Archive for the ‘Dogs’ Category

Leptospirosis: Fact or fiction?

Leptospirosis can make dogs very ill, cause long-term damage, and even be fatal. Incidence rates vary depending on where you live, your lifestyle and the area where you walk your dog, but most dogs are at some level of risk. The disease is seen in veterinary clinics all over the country and has been labelled ‘re-emerging’ as it seems to be on the increase. It’s also zoonotic, meaning it can spread from animals to humans. The human form (Weil’s disease) is thought to be the most widespread zoonotic disease in the world. There were 87 cases confirmed in people in 2017 in the UK alone, an increase from the previous year. Although usually treatable, fatalities can occur. British Olympic rower Andy Holmes died of organ failure after contracting Weil’s disease in 2010, days after competing in a marathon rowing event.

What causes it?

Leptospirosis is a bacterial disease caused by a complex group of closely-related bacteria of the genus Leptospira. Only some strains cause disease, some affect certain species more than others (cats are rarely affected), and are more prevalent in certain areas. The bacteria survive well in warm, humid areas, and are often found in stagnant water like ponds.

How is it caught?

Wild animals can carry the bacteria for years without signs, spreading it via their infected urine. Once in moist soil or stagnant water, the bacteria can remain infectious for several months. Any pet of any age, going out in any area, can be infected, but dogs that spend lots of time outside, especially in areas prone to flooding and high rainfall, are at higher risk.

As well as being inadvertently swallowed, contaminated water can more rarely pass on the infection through broken skin, such as cuts or scrapes.

Although infected pet dogs’ urine can be a source for humans, more often it comes from contact with infected water, often during watersports.

What signs should I look for?

The signs are not unique to this disease and can be vague. There is often a fever. The bacteria most commonly affects the kidneys, causing tiredness, lack of appetite, vomiting, abdominal pain, and changes in urination. Dogs with a poor immune system may not survive this phase or may go on to have long term kidney damage. Some will have less severe signs. The bacteria often affects the liver instead of, or as well as the kidneys, causing similar signs but accompanied by yellowing of the gums or skin. Some dogs have respiratory signs such as a cough, snotty nose or eyes, and less commonly, their muscles can be affected which causes trembling. The bacteria can attack blood vessels, causing nosebleeds or blood in their faeces or vomiting due to clotting issues, but this is rare.

How do you diagnose leptospirosis?

If a dog presents signs of kidney and liver disease, a fever, and is either unvaccinated or at high risk, leptospirosis will be high on the list of potential diagnoses. Blood and urine tests can confirm if there is any liver and/or kidney damage and changes to red and white blood cell counts and blood clotting tests may be helpful.

There are specific blood and urine tests looking for antibodies to the bacteria itself, but if treatment has already started these can be hard to interpret. Furthermore, if vaccinated, then the immune system will often have produced antibodies in response, so results are again hard to interpret. The most reliable test may be a repeated antibody test, 2 weeks after the first (in an infection, the antibody levels will be rising) – but obviously this does not help with initial management of the patient.

What treatment options are there?

An initial course of antibiotics is given, followed by a longer course of antibiotics to reduce bacterial shedding. Importantly, damaged organs must be supported, often via intravenous fluid therapy and with medications to address any pain and respiratory or gut signs.

In all but the mildest cases, infected dogs are usually hospitalised in an isolation ward. Whether in the hospital or at home, care is needed when handling infected dogs and their blood and urine to reduce the chance of infection. We can advise you on how to disinfect your home, and how to reduce spread as dogs may shed the bacteria for some time.  Washing your hands after contact, ideally wearing gloves, disinfecting frequently, and disposing of any soiled bedding are important. Pregnant women, immunosuppressed people, children and other dogs should avoid contact with the dog until at lower risk. Anyone who feels unwell while looking after a dog suspected of having leptospirosis, must seek medical advice.

The outlook is very variable. Some dogs seem to have minimal signs, while in others it is fatal, or causes lasting damage.

What’s the best way to prevent it?

