Southfields Vets

Arthritis in the dog


Arthritis in the Dog.

It can sometimes come as a surprise to owners when they find out that their pets can suffer the same problems that we, as humans, frequently suffer. Arthritis is one such complaint – a common problem in many of our canine pets.

What is arthritis? 

Arthritis is a very broad term, simply indicating that there is a degree of inflammation (swelling) within a joint. When the term ‘arthritis’ is used by pet owners or Vets, it is normally ‘osteoarthritis’ which is being referred to. However, there are two other broad categories of arthritis – infectious and immune-mediated – which need to be ruled-out before appropriate treatment is given.

Osteoarthritis (OA).

This is the most common cause of joint pain in the dog. ‘Osteo’ refers to bone, and when taking x-rays of joints with this disease, small ‘spurs’ of bone are often seen as a suggestion that the disorder is present. The most important consideration for management of osteoarthritis in the dog is the understanding that this complaint normally occurs secondary to an underlying problem, leading to an abnormal function in the joint. Any joint which is not working perfectly will develop a degree of osteoarthritis. The most common underlying complaints to cause osteoarthritis in the dog are hip dysplasia, cruciate ligament disease, luxating patella and elbow dysplasia. These problems all cause some joint malfunction, leading to swelling and pain within the joint. Management of the underlying problem will be a large step towards management of the joint pain (Please see Southfields factsheets regarding these diseases and their individual management). Osteoarthritis causes erosion of the articular cartilage (the smooth surface of the bones in the joint), pain, and increased volume of joint fluid and a vicious circle of pain, erosion and further inflammation. Dogs suffering from osteoarthritis often display predictable changes; they are often stiff after resting, especially if resting after a period of exercise. Owners often describe the animal ‘loosening-up eventually’. Reluctance getting up/down or on/off furniture is also common, as well as a reduced ability to tolerate anything other than light exercise.

Immune-mediated arthritis (IMA).

This type of arthritis is commonly suffered by humans. ‘Rheumatism’ in humans is a type of immune-mediated arthritis. This problem involves attack of the joints by the body’s own immune system. This problem can be linked to other immune-system disorders, or can occur in isolation. IMA often affects more than one joint at a time, and is often more ‘aggressive’ than OA, causing the animal to have other problems as well as stiffness – signs such as weight loss, lethargy and on examination the pets can have a high temperature. Diagnosis of IMA relies on taking samples of joint fluid from affected joints, and the treatment differs significantly compared to the treatment of OA.

Infective arthritis.

This occurs when an infectious agent (normally bacteria) starts to grow within a joint. The bacteria may come from direct penetration (e.g. penetration of the joint by a nail or similar), by spread from an infection elsewhere in the body, or as a consequence of joint surgery. Affected joints are often dramatically painful and swollen, and again the diagnosis is made by taking a sample of joint fluid. Thankfully, response to appropriate medical treatment is often very good in the dog. However, joints with OA (see above) are prone to developing infective arthritis, meaning that ongoing treatment of OA is necessary even when the bacteria have been eliminated.

Long-term management of osteoarthritis (OA).

With OA being the most common form of arthritis in the dog, we will consider how this disease is managed to help your pet lead a long and comfortable life. Assuming surgical management of the underlying disorder has been considered, we will now go-on to discuss the medical/environmental management of OA and joint pain.

  1. Weight control. Preventing obesity is an important part of caring for any pet, and this is even more important when OA is present. The heavier the animal, the greater the load taken by the joints and the more painful the animal will become. This will lead to a reduction in ability to exercise, greater weight gain and so on. Reduction of food intake, cutting-out treats and human food, and use of modern weight-control diets can all help our pets lose weight. Here at Southfields we run free weight clinics with our nursing team – just give us a call if you would like to take part.
  2. Pain relief. Controlling the pain associated with OA will improve the pet’s quality of life, and also encourage exercise, hence helping to stay lean and happy. Speak to your Vet regarding suitable pain relief techniques.
  3. Exercise management. Too much overzealous exercise will lead to the pet becoming sore. Too little exercise and the joints will become stiff, the pet will find it hard to prevent weight gain, and will be less happy in general. Daily, sensible/gentle exercise is recommended to strike the balance between too much and too little.
  4. Hydrotherapy. For those dogs who enjoy swimming, several hydrotherapy centres are available locally which cater specifically for dogs. Swimming allows the joints to move with minimal load, keeping them supple without becoming sore. It also helps keep weight down, and for many dogs this is the most enjoyable part of their treatment!
  5. Dietary supplements. Supplementing the dog’s diet with nutrients required by the joints can help manage the progression of OA.

