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Some Genito-Urinary System Problems And Diseases |
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Written by Myra Ehrman, RN, BA, BS, MScN
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Original Article Written by Myra Ehrman, RN, BA, BS, MScN, on behalf of the Health Education Committee, CKCSCC. Originally Published in The Cavalier King Charles Spaniel Club of Canada Newsletter,"Quotes", in March, 1997
Problems Affecting Both SexesA veterinarian in general practice in the United States, Mark E. Epstein, DVM ABVP, has outlined four basic types of problems which can fall under an umbrella description of "inappropriate urination". These include:
- Inflammation of the urinary tract (most notably bacterial cystitis or bladder infection, but it could be other things as well);
- Polyuria/polydipsia (excessive voiding/excessive thirst);
- Behavioural - the dog likes to pee;
- True urinary incontinence, as described next in this article.
Urinary Incontinence
The information in this section is based on an article by Stanley I. Rubin, DVM, MS, Diplomate ACVIM, entitled, "Diagnosis and Management of Urinary Incontinence".
Urinary incontinence refers to the loss of voluntary control of urination. The animal may leave a pool of urine where it has been lying (without any noticeable effort to urinate having been observed) or may dribble urine while it is walking. Normal urination is comprised of two phases, storage and emptying. These phases are controlled by the bladder neck and proximal urethra, and all levels of the nervous system are involved as well.
Urine storage takes place when the bladder relaxes and the internal urethral sphincter stays closed. The urethra, or the canal extending from the bladder to the outside of the body, has an internal and an external sphincter. Sphincters are circular muscles that constrict a passage or close a natural orifice.
The urine stays stored as long as pressure within the urethra is greater than the pressure within the bladder. Emptying of urine occurs when contraction of the bladder muscle is coordinated with sphincter relaxation.
There are a number of disease processes which can result in involuntary loss of urine. These include neurologic dysfunction, alterations in bladder and urethral tone, chronic diseases of the bladder or urethra (such as cancer), obstruction, disease of the prostate gland, as a secondary outcome to a spay or neuter, and congenital (present at birth) anatomic abnormalities such as ureters (tubes connecting kidneys and the bladder) not located in the normal place.
Your veterinarian will want to determine the cause as to why the animal has become incontinent. There should be a careful history-taking, physical examination, neurologic examination, observation of the dogís voiding pattern (which could include feeling the bladder and possible insertion of a catheter to determine how much urine remains in the bladder after voiding has occurred), laboratory examinations (urinalysis and possible blood work), and possibly x-rays.
There are some medications which may be used for management of incontinence, but medication would be prescribed only after anatomic abnormalities of the urinary tract, urinary tract infection, paradoxic obstructive incontinence, and other primary treatable underlying diseases have been ruled out as possible causes.
In addition to adrenergic receptors (which affect function through neurotransmitters), the urethral sphincter has receptors for the reproductive hormones estrogen and testosterone. Incontinence associated with neutering may be in part related to decreased receptor stimulation from these hormones. It is an unproven hypothesis that animals may have had marginal urethral function before neutering.
Bitches which have been spayed are fairly commonly affected by estrogen-responsive incontinence. Middle-aged to older female dogs are most prone to incontinence. Estrogen replacement, or diethylstilbestrol given orally, is the drug of choice for hormone replacement in bitches. The exact mechanism of action is not known, but estrogens may increase internal sphincter sensitivity. The drug is given at a dosage of 0.1 to 1.0 mg daily for 5 days, then weekly or less often (i.e. every 10 to 14 days) as necessary to maintain continence. The lowest and most infrequent dose which is effective should be chosen. Occasional animals will require more frequent doses (i.e. twice weekly) or higher doses (i.e. > 1.0 mg) to maintain continence. Side effects are uncommon at the low dosages usually necessary for control. Signs of estrus have been reported, in addition to bone marrow suppression. Aplastic anemia is also a potential side effect, however, it is unlikely with the low-dose regimen.
