Willebrand disease - introduction

Von Willebrand disease (vWD) / Willebrand disease is the most common inherited blood clotting disorder in dogs. It is caused by a lack of von Willebrand factor (vWF), a protein that is essential for blood clotting. Without sufficient vWF, platelets cannot aggregate properly, leading to uncontrolled bleeding.

Causes of von Willebrand disease / Willebrand disease

Von Willebrand disease is genetic and is inherited in an autosomal recessive manner. This means that both parents must have the genetic defect for the puppy to become ill. Several dog breeds, particularly Dobermans, German Shepherds and Golden Retrievers, are particularly susceptible to this condition. When diagnosed, a dog's blood sample may be tested for the amount of von Willebrand factor, and genetic testing may help determine the mode of inheritance.

(C) https://en.wikipedia.org/wiki/Erik_Adolf_von_Willebrand#/media/File:Eavonwillebrand.png

Erik Adolf von Willebrand was a Finnish internist born in Finland in 1870. He discovered von Willebrand's disease, which bears his name, in 1926 while examining a family on the Finnish Åland Islands who were suffering from unusual bleeding. He determined that it was a new type of blood clotting disorder that was different from hemophilia. His research has made a significant contribution to better understanding the genetic mechanisms behind blood clotting disorders.

Symptoms of Willebrand disease

Symptoms of von Willebrand disease / Willebrand disease (vWD) can vary depending on the severity. In general, affected dogs have an increased tendency to bleed. Here is a detailed overview of the symptoms:

1. Prolonged bleeding time

A common feature is that bleeding after injury lasts longer than normal. Even minor cuts can bleed for a long time and heal poorly.

2. Spontaneous bleeding

In more severe cases, spontaneous bleeding may occur without any obvious injury. This may include, for example, bleeding from the mucous membranes (nose, mouth) or blood in the urine or feces.

3. Nosebleeds and bleeding gums

Affected dogs are often prone to nosebleeds, especially after physical exertion or when excited. Bleeding gums can occur when chewing hard food or toys.

4. Heavy bleeding after operations

Many cases are only discovered when the dog bleeds abnormally after surgery. This may include bleeding during and after surgical procedures.

5. Bruises under the skin

Spontaneous bruising can occur without any external injury being visible. These mainly occur after minor trauma or sometimes even for no apparent reason.

6. Hematomas and swelling

Sometimes hematomas (collections of blood) form under the skin or in the muscles when blood vessels rupture and the blood does not clot properly.

7. Bleeding in the digestive tract

A rarer but serious symptom is gastrointestinal bleeding, often accompanied by dark, bloody feces (melena) or vomiting of blood (hematemesis).

8. Bleeding in joints and muscles

As with hemophilia, dogs with von Willebrand disease may experience bleeding in the joints and muscles, causing lameness, pain, and swelling.

9. Bleeding during heat or childbirth

Bitches with vWD often have increased bleeding during heat or birth due to difficulty controlling bleeding.

It is important to take these symptoms seriously as they can impact the affected dog's quality of life. If there are signs of bleeding problems, a veterinarian should be consulted as soon as possible to confirm the diagnosis and determine treatment options

Inheritance of von Willebrand disease - prevention

Von Willebrand disease type 1 (VWD1) is an inherited blood clotting disorder that occurs primarily in dog breeds such as the Doberman Pinscher. It is characterized by an insufficient amount or defective function of von Willebrand factor, which leads to an increased tendency to bleed, even from small injuries. This disease is inherited in an autosomal recessive manner and only affected dogs (vwd1/vwd1) show symptoms. Although carrier animals (N/vwd1) are clinically healthy, they can pass on the mutation to their offspring.

Heredity and genetics

The inheritance of von Willebrand disease type 1 follows an autosomal recessive pattern of inheritance. This means that both parents must have a mutated allele for the disease to occur in the offspring. There are three possible genotypes:

• N/N (genetically healthy) : The dog does not have a mutation and does not pass it on.
• N/vwd1 (carrier) : The dog is clinically healthy, but carries a mutated allele and can pass this on to its offspring at a rate of 50%.
• vwd1/vwd1 (affected) : The dog shows the symptoms of the disease and passes on the mutation 100%.

Breeding recommendations

It is essential for breeders to use genetic testing options to reduce the spread of von Willebrand disease in the population. Carrier animals should only be bred with genetically healthy dogs (N/vwd1 x N/N). Mating two carrier animals (N/vwd1 x N/vwd1) increases the risk of producing affected offspring, while affected dogs (vwd1/vwd1) should generally be excluded from breeding.

Preventive measures and handling

The use of DNA testing helps breeders identify a dog's genetic makeup before breeding. These preventive tests are particularly important to prevent von Willebrand disease from being passed on. In addition, affected dogs should be kept away from risky situations in which they could injure themselves, as even small cuts or operations can lead to serious bleeding.

Through this combination of targeted breeding, prevention and modern diagnostic technology, the risk of von Willebrand disease in dogs can be significantly minimized, and affected animals can still have a good quality of life.

