5.4 LOWER URINARY TRACT: PROSTATIC DISEASE
Diseases of the prostate are rare in cats but are common in older dogs and all may
present with similar histories and clinical signs:
Secondary complications include prostatitis (common in older dogs and one possible
cause of intractable haematuria) and perineal rupture. It is important to differentiate
benign hyperplasia (which is common) from prostate neoplasia (carcinoma) which is
less common and life-threatening. Paraprostatic cysts are also seen occasionally
and these may complicate the diagnosis. Radiography, ultrasound and physical examination
are all useful diagnostic aids which can be further reinforced by prostatic washes
pain - caudal abdomen on palpation or movement and on defaecation
straining - on defaecation or urination
dysuria - common in humans but not very common in dogs.
If prostatic carcinoma is suspected, survey radiographs should be performed to identify
evidence of metastatic spread, especially to the lungs, and also to bone and lymph
nodes Surgical removal can be difficult but is successful in providing remission
in some cases. Usually it is combined with castration. I have had some success with
surgical excision and cryoon tissue that is difficult to resect locally.
For prostatic hyperplasia, castration with or without therapeutic agents such as
stilboestrol is indicated. In old dogs that are an anaesthetic risk, medical treatment
alone may be necessary.
Paraprostatic cysts (often there are more than one lying alongside the urinary bladder)
are difficult to manage, there being no medical therapy, and surgical techniques
such as excision and marsupialisation to provide permanent drainage being reported
to have mixed success. I prefer to attempt surgical resection.
Prostatitis can be difficult to treat and quite often antibiotic therapy has to be
continued for 6-8 weeks. Ideally the antibiotic of choice will be based upon culture
and sensitivity tests and it is important that the diagnostic laboratory test for
sensitivity is based upon urine concentrations of the drug and not just the blood
concentrations achieved. A history of chronic haematuria or urinary tract infection
in male dogs should always suggest the possibility of prostatitis.
There are three main differential diagnoses of prostatic disorders in old dogs (see
Other, less common, prostatic disorders include prostatic cysts and trauma. Aids
to diagnosis include: