Rhett Marshall BVSc, MANCVSc, PhD
The Cat Clinic
189 Creek Road,
Mt Gravatt, 4122

Basic information

Glargine (Lantus) is readily available from most pharmacies with a script, is not licensed for use in cats.

Glargine must not be diluted or mixed with anything because the prolonged action is dependent on its pH.

Insulin glargine should be kept refrigerated to prolong its life.

Insulin glargine has a shelf-life of 4 weeks once opened and kept at room temperature. We have found that opened vials stored in the refrigerator can be used for up to 6 months.

Discard vial immediately if there is any discoloration. Bacterial contamination and precipitation associated with pH change can cause cloudiness.

If using an insulin pen, the manufacturer recommends that the pen and cartridge be kept at room temperature and not refrigerated. This is to reduce the changes in volume of insulin dispensed associated with changes in temperature.

When performing a blood glucose curve, samples probably only need to be taken every 4hrs over 12 hr in many cats (ie. 0h [before morning insulin], 4h, 8h and 12h after morning insulin).

Dose changes should be made based on pre-insulin glucose concentration, nadir (lowest) glucose concentration, daily water drunk, and urine glucose concentration.

Better glycaemic control is achieved with twice daily dosing rather than once daily.

Some cats that have been treated with other insulin will go into remission, usually within 1-4 months after instituting glargine. Remission in cats that have been treated for more than 2 years is extremely rare.

More accurate dosing may be achieved using 0.3ml U-100 insulin syringes.

Remission is likely to occur if the nadir glucose is in the normal range and pre-insulin blood glucose is less than 12 mmol/l. However, for some cats to achieve remission, the dose needs to be very gradually reduced, tapering off to ½ U SID before being withdrawn. Too rapid withdrawal often requires restabilising at a higher dose for some weeks.

Indications for using glargine

All newly diagnosed diabetic cats (to increase chance of remission)

Poorly controlled or unstable diabetic cats (glargine's long duration of action is likely to benefit these cats)

When SID dosing is desired or demanded (It is important to note that better glycaemic control and higher remission rates will be obtained with BID dosing. SID dosing only provides similar control and remission rates to lente BID)

Ketoacidosis - combined with regular insulin IM or IV

When corticosteroid administration is required in cats in remission. Similarly in cats at high risk of developing clinical signs of diabetes with corticosteroid administration.

Starting a cat on glargine insulin

If BG > 20mmol/L begin glargine at an initial dose of 0.5U/kg ideal body weight q12hrs (BID)

If BG < 20mmol/L begin at 0.25U/kg ideal body weight q12hrs (BID)

Perform a 12hr glucose curve with samples taken every 4hrs. Insulin can be increased daily until normoglycaemia is achieved but careful monitoring is necessary to avoid hypoglycaemia

Decrease dose if biochemical or clinical hypoglycaemia occurs

It is suggested that cats stay in hospital for 3 days to check the initial response to insulin, or home glucose curves are obtained for the first 3 days. Continuous blood glucose monitoring systems are an excellent way of obtaining initial response to therapy and we have great success using the Abbott FreeStyle Libre monitors. These can also be left in place for 2 weeks and allows owners to obtain BG readings without needing to sample blood.

Home glucose monitoring is considered best practice but for owners unable to complete at home then cats should be rechecked at 1, 2, 3 and 4 weeks and then as required.

Ketoacidotic cats may be treated with glargine s/c at the above dose rates in combination with regular insulin IM or IV (we have found 1U regular insulin IM every 2-4hrs based on glucose conc works best). This regime is continued until hydration restored and appetite returns, which usually occurs in 1-3 days.

Monitoring cats receiving glargine insulin

When performing a blood glucose curve, samples probably only need to be taken every 4hrs over 12 hr in many cats (i.e. 0h [before morning insulin], 4h, 8h and 12h after morning insulin).

With the long duration of action of glargine, there should be minimal periods when blood glucose is >14mmol/L for cats treated for more than 2 to 3 weeks, and hence well controlled cats should almost always be 0 or 1+ for urine glucose. A value 2+ or greater likely indicates that an increase in dose is required.

Dose changes should be made based on pre-insulin glucose concentration, nadir (lowest) glucose concentration, daily water drunk, and urine glucose concentration.

Adjusting glargine insulin dose

Once a cat has been stabilised on glargine insulin (i.e. after a week of therapy), the dose may need to be increased or decreased.

1. Indications for increasing the dose of glargine insulin
2. If pre-insulin glucose conc. is > 12mmol/L, then increase dose by 0.25-1.0U/injection

AND/OR

1. If nadir glucose conc. is > 10mmol/L then increase dose by 0.5-1.0U/injection
2. For well controlled cats after several weeks of therapy, an immediate "pre-insulin" glucose measurement > 12 mmol/L suggests that the dose should be increased.
3. Indications for maintaining the same dose of glargine insulin
4. If pre-insulin glucose conc. >10 - <12mmol/L)

AND/OR

1. If nadir glucose conc. 5-9mol/L
2. For well controlled cats after several weeks of therapy, aim for a nadir of 4-7 mmol/L
3. Indications for decreasing the dose of glargine insulin
4. If pre-insulin glucose conc <10 mmol/l decrease 0.5-1.0U
5. If nadir glucose conc <3 mmol/l decrease 0.5-1U
6. If clinical signs of hypoglycaemia develop, then rub honey or golden syrup onto the gums and contact a veterinary clinic immediately.
7. If biochemical hypoglycaemia develops, it can often be managed by feeding the cat, preferably a higher carbohydrate containing food, such as supermarket wet food with gravy.
8. For cats with unexpected biochemical hypoglycaemia (not clinical signs), some owners find that they can manage the hypoglycaemia by delaying the insulin injection until blood glucose increases to 10 mmol/L and then give the same dose (the following dose of insulin may need to be reduced), while others find it best to reduce the dose once glucose is above 10 mmol/L, although this may result in subsequent hyperglycaemia. In some cases, there is a "grey zone" of peak 11 - 14 mmol/L and nadir 3 - 4 mmol/l glucose concentrations. In these cases, the glargine insulin dose may be maintained or decreased depending on the water intake, urine glucose, clinical signs and length of time the cat has been treated with insulin.
9. Insulin dose may be maintained, increased or decreased depending on the water intake, urine glucose, clinical signs and length of time the cat has been treated with insulin.
10. If pre-insulin glucose conc. 11 - 14 mmol/L, or if nadir 3 - 4 mmol/l, clinical parameters are essential for adjustment of insulin dose.

Determining if the cat is in remission

1. Insulin dose should be gradually reduced by 0.25-1 U/cat/injection if nadir blood glucose is in the normal range of 4-7 mmol/L or pre-insulin glucose concentration is < 10 mmol/L. Withdraw insulin SLOWLY until dose is 0.25 - 1 U once daily (SID). Some cats require only small doses of insulin (<1 U/cat BID) and only go into remission if the dose is reduced VERY SLOWLY giving few remaining beta cells a chance to recover.
2. After a minimum of 2 weeks of insulin therapy, if the pre-insulin blood glucose is <10mmol/L and insulin dose is 0.25-1 U SID, insulin should be withheld and a 12hr glucose curve performed. If at the next due dosing time the blood glucose is >12mmol/L, then insulin can be re-administered at 1U BID and then gradually reduced as indicated. If blood glucose is <12mmol/L then continue to withhold insulin and discharge with a follow-up visit in 1 week. Water intake and urine glucose should be closely monitored and insulin reinstituted if glycosuria returns or water intake increases.
3. Some cats may have a pre-insulin glucose concentration <10mmol/L within 2 weeks, but insulin therapy should be maintained for a MINUMUM of 2 weeks to give beta cells a better chance to recover from glucose toxicity. Use 0.5-1U BID or once daily until insulin is withdrawn.
4. Some cats that have been treated with other insulin will go into remission, usually within 1-4 months after instituting glargine. Remission in cats that have been treated for more than 2 years is extremely rare. Remission is MORE likely to occur if the nadir glucose is in the normal range and pre-insulin blood glucose is less than 12 mmol/L. However, for some cats to achieve remission, the dose needs to be very gradually reduced, tapering off to ½ U SID before being withdrawn. Too rapid withdrawal often requires restabilising at a higher dose for some weeks.

Urine Glucose

With the long duration of action of glargine, there should be minimal periods when blood glucose is >14mmol/L for cats treated for more than 2 to 3 weeks, and hence well controlled cats should almost always be 0 or 1+ for urine glucose. A value 2+ or greater likely indicates that an increase in dose is required. This should be confirmed with blood glucose evaluation.

Fructosamine or Glycated Haemoglobin

Urine and blood glucose and water intake (i.e., clinical signs) are usually the easiest way to monitor therapy with glargine insulin. Since many cats go into remission after a few weeks, long-term measures of glycaemic control, such as fructosamine or glycated Hb, are of less value in monitoring patients.

General observations from preliminary use of glargine insulin

Starting doses may be high. Some cats initially require a dose of 5 or 6 U/cat BID to establish glycaemic control. This dose can usually be reduced as insulin sensitivity returns. Cats on these high doses need to be carefully monitored for hypoglycaemia.

