Canine prostatic diseases

Prostatic diseases such as benign hyperplasia, prostatic cysts, acute bacterial prostatitis, chronic bacterial prostatitis, prostatic abscessation, and prostatic neoplasia are discussed. Also discussed are diagnostic techniques such as prostatic palpation and massage, evaluation of semen and urethral discharge, and radiography.     

Effects of castration on chronic bacterial prostatitis in dogs

An Escherichia coli bacterial prostatitis was experimentally induced in dogs to determine the effect of castration on chronic bacterial prostatitis. Two weeks after instillation of bacteria directly into the prostate gland, 17 of 22 adult mixed-breed male dogs had positive urine or prostatic fluid cultures or both. Seven of the 17 dogs were randomly chosen to be castrated, and 10 of the 17 served as sham-operated controls. At weekly intervals, urine was obtained from 17 dogs for aerobic microbiologic culturing. At each week, dogs with no bacterial growth in the cultured urine had prostatic fluid collected for aerobic microbiologic culture. Dogs with negative urine, prostatic fluid, and prostatic tissue needle biopsy culture results at week 7 were euthanatized. For remaining dogs, weekly cultures were continued until the dogs were euthanatized at week 12. None of the 7 castrated dogs and 6 of the 10 dogs subject to sham operation had prostatic infection at the time of necropsy. The castrated dogs had a mean infection duration of 4.2 weeks, which was statistically shorter than the 9.5-week mean duration of infection in the sham-operated controls. Cultures of prostatic tissue obtained immediately after euthanasia correlated 100% with urine and prostatic fluid cultures taken before euthanasia. All of the 6 dogs with positive prostatic cultures at termination had moderate to marked lymphoplasmacytic chronic prostatitis. The 11 dogs that were not infected at the end of the study had normal to moderate lymphoplasmacytic chronic prostatitis on histologic examination.(ABSTRACT TRUNCATED AT 250 WORDS)     

RELATIONSHIP BETWEEN PROSTATOMEGALY, PROSTATIC MINERALIZATION, AND CYTOLOGIC DIAGNOSIS

Canine prostatic disease is commonly evaluated with abdominal ultrasound and radiographs. Mineralization of the prostate is often reported, but the clinical relevance of this finding is currently not known. The purpose of this study was to characterize the relationship between ultrasonographic and radiographic prostate mineralization and the final diagnosis. Medical records of 55 dogs with evidence of prostatomegaly or prostatic mineralization and a cytologic diagnosis were evaluated. Radiographs and ultrasound images were assessed for caudal retroperitoneal lymphadenopathy, vertebral lesions, or other signs of metastasis, and mineralization was assessed semiquantitatively. Twenty-two of 55 (40%) dogs had prostatic neoplasia. Regarding neoplasia, mineralization in neutered dogs had a positive predictive value (PPV) of 100%, a negative predictive value (NPV) of 50%, and a sensitivity and specificity of 84% and 100%, respectively. Mineralization in intact dogs had a PPV of 22%, an NPV of 96%, and a sensitivity and specificity of 67% and 77%, respectively. All neutered dogs with prostatomegaly but not prostatic neoplasia had bacterial prostatitis and were castrated within the previous 3 months. Intact dogs with prostatomegaly and mineralization but not neoplasia had paraprostatic cysts ( n =3), benign prostatic hyperplasia ( n =2) or prostatitis ( n =2). Mineralization score was not indicative of neoplasia. In conclusion, neutered dogs with prostatic mineralization were very likely to have prostatic neoplasia. Intact dogs were unlikely to have prostatic neoplasia if no mineralization was found on radiographs or ultrasound.     

