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Cancer in cats and dogs

by admin on February 1st, 2019

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Assessment of the patient
Cancer is common in human and veterinary medicine. Approximately one quarter to one third of all our patients will suffer from cancer at some point in their lives, which is similar to the incidence of cancer in human medicine. So, we encounter a large number of patients with cancer during our clinical work, and we also find that many owners themselves will have some first-hand knowledge of cancer, which may affect the decisions they make about the disease in their pet.

The investigation and management of animals suspected of having cancer or known to have cancer is relatively straightforward and generally proceeds in a similar manner for all patients, with a few basic rules followed in a stepwise manner. When investigating a particular tumour, we never forget that the tumour is attached to a patient, and that we need to carefully consider the care and needs of the pet as well as those of their owner. Our approach is one of keeping owners fully informed at each step and making plans for investigation and management of the pet only after careful discussion with the owner.

Outline:
The following information is divided into the following sections:

  • Investigation and care of the patient
  • Investigation of the tumour
  • Identification of the most appropriate therapy

The information is arranged in this way, because this is the way that our patients present to us and because we think of the patient first, his or her disease second and the proposed therapy third. In particular, we always make every effort to ensure that we have a correct diagnosis before we begin therapy and that the patient will be able to tolerate the treatment prior to us starting it.

1. Investigation of the patient

General assessment of the patient
When presented with an animal suspected of having or known to have cancer, our initial approach is to assess the patient and then assess the tumour. Each patient is different, as is each tumour, and the investigative approach is therefore tailored to the individual, although the same basic principles apply.

When presented with a patient with cancer, we want to get an accurate assessment of the long-term outlook or prognosis. The prognosis for animals with cancer depends on a number of factors:

  • The microscopic or histological type of the tumour, i.e. what cells are in the tumour?
  • The grade of the tumour, i.e. how aggressive do these cells look under the microscope?
  • The clinical stage of the tumour, i.e. is there any evidence that the tumour is affecting more than one site in the body?
  • The presence of tumour-related complications (so-called ‘paraneoplastic syndromes’)
  • The presence of other diseases

Our approach is to:

  • Assess the general health of the patient
  • Identify any other diseases present
  • Confirm the presence of a tumour
  • Gain as much information as possible about the tumour
  • Identify how the tumour is affecting the patient currently

The basic principles in assessing the patient with cancer comprise:

  • Tumour measurement
  • Staging the tumour
  • Assessment of the patient’s general health and fitness
  • Diagnostic imaging (e.g. X-rays, ultrasound, CT scan, MRI scan)
  • Blood samples to look at the various blood cells and other substances in the blood (haematology and biochemistry)
  • Examination of samples from the tumour or other sites, either samples of cells (cytology) or tissue (histology)

Two important factors are the grade and stage of the tumour, both of which must be assessed. Grade is assessed under the microscope and compares the tumour cells to the normal cells of the same type.

  • Grade predicts the biological behaviour of the tumour, e.g. benign or malignant and how different from normal the cells look
  • Grade answers the question ‘How might the tumour affect the patient in the future?’

Stage is assessed clinically and with diagnostic imaging and sometimes samples of cells or tissues.

  • Stage tells us where the tumour is within the patient, e.g. is it restricted to the site where it started growing, or has it spread to other tissues, e.g. lymph glands (lymph nodes) and other organs
  • Stage answers the question ‘How is the tumour affecting the patient right now?’

Tumour staging
One of the most important ways to assess the patient with cancer, is the ‘TNM’ system. This involves:

  • Examination of the primary Tumour (with a biopsy – see later)
  • Assessment of the regional lymph Nodes (the ‘glands’ such as we have in our necks)
  • Assessment of other sites for Metastasis (spread elsewhere)

Staging is generally performed by a combination of physical examination, diagnostic imaging and taking biopsy samples of the tumour to look at under the microscope (‘cytology’ or ‘histology’). In some cases, the appearance on diagnostic imaging may be sufficient to make a diagnosis without biopsy, e.g. nodules in the lungs seen on an X-ray of the chest suggests spread of cancer cells to the lungs.
This clinical staging represents the ‘gold standard’. However, this approach is not necessary or appropriate in all cases. For instance, for a pet with a benign tumour confirmed with a biopsy taken by sucking cells out of the tumour through a hypodermic needle (needle biopsy), the prognosis (outlook) is excellent and the likelihood of tumour spread is very low, so staging may be taken no further after gaining some information about the primary tumour.

Care of animals with cancer
We all may have our own view of how the tumour is affecting the pet and owners may well have other concerns about their pets apart from the fact that they have a tumour. The supportive care of the patient is the second part of compassionate patient care, after ‘diagnosis’ and before ‘therapy’. This is important, since we wish to avoid the tendency to leap from diagnosis to treatment without considering what supportive care is needed.
Our approach can be summarised by three important rules, which we all consider:

  • We should ensure that our patients do not experience pain or discomfort associated with the tumour or its treatment
  • We should ensure that our patients are able to eat a normal amount of food to meet their nutritional requirements, and if they cannot, we should think about how to help them to do so
  • We should ensure that our patients do not suffer side effects of the tumour or therapy, such as vomiting or feeling sick when undergoing treatment, if at all possible

Management of chronic cancer pain
When asked what our concerns about cancer would be, most of us would say that pain associated with cancer would be uppermost in our minds. As a rule, we understand how to manage acute pain after an operation (see later), but the management of chronic cancer pain in a patient where a total cure is not possible is sometimes more difficult to achieve.

