Diseases of the Male Reproductive System
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Balanoposthitis
is inflammation of the penis (balanitis) and prepuce (posthitis). Smegma is the normal
sloughing of cells and accumulation of debris. Smegma provides nutrients for bacterial
growth. Anything which disrupts the normal integumentary barrier; including wounds or
foreign bodys predispose to balanoposthitis. Clinical signs include licking the prepuce and a yellow
green discharge. The dog is normal in other respects.
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Examination of the penis is essential to rule-out foreign
bodies and lymph follicles in the area of the bulbus glandis. Treatment is to irrigate the preputial sheath with dilute
potassium permanganate, hydrogen peroxide, quaternary ammonium compounds, antibiotic
steroid combination, or mechanical removal of lymphoid follicles.
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Phimosis is when
the penis cannot be extruded from the prepuce. It may be congenital due to a small orifice
or persistent frenulum. Acquired inflammation or neoplasia reduces the size of preputial
orifice or increases the size of the penis. Depending on severity of signs, one may not
observe signs until the dog tries to copulate. Treatment is to surgically enlarge the
opening or surgical excision of masses.
Paraphimosis is
when the penis is extruded from the prepuce and cannot be returned to its normal position.
This may occur following breeding or sexual excitement such as being kenneled next to a
bitch in heat, or by a traumatic fracture of the os penis. This is an emergency. Penile
tissue dries out rapidly and becomes necrotic and gangrenous. Dysuria may develop from
compression of the urethra. Treatment includes cold packs to decrease swelling and
lubricants. It may be necessary to incise the prepuce to replace the penis and place a
temporary purse string suture in the prepuce to prevent recurrence. Amputation of the
penis is necessary if it is gangrenous.
Priapism is a
constant state of erection unrelated to sexual desire. Causes include spinal cord lesions,
genitourinary infection, or constipation. Treatment is for the underlying cause.
Bland ointments should be applied to prevent drying of penile tissues.
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Cryptorchidism is a
congenital defect of retention of the testes at some point in the course of normal
descent. Anorchidism (no testicles) vs. Cryptorchidism (retained in a location
other than the scrotum).
Cryptorchidism
can be unilateral or bilateral and is commonly observed. It is
heritable in some breeds (a simple recessive trait in Boxers) so breeding of dogs with
this abnormality should be discouraged. Testicles normally descend at birth and are
usually palpable at 2-3 months of age. If testicles are not in the scrotum, palpate the
inguinal areas. There are no behavioral changes associated with
cryptorchidism
in dogs.
Surgical correction is considered unethical due to the potential of passing on this trait
to offspring. There is a high incidence of neoplasia in retained testicles. The animal is
fertile if cryptorchidism
is unilateral.
Orchitis and
epididymitis are infections of the testicles and epididymitis. They may be caused by fight
wounds, auto injury, systemic infection (Brucella canis), or extension from prostate or
urinary tract infections. Signs of acute disease include a stiff gait, hard swollen
testicle(s), pain, and self inflicted scrotal dermatitis. When the problem is chronic the
testicles are small, firm, and nonpainful. Sterility may be a sequela. The diagnosis is
made by physical exam, semen exam and urinalysis. Treatment includes antibiotics or
castration.
Testicular tumors
should be considered when testicles are enlarged and nonpainful. Testicular tumors usually
occur in middle aged to older dogs. Metastasis is uncommon. Types of tumors include:
- interstitial cell tumors which are small and soft with
hemorrhage or necrosis and may be bilateral. Interstitial tumors do not produce hormones.
- seminomas are large and usually occur in ectopic testicles.
They do not produce a hormone.
- sertoli cell tumors vary in size and produce estrogen.
Estrogen results in signs of feminization such as symmetric, nonpruritic alopecia with
increased pigmentation, gynecomastia, attraction of other males, pendulous prepuce,
infantile penis, and bone marrow suppression.
Castration is the treatment for testicular tumors.
Below is a large sertoli cell tumor in the right testicle
and an enlarged prostate gland. Estrogen causes squamous metaplasia of prostatic
cells with resultant enlargement of the prostate gland. This prostate gland contained a
large amount of purulent exudate (pictured on the right).
Testicular atrophy occurs in old dogs due to alterations in
hormone concentrations.
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Diseases of the prostate gland
Prostatic
hyperplasia is an increase in size. The etiology is a low estrogen/androgen
ratio. It is seen in most intact male dogs over 6 years. The most common
sign associated with prostatic hyperplasia is tenesmus due to compression of the rectum by
the enlarged prostate gland. Unlike human males, dogs with prostatic hyperplasia do not
usually develop dysuria or urine retention. Human males have prostatic tissue within the
wall of the urethra so hyperplasia compresses the urethral lumen. Dogs do not have
prostatic tissue within the wall of the urethra so prostatic hyperplasia results in
enlargement directed away from the urethra. If dysuria is accompanied by urine
retention, prostatic neoplasia is more likely than prostatic hyperplasia. Hyperplastic
prostate glands often contain many small cysts which may lead to hematuria or development
of a urinary tract infection.