Canine subclinical prostatic disease: histological prevalence and validity of digital rectal examination as a screening test

The present study investigated the histological prevalence of subclinical prostatic disease in a canine mixed-breed population. The reliability of digital rectal examination (DRE) as a screening test for subclinical prostatic disease was also evaluated. DRE was performed on 500 male dogs (age range 1 to 21 years) before the dogs died of diseases not related to the prostate. Necropsies of these dogs were performed and prostates were collected for histological evaluation. The overall prevalence of subclinical prostatic disease was 75.6%. The most prevalent subclinical prostatic diseases were benign prostatic hyperplasia (BPH) (44.8%), prostatitis (23.6%) and prostatic neoplasia (3.6%). The prevalence of subclinical BPH and prostatic neoplasia increased with age but that of prostatitis was not influenced by age. The prevalence of subclinical BPH and prostatitis were higher in intact than castrated dogs. DRE had a high specificity (75%) and positive predictive value (87%), but a low sensitivity (53%) and negative predictive value (34%).     

Effects of an extract of Serenoa repens on dogs with hyperplasia of the prostate gland

OBJECTIVE: To determine effects of an extract of Serenoa repens on dogs with prostatic hyperplasia. ANIMALS: 20 mature male dogs with benign prostatic hyperplasia. PROCEDURE: Dogs were assigned to 3 comparable groups on the basis of prostatic volume per kg of body weight and degree of prostatic hyperplasia determined histologically. Dogs in 2 groups were treated for 91 days (8 received 500 mg, PO, q 8 h [1,500 mg/d], and 6 received 100 mg, PO, q 8 h [300 mg/d]). The control group of 6 dogs did not receive medication. Effects of treatment on prostatic volume, prostatic weight, prostatic histologic characteristics, radiographic and ultrasonographic assessment of prostatic size, results of CBC, serum biochemical analyses, and urinalysis, serum testosterone concentration, and semen characteristics were determined. At the termination of the study, all dogs were euthanatized, and necropsies were performed. Investigators conducting tests and interpreting results were not aware of treatment group of each dog. RESULTS: Treatment did not affect prostatic weight, prostatic volume, or prostatic histologic scores, libido, semen characteristics, radiographs of the caudal portion of the abdomen, prostatic ultrasonographs, or serum testosterone concentrations. Results of CBC, serum biochemical analyses or urinalysis, and body weights did not change during treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Treatment with an extract of S repens for 91 days did not significantly affect the prostate gland of dogs. Adverse effects were not evident. Although products containing extracts of S repens are widely advertised for men with prostatic hyperplasia, beneficial or harmful effects of this plant extract were not found in dogs with prostatic hyperplasia.     

Clinical approach to prostatic diseases in the dog

In small animal practice, prostatic diseases are increasingly encountered. All dogs may experience prostatic disease, but particular care should be addressed to breeding dogs, in which prostatic affection may lead to decrease in semen quality and fertility. The most common prostatic disease is the benign prostatic hyperplasia (BPH) followed by prostatitis, prostatic neoplasia and prostate squamous metaplasia. These diseases do not have pathognomonic symptoms, therefore, making a correct diagnosis may not be easy. An accurate clinical examination and a correct diagnostic protocol are essential in order to begin the most appropriate treatment, and also to do a good prophylaxis where it is possible. BPH therapy is usually recommended when mild‐severe signs are present or if symptoms disturb the patient. New therapeutic approaches, both medical and surgical, allow to maintain fertility in most animals with prostatic disorders. Prostate cancer is relatively infrequent. Elective therapy is the surgical one, but it is considered palliative and can result in important post‐operative complications. The aim of this paper is to lay down the most appropriate diagnostic process describing the aetiologies of prostatic disease, their symptoms, the right investigative tools and therapy.     

Study of prostatic disease in dogs: 177 cases (1981-1986).