Fortunately, vaccines are available – we include them in the regular primary course in dogs. Unfortunately the immunity does not seem to last as long as with many other vaccines. The manufacturers recommend yearly boosters to keep immunity at a protective level. In the past, two main strains were responsible for most disease in the UK, but recently additional strains have been implicated. Vaccines are now available covering the four most disease causing strains in Europe (L4), compared to the previous two (L2), (vaccinations for which have now been discontinued by major pharmaceutical manufacturers). Vaccination may reduce bacterial shedding in dogs carrying the bacteria without signs, so are of value to public health protection.

If your pet goes outside, it’s hard to eliminate the risk. Avoid stagnant, shady water, especially after flooding, as the bacteria is rapidly destroyed by light and temperatures above 20C.

More information can be found at https://uk.mypet.com/pet-health/pet-health-issues/the-low-down-on-leptospirosis/

IMHA in dogs: What do you need to know?

IMHA stands for Immune Mediated Haemolytic Anaemia. It’s a bit of a mouthful so is often known as its less tongue-twisting abbreviation. It’s not as complicated as it sounds and here we will attempt to demystify it.

What is IMHA?

IMHA belongs to a group of diseases known as autoimmune diseases. These occur because the body’s own cells are incorrectly identified as foreign by the immune system. These cells are then attacked and destroyed. With each autoimmune disease, different cells are targeted. With IMHA, red blood cells are targeted and destroyed leading to reduced numbers (anaemia). Two thirds of dogs with IMHA also experience a similar destruction of platelet cells. Platelets are involved in clot formation, and a lack of them (known as thrombocytopenia) leads to abnormal bleeding and is known as Immune Mediated Thrombocytopenia (ITP). When the two conditions occur together we call it Evans syndrome.

What causes this?

Body cells have a protein on the surface called an antigen. The immune system uses this protein to identify its own cells. In IMHA, red blood cell antigens are falsely recognised as foreign which stimulates the production of an antibody by the immune system. The antibody attaches to the antigen and causes the cell to swell and burst. Cells also become more likely to clump (agglutinate) giving higher risks of abnormal clotting.

When the cause of a disease is unknown we call it idiopathic. This is the case in around 70% of IMHA, so we call it idiopathic IMHA, or primary IMHA.

In the other 30% there is an underlying cause called secondary IMHA. Certain infections, mainly spread by parasites like ticks, can lead to secondary IMHA. Most are uncommon in the UK, but should be considered, especially if your pet has travelled abroad. Certain medications have been known to trigger IMHA, such as some antibiotics and painkillers. Some forms of cancer can also trigger IMHA. Recent vaccination has been suggested to trigger the disease but lacks evidence at present. Vaccination prevents serious life-threatening diseases and in the majority of dogs the benefits vastly outweigh the risks.

There seems to be a genetic predisposition in cocker spaniels and Old English sheepdogs, but any breed can be affected.

What are the symptoms?

Symptoms are largely due to the resulting anaemia. Signs may be vague such as weakness, lethargy and a poor appetite. Red blood cells are needed to carry oxygen around the body, so there is often a fast heart rate and breathing rate as the dog tries to compensate for the lack of oxygen. Usually we see pale gums, but there may be a yellow tinge to the gums as when red blood cells rupture they are broken down into a yellow tinged product called bilirubin.

Damage through lack of oxygen within any organ can cause varied signs and, as there is a tendency for red blood cells to clump, clots may form anywhere.

How is IMHA diagnosed?

After an examination and taking a history we may be suspicious.

Firstly we confirm the presence of anaemia. Anaemia has many causes so we need to further define the type of anaemia present. Most dogs with IMHA have a regenerative anaemia, where the body is stimulated to produce more red blood cells to make up for lost ones. In rare cases where the bone marrow is affected then a non-regenerative anaemia is possible.

Next we rule out other causes of regenerative anemia, and other rarer causes of haemolysis like onion poisoning or heavy metal toxicity, and identify whether your pet has had any recent medications or vaccinations. We may carry out further tests to identify infectious causes or cancers.