Rectal and abdominal palpation reveal an enlarged
nonpainful prostate that is usually symmetrical unless large cysts are present.
Radiography can demonstrate prostatic enlargement and dorsal displacement of the colon.
Ultrasound often identifies many small cysts within a hyperplastic prostate gland. There
are no hematologic or biochemical abnormalities associated with prostatic hyperplasia. The
urinalysis may be normal or disclose hematuria and/or evidence for urinary tract
infection.
The prostate can be evaluated by collection of a prostatic
massage sample, ejaculate, needle aspirate or biopsy. The sample can be evaluated for cell
type and culture.
Castration will cause reduction in the size of the prostate
gland if enlargement is due to hyperplasia. The prostate begins to involute within
days of castration and continues to involute for 2-3 months.
Reference on use of Finasteride in treating dogs with BPH
Prostatitis is common in the dog but rare
in the cat. There is no age or breed predisposition. Prostatitis may develop by
hematogenous spread of bacteria or more commonly, by extension from the urinary tract.
Prostatitis may be acute or chronic. The infection may be diffuse or may
coalesce as a
prostatic abscess.
Prostatitis may serve as nidus for recurrent urinary tract
infection and visa versa. Normal basal secretory rate of prostatic fluid in the absence of
ejaculation or urination results in reflux of prostatic fluid into the bladder. Intact
male dogs that develop urinary tract infections will almost always have concurrent
infection of the prostate gland. Prostatitis is uncommon in castrated dogs. Acute clinical
signs include fever, arched back due to pain, depression, dripping pus or blood from the
penis, constipation, or pollakiuria related to urinary tract infection. Chronic clinical
signs are subtle and may include a urethral discharge.
Leukocytosis may develop with acute prostatitis and
prostatic abscess. The urinalysis discloses pyuria, hematuria, and bacteriuria in
dogs with acute disease. Urine culture often reflects the agent causing prostatitis.
Samples obtained by prostatic massage contain neutrophils and prostatic cells. The
radiographic appearance is similar to that of prostatic hyperplasia; enlargement of the
gland with displacement of the colon. Treatment is with antibiotics, selected on the
basis of urine or prostate culture. Abscesses may need to be marsupialized (drained to the
outside) or drained using an ultrasonic aspirator. Prostatectomy is a last resort as
it is technically difficult and often results in urinary incontinence.
Prostatic neoplasia
occurs less commonly in dogs compared to man. Prostatic neoplasia occurs in both intact
and castrated dogs. Prostatic neoplasia often grows into the lumen of the urethra
causing dysuria and/or obstruction. If prostatic enlargement is identified in a neutered
dog or if urine retension is associated with prostatic enlargement the diagnosis is most
likely prostatic neoplasia. Neoplastic cells may be seen in prostatic massage fluid, semen
or occasionally in urine. Prostatic tumors will metastasize to the sublumbar lymph nodes
and sublumbar spine. Treatment is usually unsuccessful and includes prostatectomy and/or
chemotherapy. Urinary diversion procedures such as placement of a prepubic urinary
catheter can be used pallatively.
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Castration
can be performed for medical reasons, sterilization, or behavioral modification to reduce
wandering, spraying, mounting, and aggression. Warn owners that castration may not affect
the undesirable behavior. Castration as soon as possible after development of the
undesirable behavior has a better chance of altering the behavior.
Brucellosis
affects predominately the reproductive organs of both sexes of dogs but can also cause
uveitis, diskospondylitis, osteomyelitis and dermatitis. Transmission is through genital
discharges, aborted material, semen and occasionally urine. Transmission may occur across
oral, conjunctival, or vaginal membranes as well as transplacentally. The most common
signs of infection are abortion in otherwise healthy females and male infertility.
Diagnosis is by isolation of the organism from aborted
materials, vaginal discharge, blood, urine or semen; or by serologic testing.
Serologic tests include the rapid slide agglutination test, tube agglutination and agar
gel immunodiffusion. The rapid slide test is sensitive and easy but may yield false
positive reactions which should be confirmed with another serologic test. Transmission to
humans is possible but uncommon. Response to treatment is incomplete, with animals often
continuing to harbor and shed the organism. Antibiotics used include minocycline,
tetracycline plus streptomycin or quinolones may be used. Dogs should be neutered to
minimize shed of the organism. In a kennel environment, positive animals should be removed
from the colony.
Last Edited: Jul 26, 2007 1:51 PM