We have detailed methods of assessment of pain and discomfort and understand the importance of treating and managing any pain or discomfort associated with cancer. It is important to realise that management of pain does not just involve drugs traditionally thought of as ‘painkillers’ but may also include other drugs that have an effect on the way nerves and the brain deal with pain (e.g. gabapentin and amitryptiline) or drugs and other therapies that have an effect on the tumour itself (e.g. bisphosphonates or radiotherapy in cases of the bone tumour, osteosarcoma).

We should also bear in mind that in some tumours the most successful method of pain relief may be surgical removal of the tumour itself, whether that is a procedure designed to cure the patient or a treatment designed to remove or reduce the clinical signs associated with the presence of the tumour without totally curing it.
2. Investigation of the tumour

Tumour biology
As a general rule, if we do not understand the basic biology of a disease i.e. the behaviour of the cancer cells in the patient’s body, we cannot provide appropriate treatment. One important lesson that has emerged from both human and veterinary oncology over the past few years is that, when it comes to cancer, the biology of the disease will dictate what happens in the long-term.

A common question asked when a diagnosis of cancer is made in our pet is ‘What caused the cancer?’ While we know something about some causes of cancer (and what is happening in the cancer cells and their genes), for the most part, we do not know the cause.

The total number of cells in a person or animal is a balance between the number of cells growing and those dying. For a long time it has been considered that cancer is a disease caused by uncontrolled cell growth. However, of more importance is the fact that cancer cells refuse to die when programmed to do so (this programmed, and perfectly normal, cell death is called ‘apoptosis’). Cancer therapies that encourage cell death are likely to be just as important as, if not more important, than therapies that prevent cell growth.

Other examples of cutting edge treatments in humans that have been developed as a result of understanding tumour cell biology include those designed to stop the early phase of tumour spread (metastasis) by preventing tumour cells moving through the tissue, and those causing a reduction in tumour growth by preventing the tumour causing the growth of new blood vessels (angiogenesis) which the tumour needs in order to grow.

Tumour pathology
Pathologists play a critical role in the investigation of the patient with cancer by examining tissue from the primary tumour (the original site of the growth) and, in some cases, the lymph nodes and other potential sites for spread (metastasis).

Assessment of cells obtained from a mass with a hypodermic needle (cytology) is often the first approach in the diagnosis of an animal suspected of having cancer, but in most animals, examination of a tissue sample (histology) is necessary at some point during the assessment of the patient.

Histological assessment of the tumour may also provide more specific information regarding the outlook or prognosis:

  • Examination of the tumour edges after the growth has been surgically removed may tell us whether the tumour is likely to grow back in the same place (i.e. if there are tumour cells at the edge of the specimen, it is likely that tumour cells have been left in the patient)
  • Examination of a large specimen for evidence of tumour cells spreading into the blood vessels or lymph drainage vessels may suggest whether the tumour is likely to spread

Other effects of the tumour (Paraneoplastic syndromes)
Paraneoplastic syndromes are additional effects that cancer might have in parts of the body away from the primary (or original) tumour. These abnormalities may have an effect on the patient’s health and may affect their ability to tolerate sedation or anaesthesia and treatment. The paraneoplastic syndrome may be the main reason for the animal being taken to the veterinary surgeon in the first place (the owner may not even realise that there is a tumour somewhere) and these syndromes also may provide a useful guide to the success of therapy, i.e. if the paraneoplastic syndrome gets better, this suggests that the tumour tissue has been removed or destroyed. In rare cases, the paraneoplastic syndrome may be very obvious but the location of the underlying primary tumour is more difficult to find, even for the veterinary surgeon. In such cases, additional imaging procedures can prove very helpful.

Examples of these syndromes are alterations in the number of red blood cells or white blood cells in the circulation and abnormalities in the blood level of glucose or certain salts or ‘electrolytes’ (e.g. calcium).

3. Treatment of the patient with cancer

Achieving a diagnosis
As a general rule, a biopsy (taking cells or a larger piece of the tumour for analysis) is needed before beginning any therapy, unless we have a good reason not to take a biopsy. A biopsy may be omitted if knowing more about the tumour would not change the treatment plan or the willingness to treat the patient. However, care is taken to ensure that these reasons apply in any individual patient. A biopsy should always be tailored to the individual tumour and we will always consider whether a biopsy of the regional lymph node (gland) or other sites of potential metastasis (spread) is needed at the same time.

Selecting the best cancer treatment for the patient
Once a diagnosis has been achieved and we have information on clinical staging, the effect of the tumour on the patient and any concurrent diseases, and once we have identified whether the patient needs additional supportive care, we can start to consider different treatment options.

The main treatment options for the management of cancer are:

  • Surgery: The physical removal of the tumour
  • Radiotherapy: The use of a strong X-ray beam to destroy the cancer cells where they sit
  • Chemotherapy: The use of anti-cancer drugs to kill cancer cells wherever they are

Each of these has specific advantages and disadvantages and may be used singly or in combination. All of the factors listed above, particularly the tumour type, grade, stage and location and the presence of other health problems will help to decide what the most appropriate therapy is. Therapy may be designed to cure the patient or to remove the signs of illness for as long as possible, if a complete cure is not possible.