Because osteoarthritis is not a condition that can be cured, it is common for pet owners to become frustrated with the outcome for their pet. However, by using a combination of the above principles, the quality of life and comfort experienced by our OA patients can be improved significantly. Just get in touch if you think you would like to discuss arthritis, or would just like to have the weight of your pet checked!


Cruciate ligament disease


 Cruciate ligament disease in the dog. 

The most common cause of severe hindlimb lameness in dogs is disease of the cranial cruciate ligament (in humans this is called the ‘anterior’ cruciate ligament). The cruciate ligaments are found in the knee, and the job of the cranial cruciate ligament is to allow the knee joint to act as a hinge, but to prevent other movements such as forward motion of the shin bone. This forward motion is referred to as ‘cranial draw’; it causes pain in the knee joint and discourages the animal from using the limb.

We use the term ‘disease’ of the cruciate ligament rather than simply ‘rupture’ because in dogs, as opposed to humans, rupture of this ligament is usually preceded by a period of gradual breakdown, partial tearing, and inflammation within the joint. It is common for dogs to show a mild, waxing and waning lameness prior to full rupture of the ligament and more severe lameness. When the ligament breaks, the joint becomes unstable and the process of inflammation (osteoarthritis) increases. This causes pain when walking and also loss of muscle size in the upper limb due to reduced use of the painful limb.

Options for management of cruciate ligament disease depend on a variety of factors. Sadly there is no single’ best’ treatment; each animal differs hence the variety of options. Factors to consider include the size/weight of the animal, activity level, age of the animal (and the presence of any other health problems), whether one or both knees are affected, and available funds for treatment. From this list it is apparent that treatment choices would differ between a lively 3 year-old Labrador weighing 30 kilos and a relaxed 13 year-old Cavalier King Charles Spaniel weighing 10 kilos who is also receiving heart medication. Management options can be broadly split into 3 categories, and these include:

  • ‘Conservative management’. This means giving pain relief and anti-inflammatory medication to the animal and restricting exercise to short lead walks only, until the body affects a repair itself by producing scar tissue (fibrosis) around the knee joint, improving stability. This option is more likely to be successful in smaller breed dogs, especially those who can be easily rested. It is also the treatment of choice when other ailments preclude surgery.
  • ‘Lateral suture’. This technique implies that during surgery, a false ‘ligament’ is placed outside the knee to do the job of the cruciate ligament. The aim is to stabilise the knee until the body can provide long-term comfort with scar tissue. It is known that these prosthetic ligaments eventually stretch and break, but if the patients are well-chosen the knee should have enough scar tissue present by the time this occurs. This technique is reported to be more suited to smaller breeds of dog in the 15-25 kilo range, with the caveat that more energetic dogs may be better suited to ‘osteotomy’ techniques (see below).
  • ‘Osteotomy techniques’. An osteotomy is where a cut is made in a bone. These techniques have been designed with the aim of changing the anatomy of the knee such that when the dog puts its foot on the ground, there is no/minimal cranial draw. In essence, the aim is to make the knee manage without a cranial cruciate ligament. The two main groups here include the TPLO (tibial plateau levelling osteotomy) and TTA (tibial tuberosity advancement). The TPLO involves a circular cut in the shinbone of the knee joint, allowing the angle of this bone to be changed. A plate is applied to the bone to allow healing to take place. The TTA involves a straight cut on the front of the shinbone. This bone is then pushed forward and stabilised with a plate or similar. Choosing one technique over the other is influenced by the anatomy as seen on x-ray, and also surgeon preference. These techniques are considered more suitable for large breed and/or more active animals. To ensure a good outcome and avoid problematic complications, strict attention to post-operative care is needed. This is also true of the lateral suture techniques, though the possibility for severe complications is less with lateral sutures. Osteotomy techniques are the most expensive procedures and this factor always warrants consideration.

The meniscus.

Inside the knee joint is a structure known as the meniscus. This lines the knee joint, improving the contact between the thigh bone (femur) and shin bone (tibia). When the knee becomes unstable, damage to the meniscus is common. If this has occurred, lameness will persist despite other management strategies (e.g. surgery). This means that during surgical correction for cruciate disease, the joint itself is often inspected. If the meniscus is torn, the torn portion is removed to help with long-term comfort. Sadly, the meniscus will occasionally tear after surgery. In these cases, repeat joint surgery is needed.