Some cats require only small doses of insulin (<1 U/cat BID) and only go into remission if the dose is reduced very slowly giving the few remaining beta cells a chance to recover.

Nadirs can be variable. For many cats, the time at which the nadir (lowest) glucose concentration occurs is often not consistent from day to day, or between cats. Sometimes it occurs somewhere between the two doses, but sometimes the nadir occurs around the time of the next dose. Some cats consistently have their nadir glucose concentration in the evening just before the next insulin injection, and less commonly, it occurs around the time of their morning injection.

BID dosing to start. Better glycaemic control is achieved with twice daily dosing rather than once daily.

To increase the chance of remission, we suggest aiming for perfect control or possibly slightly overdosing during the first 2 months, provided the veterinarian and owner can carefully monitor the cat. There is the potential risk of hypoglycaemia, but we believe this is outweighed by the benefit of diabetic remission to the cat and owner.

Cats requiring intermittent or chronic corticosteroid administration that are either in remission or at risk of developing diabetes can usually safely be placed on 1U SID or BID.

It is a very common observation by owners that when long-term stable diabetic cats are changed over to glargine, usually they do better clinically, even if blood glucose results do not support the clinical improvement.

REFERENCES

Journal Articles

1. Rand JS, Marshall, RD. Diabetes Mellitus in Cats. Vet Clin Small Anim., 2005;35[1]:211-224.
2. Weaver KE, Rozanski EA, Mahony OM, Chan DL, Freeman LM. Use of glargine and lente insulins in cats with diabetes mellitus. J Vet Intern Med. 2006;20(2):234-8.

Proceedings

1. Stenner,V.J., Fleeman,L.M. & Rand,J.S. Comparison of the pharmacodynamics and pharmacokinetics of subcutaneous glargine, protamine zinc and lente insulin preparations in healthy dogs. Proceedings ACVIM 2004.
2. Marshall RD and Rand JS. Treatment with glargine results in higher remission rates than Lente or protamine zinc insulins in newly diagnosed diabetic cats. Proceedings ACVIM 2005.
3. Marshall R, Rand J. Comparison of the Pharmacokinetics and Pharmacodynamics of Glargine, Protamine Zinc and Porcine Lente Insulin in Healthy Cats. Australian College of Veterinary Scientists Science Week, 2003.
4. Marshall R, Rand J. Comparison Of The Pharmacokinetics And Pharmacodynamics Of Once Versus Twice Daily Administration Of Insulin Glargine In Normal Cats. Proceedings ACVIM 2002
5. Marshall R, Rand J. Update on Insulin Glargine Use in Diabetic Cats. Proceedings ACVIM 2005
6. Weaver KE, Rozanski EA, Mahony O, Chan DL, Freeman LM. Comparison of Glargine and Lente Insulins in Cats with Diabetes Mellitus. Proceedings ACVIM 2005.

Tick Toxicity in Cats

With the onset of Spring comes the onset of the Tick Season in Brisbane. The Paralysis tick (Ixodes holocyclis) is unique to the east coast of Australia. Where the ticks occur in Australia seems to coincide with where the long-nosed bandicoot has its natural habitat, because this bandicoot can carry the different life- stages of the tick. However other native animals like possums and lizards can also transport the tick.

The paralysis tick is also believed to climb trees vertically until it hits an angled branch. It will then follow this branch to the end and can drop off to attach to unsuspecting animals. This might explain why backyards with overhanging trees from a neighbour’s yard may have paralysis ticks, whilst not necessarily having much in the way of trees or possum habitat itself.

The Paralysis Tick (Ixodes holocyclis)

As in most conditions, cats are unique in how they present their signs of illness compared to other species such as dogs. For one thing the ‘paralysis’ aspect of this condition may not be the first sign seen or noticed in the cat. We may therefore refer to this condition as “tick toxicity”, rather than “tick paralysis”.

Cats may look as if they are quieter in behaviour than normal, reluctant to take more than a few steps before lying down again. The other important signs to look out for are increased breathing effort and changes in breathing noises, especially a ‘grunting’ sound when breathing out. A ‘wheeze’ or asthmatic sound may also be heard. Some cats may have a change in their meow.

Very particular and peculiar to our cats is a throat clearing type of action. Your cats mouth may open wide with a gagging sound, making many owners think their cat has something caught in the throat. This action is happening because the cat’s vocal chords are paralysed and small amounts of saliva or mucus are very irritating on the larynx, making the cat feel like he or she is choking.

This can be extremely distressing to your cat, and the more anxious they are, the more difficult it is for them to clear the throat. This is why veterinary attention for your cat often starts with medications to relax and reduce anxiety, after which breathing becomes a while lot easier.

