurrent benign prostatic hyperplasia. This does not occur, or is exceedingly rare, in neutered males because the prostate gland atrophies after castration. As the prostate gland enlarges, changes occur in the flow of urine and prostatic fluid. Since the prostate gland and urethra communicate via prostatic ducts, bacteria in the urinary tract can get into the prostate gland and become established there, leading to prostatitis and prostate abscesses. These dogs are SICK – usually running a fever, not eating, and lethargic – and prostatitis can be fatal if the infection spreads into the abdomen, causing peritonitis, or becomes blood-borne, causing septicemia.
- Prostatic cancer – typically either adenocarcinoma originating in the prostate gland, or transitional cell carcinoma that has spread from the bladder; although, there can be other types of cancers including leiomyosarcoma and hemangiosarcoma that affect the prostate gland. This is more common in neutered males than in intact males and the prognosis is poor, although medical management may be achieved for a short time. Prostatic enlargement in a neutered dog is almost always due to prostatic cancer.
- Paraprostatic cysts – these are uncommon and are located adjacent to the prostate gland, but not within the gland itself. Paraprostatic cysts are fluid-filled and can become large enough that they look like an additional urinary bladder on x-rays. Problems can occur with these cysts if they become large enough to obstruct urine and prostatic fluid flow.
Back to Samson: Once Dr. Crawford was able to determine the cause of Samson’s clinical signs, he went to work determining the appropriate treatment. With the presence of rod-shaped bacteria in the urine, it was assumed that Samson’s prostatitis was the result of an ascending infection from the urinary tract. The urine was submitted to Idexx Laboratories for urine culture and sensitivity testing to determine which antibiotics would be effective in treating Samson’s infection. Samson was immediately started on an antibiotic, with the understanding that an antibiotic change may be necessary, based on the results of culture and sensitivity testing.
Fortunately, the bacteria causing the infection were sensitive to the antibiotic that Dr. Crawford originally started Samson on and he remained on that antibiotic for 6 weeks. Samson is currently doing well and will be seeing Dr. Crawford for follow up ultrasound of his prostate and to determine additional treatments or procedures.
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