Dogs may be affected by hormone-responsive incontinence after neutering as well, though this occurs less commonly than in neutered bitches. Testosterone is usually administered intramuscularly. Testosterone propionate at a dose of 2.2 mg/kg is usually effective, but may need to be administered as often as three times a week. Testosterone cypionate is more convenient because it is effective at a dosage of 2.2 mg/kg every 30 days. Because of rapid degradation by the liver, oral testosterone is often ineffective, unless high doses are used. Testosterone administration is not without its downside, and may aggravate or cause the recurrence of problems which were previously testosterone-related, such as prostatic disease, perineal hernia and perianal adenoma. Behavioural changes can also occur, such as inappropriate urination, aggression, etc.
Other medications which may be used are prescribed as alpha-adrenergic agonists, which stimulate the receptors (directly or indirectly) in the urethra, resulting in increased resting urethral tone. All the drugs in this class must be given continuously to be effective, although the dose may be prescribed to the lowest and least frequent necessary to maintain control. Side effects of these drugs include Central Nervous System (CNS) stimulation (e.g. anxiety, restlessness), hypertension, urinary retention and changes to cardiac rhythms. These drugs are ephedrine, phenylpropanolamine, and pseudoephedrine.
Ephedrine has been shown to increase urethral closure pressure throughout the entire urethral length in people. It is effective in improving urinary incontinence related to decreased urethral resistance. It is supplied in 25 and 50 mg tablets, though the recommended maximum dose is 4 mg/kg (for an 8 kg, or 17.6 lb Cavalier, that translates to 32 kg total in a day).
Phenylpropanolamine functions in a similar manner to ephedrine, and seems to cause less CNS stimulation. Pseudoephedrine also has fewer CNS stimulating actions than ephedrine, and the usual dose is 15 to 30 mg two - three times a day. The animal is usually started on a lower dose, which may be increased if there is no clinical response.
Cystitis (bladder infection)
You will know your dog is having a problem when you see signs of frequent, painful urination, perhaps with some blood visible in the urine or with some straining. Some dogs break housetraining, or are anxious to get outside. The dog may take an unusually long time to complete urination, or produce a smaller than usual or intermittent stream.
Cystitis is defined as a bacterial infection of the bladder lining. Bitches may lick themselves and have a discharge from the vagina. It is usually diagnosed by a combination of the history you give to the veterinarian, and an urinalysis to check the presence of hemoglobin and protein, as well as increased amounts of red blood cells, white blood cells, and bacteria. A C & S, standing for culture & sensitivity, test may be performed as well. In a C & S, a sterile sample of urine is cultured in the laboratory to see which bacteria grow on the plate and which antibiotics are effective in limiting the bacteriaís growth (the sensitivity part).
Treatment will be with several weeks of a prescribed antibiotic, either one determined by the C & S test, or at least one considered to be broad-spectrum and usually effective against most of the causative agents. It is very important to give all the medications until they are finished, and then to return to your veterinarian for a repeat urinalysis. He or she will probably advise you to return 3-5 days after finishing the antibiotic. Donít forget or overlook this return visit; the infection may not be completely cured, and an additional course of antibiotic treatment may be warranted. If the infection is not completely knocked out, there is a risk it could move up the urinary tract and eventually damage the dogís kidneys.
Problems Affecting Bitches Only
Pyometra
This is a disorder in which the mucous membrane lining of the uterus is abnormal, and there is a secondary bacterial infection. It occurs most commonly in bitches over six years of age. Bacteria from the normal vaginal flora are most likely the source of contamination; E. coli (see January, 1997 HealthWatch) is the most common bacterium to be cultured in cases of pyometra, although Staphlococcus, Streptococcus, Pseudomonas, and Proteus have also been found to be involved.
