Canine Prostate Diseases Flashcards
Prostate anatomy
2 lobes, prominent median septum that surrounds urethra
- deep in pelvic canal, not easily found in large breeds
- produces seminal plasma, responsible for fluid components of all 3 ejaculate fractions
Testosterone conversions
Testosterone from Leydig cells –> 5alpha reductase (prostatic epithelium) –> dihydrotestosterone
Physical exam
Necessary to palpate prostate per rectum in older dogs, when pelvic obstruction suspected, BSE, semen collection abnormalities
Diagnostics
- collect and evaluate prostatic fluid
- color, volume, pH, motility, morphology of sperm rich fraction
- color, pH, cytological evaluation of prostatic fluid
- ultrasound
- radiographs
- culture
- FNA, biopsy
Benign prostatic hyperplasia
Most common disease of K9 prostate!!
- older, intact male dogs: >80% of dogs over 5 years have gross or microscopic evidence of BPH (hyperplasia and hypertrophy)
- no breed predisposition
- result of natural aging and hormonal influences on prostate gland
BPH pathogenesis
Dependent on testosterone, age
- testosterone converted to DHT in epithelial cells via 5a-reductase pathway
- DHt is key to prostatic stimulation leading to stromal and glandular growth
- estrogen sensitizes prostate to DHT (target of some therapeutic agents)
BPH clinical signs
- usually absent
- bloody urethral discharge
- hemospermia
- tenesmus
- hematuria
- stranguria
BPH - physical exam
Usually unremarkable except for prostatic changes
- enlarged prostate on digital exam
- generally symmetrical
- non painful to mild discomfort
Diagnostic imaging
Prostatomegaly
- dorsoventral prostate dimension is >70% of distance between the sacral promontory and pubis on lateral view
- homogenous, hyperechoic pattern
- small cystic areas
BPH - diagnosis
Made based on clinical signs, history, PE
- prostatic massage and wash
- FNA
- tru-cut biposy
BPH - treatment
Required only if clinical signs are present
- castration: 1/2 size within 3 weeks, 70% reduction by 9 weeks
- finasteride
Finasteride
Inhibits 5a-reductase
- stops conversion of T to DHT
- wide dose range
- treat for at least 2-3 months
- libido is maintained
- castration recommended once breeding is done
Prostatic cysts
Associated with BPH
- fluid retention from obstructed canaliculi
- creates cavitating lesion filled with fluid (can become an abscess)
Prostatitis
Acute or chronic
- occur at any age (more common in older dogs with BPH)
- rare in castrated males (concurrent neoplasia)
Prostatitis - pathophysiology
Glandular changes occur which leads to a disruption of prostatic fluid or urine flow and predisposes gland to infection –> secondary to squamous metaplasia or cysts
- ascending infection
- rarely does prostatits occur in an otherwise normal prostate
Defense mechanisms
- frequent urination
- urethral pressure
- local production of IgA, IgG
- breakdown in face of bacteria predisposes the prostate to infection
Prostatitis - clinical signs
- urethral discharge
- hematuria
- pollakiuria or dysuria
- tenesmus
- fever
- caudal abdominal pain
- painful prostate on rectal exam
- anorexia
Prostatitis - diagnostics
- CBC changes depend on severity and duration (possible neutrophilia with a left shift)
- serum chem unremarkable
- UA shows pyuria, hematuria (urine culture is positive)
- semen evaluation: leukospermia, excessive WBCs in prostatic fraction, hemospermia
Ultrasound
Profound changes in echogenicity
- focal to diffuse hypoechoic areas
- moth eaten look
- small cystic areas with flocculent fluid
Chronic prostatits
- much harder to diagnose
- subtle clinical signs
- prostatic massage with culture
- prostate may not be enlarged or painful
Common bacteria
- E coli!!
- kelbsiella
- staphylococus
- streptococcus
- proteus
- pseudomonas
- will be a single organism 70% of the time
Prostatitis treatment
Culture and sensitivity results
- highly lipid soluble drugs enter prostate (fluoroquinolones, chloramphenicol, TMS)
- antibiotics w/ high pH enter acidic environment of prostate well (erythromycin, TMS)
- long term treatment (at least 4-6 weeks!!)
Prostatic abscess
Severe sequela to prostatitis
- abscess can rupture, creating fulminating peritonitis
- treat aggressively
- surgical drainage with omentalization
- US guided aspiration gaining popularity
Prostatic abscess - treatment
Don’t treat with antibiotics alone
- rarely results in cure due to inability of antibiotics to penetrate prostate and/or abscess
- castration or finasteride
- surgical drainage if needed
Prostatic neoplasia
Incidence of 0.2-0.6%
- age at diagnosis: 5-17 years
- increased risk in neutered males compared to intact males
What is the most common prostate condition found in neutered males
Prostatic neoplasia
- always palpate prostate at physical exams
- palpable prostate in neutered male should be assumed to be neoplasia until proven otherwise
Prostatic neoplasia - clinical signs
- tenesmus (colon impingement)
- weight loss
- stranguria
- dysuria
- systemic illness
- hindlimb weakness or pain (skeletal metastasis)
Neoplasia radiographs
Prostatomegaly, irregular border, mineralization, lymphadenopathy, periosteal new bone formation
- met check is warrented
Prostatic tumors in dogs are typically _______
Androgen independent
- poor success rate with dogs (survival time is only a few months)
Transmissible venereal tumor
Tropical and sub tropical areas
- only contagious tumor in small animals
- histiocyte cell line
- penis is primary site in males, vagina in females
- cauliflower like mass, very friable, ulcerated mass
TVT treatment
- metastasis is rare
- diagnose via cytology, biopsy
- treat with vincristine, adriamycin
- prognosis is good
Persistent frenulum
Young dogs prior to puberty
- frenulum is normally lost at time of puberty
- prevents copulation
- corrected with surgery
- heritable in other species
Paraphimosis
Failure of penis to retract into prepuce
- lead to ischemic necrosis of penis
- prevent by facilitated retraction of penis into prepuce following breeding
- surgical amputation is needed in severe cases
Cryptorchidism
Most common disorder of sexual development in dogs (13%)
- heritable trait
- testicular descent not completed until birth
- should not confirm a case until 4-6 months of age
Risk for _____ is higher in retained testicle
Neoplasia
How to diagnose cryptorchidism
Cox test
- GnRH or hCG followed by measurement of testosterone
Balanoposthitis
Non specific inflammation of penis
- trauma, neoplasia, infeciton, herpes virus, foreign bodies
- histopath provides a more accurate diagnosis
- treat symptomatically