In addition, other ways of treating various types of cancer are becoming more common in human oncology, and these benefits will become available for our patients in due course.

These include:

  • Immunotherapy, e.g. vaccination with melanoma-specific antigens in patients with melanoma (a tumour of the pigment cells in the body)
  • Targeted therapy with small molecule inhibitors, e.g. tyrosine kinase inhibitors (TKIs) which may be used in some patients with mast cell tumours

Monitoring the response to therapy
Once the cancer has been treated, the patient will still be monitored in various ways, depending on the nature of the tumour and the aim of the therapy. This may involve a number of the tests (e.g. blood samples, X-rays) used to make the diagnosis in the first place and a plan for monitoring will be tailored to the needs of the patient. This may include:

  • Monitoring for the return (local recurrence) of the tumour at the original site
  • Examining for the presence of tumour spread elsewhere
  • Monitoring for the development of new primary tumours at other sites

If you have any questions about your pet’s condition, or his or her treatment, please do not hesitate to contact us.

Cancer in dogs and cats

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Pet of the month – February – Jackson

by admin on February 1st, 2019

Category: Pet of the Month, Tags:

Pet of the month is lovely Jackson, who pops into the clinic every week for socialisation clinic with our nurses. He has been coming in since he was a small puppy. He’s now 5 months old and still comes in weekly and LOVES it!

It’s a great way of ensuring a stress free visit for you and your pet and a prime age for socialisation skills for puppies! If you have a puppy and would like to do the same, please contact us, we’d be happy to help!

Jackson

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Special offer – February 2018

by admin on February 1st, 2019

Category: Special Offers, Tags:

Feb Neutering Offer

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Special offer – January 2018

by admin on January 2nd, 2019

Category: Special Offers, Tags:

Dental Offer 2019

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Pet of the month – January – Brooke

by admin on January 2nd, 2019

Category: Pet of the Month, Tags:

Pet of the month for January is Brooke, a 9 year old Jack Russell Terrier cross, who has suffered from Diabetes Mellitus since last August. We are delighted to report that she is doing very well and has just been into the clinic for one of her regular monitoring appointments called a ‘blood glucose curve’ (see below).

What is Diabetes Mellitus (Sugar Diabetes)?
Most of the food that animals eat is turned into sugars to provide energy for the body. The sugar in the blood then needs to get into the cells of the body to help them work. A hormone called insulin, which is produced by the pancreas (an organ in the tummy near the stomach), helps the sugar to get into the cells. Diabetes develops when the body does not produce sufficient insulin. Insulin regulates blood sugar levels, and when the insulin levels are too low, blood sugar (glucose) levels increase, resulting in diabetes. Diabetes is a potentially life threatening illness, but fortunately it is one which we are able to treat successfully in the majority of cases.

Diabetes occurs most commonly in older dogs, and in middle-aged overweight cats. Some dogs and cats develop diabetes when they are younger, because they have a genetic predisposition for the condition.

What are the signs of Diabetes?

  • Increased thirst
  • Increased frequency and/or volume of urination
  • Possible increased appetite
  • Possible weight loss
  • Possible smelly urine – because of the presence of ketones (see below) or infection
  • Possible lethargy/tiredness

How is Diabetes diagnosed?
Diabetes is diagnosed by careful assessment of the patient’s history and a physical examination, followed by blood and urine tests. Excessive levels of sugar in the urine and blood are highly suggestive of diabetes, although occasionally a sick or anxious patient may have increased sugar levels as a result of stress (such as visiting the vets!). If there is some doubt about the significance of a single high blood and urine sugar result, we may perform a special blood test (fructosamine) which gives us an indication of the blood sugar levels over several previous weeks.

When a patient is diagnosed with diabetes, we often look for underlying causes of diabetes such as obesity, Cushing’s syndrome (a steroid hormone imbalance), pancreatitis (inflammation of the pancreas – the organ that produces insulin) or previous administration of some medications. If we find any of these underlying problems, they also need to be managed alongside the diabetes.

What effects does diabetes have?
Diabetes leads to a build up of sugar in the bloodstream and in the urine, and not enough sugar can actually get from the blood into the tissues that need sugars to work properly. This leads to widespread effects on the body, including urinary tract infections, kidney disease, liver disease and eye disease.

If diabetes is left untreated or poorly controlled, the body is starved of glucose-based energy supplies, and the body reacts by using up protein and fat stores for energy instead. Protein stores can be converted to glucose, but using up stored fat leads to the production of substances called ketones. A build up of ketones can lead to a very serious condition called Diabetic Ketoacidosis (see later) – this is a medical emergency requiring intensive care.

How is Diabetes treated?
Diabetes is best treated with insulin. In most cases, insulin is administered as an injection under the skin twice a day. There are also tablets that can be used to help regulate blood glucose levels, but these are not the best way of treating the condition.

Although owners are often concerned about giving injections to their pet, most dogs and cats are very amenable to being given injections. If your pet is diagnosed with diabetes, we will spend as much time as is necessary to teach you how to give insulin injections and how to look after the insulin and syringes.