More advanced stages of tick toxicity will include a more obvious difficulty in walking, staggering and swaying. Or your cat may be found lying down on his or her side, unable to sit up at all. Immediate veterinary attention must be sought.

The paralysis ticks themselves are grey in colour with orange legs and head part, with the legs all coming out from the “head” end rather than down the sides of the body. This describes the adult female tick, the main cause of tick toxicity.

Larval stages can cause signs of tick toxicity but usually in large numbers, and this occurs much less commonly. The tick itself can be tiny to start but is usually about 4mm across by which time it causes signs of tick toxicity. The tick may have been present for a few days before reaching this size, hence ticks found early and removed may prevent signs of tick toxicity.

Finding ticks in your cat’s coat is best done by “finger walking” through the coat, rather than looking for them visually. The most common areas to find ticks are around the head and neck, around or in the ears, even inside the lips. The next place to look is the front end of the body up to about the level of the elbows. All of these areas are more difficult for the cat to reach and groom.

Also the ticks are attracted to carbon dioxide. Hence the other area to look for ticks is around the back end, the bottom, tail and genital area. We are much less likely to find ticks in the ‘middle’ area of the cat, but would advise thorough searching. Cats who go outside in areas where possums and bandicoots are prevalent should be checked for ticks daily.

The availability of commercial products that may help prevent ticks is very limited for cats, and in fact it should be noted that products labeled for use in dogs only for tick prevention can be HIGHLY TOXIC and possibly fatal for your cats. If you wish to discuss use of products for assisting in tick prevention please call our clinic for a consultation. It is worth noting that there is no single product that can be relied on for tick prevention in cats an ‘finger walking’ is still recommended despite the use of products.

If you find a tick on your cat, despite urban myths and legends, you are advised to pluck the tick off immediately. It is not possible to ‘leave behind the head’ or to ‘inject more toxin’ by doing so. You may use fingers, tweezers, or special tick hooks are available. You are then advised to seek veterinary attention. There is a tick toxin anti- serum that can be administered to your cat, along with other supportive care deemed necessary.

It is not the anti- serum alone that treats these affected cats, as this ‘antidote’ can only remove some of the toxin in the blood stream and cannot reverse the toxin already affecting your cat. The overall supportive care for your cat’s breathing and comfort is equally as important as this medication. On average, cats may need two to four days in hospital for a full recovery.

We are happy to report that most cat’s recovery from tick toxicity is excellent. Just as cats present differently to dogs with tick toxicity, they also experience far fewer of the complications that befall their canine cousins. Confirming yet again that cats may indeed enjoy nine lives, with a little help from their friends: you the owner, and your veterinary team.

What is pyothorax?

Pyothorax refers to the presence of infected fluid and bacteria (pus) within the chest cavity.

What causes pyothorax?

Pyothorax is usually caused by a bacterial infection in the chest cavity. Usually, pus is present in both sides of the chest although occasionally only one side will be affected.

The source of the infection is rarely found although possible causes include:-

1. Penetrating wounds to the chest wall.

2. Wounds to internal structures such as the oesophagus (food pipe), trachea (wind pipe) for example following ingestion or inhalation of a foreign body.

3. Migrating foreign body such as a grass seed which entered the body elsewhere.

4. Extension of infection from a lung infection (pneumonia) - this is the most likely cause in the majority of cases.

What are the clinical signs seen with pyothorax?

Rapid shallow breathing which may be painful, depression, lethargy and other signs of ill health such as a reluctance to eat are seen in most cats with pyothorax. The severity of these signs is extremely variable and rarely cats may suddenly die without having had any previous signs of illness.

Cats with pyothorax usually have a high temperature which contributes to some of the clinical signs seen. The breathlessness is caused by the presence of fluid in the chest which prevents the normal expansion of the lungs.

Pectus excavatum is a congenital malformation of the sternum and costochondral cartilages resulting in a ventral dorsal narrowing of the chest or a depression of the sternum into the chest cavity. This deformity reduces effective pulmonary function and may also interfere with cardiac function.

Causes that have been discussed have included congenital predisposition, intrauterine pressure abnormalities, shortening of the central tendon of the diaphragm, thickened substernal ligament, congenital deficiency of the musculature in the cranial diaphragm, abnormal osteogenesis and chondrogenesis, upper respiratory obstruction, environmental factors, and posturing difficulties.

In humans, it is more frequently found in males and may be inherited as an autosomal dominant characteristic. In one survey it was twice as frequent in male than female cats, but not in dogs.

Signs often include exercise intolerance, weight loss, dyspnea, pneumonia, cyanosis, coughing, postural deficits. A heart murmur may be asculted and echocardiography is recommended to exclude the possibility of a concurrent primary heart disease. This is especially true in older cats that develop clinical signs as adults. It has been associated with other congenital defects e.g. pericardio-diaphragmatic hernia.