Historical and physical signs associated with prostatic disease diagnosed in dogs over a 5.5-year period were defined. One hundred seventy-seven male dogs were determined to have prostatic abnormality. Of the 177 dogs, 87 were determined to have specific prostatic disease. The most common prostatic disease identified in this study was bacterial prostatitis, followed by prostatic cyst, prostatic adenocarcinoma, and benign hyperplasia. The most common prostatic disease identified in neutered dogs was prostatic adenocarcinoma. Mean age at onset of prostatic disease was 8.9 years; statistically significant difference was not observed between age at onset of the various types of prostatic disease identified. Doberman Pinscher was the most common breed with prostate disease. Twenty-nine percent of dogs with a specifically identifiable prostatic disease had signs of systemic illness, 41% had signs of lower urinary tract disease, 28% had signs of gastrointestinal tract abnormalities, and 13% had signs of locomotor difficulty.     

Evaluation of Serum and Seminal Plasma Markers in the Diagnosis of Canine Prostatic Disorders

Serum and seminal plasma concentrations or activities of acid phosphatase (AP), prostate specific antigen (PSA), and canine prostate specific esterase (CPSE) were measured in normal dogs, dogs with benign prostatic hyperplasia (BPH), dogs with bacterial prostatitis, and dogs with prostatic carcinoma to determine if these assays would be of value in differentiating dogs with prostatic carcinoma from normal dogs, and dogs with other prostatic disorders. In addition, tissue sections of prostatic adenocarcinomas were stained with antiprostatic AP, anti-CPSE, and anti-PSA antibodies to determine if these would be suitable immunohistochemical markers of prostatic carcinoma. Prostate-specific antigen was not detected in canine serum or seminal plasma. Serum and seminal AP activities did not differ significantly between normal dogs and those with prostatic diseases, or among dogs with different prostatic disorders. Serum CPSE activities were significantly higher in dogs with BPH than in normal dogs. Mean serum CPSE activities in dogs with BPH, bacterial prostatitis, and prostatic carcinoma were not significantly different from each other. Slight to moderate immunohistochemical staining of canine prostatic adenocarcinomas was noted for prostatic AP and PSA; most tumors did not stain for CPSE. These results show that proteins of prostatic origin appear in the serum of dogs as a result of prostatic pathology, especially BPH. Canine prostatic adenocarcinoma does not appear to be associated with significant increases in CPSE or AP activities, possibly because of down-regulation of these enzymes by prostatic carcinoma cells. It is also possible that failure to detect significant differences resulted from limited statistical power for some groups and pairwise analyses because of the small number of dogs evaluated.     

Lymphoreticular lesions in beef cattle at an ontario abattoir

During the period April 1983 to March 1986, lymphoreticular lesions in cattle were surveyed at an Ontario abattoir. Postmortem examination of 171,157 cattle revealed macroscopic lesions in 696 animals (0.4%). The most frequent finding was abscessation of a single lymph node, a finding that was observed in 353 cases (50.7% of animals with lesions/0.2% of total slaughter). Actinobacillary granulomas were present in 252 lymph nodes (36.2%/0.1%). Other specific lesions included mycobacteriosis and mycotic or parasitic lymphadenitis. Cases of nonspecific chronic lymphadenitis or granulomas in lymph nodes, pigmentations, malformations, hyperplasia, and neoplasia were also seen. Abscesses were the most common splenic lesions. One animal had localized lymphangiectasia of the epicardium.     

Comparison of two sample collection methods for quantitative bacteriologic culture of canine prostatic fluid

Ejaculate, urine, urethral swab specimens, and ultrasonography-guided small-needle prostatic cyst aspiration and/or tissue core biopsy specimens were collected for bacteriologic culture from 25 dogs in which prostatic disease was suspected on the basis of history, clinical signs of disease, or results of physical examination. The prostate gland in each dog was examined ultrasonographically, and the tissue core biopsy specimens were examined histologically and bacteriologically. Two methods were used to assess bacterial prostatitis. In 5 dogs (20%), bacteriologic culture results of paired urethral swab and ejaculate specimens differed from culture results of specimens obtained by needle aspiration of prostatic cyst fluid or tissue core biopsy. The prostate gland in 17 dogs had 1 or more cystic, fluid-filled structures (0.5 to 4.0 cm in diameter). Ultrasonographic appearance of the prostate gland did not have obvious correlation with culture results from dogs of the study. Histologic results of prostatic tissue core biopsy specimens correlated well with culture results.     