There are several types of insulin, and the dose of insulin is very individual. It is very important that you do not change the dose of insulin without instructions from your veterinary surgeon. Most dogs and cats need a little modification of the doses of insulin with time, and these changes will be made based on monitoring and blood tests. You may be instructed on how to monitor blood or urine glucose/ketone levels at home. Urine should be checked regularly for the presence of ketones, as the presence of these for two or more days can indicate a complication of uncontrolled diabetes – Diabetic Ketoacidosis (see later).

Care and use of insulin:
It is important that affected dogs continue to exercise regularly as this will help to keep their weight down. Also exercise has also been shown to make insulin work better, resulting in better stability of the blood sugar levels.

  • Diet - In addition to insulin, it may be important to modify your pet’s diet, particularly if your dog or cat is overweight, or has inflammation of the pancreas (pancreatitis) in addition to diabetes. These dietary changes will be directed by your veterinary surgeon. Once stabilised, dogs and cats are fed just before the insulin is administered, to make sure that they have eaten before the insulin is given. We have a full-time veterinary nutritionist who can be consulted regarding the specific dietary needs for your pet.
  • Exercise - It is important that affected dogs still exercise regularly. This helps them to maintain a healthy weight, and it helps to keep the blood sugar more stable.

How quickly does the treatment work?

  • Don’t expect a quick fix. It can be very difficult to regulate the blood sugar in some diabetics. Even in the best situation, it will take several weeks, including check-ups and blood tests, before your pet’s diabetes can be stabilised. It is important to discuss any concerns you have about giving insulin with your vet at any check-up. We may ask you to show us how you are storing insulin and administering it, should control be proving difficult.

Some medications (such as steroids e.g. prednisolone), hormones (such as progesterone) and diseases (e.g. infections such as tooth and gum infections) will interfere with insulin’s action in the body. Any additional medications that your pet is having should be discussed with your veterinary surgeon prior to use. Because hormones affect the action of insulin, it is important that entire female bitches are neutered (spayed) to help to control their diabetes.

What is a ‘hypo’ episode (hypoglycaemia)?
Hypoglycaemia is a low blood sugar level. This occurs when too much insulin for the amount of food eaten results in too little sugar circulating in the blood. This most often occurs when a pet does not eat and still has insulin given, or is accidentally given a higher than normal dose of insulin (most often because the insulin is given twice, by mistake). Low blood sugar levels will make the affected animal very weak, and this can result in collapse or twitchiness and seizures (fits). If you are ever concerned that you have given your pet too much insulin, or that you have given insulin and your pet has not eaten, or has vomited up his or her food, please contact us.

How to monitor your pet’s diabetes at home
There are many features you can measure or observe at home to help to monitor your diabetic pet:

  • Amount of water being drunk
  • Frequency and volume of urination
  • Appetite – how much is eaten?
  • Body weight
  • Behaviour
  • Presence of ketones/glucose in your pet’s urine (using a special dipstick that you put into the urine)

It is very helpful to make a diary with this information in it, and provide it to your vet at every check-up.

Follow-up consultations are performed frequently (the frequency depends on the individual patient). These follow-up visits may include a single blood test (fructosamine), or they may be followed by admission of your pet into hospital for the day for a ‘blood glucose curve’. A blood glucose curve involves us performing several small blood tests throughout the day, and plotting the results on a graph (making a ‘curve’ on the graph). This allows us to see how your pet’s blood glucose changes throughout the day which can be useful for adjusting your pet’s food intake and insulin dosing regime.

What are the possible complications of diabetes?

  • Cataracts – cataracts are changes in the lens inside the eye which can lead to blindness. Many dogs develop cataracts within 6 to 12 months of developing diabetes. Specialist treatment is available, and the majority of diabetic patients do very well after cataract surgery. Diabetic cataracts do not tend to develop in cats unless the diabetes occurs when they are very young • Retinal disease – degeneration of the sensitive area at the back of the eyes
  • Neuropathy – disease of the nerves causing weakness
  • Nephropathy – kidney disease
  • Infections – it is common for diabetic patients to develop infections, especially of the urinary tract (bladder and kidneys)
  • Ketoacidosis – in cases of uncontrolled diabetes, toxic (poisonous) metabolites (natural break-down chemicals) are produced which can lead to illness, lethargy, coma and death

The better the stabilisation of the patient, the better these complications are likely to be controlled or prevented.

What is the long term outlook?
Diabetes can be a very rewarding condition to manage. Most pets are very amenable to treatment, and diabetic animals can have a very good quality of life. Diabetes in cats can be temporary, and affected cats may only require insulin administration for a limited time (often 3 to 6 months) provided that the underlying cause, such as obesity or pancreatitis, is removed. Many dogs with diabetes eventually develop cataracts and these can cause quite rapid onset blindness. Fortunately most diabetic dogs with cataracts are good candidates for surgery, and Specialist eye vets are very experienced in treating cataracts.

Patients should be reassessed at regular intervals set by your veterinary surgeon. Pets that are having insulin treatment should also be reassessed if they:

  • become unwell
  • are losing weight
  • have a change in appetite
  • have excessive thirst or urination
  • become weak, wobbly or disorientated (this can be an emergency due to hypoglycaemia or severe diabetic ketoacidosis – see above)
  • have ketones in their urine for more than 2 consecutive days

If you have any concerns about your diabetic pet please do not hesitate to contact us.