Radiographic findings may include decreased thoracic volume, cardiomegaly, and left displacement of the cardiac silhouette.

Causes:
Congenital, Genetic, hereditary

Sex predilection:
Male

Age predilection:
Juvenile
Newborn

Clinical findings:
AFEBRILE, ANOREXIA, CARDIAC MURMUR, COUGHING, CYANOSIS, DYSPNEA, GAIT ABNORMAL, WEAKNESS
Cachexia, Malaise, Weight gain insufficient
Exercise intolerant or reluctant to move, Walking difficulty
Heart sounds muffled, moist lung noises
Rapid breathing, Panting, Hyperventilation, Restrictive breathing pattern
Pulmonary infections recurrent

Diagnosis:
Thoracic radiographs showing cardiac displacement, cardiomegally, lordosis and sternal concavity.

Treatment/Management/Prevention:
SPECIFIC
1. Those with moderate to severe deformity should be treated surgically with placement of an external fiberglass splint contoured to normal thoracic shape.  One possible adverse side effect of exteral splint correction is re-expansion pulmonary edema.
2. Older patients who have less thoracic compliance may benefit from a partial sternectomy.

To understand your cats kidney disease (renal disease), it is important to know some background information about the roles and functions of the kidneys.

The kidneys perform a number of essential roles necessary to sustain life.

The major ones are:

• Removal of waste products from the blood stream (urea and creatinine)
• Regulation of body water
• Balance of acid-base and electrolytes
• Production of erythropoietin, a hormone necessary for production of blood cells.

Each kidney contains about 200,000 nephrons, tiny units that perform those functions.  Kidney disease occurs when nephrons are destroyed.  If enough nephrons are destroyed that the kidneys can no longer perform their essential functions, kidney failure results.

Causes of Kidney Disease

There are numerous causes of chronic kidney disease in the cat and they can be very broadly classified into the following categories:

• Inflammation
• Infection
• Congenital or hereditary problems
• Toxins
• Cancer

Staging of Kidney Disease in Cats

An international staging system (IRIS) has been developed to categorise these different stages and can be found at http://www.iris-kidney.com/.  Cats' kidney disease can be staged based on their urine concentration and blood creatinine levels.

As nephrons are destroyed, the kidney becomes damaged, and it can’t perform normally.  The cat enters a stage of chronic renal insufficiency (Stage 1 IRIS) where they are still able to excrete waste products and maintain their weight, but will drink more water in order to do it. They may remain in this stage for several weeks to many years. They may be relatively healthy unless they get stressed or sick.

Eventually all cats will enter a stage of chronic renal failure (Stage 4 IRIS), which is the progression of disease which results in build up of waste products, dehydration, anaemia and eventually death.

There is also a new test called SDMA, offered by IDEXX labs, which can indicate the presence of kidney disease even before creatinine levels are high. A high SDMA level can prompt further diagnostics and increased monitoring of a cat, so kidney failure can be slowed down as much as possible.

Clinical signs of kidney failure

• Excessive drinking or urinating
• Weight loss
• Poor appetite
• Lethargy
• Vomiting
• Bad breath and mouth ulceration
• Unkempt or dull fur coat

Diagnosis

The most common way of diagnosing kidney disease is with blood and urine tests. Unfortunately, demonstrating a high level of waste products (urea/creatinine) in the blood tells us that the kidneys are not working properly, but it does not tell us what has caused the initial problem. Additional tests are often needed and may include:

• Urinalysis, where we look at urine concentration, and the presence of glucose, protein, blood, bacteria, crystals and cells in the urine
• Urine culture and sensitivity if infection is suspected
• Abdominal ultrasound
• Abdominal X-ray
• Needle aspirates or biopsies.  This is often done under ultrasound guidance if the kidneys are enlarged.
• Other tests, such as excretion tests, protein:creatinine ratios, etc

It is important to identify the cause as many diseases are treatable. In many cases it is impossible to identify the underlying cause without the use of these additional tests.

Treatment

The treatment for kidney disease will be different for every cat, depending on the cause and severity of the disease.

These include:

• Fluid therapy (intravenous or subcutaneous)
• Dietary protein restriction
• Dietary phosphorus restriction
• Controlling high blood pressure
• Iron and specific vitamins
• Appetite stimulants
• Erythropoietin
• Other specific treatments depending on the cause of kidney disease

If your cat has been diagnosed with chronic renal insufficiency, they should see a veterinarian every 3-6 months in order to record her body weight, get blood and urine samples and measure her blood pressure. This careful monitoring allows the vet to change her treatment if it becomes necessary.