Canine prostatic disease--comparison of radiographic appearance with morphologic and microbiologic findings: 30 cases (1981-1985)

A retrospective analysis was made of radiographs from 24 clinically normal young adult male Beagles used in previously reported base-line research on the distal male urinary tract. The ventrodorsal and craniocaudal prostate gland dimensions were measured, as visualized on the lateral radiographic view, and expressed as a ratio of the distance between the cranial aspect of the public bone and the sacral promontory. In 17 of these 24 dogs, there was sufficient image clarity to permit confident measurement of prostatic dimensions. From these data, the largest acceptable prostatic dimension, as visualized on the lateral radiographic view, was 70% of the public-promontory distance. A retrospective analysis was made of 30 cases of canine prostatic disease, with the objective of identifying the radiographic (survey and distention retrograde urethrocystogram) appearance most often associated with the various spontaneous prostatic diseases. Prostatomegaly was not specific for the cause of prostatic disease, except if the apparent parenchymal dimensions were greater than or equal to 90% of the public-promontory distance wherein neoplasia, abscess, and paraprostatic cysts (readily differentiated from diffuse intraparenchymal disease by ultrasonography) were the principle considerations. Multifocal, irregularly shaped, parenchymal mineral densities were observed only in dogs with prostatic carcinoma (4/7 cases) or prostatitis (1 case of chronic prostatitis). Narrowing of the prostatic portion of the urethra was observed only in association with abscess, neoplasm, or noninflammatory nonneoplastic disease (possibly benign hypertrophy/hyperplasia), whereas widening of this part of the urethra was not observed.(ABSTRACT TRUNCATED AT 250 WORDS)     

PROSTATIC REFLUX DURING POSITIVE CONTRAST RETROGRADE URETHROGRAPHY IN THE DOG

Forty-five positive contrast retrograde urethrograms in which contrast medium reflux into the prostate was identified were evaluated to determine whether a correlation existed between the time and pattern of reflux and the nature of the prostatic disease. Prostatic diseases identified included prostatitis (25 dogs), prostatic tumor (13 dogs), and prostatic hyperplasia (1 dog). Six dogs with contrast medium reflux had no evidence of prostatic disease. No correlation was found between presence of prostatic reflux and specific prostatic diseases; however, prostatic tumor or infection was observed more frequently than hyperplasia, metaplasia, or cyst in the dogs with contrast medium reflux. A linear pattern and irregular, indistinct margination of the contrast medium reflux were associated with prostatitis; however, these patterns were also observed in dogs without prostatic disease     

Cytology of the canine reproductive system

The methods for semen collection, its laboratory examination, and the interpretation of findings are presented in this article. The lack of comprehensive data for normal dogs and the lack of data associating actual percentages of spermatozoa with specific abnormalities with fertility or infertility are highlighted. Consequently, there is a need for standardization and completeness of semen examination procedures, especially in studies destined for publication. Collection and analysis of prostatic samples then is discussed, and the distinguishing cytological features of benign prostatic hyperplasia, prostatic adenocarcinoma, prostatis (including prostatic abscessation), and prostatic cysts are presented. This is followed by an assessment of the clinical usefulness of vaginal cytology, particularly to assist in the management of normal canine reproduction and in the diagnosis of reproductive disorders. The ways in which vaginal smears can facilitate the diagnosis of the stage of the estrous cycle and the diagnosis of abnormalities of the cycle and other disorders of reproduction are presented. Further consideration is given to its use to estimate the time of ovulation retrospectively and estimate the time of whelping prospectively. Finally, two specific diseases that can affect dogs and bitches are reviewed, namely, canine brucellosis and transmissible venereal tumor.     