Brooke

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Canine Demodicosis

by admin on January 2nd, 2019

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What are Demodex mites? And what is demodicosis?
Demodex spp. are cigar shaped microscopic parasitic mites that live within the hair follicles of all dogs. These mites are passed to puppies from their mothers in the first few days of life, and then live within the hair follicles for the duration of animal’s life without causing problems. It is thought that the body’s immune system helps to keep mite numbers ‘in check’ and prevent the populations getting out of control. For the vast majority of dogs, these mites never cause a problem. However in some instances, mite populations become huge resulting in inflammation and clinical disease. This disease is called demodicosis.

What causes demodicosis?
There are two presentations of demodicosis depending on the age at which it develops. Juvenile onset demodicosis tends to occur in puppyhood between the ages of 3 months and 18 months, and occurs in both localised and generalised forms. The exact cause is quite poorly understood but probably occurs due to a mite specific genetic defect in the immune system which allows mite numbers to increase. This defect may or may not resolve as the puppy ages. It is thought to be ‘mite specific’ because these puppies are healthy in all other respects and do not succumb to other infections. Generalised demodicosis can be a very severe disease. Adult onset demodicosis usually occurs in the generalised form and in dogs over 4 years of age. It is generally considered a more severe disease than its juvenile onset counterpart. In these cases, mite numbers have been controlled in normal numbers in the hair follicles for years prior to the onset of disease, which tends to result from a systemic illness affecting the immune system. Common triggers for adult onset demodicosis include hormonal diseases and cancer.

What are the clinical signs?
Localised demodicosis in juvenile dogs presents as patches of hair loss and red inflamed skin. These patches often occur around the face, head and feet and are not typically itchy.

Generalised disease in juvenile and adult dogs is a more serious disease, although there is no uniformly accepted way of defining the number of lesions needed to classify generalised disease. Patches of hair loss and inflammation develop which often coalesce into large areas of thickened skin and sores. As the parasites damage the hair follicles, secondary bacterial infections are very common and affected dogs can develop discharging lumps within the skin. Bleeding from these lesions is not uncommon. As with the localised form, lesions often start around the head, face and feet, but often spread to involve large areas of the body surface. The ears can also be affected with this parasite, resulting in secondary infections. Itchiness and pain are commonly seen.

How is it diagnosed?
Demodicosis can often be suspected following a review of the animal’s history and assessment of the clinical signs. The parasitic mites within the hair follicles result in plugging and the formation of ‘black heads’. The plugged follicles also cause large amounts of scale to be present on the hairs themselves. Demodicosis can usually be diagnosed relatively easily. Hairs can be plucked from the affected skin and then examined under a microscope for the presence of the mites. Alternatively, the skin can be squeezed and then scraped with a blade to collect up the surface debris from the skin. This material is then also examined under a microscope for the parasites.

If the numbers of mites are abnormal and if mites can be recovered from multiple sites, demodicosis can be diagnosed. Rarely, a biopsy of affected skin is needed to diagnose the condition.

Is it contagious?
Demodex mites from dogs are considered non-infectious to in-contact animals and people. It is thought that Demodex mites can only be passed between dogs in the first few days of life from the mother to the pup.

How is it treated?
The treatment used for demodicosis depends on the age of the animal and the severity of the disease. Mild and localised forms of demodicosis in young dogs may not require treatment, and may resolve spontaneously as the animal ages. These cases should be closely monitored if no treatment is given. Generalised cases in young dogs and those in adult dogs require intensive treatment. Secondary infections must be treated with courses of antibiotics, and a swab is often submitted to a laboratory to grow the organisms to ensure the correct antibiotic is selected. The licensed treatments for demodicosis in the UK include a dip solution called Aludex and a spot-on product called Advocate. The dip is performed on a weekly basis until mite numbers are brought under control. Advocate spot-on is generally used for milder cases and is usually used monthly. In severe cases not responding to the licensed treatments, off-licence treatments must be used. Some of these drugs, such as Ivermectin and Milbemycin, are used for demodicosis in other countries.

An essential part of treating adult onset cases is to identify the underlying illness that triggered the problem. This often requires blood testing and scans (CT, ultrasound) to investigate.
Treatment must continue until mite numbers have returned to a normal level and this can take a very long time. This can only be assessed by repeat sampling of the patient using plucks of the hair or scrapes of the skin

What is the prognosis?
The prognosis for localised disease in young dogs is very good, and most recover uneventfully from the disease. Generalised cases in young dogs can take many weeks or even months of treatment, but it is usually possible to control the disease with a good long term outlook.

The prognosis for adult onset generalised demodicosis is far more uncertain, as many of these dogs have an underlying systemic illness. If this illness can be identified and cured, the prognosis for managing the demodicosis is much better. Some cases require long term medication to keep mite numbers controlled.

 

Demodex mite

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Patellar Luxation

by admin on December 3rd, 2018

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What is patellar luxation?
The patella is a small bone at the front of the knee (stifle joint). In people it is referred to as the ‘knee-cap’. It is positioned between the quadriceps muscle and a tendon that attaches to the shin bone (tibia). This is termed the quadriceps mechanism. The patella glides in a groove at the end of the thigh bone (femur) as the knee flexes and extends.