The treatment for cats with chronic kidney failure will depend on many factors and may change as the disease progresses. Most cats will be treated with special diets, vitamins, iron, appetite stimulants, subcutaneous fluids and, if anaemic, will receive erythropoietin injections.

Outcome for Cats with Chronic Renal Failure

With early diagnosis and appropriate therapy, cats may live for years with chronic renal failure. It is impossible to give an accurate prognosis or life expectancy as there is a lot of variation between individual cats and the type of kidney disease present.

When is it time?

Chronic renal failure is usually a progressive condition. Our aim is to slow the progression as much as possible and maintain a good quality of life for your cat.

As the disease progresses, your cat will get weaker and sicker, and they will eventually die.  This is a very emotional time and careful assessment of your cat’s condition needs to be made.

As a general rule, once your cat loses his appetite despite our therapy, we will recommend that they should be put to sleep. The “right time” will be very different for every cat and for every owner. We will always be available to discuss your situation and do our best to make things as comfortable as possible for you and your cat.

Water Intake Test

Water intake tests are very important to help us work out whether your cat is drinking too much water. Some diseases make cats drink more water than they should. Monitoring the water intake can be an important part of checking the response to treatment for diabetic cats.

Water intake can vary depending on many factors, including the weather, the type of food your cat eats and how much activity he or she does. Consequently the amount of water your cat drinks can vary from day to day. Because of this, we do a Water Intake Test over 2 consecutive days (2x 24 hour periods) so that we can average out how much is actually taken.

It is very difficult to assess water intake if there is more than one animal in the household, as they share water sources. To do a Water Intake Test accurately, animals may need to be kept separate over the time of the test. Alternatively they may need to be hospitalised so that they only get to drink from one source.

Step 1: Empty out all bowls that your cat normally drinks from, inside and outside the house.

Step 2: Measure exactly how much water you add to each bowl. Make a note of this.

Step 3: Don’t allow the bowl to be empty of water. Note down the amount of water you add to the bowl during the day and add this figure to the figure from Step 2.

Step 4: After 24 hours, measure exactly how much water is left in each bowl or bucket.

Step 5: Subtract the amount left over from the amount in Step 3.

Step 6: Repeat Steps 1-5 over 1 more 24-hour period.

Bring your calculations into the clinic or call us so we can assess the amount taken in and work out whether this is normal or abnormal.

What is spraying?

Urine spraying is part of the cat's normal scent-marking behavioural repertoire which also includes scratching, rubbing, chinning, bunting (depositing secretions from head glands on twigs etc., and middening (leaving faeces uncovered). Using these scent markers cats can deter others from their range and cats which share a hunting range can avoid one another without coming into direct conflict.  Spraying is also designed to help females in oestrus ('in season' or 'on heat') to attract males for breeding.  When spraying the cat stands with its tail vertical (often quivering at the tip) while it delivers a squirt  of urine backwards onto a vertical surface.  This spray probably contains information about sex, age, hormonal state, assertiveness and general health.

Why do cats spray?

Cats may spray when frustrated, upset or subject to competition or challenge and spraying can be interpreted as the cat increasing its own sense of security by surrounding itself with signals of its own occupancy in its territory.  The more anxious the individual, the more he or she will need familiar odours for comfort.

Do only tom cats spray?

No, all cats, male or female, neutered or not, may spray, usually outside where we may not see them.  Un-neutered toms and queens in oestrus will spray more.

Why do cats spray indoors?

Most neutered pet cats feel sufficiently relaxed in their own home and do not spray.  They identify it by rubbing scent from their body and do not need to mark by spraying, scratching or middening. 

The most common sites for indoor spraying are near entrances to the house or room, curtains and new items brought into the house, e.g., plastic bags, new furniture etc., although individuals may have their own idiosyncratic targets such as washing machines, video players or even certain people!  As with most behavioural problems a little detective work may be needed to get to the root of the behaviour problem.  While there may be no 'quick fix' solution in some cases, helping to find and understand the motivation for the behaviour will help while you work towards a solution.

There can be many triggers for a cat marking indoors:-

1.      The arrival of a new cat, dog or person in the family, or a bereavement.

2.      Changes in the home area such as furniture or new carpets. Disruptions such as  building work.

3.      Installation of a cat flap which can make the cat feel insecure indoors.

4.      In rare cases, spraying can be a learned attention-getting behaviour.

Occasionally urine marking may be carried out from a squatting position usually on the floor, but often on bedcovers or chairs. The cat may still use the litter tray for eliminating larger volumes of urine.  This often occurs when owners leave their cat at home but in their neighbour's care when they go on holiday and may be a form of 'associative 'marking - the cat feeling anxious because it is alone, is relieved when it associates its smell with that of the owner - usually in a spot where the owner's smell is concentrated such as on the bed or armchair.