Canine prostatic fluid: techniques of collection, quantitative bacterial culture, and interpretation of results

Specimens of prostatic fluid were collected by ejaculation from 104 dogs after collection of a specimen of urethral contents and after collection of a urine specimen by antepubic cystocentesis. For purposes of data analysis, results of bacterial culture of the specimens were grouped according to individual colony counts in each specimen group (ie, urine, urethra, prostatic fluid). For purposes of this study, prostatic infection was defined as greater than or equal to 2 log10 of one or more bacterial species in prostatic fluid over the number of colonies of the same species in the paired urethral specimens.     

Effects of bacterial infection and castration on prostatic tissue zinc concentration in dogs

An Escherichia coli bacterial prostatitis was experimentally induced to determine the effect of bacterial infection on prostatic tissue zinc concentrations in castrated and gonadally intact male dogs. Five of the 22 mixed-breed dogs (group 1) had no culture evidence of infection 2 weeks after the instillation of bacteria into the prostate gland. The remaining 17 infected dogs were allotted to 2 groups; 1 group of dogs was subjected to castration (group CA, 7 dogs), and the other group of dogs was subjected to sham operation (group SO, 10 days). The groups were divided into groups of dogs with prostatic infection at necropsy (groups CA-I and SO-I), and those dogs without prostatic infection at necropsy (groups CA-N and SO-N). Urine, prostatic fluid, and prostatic tissue (week 0, 7, +/- 12) specimens were obtained for bacteriologic culturing to determine whether prostatic infection was present. Prostatic tissue was obtained at necropsy (week less than 6, 7, or 12) for analysis of zinc concentration by atomic absorption spectrophotometry. The logarithmic mean prostatic tissue zinc concentrations were compared between groups. Group CA had a significantly lower prostatic zinc concentration than all other groups. Zinc concentrations were not statistically different between any of the other groups. Castration did decrease the prostatic tissue concentration of zinc, a known natural antibacterial factor. However, resistance to infection and resolution of infection were not correlated with prostatic tissue zinc concentrations in this experimental model.     

Surgical management of perineal paraprostatic cysts in three dogs

Three intact male dogs were presented with faecal tenesmus and obvious perineal swelling. All three animals had paraprostatic cysts originating within the abdominal cavity and extending caudally through the pelvic canal, causing perineal swelling. Two of the dogs were found to have concurrent benign prostatic hyperplasia, while the third had chronic active prostatitis. This report describes the investigations, surgical management and outcome for the three dogs presented.     

Transurethral resection in the management of urethral and prostatic neoplasia in 6 dogs

OBJECTIVE: To assess cystoscopic transurethral resection (TUR) for the palliative management of dogs with neoplastic infiltration of the urethra. STUDY DESIGN: Prospective clinical trial. ANIMALS: Six client-owned dogs. METHODS: Cystoscopic examination and electrosurgical TUR were performed in dogs with urination difficulties caused by prostatic or urethral neoplasia. TUR was performed in a retrograde manner in female dogs and antegrade in male dogs via exploratory celiotomy and ventral cystotomy. Cystoscopic examination was used to determine the extent of neoplastic involvement of the urethra. TUR involved piecemeal removal of neoplastic tissue from the urethral lumen using an electrocautery cutting loop. Hemorrhage was controlled with a cystoscopic cauterized roller-ball. In 2 male dogs, intraoperative radiation therapy (IORT) was used to treat both prostatic neoplasia and the sublumbar lymph node bed. Surgical technique, complications, adjuvant treatment, and outcome were recorded. RESULTS: TUR was performed in 3 male dogs with prostatic carcinoma and 2 female dogs with urethral transitional cell carcinoma (TCC). In 1 female dog, TUR was attempted but not successful because of cystoscope diameter. Iatrogenic urethral perforation occurred during TUR in 3 dogs. In 2 dogs, prolonged exposure to lavage fluid resulted in clinical and biochemical abnormalities consistent with TUR syndrome. Dysuria resolved in 5 dogs within 10 days of TUR. Treatment-related complications included urinary tract infection and tumor seeding. Local tumor progression and metastasis occurred in all dogs. CONCLUSIONS: TUR (in combination with chemotherapy+/-IORT) resulted in rapid palliation of urination difficulties in male dogs with prostatic carcinoma. In female dogs with urethral TCC, however, electrosurgical TUR cannot be recommended because of a high intra- and postoperative complication rate with no improvement in postoperative management compared with historical reports of tube cystostomy. CLINICAL RELEVANCE: TUR is a novel alternative for the palliation of male dogs with prostatic carcinoma. In female dogs with urethral TCC, electrosurgical TUR does not provide any advantages compared with tube cystostomy.     