Occasionally the patella slips out of the groove. This is called luxation, or dislocation, of the patella. Most commonly the luxation is towards the inside (medial aspect) of the knee, however, it can also dislocate towards the outside (lateral aspect) of the joint.
Patellar luxation can affect dogs and cats.

Why does the patella luxate?
The patella luxates because it (and the quadriceps mechanism in general) is not aligned properly with the underlying groove (trochlea). The resultant abnormal tracking or movement of the patella causes it to slip out of the groove.

The cause of the abnormal alignment is often quite complex, involving varying degrees of deformity of the thigh bone (femur) and shin bone (tibia). In severe cases in dogs, the thigh bone (femur) is bowed at the end due to abnormal growth. These dogs often have either a bow-legged or knock-kneed appearance.

Patellar luxation is most common in certain breeds of dogs, such as Poodles, Yorkshire Terriers, Staffordshire Bull Terriers and Labrador Retrievers. Both knees (stifles) are often affected. These features suggest the condition may be genetic.

Luxation of the patella due to injury (trauma) is uncommon.

Is patellar luxation associated with any other knee (stifle) problems?
Patellar luxation is associated with the development of osteoarthritis within the knee (stifle). This occurs in every case. Osteoarthritis tends to be a progressive disorder and it is doubtful whether treatment of the patellar luxation reduces or stops this progression.

Occasionally luxation of the patella is associated with rupture of the cranial cruciate ligament in the knee (stifle). This may be due to chance or possibly due to abnormal forces on the joint that weaken the ligament.

What are the signs of patellar luxation?
The signs of patellar luxation can be quite variable. A ‘skipping’ action with the hind leg being carried for a few steps is typical. This occurs when the patella slips out of the groove and resolves when it goes back in again. If both patellae luxate at the same time, dogs and cats can have difficulty walking, often with a crouched action.

How is patellar luxation diagnosed?
Examination may reveal muscle wastage (atrophy), especially over the front of the thigh (the quadriceps muscles), although this is often minimal. Manipulation of the knee (stifle joint) may enable the detection of instability of the patella as it slips in and out of the groove. In some dogs the patella is permanently out of the groove. The severity of the luxation is graded from 1 to 4, with a grade 4 being the most severe.

X-rays (radiographs) provide additional information, especially regarding the presence and severity of osteoarthritis. Specific views may be necessary to assess the shape of the thigh bone (femur) and shin bone (tibia).

How can patellar luxation be treated?
Some dogs with patellar luxation can be managed satisfactorily without the need for surgery. The smaller the dog and the milder the grade of luxation (e.g. grade 1 out of 4), the more likely it is that this approach will be successful. Exercise may need to be restricted. Hydrotherapy is often beneficial. Dogs that are overweight benefit from being placed on a diet. Tit-bits may need to be withdrawn and food portions reduced in size. Regular monitoring of weight may be necessary.

Many dogs with patellar luxation benefit from surgery. The key types of surgery, which are described below, are: 1. quadriceps mechanism realignment, 2. trochlea deepening and 3. femoral osteotomy.

1. Quadriceps realignment surgery
The aim of this surgery is to move a small piece of bone (the tibial tuberosity) at the top of the shin (tibia) that is attached to the patella and reposition it so that the patella is correctly aligned with the groove in the thigh (femur) bone. This procedure is called a tibial tuberosity transposition. The transposed piece of bone is re-attached with one or two small pins, with or without additional support with a figure-of-8 wire.

Exercise following quadriceps realignment surgery must be very restricted for the first few weeks until the cut bone and soft tissues heal. It must be on a lead or harness to prevent strenuous activity, such as chasing a cat or squirrel. At other times, confinement to a pen or a small room in the house is necessary. Jumping and climbing should be avoided. After a few weeks, exercise may be gradually increased in a controlled manner (still on a lead). Hydrotherapy may be recommended.

2. Trochlea (groove) deepening surgery
In dogs and cats with patellar luxation the groove (trochlea) at the end of the thigh bone (femur) is often shallow. In these cases it may be necessary to deepen the groove. This can be done by removing a block or wedge of bone and cartilage from the groove, deepening the base, and replacing the block or wedge. These techniques are called ‘recession’ techniques since they recess the surface of the groove and thus make the groove deeper, while at the same time preserving the surface (cartilage) of the groove.

3. Femoral osteotomy surgery
Femoral osteotomy surgery involves changing the shape of the deformed thigh bone (the femur) by cutting it just above the knee (stifle) and stabilising it in a new position with a plate and screws. This may be all that is needed to prevent the patella luxating, however, in some dogs it is also necessary to perform a tibial tuberosity transposition.

Exercise following femoral osteotomy surgery must be restricted until the cut bone has healed. Exercise must be on a lead or harness to prevent strenuous activity. Jumping and climbing should be avoided. X-rays (radiographs) are necessary between six and eight weeks following surgery to ensure bone healing is progressing without complication. Exercise may then be gradually increased in a controlled manner. Hydrotherapy may be recommended.

What is the outlook with patellar luxation surgery?
The outlook or prognosis with patellar luxation surgery is generally good. Although all dogs and cats develop osteoarthritis to some degree, this is often not a cause of pain or lameness. Stiffness, especially after rest, can be a feature in some cases. Potential complications include recurrence of the patellar luxation and loosening of implants. These are uncommon.