Can urinary tract infections cause spraying behaviour

Quite commonly cats with urinary tract infections or inflammation will also spray urine. For this reason, it is important for the veterinarian to perform a urinalysis on all spraying cats to ensure that the correct therapy is instituted. The treatment for a urinary tract infection will be very different to behavioural spraying so a correct diagnosis is necessary.

Can the problem be treated?

Cats marking indoors clearly require a clear and extensive approach to diagnosis of cause(s) and careful development of treatment which will not unsettle them even more!  It is vital to discover under which situations the problems occur as treatment often depends on defining any specific anxiety-inducing trigger(s) for the behaviour.

It is useful to know the following:-

1.      When did the problem first occur?

2.      Which people or other animals are normally present in the house. What are the attitudes of all the family towards the cat.  What are they doing before, during and after the problem occurs.

3.      Are there any other behaviour problems in the cat or its feline housemates and is it receiving any medical treatment?

4.      Where is the marking occurring? The layout of the house and even the garden may be important. Are there rival cats outside?

5.      What is the cat's daily routine? Does it have free access to outside? Where does it eat and sleep, how much time is spent interacting with the owner and what do they do together.

6.      What methods have already been tried to solve the problem? How are the marks cleaned?

The main aim of treatment is to reduce the perceived threat to the cat and make it feel more secure in its home territory, thus reducing its levels of arousal and curtailing the need to scent mark. 

Identifiable sources of stress should be removed, e.g., by excluding local rival cats from entering the home by blocking the cat flap or replacing it with a selective one.  Carefully introduced friendly routines of handling, feeding and playing will help provide reassurance, providing such contact does not further alarm the cat at any stage.  In many cases there may be no single obvious threat and the cat's behaviour may be the result of the cumulative effect of several influences. 

If such sources of stress cannot be removed or even fully identified the cat should be provided with a safe haven of a small core territory of one room in the house to which it can safely retreat or be placed to relax without fear of disturbance for regular periods and where it should only feel the need to mark normally by rubbing and bunting.

Often people simply become 'over-catted' - they enjoy their feline housemates and because one extra takes up little more physical space and is no more effort to feed, they will continue to collect more.  This may be fine until a certain mix of characters just doesn't gel and relations within the group become strained and spraying begins. 

Careful introductions can help but sometimes certain individuals simply cannot share a home without stress and it is better to re home one or more.  Although this may not be a popular decision, it may be the only option if home hygiene is to be maintained as trying to manage the problems can be very difficult with a number of cats and associated variables.

All forms of punishment should be discontinued (even if the cat is 'caught in the act') as this is only likely to raise the cat's level of arousal and anxiety.  You may feel often angry and want to react if you catch the cat 'in the act', however, stopping all punishment and threatening behaviour is an essential first step towards improvement.

Placing food (dry food is best) or a bed at the base of spraying sites is often helpful at protecting those particular areas as cats are extremely reluctant to spray their own key resources, although they may simply move to other areas and mark there instead.  Food and beds are also reassuring and may reduce anxiety.

Spraying can be triggered by the smell of previous marks so marked areas should be thoroughly cleaned (not with ammonia-based products as ammonia is a constituent of cat urine). A damp cloth should be used to remove any fresh urine marks and while some commercially available 'urine digester' products remove the smell (to the sensitivity of the human nose at least), no data has been published on relative efficacies. 

An enzymatic or biological washing powder or liquid may be just as effective at removing residues. Follow with agitation using a light brush with a low grade alcohol (test the colour fastness of material/carpets first).

It is unlikely that spraying will be effectively resolved with drugs without trying to ascertain the cause of the problem and without employing management changes and behaviour modifications. 

Some very good drugs are available but their use should be based on sound understanding of the problem, cat and the effects of the drug on the feline physiology. Drugs should alter a cat's mood to enable it to learn new forms of behaviour and the drugs should then be withdrawn.

Recently a plug in diffuser called “FELIWAY” has been available which supplies a feline facial pheromenone to a 75m2 area and has been very effective controlling many feline behavioural problems, including urine spraying.

What is hyperthyroidism?

Hyperthyroidism is the most common endocrine (hormonal) disorder that affects cats. It is rarely seen in cats less than eight years of age and there is no sex or breed predisposition. It is caused by an excessive production of thyroid hormone by the thyroid glands situated in the neck.

Thyroid hormone controls the body’s metabolic rate, or activity level, and too much of it (hyperthyroidism) causes your cat to be hyperactive and to lose weight even if he is eating well.

What causes hyperthyroidism?

