In part 1 of this article we looked at the difference between urine marking and inappropriate elimination in cats, and urine marking was discussed in more depth. In this article we will look at the reasons for inappropriate elimination as well as the diagnosis and treatment of both inappropriate elimination and urine marking.
In order to understand disease of the urinary system it is important to understand the anatomy of this system. The urinary system comprises two kidneys which are linked to the bladder by two tiny tubes called the ureters. The ureters terminate in the lower part of the bladder commonly referred to as the neck of the bladder. The bladder is a balloon like structure which can expand to many times its empty size when it is filled with urine. The main tube taking urine from the bladder to the genital organs is called the urethra. The urethra terminates in the vagina in female and in the penis in males.
Any obstruction, disease or abnormality from the kidneys right down to the penis or vagina can cause inappropriate elimination. Some of the more common medical conditions leading to inappropriate urine elimination include sterile and non sterile infections as well as crystals and stones in the kidneys, the bladder and the tubes running between and from these organs, cancer of the bladder, structural defects in the urinary tract like a ureter terminating in the bladder wall or the urethra rather than the neck of the bladder (called an ectopic ureter), kidney failure, nerve inervation problems and/or systemic conditions like diabetes or other organ failure. Further to this, behavioural abnormalities always need to be considered as a differential diagnosis when inappropriate elimination is observed in cats.
Starting at the top of the urinary system at the kidneys where urine is formed, the most common cause for inappropriate elimination is kidney failure. Kidney failure can either be acute, for example as a result of a poisoning, or chronic, most commonly as a result of old age and organ failure. Cats are obligatory carnivores, meaning they have to have proteins in their diet to survive. The by-products of protein breakdown and metabolism in the body have to be excreted by the kidneys. Cats’ kidneys work hard and non-stop to eliminate unwanted by-products of their high protein diet. Chronic kidney failure is therefore a very common problem in
old cats, where the kidneys have literally been “worn out” over the life time of the cat. The kidneys are remarkable organs and will function even though they may be quite diseased. The problem with this is that chronic kidney failure is often only diagnosed when the animal is way past the point of no return. Cats with kidney failure may only start exhibiting signs of kidney failure when 75% of the organs are no longer functioning, leading to a guarded prognosis for long term treatment. The other problem is that kidney cells, unlike liver cells, cannot regenerate. The kidneys therefore do not have the capacity to “replace” damaged cells, and treatment is mainly based on lowering the load on the kidneys, and preventing further destruction and deterioration of kidney cells.
A diagnosis of kidney failure is usually confirmed by a combination of analysing the urine of the animal, and blood tests. Other diagnostic means include X-rays or ultrasound scans, or taking a small piece of kidney tissue by means of a biopsy and having it examined histologically (examining the cellular structure by means of special microscopes).
Moving from the kidneys to the tubes which carry the urine from the kidney to the bladder, namely the ureters; an obstruction of the urether (being a thin tiny tube) by means of stones or urinary crystals, can lead to inappropriate elimination. Medical problems associated with the bladder, urethra and genital area is collectively termed Feline Lower Urinary Tract Disease (FLUTD). Bladder infections and crystals in the urine are the most common causes from FLUTD. Urine is sterile and in order for an infection to occur, bacteria have to enter the urinary system either from the kidneys downward, or from the genitals upward, to cause bacterial or non-sterile urinary tract infections. An infection of the bladder is termed cystitis. If cystitis is of bacterial origin, it can usually be successfully treated with antibiotics. There are several kinds of bacteria that can cause infections of the urinary tract and the vet will usually try to establish which type of bacteria is causing the problem by taking a sample of urine by means of a cystocentesis (sticking a sterile needle into the bladder and collecting some urine). This procedure has to be performed with utmost sterility in order to prevent other bacteria from the vagina, penis, or skin, to contaminate the sample. This sample is then sent to a laboratory for doing a culture (growing bacteria from the sample) and identifying which bacteria is causing the infection. A culture is usually followed by an antibiogram, which is a process to establish which antibiotic will be effective against those bacteria. Bacterial resistance is common and treating with the wrong antibiotic may not only be ineffective, but also harmful to the animal.
Bladder stones and crystals in the urine used to be a very common problem in cats in the past. However research into diet and nutrition has made major strides in combating this problem. Feeding cats scientifically formulated diets manufactured to the highest quality and standards have reduced the incidence of this problem dramatically. Crystals and bladder stones can however still form in a small number of cats regardless of which diet they are fed, and these cats may need extra medical treatment and even surgery to treat and correct the problem. Male cats are especially prone to major complications in this regard because they have a very small and thin urethra. Crystals tend to form a sludge in the urethra of male cats, which leads to the urethra becoming partially or completely blocked. The cat’s bladder expands and becomes extremely painful and will eventually burst if not attended to. A blocked bladder or urethra which is not attended to with the correct veterinary treatment, will most certainly lead to death. There are different types of crystals containing different types of minerals, and treatment and therapy will depend on which type of crystal or stone the cat has. Some crystals stay small, whilst others eventually form stones. In a large number of cases surgery has to be performed to remove these stones.