Patellar luxation

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Special offer – December 2018

by admin on December 3rd, 2018

Category: Special Offers, Tags:

Arthritis Awareness

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Pet of the month – December – Barry

by admin on December 3rd, 2018

Category: Pet of the Month, Tags:

Pet of the month for December is Barry, a name we chose for a semi longhaired domestic cat brought into the clinic this week following a road traffic accident.

We are delighted to report that he has responded well to treatment but unfortunately we have been unable to locate Barry’s owner. Fingers crossed!

BARRY

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Cataract Surgery

by admin on November 1st, 2018

Category: News, Tags:

What is a cataract?

A cataract is an opacity or clouding in the lens in the eye. The opacity normally makes the lens look white. The lens in the eye is like the lens in a camera except that, rather than being at the front as it is in a camera, the lens in the eye is deep inside it, just behind the coloured part of the eye (the iris). The lens shows up as black in the central part of the eye (the pupil). The lens is normally crystal clear but it looks black because the darkness inside the eye shows through it. The lens is there to focus light on the sensitive tissue at the back of the eye (the retina).

Cataracts often form in both eyes and they frequently get worse. One eye is often more affected than the other, at least initially. It is not known why most cataracts develop. They are most common in older dogs and sometimes they occur due to other problems such as diabetes or disease in the back of the eye (the retina). Some cataracts are inherited.

What treatment is there for cataracts?
At the moment the only treatment for cataracts is surgery. Unfortunately not every cataract is suitable for surgical treatment, and it is necessary for the eye specialist to assess each patient and decide what therapy might be possible. Some cataracts are more complicated to treat than others, and the specialist will give guidance depending upon the circumstances in each case.

When is the best time to operate on a cataract?
The previous belief that it is best to let a cataract ‘ripen’ and the eye to become totally blind before removing the opaque lens (the cataract) has been proven wrong. Any cataract that is developing will cause potentially damaging inflammation in the eye due to release of lens proteins – a condition called ‘lens-induced uveitis’. Lens-induced uveitis can be subtle and easily missed – or, in some cases, it can be severe and associated with an obviously sore and inflamed eye.

Left untreated, even low levels of lens-induced uveitis are likely to result in complications, including adhesions (sticking) between the iris and the lens, retinal detachment (where the light-sensitive tissue at the back of the eye comes away from the back of the eye and stops working) and glaucoma (increased pressure in the eye which is potentially blinding and painful). Many eyes with long-standing cataracts that have not been operated on will eventually become irreparably blind and painful, and have to be removed as a result of the effects of lens-induced uveitis.

Early cataract surgery is therefore recommended in order to avoid the detrimental effects of lens-induced uveitis, and in general surgery is carried out once a cataract starts to interfere significantly with vision. This especially applies to young and diabetic patients, where progression of cataracts can often be rapid and result in significant complications if treatment is delayed. We will endeavour to see such patients at short notice and we will also often advise the referring veterinary surgeon to start treatment with topical anti-inflammatory drugs to manage lens-induced uveitis prior to us seeing the patient.

Cataracts in older dogs or patients with very slowly progressive cataracts may be monitored, but we will often recommend the prophylactic use of anti-inflammatory drugs in such cases.

The surgery
Your dog will usually be admitted on the morning of the surgery and no breakfast should be given. Water should not be withheld overnight. Diabetic patients need special management, and this should be discussed with the vet involved. After the patient is admitted, drops are given every 15 minutes prior to surgery to prepare the eye for the operation. These drops help to dilate the pupil and reduce the effects of inflammation which always happens in dogs having cataract surgery.

Before surgery all patients have an ultrasound scan to check for problems such as retinal detachment or rupture (bursting) of the lens. These changes are more common in advanced cases. The scan is performed under sedation. Some patients may be found to be unsuitable for surgery when the ultrasound scan is carried out.
Cataract surgery is performed under a full general anaesthetic and a muscle relaxant is given so that the eye comes into the correct position for the operation. This means that a ventilator needs to be used to inflate the chest during the procedure. We monitor your dog very carefully throughout the surgery using very modern sensitive equipment and the staff involved are specially trained in the procedure. This helps to reduce the risks of the anaesthetic to a very low level.

The operation is very delicate and involves the use of an operating microscope and tiny instruments. Two small cuts are made in the window of the eye (the cornea), near where the coloured part (the iris) joins the white part.

The lens is just behind the iris and lies in a delicate bag of tissue called the capsule. After the eye has been filled with a special gel called a viscoelastic, some of the lens capsule is taken out. The gel which is used helps to inflate the eye and protect the structures inside it from the effects of the surgery, and especially from the instruments and the ultrasound. The cataract (in other words, the lens) is then removed through the hole in the capsule using a technique called phacoemulsification – this is an ultrasound procedure using very sophisticated equipment which is exactly the same as that which would be used on a human eye. This type of surgery has been shown to give the best results in dogs’ and humans’ cataracts. There is currently no laser treatment for cataracts in dogs or humans.