Usually, hyperthyroidism is caused either by excessive growth (hyperplasia) of the thyroid gland, or by a benign tumour of the thyroid (adenoma). Both thyroid glands are usually involved, although one gland may be more severely affected than the other. The cause of this benign change is unknown. However, it is likely that multiple factors are involved, including genetics, diet, environment and the immune system.

In rare cases, the disease may be due to a malignant tumour (thyroid adenocarcinoma).

What are the signs and symptoms of hyperthyroidism?

Clinical signs of hyperthyroidism are usually subtle at first, and get more severe as the disease progresses. The most characteristic signs are:

• Weight loss
• Increased appetite
• Hyperactivity and restlessness

Less common signs include:

• Increased heart rate (tachycardia)
• Increased urination and/or thirst
• Vomiting or diarrhoea

In advanced cases, your cat could become lethargic and weak and lose her appetite.

Are there any complications of hyperthyroidism?

Yes.  Cats with untreated hyperthyroidism can develop hypertrophic cardiomyopathy (in which the heart muscle becomes abnormally thickened) and hypertension (high blood pressure). Initially, these complications may require specific treatment, but usually resolve once the underlying hyperthyroidism is well controlled.

How is hyperthyroidism diagnosed?

Once hyperthyroidism is suspected, a thorough physical examination and some blood tests will be required to confirm the diagnosis.

On physical examination, an enlarged thyroid gland may be felt as a small, soft mass, on either side of the neck. It may be difficult to detect, as the glands are freely movable and can slide along and behind the windpipe (trachea). In some cats, it may not be able to be palpated.

Diagnosis is confirmed by determination of serum thyroid hormone levels. In most affected cats, both thyroxine (T4) and triiodothyronine (T3) are elevated. However, elevation of T4 is a more reliable indicator of hyperthyroidism.

In rare cases, a cat may have normal thyroid hormones, but has all the symptoms of hyperthyroidism. In those cases, your vet may do further testing. Usually all that is required is to repeat the thyroid hormone testing at another time.

Other laboratory tests that might be ordered are:

• Liver enzymes, which may be elevated with hyperthyroidism
• Chest x-ray or ultrasound if cardiomyopathy is suspected
• Doppler blood pressure monitoring to check for high blood pressure
• Testing for renal failure before starting treatment.

How is hyperthyroidism treated?

There are three options available for the treatment of hyperthyroidism: administration of anti-thyroid drug therapy, surgical thyroidectomy and radioactive iodine therapy.

Anti-thyroid drug therapy

Anti-thyroid drugs act by interfering with the production of thyroid hormone. These drugs control hyperthyroidism, but do not cure it.  Your cat will need treatment for the rest of his life.

Most of the time you will need to give your cat the medication three times a day for two or three weeks, until her thyroid level is normal. After that, she will need the medication twice a day. She will also need regular follow-up appointments with the vet.

Some cats experience mild and usually transient side effects from the medication. They usually go away within a few weeks. You could see:

• Poor appetite
• Vomiting
• Lethargy

More serious side effects include low white blood cell count, clotting problems or liver disorders. Your vet will perform routine blood tests to monitor for these problems.

Surgical thyroidectomy

Surgical removal of the affected thyroid gland (thyroidectomy) can produce a permanent cure. However, in some cats, signs of hyperthyroidism may recur, due to the production of thyroid hormone at other sites previously unaffected.

Surgical skills and experience are necessary to minimise the risk of post-surgical complications.

The major risk associated with thyroidectomy is inadvertent damage to the parathyroid glands. They lie just next to the thyroid glands and are essential in regulating blood calcium levels.

If your cat has hypertrophic cardiomyopathy because of the hyperthyroidism, using general anaesthesia is a concern.  To reduce the risk of anaesthetic complications, these cats are usually stabilised with medications for a few weeks prior to surgery.

Radioactive iodine therapy

Radioactive iodine therapy (I131) can be used to provide a safe and effective cure for hyperthyroidism. Radioactive iodine is selectively taken up by active thyroid tissue and destroys the tissue.  Radioactive iodine therapy is a good option when surgery is contraindicated, or when the excess thyroid tissue can’t be surgically removed.  A single dose is curative in the majority (98%) of cats.

Radioactive iodine is the only effective treatment for cats with thyroid adenocarcinoma.

The treatment can only be performed in a specially licensed facility. Your cat will usually have to stay in the hospital until the radiation level has fallen to within acceptable limits. This is usually for a period of 7 days following treatment.

Summary

Hyperthyroidism is a common disorder of older cats and is due to an increased production of thyroid hormone. Due to the action of thyroid hormone on multiple body organs, it can have wide and varied effects. However, if recognised early and treated appropriately, the outlook for affected cats is generally good.