Advances in Prostatic Diagnostics in Dogs: The Role of Canine Prostatic Specific Esterase in the Early Diagnosis of Prostatic Disorders

In last years, following the increased canine life expectancy and the rising attention pet-owners devote to their animals, several authors have carried on investigations concerning new techniques to early identify canine prostatic disorders that might affect the dog's quality of life. Prostatic disorders often have an asymptomatic onset and their early diagnosis is difficult: hence, they are usually identified at an advanced stage, only. Traditionally, the diagnosis of prostatic disorders is based on noninvasive tools, such as transrectal and abdominal palpation, seminal or prostatic fluid evaluation, and urinalysis and imaging. On the other hand, a definite diagnosis of prostatic abnormalities could be achieved through prostatic parenchyma Fine Needle Aspiration (FNA) or biopsy. However, these investigations are performed rarely because of their invasiveness. Thus, several authors investigated canine serum biomarkers in order to achieve an earlier diagnostic timing and to apply therapeutic strategies for better outcomes. The Canine Prostatic Specific Esterase (CPSE) has been identified as a suitable biomarker to be included in a prostate health screening program, following the model of prostate-specific antigen (PSA) in human medicine. A higher CPSE in dogs suffering from several prostatic diseases, such as benign prostatic hyperplasia, bacterial prostatitis, or prostatic carcinoma, was reported in literature. Thanks to the potential usefulness in clinical practice, further studies should investigate the potential role of CPSE in monitoring the medical treatment success in the male reproductive system. Moreover, the spreading availability of serum biomarkers, easily carried out on blood samples in clinical practice, could assure a more accurate evaluation of the actual prevalence of prostatic disorders. The CPSE is actually recognized as a promising diagnostic tool for the detection of prostatic disorders in a "prostate health screening program," in order to properly select those patients requiring further more accurate and expensive diagnostic investigations.     

Intracapsular Prostatic Omentalization: A New Technique for Management of Prostatic Abscesses in Dogs

Twenty dogs with abscessation of the prostate gland were treated by celiotomy, drainage, and digital exploration of the gland through bilateral capsulectomy wounds. Omentum was introduced through the capsulectomy wounds and packed into the abscess cavities around the prostatic urethra. Most dogs were discharged from the hospital within 48 hours of the surgery. Long-term resolution of the problem (no recurrence within 12 months) was achieved in 19 dogs. One dog had recurrent abscessation that was managed by the placement of dependant Penrose drains. Temporary tube cystostomy was performed postoperatively in one dog for the management of transient dysuria. One dog with septic peritonitis resulting from preoperative abscess rupture was managed by concurrent open peritoneal drainage. Intracapsular prostatic omentalization was a simple and effective means of managing prostatic abscessation with minimal requirement for postoperative hospitalization of the patient. The frequency of serious complications, including postoperative urinary incontinence, was low.     

Relationship of seminal volume to size and disease of the prostate in the beagle.

The seminal volume of young adult Beagles was correlated with the size of and disease in their prostates. The ejaculate volume of naturally collected semen increased in a linear manner with prostatic weight in dogs with normal or glandular hyperplastic prostates. This correlation was not observed in the dogs with cystic hyperplasia, in which there was a reduction in volume of 50% in the semen produced for each gram of prostate. There were no significant differences in other seminal characteristics regardless of prostatic size of disease.