Do you assume that if your dog is straining to defecate they have simple constipation?
It is one possibility but not the only one. For example, your dog can strain to poop for the opposite reason —diarrhea. Sometimes, however, the problem can be even more serious.
Luca, a neutered eight-year-old Shetland Sheepdog, was having difficulty with his bowel movements.
His new dog walker noticed that Luca was straining and squatting for extended periods without passing stool. Further, while Luca’s first-morning pee appeared normal, repeated attempts to “go,” with only dribbles followed.
When hearing this from the dog walker, Luca’s owner couldn’t believe it. Luca had a good appetite, was acting normally at home, with no sign of malaise. He checked with the previous dog walker, who, on reflection, confirmed Luca had been doing this for a while.
It hadn’t registered that there was a problem.
Luca’s owner brought to a veterinary hospital examination and assessment. As it turned out, Luca’s painful defecation and periods of straining during urination traced back one to two months.
A digital rectal exam revealed a startling situation. There was a large, palpable bilobed mass consistent with an enlarged prostate.
This is most unusual in a dog that was neutered as a puppy.
Was this a prostatic tumor, prostatic hyperplasia, a prostatic cyst, or a prostatic infection? The doctors knew further investigation and diagnostics were necessary.
Radiographs revealed an abnormal soft tissue mass in the pelvic canal at the entrance to the pelvic inlet. Further, the bone on the floor of the pelvic canal was not as smooth as it should be. Instead, it was raised and rough, indicating reactive bone.
It was necessary to obtain samples for urinalysis and cytology, preferably in a non-invasive manner. Placing the gathered proved challenging but the veterinarian was able to acquire both urine and a prostatic wash for analysis.
Unexpectedly, there was a gush of blood from the penis following the removal of the catheter. Blood was also visible in the urine sample.
The odds of prostatic cancer were high. But, as Luca was comfortable, his owner decided to take him home with the prescribed antibiotics and await the test results.
The cytology results were ambiguous, revealing cells that represented inflammation but were not abnormal enough to be cancer. It was time for ultrasound imaging.
The ultrasound revealed the following areas of concern:
- The prostate was an enlarged irregular mass, showing mineralized tissue within.
- The bladder contained bits of dense material consistent with tiny stones and polypoid mucosa that stem from a developing tumor
- Nodules were found throughout the liver tissue, the pattern suggesting something sinister. They could represent Hyperplastic bile ducts, a benign process. Or it could be a secondary neoplasia metastasized from the prostate.
- Early changes in his gallbladder consistent with a mucocele (inflammation of the gallbladder with mucus build-up in its walls).
The veterinarian was able to insert the ultrasound probe into Luca per rectum, thus visualizing the prostate. He then passed a catheter through to the prostatic urethra, intending to collect cytology. Although gently advanced, the catheter penetrated through the friable and weak urethral wall and into the prostatic parenchyma. As a result, cores of solid tissue samples were collected from a urinary catheter.
The pathology results confirmed what all of the doctors had suspected. Sadly Luca had prostatic carcinoma.
This type of cancer grows rapidly. It likes to invade nearby tissues and spread to local, lymph nodes and bone, liver, and lungs. In dogs, the behavior of prostatic cancer results in rapid progress and a poor outcome; in humans, progress and prognosis are much different.
Luca’s veterinarian consulted with an oncologist who offered the following treatment options.
The first would be surgical removal of the prostate to minimize the volume of cancerous tissue. The second would be radiation, the third chemotherapy. The fourth would be a combination of the previous three.
The risks of surgery are many. The side effects of the treatments might be harsh and make the dog feel sick and uncomfortable. Even with these treatments, the prognosis is poor, often only buying a matter of a few months. Luca’s veterinarian spoke with Luca’s owners and offered a referral to a local oncologist. The owners decided that conservative treatment and palliative care would be best for the dog and the family.
Facing the diagnosis of prostatic carcinoma and inevitable poor prognosis, Luca’s owners passed on further tests.
Luca’s pain originated from the pressure of the stool moving through the colon over the inflamed prostate.
Luca went home with medications, a low residue diet, and lots of TLC.
Difficulty Defecating in Dogs: Why Is My Dog Straining to Poop?
Prostate Cancer in Dogs