The bitch usually becomes symptomatic about 4-8 weeks after having been in standing heat, or following administration of progestin hormones. Indications of a problem brewing include lack of energy, lack of appetite, more frequent drinking and urination, and vomiting. When the cervix is open, a discharge containing pus and often blood, is found. When the cervix is closed, there is no discharge and the enlarging uterus may cause abdominal distention. The bitch with closed-cervix pyometra is usually quite ill by the time medical intervention is sought due to the lack of readily recognized discharge. Left untreated, the bitch may go into shock and die.
This condition is extremely common; the veterinarian will need to determine if the bitch is suffering from closed pyometra or diabetes, as the symptoms are similar. The usual tests performed will include a complete blood count (CBC) and biochemical profile, urinalysis, and culture and sensitivity of the uterine discharge. Abdominal ultrasound testing can also be used to confirm pyometra.
Usually a complete spay (ovariohysterectomy) is the treatment of choice. IV fluids and broad-spectrum, bactericidal antibiotics will be administered in order to correct fluid balances and to aggressively attack the infection. Oral antibiotics will be continued for several days after the surgery.
It is possible to try only medical management (no spay) to treat the condition if the bitch is still fairly young and the owner wishes to try and salvage her reproductive potential. This is more likely to be successful if the uterine lining is not abnormal or being affected by other disease processes (best determined by ultrasound testing), and if the pyometra was of the open type. Naturally occurring prostaglandin (PG) F2a is administered once daily for five days, and broad-spectrum antibiotic therapy continued. The PG induces uterine contractions, relaxation of the cervix, and expulsion of the uterine discharge. The PG is not without its own side effects, including restlessness, pacing, panting, excessive salivation, pacing, abdominal pain, faster heart rate, vomiting, and diarrhea. The animal needs to be reexamined regularly following this treatment; if after two weeks, there is still pus and blood in the discharge or uterine enlargement is still present, it is unlikely the reproductive functions can be salvaged.
The Merck Veterinary Manual (Seventh Edition) reports that of bitches treated medically for pyometra, 70% had recurrence within two years. The Manual says (p. 681), "It is recommended that the animal be bred on the next and each subsequent cycle until the desired number of puppies...has been obtained, and then spayed."
Acute Metritis
This is an acute infection of the uterus which generally occurs when the bitch is postpartum. It may be associated with abortion, fetal infection, retained placentas, uterine manipulation during whelping, or an infection ascending from the vagina following an apparently normal whelping. Less frequently, it may occur following breeding.
The symptoms are quite similar to those described in the section on pyometra. Usually a fever is present, along with lack of energy and appetite, and the appearance of a foul-smelling vaginal discharge full of pus. If may be necessary to take x-rays to see if puppies were retained. Treatment is essentially similar to that for pyometra as well, including IV fluids, broad-spectrum bactericidal antibiotics, and possibly the administration of prostaglandin (PG) F2a to help empty the uterine contents. Immediate spaying is recommended if the animal is extremely ill; otherwise, it may be performed after the puppies are weaned.
Chronic Metritis
This is a low grade infection of the uterus; it is caused by bacteria moving upward from the vagina. Since it does not have the same obvious symptoms as acute metritis, it is difficult to diagnose. Smears and cultures taken from the cervix aid when pinpointing the diagnosis. Indications the bitch may have chronic metritis are that she refuses to accept the male; when she is bred at the correct time in her cycle, but fails to conceive, especially when this happens at least twice in a row; and when she produces still-born puppies or puppies who fail and die within the first few days. Antibiotics are used to treat the infection.
Problems Affecting Dogs Only
Monorchidism and cryptorchidism
First, the definitions. Monorchidism literally means one descended testis, and is very rare. Cryptorchidism is the retention of one or both of the testes, usually in the abdomen. Cryptorchid testes can also be outside the body wall under the skin. The danger with cryptorchidism is that if the testis is in the abdomen, it is being exposed to a higher body temperature and is at great risk for Sertoli cell tumor (13 times more often than dogs with descended testes). Affected animals should be castrated (neutered). It is suspected to be a hereditary condition. Dogs which are unilateral cryptorchid (one testis is descended, one is not) can still be fertile and can pass the trait on to offspring.