We often examine the blood under the microscope, looking for certain types of cells known as spherocytes, which are small, round red blood cells often associated with IMHA. We may see more immature red blood cells (reticulocytes) telling us the anaemia is regenerative. We often send samples to a lab for confirmation alongside other specific tests such as the Coombs test, which looks for antibodies on the red blood cells. A saline agglutination test looks for clumping of red blood cells when mixed with saline. It is quick and relatively inexpensive, but can be hard to interpret.

Can this condition be treated?

The first-line treatment for many autoimmune conditions is a corticosteroid called prednisolone, which suppresses the immune system. High doses may be needed initially, aiming to lower and possibly stop medication in the long run. A second immune suppressing drug can be tried in severe cases, or if prednisolone causes severe side effects or doesn’t work. Azathioprine is most commonly used as it is inexpensive, but takes time to work and requires handling precautions. Cyclosporine is licenced for use in dogs but expensive, has an unpredictable dose range and side effects.

A last resort is to help stop red cell destruction in the spleen by removing it (splenectomy). Pets by this stage are very sick and the procedure risky. Many owners would sadly have to consider euthanasia as an alternative.

If we think there’s a risk of excessive clotting we may prescribe medications such as aspirin to mitigate this.

A blood transfusion may seem obvious, but new cells may be destroyed quickly, worsening the signs. However, damage caused by the lack of oxygen in severe anaemia may be a bigger risk, so a transfusion may be recommended.

We would monitor the response to treatment with blood tests regularly. Hopefully once a response is seen, we can taper any medication gradually, whilst continuing to sample for any worsening in parameters. We may also want to monitor for any side effects of the medications.

What is the outlook?

The prognosis with IMHA is variable, carrying a mortality rate of 30% to 70% within 1-2 months of diagnosis. If patients suffer IPT at the same time, or if the bone marrow is affected, the outlook may be worse. The condition can come back, and some animals need lifelong medication.

What is haemangiosarcoma?

Haemangiosarcoma is an aggressive type of cancer which arises from cells that line blood vessels. In this blog we will focus on haemangiosarcoma in dogs as, although it can occur in other species such as cats, this is very rare.

Where do dogs get these tumours?

These tumours have a point of origin (primary tumour), but very often metastasise (spread) to other organs causing tumours elsewhere (secondary tumours).

As blood vessels are almost everywhere in the body, they can occur in many places. Primary tumours most commonly appear on the spleen, but they are also frequently seen in the heart, liver, skin and subcutaneous tissue.

Haemangiosarcoma is the most common type of tumour affecting the heart, accounting for around 69% of heart tumours. It is also the most common malignant tumour to affect the spleen. Much of this blog will relate to haemangiosarcoma of the spleen (splenic), as this form often creates the most discussion, concern, and questions.

Why did my dog get this?

We do not know why certain individual dogs are affected, although we know that, in skin, haemangiosarcoma is linked to sun exposure.

Certain breeds are predisposed. While German shepherds and golden retrievers are prone to the visceral (organ related) forms, whippets, dalmatians and bull terrier breeds are prone to the skin forms.

What signs might my dog have?

The signs depend on where the tumour is.

Haemangiosarcomas of the skin usually appear as a small red or bluish-black lump. They can also occur in deeper subcutaneous tissues, often sitting under normal looking skin.

Haemangiosarcomas located in the liver or spleen often grow rapidly, forming cavities containing blood, often only revealing signs when they rupture causing bleeding. This sudden blood loss can lead to weakness or collapse, and is the most common way dogs with this condition present to vets for the first time. Collapse can also be caused by disturbances in the rhythm of the heart, which can happen in primary heart tumours, but also those in the spleen. Occasionally these tumours are picked up early due to swelling of the abdomen or vague signs of illness. Because the tumour and blood loss can cause clotting issues, bleeding from the nose, or another area, may occur.

How will my pet be diagnosed?