Long-term management. 

A successful outcome for surgical cases is seen in approximately 80% of cases.Although the outcome after surgery is normally very good, the knee is never ‘cured’ or brought ‘back to normal’. Because of this, arthritis will persist and long-term management will include weight control, careful use of anti-inflammatories when necessary, and physiotherapy such as hydrotherapy/swimming. It has been shown that, particularly in large breed dogs, if cruciate disease has occurred in one knee it will frequently occur in the other knee at a later date.

I hope this has helped outline some of the treatment options and expected outcomes for dogs with cruciate ligament disease. Here at Southfields we are always happy to discuss orthopaedic problems with you, so don’t hesitate to give us a call if you need further information.

 


Luxating Patella


Luxating patella in the dog (dislocating kneecap). 

The disease termed ‘luxating patella’ is a common problem in pet dogs. It involves the kneecap slipping in-and-out of its normal position on the hindlimb, often causing lameness and the development of arthritis in the affected limb.

Normal anatomy.

The kneecap is a pebble-shaped bone that lives in the tendon of the quadriceps muscles (found on the front of the thigh). This continues as a strong ligament which inserts onto the shin bone (tibia). When the quadriceps contracts, the shin bone is lifted, like a human kicking a football.

In a normal knee (known as a ‘stifle’ in the dog), the kneecap sits in a groove in the last part of the thigh bone. This groove is known as the trochlear groove. When a dog has a luxating patella, the kneecap slips into and out of the groove. This normally occurs towards the midline of the animal rather than towards the outside of the knee. This is referred to as ‘medial patellar luxation’, where ‘medial’ means towards the midline and ‘luxation’ means dislocation. Luxation in the other direction (termed ‘lateral’ luxation is less common but is still seen, especially in the larger breeds or in spaniels). Dogs are affected to different degrees, and these are given ‘grades’ of severity (grades 1-4). Grade 1 is a minor luxation, where the patella prefers to sit in the normal position most of the time, and grade 4 is severe, where the patella cannot be put in the correct position by hand. Often grade 1 problems are not noticed until the animal is examined, for example at routine annual booster vaccination. Higher grade problems often cause lameness; this could be ‘hopping’ occasionally, or an unwillingness to use the limb.

Typical breeds.

There are two main categories of dogs which commonly suffer from luxating patella. Small breeds are often affected; terrier such as Jack Russels, also Chihuahuas, French bulldogs and Shi tzus. On the other hand, large breed dogs also develop this problem; Labradors, Staffordshire Bull Terriers and Mastiff-types are common breeds.

Long-term effects.

Initially there may be either mild lameness or no lameness. Because the knee (stifle) is not functioning in a normal manner, arthritis will develop. Erosion of the groove in the thigh bone means that the grade of the problem will often get worse with time. Due to increased torsion (twisting) force in the knee, these cases are high risk for developing  tears of the cruciate ligament at the same time. See our notes on ‘disease of the cruciate ligament’ for further information here.

Treatment options.

In mild cases, or where surgical correction is either not wished for, or medical reasons prohibit this, anti-inflammatory painkillers can be used in combination with restricted exercise. For cases with a higher grade, or more marked lameness, surgery is normally the treatment of choice. Surgery of more mild cases can be considered in order to reduce the amount of arthritis in the stifle, to avoid worsening luxation later in life, and to help prevent cruciate ligament disease. The more common surgical procedures involve two main procedures:

  • Deepening of the trochlear groove. The groove in which the patella sits is made deeper by making a wedge-shaped incision into the bone, while retaining the overlying smooth cartilage which allows the patella to move with minimal friction. This part of the surgery is called a ‘trochleoplasty’, where ‘plasty’ refers to changing the anatomy, and ‘trochleo-‘refers to the groove itself.
  • Moving the patellar ligament. An incision is made into the front of the shin bone called the tibial crest. This is where the ligament below the patella inserts. By moving this piece of bone away from the midline (in what we call a ‘lateral’ direction), the kneecap is pulled into its proper position in the groove, rather than luxating towards the midline. This part of the procedure is called a ‘tibial crest transposition’.
  • Occasionally, for dogs with high-grade luxations and curved thigh bones (next time you see a Staffie, look at its back legs and think of John Wayne!), the above procedures are not enough, and surgery to correct the shape of the thigh bone is necessary. These cases are rare. At Southfields, we are happy to carry-out the traditional surgery for luxating patella, but for these rare cases with a marked curve to the thigh bone we refer these cases to a specialist orthopaedic facility.