Cryptorchidism occurs most frequently in purebred dogs, in certain breeds, and within certain families of a breed. According to a vet in The Netherlands, cryptorchidism appears in 13% of male dogs and is more common in toy breeds.
Prostatitis
The exact role of the prostate gland is not known; it is thought to play a role in the nutrition and transport of sperm. Fluid produced by the prostate carries sperm and may protect the lower urinary tract against bacterial infections. The gland is found in either the pelvis or lower abdomen, and surrounds the urethra close to the urinary bladder opening. The infection may be of either an acute or chronic nature.
The signs of acute prostatitis include the dog having a fever, an arched back or tucked-up abdomen, pain on urinating, and difficulty in voiding. As well, the dog may have a lack of energy and of appetite, and abdominal pain. The dog may have a penile discharge which has blood and pus in it. The bacteria involved are similar to those causing urinary tract infections, and include E. coli, Staphlococcus, Streptococcus, Klebsiella, Enterobacter, and Mycoplasma. The disease can become chronic with periodic episodes recurring. Chronic prostatitis can be responsible for urinary tract infections, chronic orchitis (see further in this article), and infertility in an otherwise healthy and intact male.
Diagnosis is made by bacterial culture of urine, semen, or prostatic fluid, in addition to the ownerís report of the dogís history, and the physical findings. Appropriate antibiotics should be administered for a minimum of three weeks for an acute episode, and for three months once it becomes chronic. A follow up culture should be taken after the course of antibiotic therapy is completed to be certain there is no residual infection. Neutering is recommended if there is no response to the antibiotics.
Orchitis and Epididymitis
Orchitis refers to inflammation of the testicle. Epididymitis is the inflammation of the epididymis, which is an elongated, cordlike structure along the posterior border of the testis in the ducts of which the sperm are stored. These infections usually occur together, and typically are caused by bacteria. The bacteria gain access through a traumatic event such as a puncture wound, backflow from infected urine or prostate gland secretions, or spread from a blood-borne infection. Without treatment, chronic inflammation and destruction of the sperm-producing capacity of the infected testis may result.
Clinical signs of this problem include sudden pain, scrotal swelling, lack of energy and appetite, and a reluctance to stand or walk. Donít delay, take the dog into your veterinarian immediately. In addition to collecting urine and semen for culture, your veterinarian will want to run a test for Brucella canis as well (see January, 1997 "Quotes"). Once again, antibiotics will need to be administered for at least three weeks, if not longer. If the problem is chronic in nature, the only way this may be determined is through his infertility, as most dogs do not show any symptoms.
Neutering is recommended unless the owner is hoping to use the dog for breeding again. Even with treatment, the likelihood of preserving his fertility in the long run is not good, as the sperm-producing cells and tubules in the testis can be adversely affected by the infection. These untoward effects can occur months after the original infection. His semen should be re-evaluated for fertility at least three months after treatment.
Benign Prostatic Hypertrophy (BPH)
This disorder is caused neither by inflammation nor by cancer. It is an enlargement of the prostate gland caused by multiplication of cells, and is the most common disorder affecting the dogís prostate gland. Most intact males six-eight years and older will have this to some degree. The dog may experience some constipation and straining on defecation, and blood may be present in the urine. Diagnosis is made by rectal examination of the prostate.
No treatment is required unless the dog is exhibiting signs of difficulty. Neutering then becomes the recommended option; the prostate gland will decrease in size within weeks of the operation. Hormonal treatment has been used, but is not nearly as effective.
Conclusion
This article is not an exhaustive listing of all genito-urinary disorders which can affect dogs of both sexes, but rather the more commonly occurring ones. As always, whenever your dogís behaviour changes dramatically and any unusual signs and symptoms present themselves, your best recourse is to high-tail it off to your vet.
Disclaimer: Your veterinarian is the most qualified person to answer all of the questions you have about your pet's health. Nothing in this article should be construed as medical advice regarding any individual animalís condition.
© Copyright April 12, 1999.
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