The appearance of skin or subcutaneous masses may lead to our vets advising a biopsy, or removal of the mass. Samples sent to a lab can confirm a diagnosis.

With the visceral (organ) forms, diagnosis can be challenging. Dogs we suspect of having a heart, splenic or liver haemangiosarcoma often arrive as an emergency, with severe internal bleeding. Suspicion may be increased by finding a mass via ultrasound scan of the heart or abdominal organs. However benign tumours, malignant tumours (such as haemangiosarcoma), or non-tumours can look similar on an ultrasound scan, but would all carry very different outlooks. If there is evidence of more than one organ being affected, metastasis is suspected, increasing the likelihood of haemangiosarcoma. There is currently no concrete way of confirming the mass type until tissue samples are examined after surgery. A recent study showed that 63-70% of dogs that present to the vets with abdominal bleeding (not caused by trauma) have haemangiosarcomas.

Occasionally a mass is picked up during an ultrasound scan for a different problem. This gives more time for decision making and surgical planning.

How are these tumours treated?

The skin and subcutaneous tumours can be surgically removed with margins of normal skin. As 30-60% of these tumours will metastasise, it is important to remove them. However they may have already spread at the time of diagnosis. Tumours extending into deeper tissues may benefit from chemotherapy (anti-cancer drugs), or radiotherapy, in addition to surgery.

Treatment of splenic haemangiosarcoma involves surgery to remove the spleen, with an additional option of chemotherapy. These drugs are usually well tolerated but can sometimes have side effects like lethargy, anorexia, vomiting, diarrhoea, and fever. Mild to moderately low white blood counts occur in up to half of dog cases but usually do not require treatment.

Because splenic masses often present as an emergency, decisions regarding surgery often have to be made before a clear diagnosis, and thus prognosis, can be given. Removing the spleen is a major operation and can be risky, with some dogs not surviving the procedure. If the dog is subsequently diagnosed with haemangiosarcoma then the outlook is very gloomy.

Factors such as age, other illnesses and signs of spread must be taken into consideration with decision making. All situations are individual, but for some dogs euthanasia may have to be considered as a treatment option, especially if the outlook is poor.

What is the prognosis?

Skin and subcutaneous tumours, once removed, can be examined to give better information on the severity or ‘stage’ of the tumour. Stage I tumours just affect the skin and are associated with an average survival rate of 2 years, whereas stage II and III tumours that either involve the subcutaneous tissues or muscle have a worse prognosis if treated with surgery alone. Chemotherapy or radiation therapy may improve this.

Sadly haemangiosarcoma of the spleen tends to carry a poor outlook. They are often malignant, and most individuals survive less than 3 ½ months with surgery alone, with very few living beyond a year. If there is no evidence of spread, or tumour rupture, and chemotherapy is used, there is an average life expectancy of around 8 months. If the tumour has ruptured, it can be expected to reduce to an average of 6 months.

Although haemangiosarcomas can be found in many places, the splenic form often creates most difficulties in decision making. Our team will be there to support you, talk you through all of the options, and help you through any difficult decisions. If you have any questions on what you have read, or need more information, please talk to one of our vets.

Why shouldn’t my collie have ivermectin wormers?

Ivermectin is a very commonly used wormer, suitable for horses, cattle, sheep, birds, and a wide range of small mammals. It is occasionally used in dogs – but never in collies and other herding breeds.

What is Ivermectin?

Ivermectin is part of a family of drugs called the avermectins (which, in turn, are one variety of macrocyclic lactones). They work by binding to receptors in worm, mite and insect cells which control how much chloride enters the cell. The drug causes chloride to flood into the cell, causing paralysis and death.

That sounds horrible! Why do we use it in our pets if it’s that nasty?

Because the cells in most of a mammal’s body have a different type of receptor, and ivermectin doesn’t bind very well to it. So, at normal doses in normal dogs, it’s a very safe drug. The one caveat is that you mustn’t inject it into the brain (not that most people would…), as there are receptors in the brain that the drug does activate – but giving it by mouth, or by injection under the skin (or even into the bloodstream directly) is fine.