Post-operative care and long-term outcome.

During corrective surgery, an incision is made into the shin bone creating what is called an ‘osteotomy’. The osteotomy is held in place using metal pins and wire. Attention to post-operative care is critical to avoid complications and the need for repeat surgery. The animal should receive strict rest – preferably in a suitable cage – with short lead walks only for toileting duties. The osteotomy is expected to heal in 6-7 weeks (this will be confirmed with an x-ray) and once healed, normal activity can be resumed.

Surgical correction of luxating patella is reported to carry a 90-95% success rate for resolution of the animal’s lameness. Post-operative complications which can occasionally be seen include re-luxation despite the surgery, infection of the implants, loosening of the implants or fracture of the tibial crest. Some of these complications require further surgery for correction, but this is in the small minority of cases.

At Southfields we are happy to advise you if your dog has luxating patella, and happy to carry-out corrective surgery if needed. Please contact us if you have any questions or would like to have you dog examined.


Cancer in dogs and cats


Dealing with cancer in our canine and feline pets. 

The vast majority of health disorders which affect humans can also affect our pet animals. This means that dealing with a diagnosis of cancer is something which pet owners are frequently faced with. Because most owners have known of family members or previous pets which have been diagnosed with cancer, it is a topic that can be difficult for many of us to come to terms with. The aim of this document is to help you as an owner to understand what a diagnosis of cancer means to your pet.

What is cancer?

All tissues in the bodies of our pets are made up of cells. These cells will grow and die, being replaced by new cells. Cancer occurs when cells multiply in a manner which is outside of the normal controls of birth and death. This leads to an over-accumulation of this cell type, starting in its original organ.

Terms used to describe cancer.

Not all cancers pose a threat to the health of our animals. The terms used to describe cancers can be confusing. Here are a few common examples of the terms used and their explanations:

  • Benign: when a cancer is described as benign this means that although the cancer is present, it is unlikely that the cancer will spread to other tissues in the body. The majority of benign tumours do not pose a threat to the animal’s health.
  • Malignant: when tumours are described as malignant, this means that the cancer itself is likely to act in an aggressive way. This means either by spreading into other tissues in the body or by growing in its local area and invading local tissues. Some tumours will do both.
  • Metastasis: spread of cancer cells to other organs is known as metastasis.
  • Lymph nodes: these are small glandular organs found throughout the body. Their job is to process abnormal cells and foreign invaders such as bacteria or viruses. Spread of cancer (metastasis) will often involve the lymph nodes near the origin of the cancer.
  • Prognosis: this is a word used to describe the animal’s expected outcome after diagnosis. The way that different cancers are treated will often have different outcomes, and this needs consideration before choosing how to treat the animal, or even whether treatment should be given or not.
  • Palliation: this is a term used to describe treating an animal’s symptoms of cancer without actually treating the cancer itself. These symptoms are often related to pain, but can also include things like vomiting, diarrhoea, loss of appetite etc. Palliation avoids some of the complications of directly treating the cancer but is normally associated with a shorter life-expectancy (prognosis).

What types of cancer are there? 

Because all tissues in the body are made-up of cells, any tissue can develop cancer. Cancer is normally thought of as a ‘lump’, often described as a ‘mass’, however this is not always the case. Cancer of blood cells can lead to changes in the blood without any ‘mass’ being present.

How does cancer cause illness? 

Here are three main ways that an animal may become unwell due to cancer.

  1. Local growth. Some cancers will grow in size in their original location. This may cause pain by invading local organs, or by ulcerating at the surface. If growing inside the body, cancers may cause difficulty breathing (if in the chest) or problems with digestion (if found in the stomach or gastrointestinal tract).
  2. Metastasis. By spreading to other organs in the body, cancers can cause illness. Most commonly, cancers will spread to the liver, the lungs and the lymph nodes. However, spread to other sites such as the bones or the spleen is also possible.
  3. By causing ‘paraneoplastic syndromes’. Although ‘paraneoplastic’ is a long and unusual word, what it means is that the cancer is causing changes in the body due to interfering with normal stable processes. This can be seen when cancers produce excessive hormones, leading to an increase in thirst (parathyroid hormone), lowered blood sugars (insulin hormone) or weight loss despite a ravenous appetite (thyroid hormone). Paraneoplastic syndromes are often the reason why the animal is brought to the vet. Successful treatment of the cancer will stop the signs caused by the paraneoplastic syndrome.

How is a diagnosis of cancer achieved?