In most patients it is possible to put in a special artificial lens where the old lens was. Plastic lenses make vision in the eye similar to the way it used to be before the cataract developed. The lenses used in our patients are made especially for dogs as they are bigger and more powerful than human lenses. They are permanent and buried deep inside the eye. The complication rate of lenses is very low indeed. For technical reasons it is not possible to implant an artificial lens in some eyes. Not having a lens implanted does not make the difference between being blind and having sight – it is similar to someone who wears glasses not putting them on.
At the end of the surgery the wounds in the eye are closed with tiny dissolving stitches. These are absorbed over the next few weeks, leaving only very small scars.

Some dogs can have both eyes operated on at the same time. The main reason for doing this is that it makes it more likely that the patient will have vision after the surgery – if something goes wrong with one eye, hopefully it will not also go wrong in the other one. However, a dog with one good eye will have overall vision which is almost as good as that in a dog with two good eyes, and so it is not essential to have both eyes operated on.

Most patients stay in overnight after their operation and are discharged the following day, provided that progress is satisfactory. Most dogs can see something on the day after surgery, but it frequently takes a few weeks for vision to settle down as the eye adjusts to the effect of surgery and the presence of a plastic lens implant. In addition, there is often some clouding inside the eye which takes time to clear.

Aftercare
The aftercare following cataract surgery is intensive. All patients  develop inflammation inside their eyes after surgery. This happens more in dogs than in humans. Usually there are several types of drops used. The most frequently applied drops are used six times daily initially. The number of applications gradually decreases over the next two months or so. There are also tablets to be given for a few weeks after the surgery.

Your dog will need to be kept as quiet as possible for a few weeks after the surgery, although this can obviously be difficult with many of our patients! You can only do your best in this regard. Pulling on a lead should be avoided for several weeks after surgery, as this puts up the pressure inside the eye and can encourage bleeding. Avoiding pulling around the neck is best achieved by using a harness, and it is a good idea to obtain one before the operation – it can be fitted at the time that your dog goes home. A plastic Elizabethan collar also has to be worn for about a week after the operation.

There will need to be at least four or five re-examinations after surgery. These are mostly within the first two to three months after the operation. Some patients, especially those with complicated cataracts, may need longer term treatment and more check-ups than average.

Risks and complications
The success rate of cataract surgery in dogs is about 90 to 95% initially. This means that 5 to 10% of patients cannot see in the operated eye after surgery. There are various reasons why not all patients have a successful outcome or may have a less straightforward recovery than normal. These include:

Inflammation
Every patient gets inflammation after surgery, no matter how smoothly the surgery goes. This is usually well controlled by the medications which are given. The occasional dog gets more inflammation than average, and this can lead to changes in the eye. These may not be of any great significance, but sometimes they can cause reduced vision.

Occasionally an injection into the eye is needed to dissolve inflammatory clot material. Inflammation is the main problem in dogs after surgery, and is the major reason why frequent medications and regular post-operative check-ups are required.

Infection
This can be very serious, but is extremely rare. Antibiotics in the form of tablets and ointment are used before and after the surgery to help to prevent this.

Wound breakdown
This means that the wound gives way. Again this is an uncommon complication, but if it occurs another general anaesthetic will be required to re-stitch the wound.

Bleeding
A very small amount of bleeding at the time of surgery is not unusual and this is not a major problem. Very occasionally a larger haemorrhage can develop and this can affect vision.

Increased pressure
The pressure in the eye can occasionally go up in the first few days after surgery, but eye drops will usually settle this down very quickly. Rarely a more severe increase in pressure may develop (glaucoma). If this problem develops it will involve additional medication and possibly surgery. It can lead to blindness and even loss of the eye in severe cases which don’t respond to treatment.

Ulcers
Occasionally the surface layer of the window at the front of the eye (the cornea) can partly come away after surgery. This is usually a very minor problem which normally resolves within about a week.

Corneal oedema (water-logging)
The window at the front of the eye (the cornea) can very occasionally go blue after surgery due to disturbance of its inner layer. Careful surgery and the use of viscoelastic gel (as previously mentioned) help to reduce the chances of oedema developing.

Retinal detachment
This is an uncommon complication, but if the sensitive tissue at the back of the eye detaches it can lead to loss of sight. A routine ultrasound scan before the surgery helps to identify at-risk patients.

Poor vision
Some dogs have problems inside their eyes (for example with their retina) which cannot always be detected before the surgery, and this may then mean that the surgery is not successful, or that the vision given by the surgery is not as good as it once was. Some suspect cases may have an electrical test (an electroretinogram) performed on the eyes to look for retinal problems before surgery, but this may well require sedation or even general anaesthesia and is not necessary or recommended for every case.

‘After-cataract’
A small percentage of dogs that see well immediately after their surgery may not continue to do so for the rest of their lives. This later deterioration may happen for many reasons (such as some of the complications mentioned). However, one such problem is known as after-cataract, in which a white membrane can grow across the pupil inside the eye. In most patients the amount of after-cataract which forms is not significant, but it can very occasionally affect vision in the long-term. Having a plastic lens implant has been shown to help to prevent the membrane growing across the pupil.
If after-cataract becomes very severe it can be removed surgically, although this is very rarely necessary.

Conclusion
The success rate of cataract surgery in dogs is high, and the great majority of patients do very well after their operation. It is undoubtedly a major undertaking, but the procedure is one which is commonly performed.

Dog Cataracts

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