So what stops it getting into the brain, if it’s in the dog’s bloodstream?

All mammals, including dogs, have a special membrane surrounding the brain, called the Blood Brain Barrier. It works to prevent nasty chemicals getting into our brains and causing problems with the sensitive nerve cells there.

So there’s something unusual about the Blood Brain Barrier in collies then?

Yes, exactly. There is a particular genetic mutation, called MDR1? (also known as ABCB1, just to confuse people…) that means the barrier doesn’t work properly, and allows certain types of chemical through. One of these types is (you’ve guessed it!) the macrocyclic lactones – including ivermectin.

So all collies have this mutation do they?

No – but lots (perhaps as many as 75%) of them do. And a wide range of other dogs also have high incidence of this mutant gene – in fact, we’d generally advise against the use of ivermectin in any herding-type dog.

So, what problems does it cause? Do they become paralysed too?

Not normally – a dog’s brain is a lot more complicated than that of a worm or a flea! The typical symptoms seen include:

  • Altered behaviour – typically sleepiness, lack of normal responses, or coma.
  • Wobbliness and difficulty standing up.
  • Drooling and vomiting.
  • Slow heart rate and breathing (in some cases, the heart may even stop).
  • Tremors or twitches.
  • Seizures.

Can it be treated?

In most cases, toxicity will be managed symptomatically – with drugs to control the seizures and other symptoms until the body can deal with the poison. However, this particular drug is excreted by the liver into the bile; the bile then moves into the intestine, and the drug is then reabsorbed into the body. This is known as enterohepatic recirculation, and means it takes the body a long time to remove it.

As a result, the preferred treatment involves symptomatic therapy (intensive care nursing, intravenous fluids, drugs to prevent seizures and vomiting, and in severe cases medically inducing a coma), plus a specific antidote. This is a treatment called “Intravenous Lipid Infusion”, where a fatty chemical is injected into the bloodstream to “mop-up” the ivermectin.

Are there any other drugs I should avoid? What about selamectin and moxidectin – they sound very similar…

They sound similar because they’re part of the same family. So is milbemycin oxime (another common wormer). However, these drugs are safer in collies (and other affected dogs), because they have an even lower affinity for mammal receptors. However, it is very important that if you are using them, you give exactly the right dose – because it’s much easier to overdose an MDR1? dog than a normal one. For example, if you give your dog an anti-flea spot-on containing moxidectin, you mustn’t give a wormer containing milbemycin at the same time, because together, they could result in an overdose.

If in doubt as to what drugs you can mix, have a chat with one of our vets about it!

If you think your dog may be a high-risk breed and has been exposed to ivermectin, get them to us as soon as possible.

 

Reducing Roaming

One of the most common causes of death for dogs is, sadly, traffic accidents. However, entire male dogs are at a significantly higher risk than others. The reason is biological – but the risk can be dramatically reduced by neutering!

Why do we recommend neutering?

There are a number of advantages to having a dog neutered – eliminating the risk of testicular cancer, reducing the risks of prostate disease, some types of anal cancer, and unwanted behaviour such as humping and, crucially, “roaming”.

What is roaming?

When a female dog is in season, she releases pheromones that can be smelt by dogs for miles around. Male dogs are driven by instinct to seek out the bitch to mate. As a result, even well trained dogs will sometimes run away when lured by the attractive scent. This behaviour is sometimes called “roaming”, but in our modern built-up environments, this usually means crossing busy roads and potentially coming to grief.

What is the procedure?

Neutering of a male dog is a very straightforward procedure, involving the removal of both testicles under a general anaesthetic. Your dog will come in to us in the morning, have the procedure, wake up, and then almost always go home the same day. In fact, in most cases the procedure only takes 15 minutes or so! Without testicles, the dog no longer produces significant amounts of testosterone, and this instinctive behaviour is dramatically reduced.

If you want to know more, please get in touch and talk to one of our vets!