It is uncommon to be able to give a diagnosis of cancer from simply examining the animal, although it can often be a consideration after the initial consultation. If a diagnosis of cancer is considered, taking a logical step-by-step approach allows us to work-out the full extent of the disease. This is known as ‘staging’. Staging allows us to get a diagnosis of the initial cancer, plus work-out the extent of any possible spread throughout the body. Here is how we stage a cancer:

  • X-rays are taken of the chest. This is to work-out if there is any sign of spread (metastasis) to the chest.
  • Ultrasound scanning is used to check the organs of the abdomen (liver, spleen, lymph nodes etc.) for any evidence of metastasis. If we are in any doubt regarding the findings of x-ray or ultrasound, the animal may be sent for a CT scan to confirm the findings.
  • Blood samples are taken to check for any evidence of paraneoplastic syndrome. It is very rare indeed that a cancer can be diagnosed by a blood test. The exception to this is some leukaemias (blood cell tumours) which can be diagnosed in a few select laboratories.
  • A biopsy is taken of the tumour. Taking a biopsy means taking a piece of tissue from the tumour. This can be done with a needle (called fine-needle aspiration or FNA) or done as a surgical procedure where a tissue sample is achieved. FNA biopsy can often be done quickly, without the need for sedation or anaesthesia, but if tumour cells are missed, FNA can give a negative result inaccurately. Choosing which cases are suited to FNA will help to avoid this problem. Surgical biopsy is more accurate, but requires general anaesthesia, is more expensive and requires more attention to pain relief than FNA. Sometimes we choose to remove a tumour in its entirety at the first surgery. This is called an ‘excisional biopsy’. Essentially, this procedure means the tumour is fully removed and then sent for biopsy. However, if this procedure is carried-out without proper attention to ‘staging’, there is the possibility that tumour cells could be left in place, making long-term management more challenging. Excisional biopsy should only be selected for cases where complete tumour removal is expected.

How can cancer be treated?

Carrying-out the ‘staging’ process allows us to know what the diagnosis is (by biopsy) and once we know the extent of any spread, we can suggest an appropriate course of treatment. Broadly speaking, treatment options for cancer include surgery, chemotherapy and radiation therapy. I will outline their uses and differences below:

Surgery: for types of cancer which develop as a mass lesion, surgical removal of this mass is frequently the treatment of choice. If the tumour cells can be removed 100%, surgery gives the possibility of curing the animal. If tumour cells remain after surgery, these can often be managed by using chemotherapy or radiation therapy.

Chemotherapy: as many pet owners know of friends or family which have received chemotherapy, this treatment often has a stigma associated with it. However, in many types of canine cancer, chemotherapy offers the most successful and least invasive way of managing the disease. Chemotherapy refers to the use of medications to halt the growth of cancer cells, or to kill them outright. Cancer cells differ from most ‘normal’ cells due to their rapid multiplication. Because of this difference, drugs can be used to target the cancer cells with minimal effect on ‘normal’ cells. Nonetheless, chemotherapy carries the risk of some side effects and these need consideration before starting treatment. Some tumours are more responsive to chemotherapy than others. Lymphoma, a white blood cell tumour, can be treated with chemotherapy alone, while other tumours (e.g. bone tumours) are normally treated with both surgery then chemotherapy.

Radiation therapy: this involved using a beam of radiation to target areas where cancer cells are known to exist. The radiation beam targets cancer cells specifically, causing them to die. Radiation therapy is very useful for post-operative management where some cancer cells are still remaining, or for tumours which are not suitable for surgery, but are known to respond poorly to chemotherapy – tumours of the nose, for example. Radiation therapy can cause heat-related side effects to local structures, but these side effects subside with time. We cannot carry-out radiation therapy at Southfields, but we work with centres that do, allowing us to refer suitable cases to them.

As mentioned above, in those cases where ‘treatment’ of the cancer is not feasible or not wished-for by the owners, palliative therapy involves giving medications to relieve the pain or other side effects of the disease process with the goal of improving the animal’s quality of life, if not it’s lifespan.

The diagnosis and treatment of cancer can be worrying and stressful for owners. Here at Southfields we aim to help explain the situation and allow owners to better understand any problems their pet may have. We aim to offer the most suitable treatment plan for each individual case and are always happy to listen to the opinions and wishes of owners regarding their own personal expectations.

If you have any questions regarding your pet, or would like to have you pet checked by a Veterinary Surgeon, please don’t hesitate to be in touch.

Best regards,

The team at Southfields.