A less common cause of FLUTD is sterile infection of the bladder often described as idiopathic cystitis. The word idiopathic means that the origin of the problem is not known at the time of making the diagnosis. Sterile cystitis, as the name indicates, is not caused by bacteria. Some causes of sterile cystitis include obesity, stress, low water or fluid intake, certain diets, a lack of exercise or being restricted from using a sandbox or going outside to urinate (often referred to as retention cystitis). Behavioural problems like an aversion to a litter box, litter type, placement of the litter box, dirty litter or anxiety and stress can also lead to cystitis. These problems are often encountered in multi cat households where there are distinct pecking orders.
Finding the cause of sterile cystitis may be simple, but in most cases is quite complex, and can often be caused by a combination of factors. Symptoms may also be intermittent and may occur for 5 to 7 days, only to disappear and then re-appear some time later. Treatment of this condition can be very difficult and frustrating. The best way to approach a case like this is to use all diagnostic tools available to vets to eliminate all possible causes, one after the other. In some cats this condition becomes a lifelong condition which is not cured but only managed with the correct treatment as soon as symptoms appear.
Cancer of the bladder is also a less common cause of FLUTD and may be difficult to diagnose because the symptoms may mimic a sterile cystitis or may be complicated by a secondary bacterial cystitis, which may be improved with antibiotics, but will re-occur, because the underlying cause is not addressed. The reason why it may be challenging to make this diagnosis is because the cancer does not necessarily form a tumour or lump, but may have a flat and elongated structure, and may present merely like an inflamed bladder wall. Diagnosis of cancer of the bladder may require ultrasound, radiographs and urine and/or blood tests and/or surgical biopsy of the bladder wall or affected area.
Making a diagnosis of which problem is causing urine marking or inappropriate elimination due to disease can be a challenge. A thorough history of the problem will be the starting point. Important factors include, when and how the problem started and how it has progressed, the location of the offending deposits, the type of litter box and substrate (sand, clumping litter, crystal litter etc) used, the medical history of the cat, social interactions between the animals at home, social interaction between the animals and humans at home, and the availability of resources like food and water. Answers to these questions will assist the vet in making the correct diagnoses. For example urine on an upright piece of furniture near a doorway will indicate a marking problem rather than an inappropriate elimination problem, whereas a small amount of red tinged or blood filled urine in the bathroom, may indicate an infection rather than a marking problem. With the help of an observant owner, the diagnostic process can be substantially shortened and improved.
The clinical, hands on, examination of a cat with inappropriate elimination or marking problems is paramount to the diagnosis. This examination may include the vet taking the cat’s temperature, listening to its heart and lungs, and feeling the organs in the abdomen. Getting a urine sample may be done either by cystocentesis (as explained earlier), or a free flow sample, by expressing the bladder. If a cat with a potential urinary problem has an empty bladder, the vet may request to keep the cat in hospital until such time as it is possible to get a urine sample. If the vet suspects a possible stone in your cat’s bladder, he or she will advise an ultrasound scan or radiograph (X-ray). This will also apply for suspected cancer of the bladder and certain anatomical defects of the urinary tract. Sometimes a special type of X-ray (called a contrast study) may be advised. This is where a radio opaque substance is injected either via the bloodstream to be eliminated by the kidneys, or directly into the bladder, to see more clearly what the structures of the organs look like. Blood tests form an important part of diagnosing upper urinary tract problems and will be recommended in cases where the vet suspects kidney problems.
Once a diagnosis has been made, treatment and management of the problem will be advised. Treatment may vary from surgery, to medical treatment to diet change to behavioural treatment. If it has been established that there is no medical or underlying pathological urinary tract disease and a diagnosis of inappropriate elimination due to territorial marking is made, a treatment plan and strategy will be advised. Many cases of urine marking can be resolved completely, but sometimes only a reduction in the number of sprays can be achieved, and relapses are common. Management options and behavioural modification for urine marking include the following:
Veterinary treatment for inappropriate elimination associated with illness or disease may include the following;
As with most things in life there are seldom quick fix solutions for complex problems. Some urine marking and inappropriate elimination problems may be treated very successfully with distinct, down to the point, short term treatments. Others may take month or years to treat. Some urinary tract condition can only be managed, but not cured.
© 2012 www.vetwebsites.co.za