For further details and comprehensive genetic testing, we recommend visiting specialized animal genetics service providers.

Inheritance of von Willebrand disease in dogs

Von Willebrand disease (vWD) occurs in three different types, which differ in the severity and type of symptoms as well as the function of von Willebrand factor (vWF):

Type 1:

• Description : Mildst form of von Willebrand disease.
• Characteristic : There is a partial reduction in vWF in the blood, but the factor is functional.
• Symptoms : Usually mild bleeding tendency, e.g. B. in the event of injuries or operations.
• Dogs Affected : Particularly common in Dobermans and other dog breeds.
• Treatment : Desmopressin (DDAVP) can be used to promote the release of vWF.

Type 2:

• Description : A rarer and more severe form than type 1.
• Characteristic : The von Willebrand factor is present but its structure or function is impaired. This leads to inadequate binding to platelets.
• Symptoms : Heavier and more spontaneous bleeding, often occurring without visible injury.
• Dogs affected : Common in dog breeds such as the German Shorthaired Pointer, the Pointer or the Wirehaired Pointer.
• Treatment : Desmopressin is less effective; Blood or plasma transfusions are often required.

Type 3:

• Description : The most severe form of von Willebrand disease.
• Characteristic : Almost complete lack of von Willebrand factor in the blood.
• Symptoms : Severe bleeding that can occur even without external injuries. Dogs can suffer from life-threatening bleeding, such as: B. after an operation or trauma.
• Dogs Affected : Particularly common in breeds such as the Scottish Terrier or the Shetland Sheepdog.
• Treatment : Regular plasma transfusions or special clotting factor concentrates are often necessary to support clotting.

The differences between the types lie primarily in the amount and functionality of the von Willebrand factor. Type 1 is the mildest form in which vWF is reduced but functional. Type 2 is characterized by structural defects of the vWF, while in type 3 there is almost no vWF. Treatment approaches vary depending on the severity, from mild cases that can be treated with desmopressin to severe cases that require regular blood transfusions.

Diagnosis of von Willebrand disease / Willebrand disease

Diagnosis of von Willebrand disease (vWD) requires careful evaluation because symptoms are often nonspecific and can be confused with other blood clotting disorders. Here is a detailed overview of the diagnostic process:

1. Clinical history and symptoms

The first step in diagnosis is to accurately record the dog's medical history and describe the symptoms. Because many dogs remain asymptomatic until an injury or surgery occurs, it is important to also consider family histories of bleeding disorders. Dog owners should report any unusual bleeding tendency - such as severe nosebleeds, prolonged bleeding after injuries or spontaneous bruising - to the veterinarian.

2. Blood tests

Specific blood tests are necessary to determine the amount and function of von Willebrand factor (vWF):

• vWF antigen test (vWF ) : This test measures the amount of von Willebrand factor in the blood. Values ​​below 50% are considered abnormal, although severely affected dogs often have very low values.
• Bleeding time (Buccal Mucosa Bleeding Time, BMBT) : The bleeding time is measured after a small incision in the oral mucosa. Bleeding time is significantly prolonged in affected dogs.
• Factor VIII test : Since von Willebrand factor works together with coagulation factor VIII, this test can also be carried out. In von Willebrand disease, factor VIII is often lower than normal.
• vWF function tests : These tests check whether vWF is working properly by measuring its ability to bind to platelets and clotting factors.

3. Genetic testing

Modern genetic testing plays an important role in diagnosing vWD. Carriers of the defective gene can be identified through DNA analysis. This test is particularly helpful for breeders who want to ensure that they are not producing affected puppies. The test can be carried out in puppyhood and provides clear results regarding the genotype:

• N/N (healthy) : The dog is genetically free of the mutation.
• N/vwd1 (carrier) : The dog is healthy but carries the mutated gene.
• vwd1/vwd1 (affected) : The dog has the disease and is showing symptoms.

Differential diagnosis

Since there are many other diseases that can also lead to bleeding disorders, von Willebrand disease must be differentiated from these:

1. hemophilia

Hemophilia (usually factor VIII or factor IX deficiency) causes similarly severe bleeding. It is also a hereditary disease, but almost exclusively affects male animals and usually has a different inheritance pattern (X-linked recessive). A specific test for the activity of coagulation factors VIII and IX helps to differentiate the diagnosis.

2. Thrombocytopenia

A reduced number of blood platelets (thrombocytes) can also lead to increased bleeding. Thrombocytopenia can arise from many causes, e.g. B. due to autoimmune diseases or infections (e.g. Ehrlichiosis). A simple blood count is often sufficient to diagnose thrombocytopenia.

3. Liver diseases

The liver plays a central role in the production of clotting factors. Liver diseases such as liver failure or cirrhosis can lead to clotting disorders. A comprehensive blood count and liver enzymes help differentiate this disease from von Willebrand disease.

4. Vitamin K deficiency

A deficiency of vitamin K, which is necessary for the synthesis of several clotting factors, can also lead to bleeding. This often occurs in poisoning with rat poison (anticoagulants) or in serious diseases of the digestive tract. A vitamin K test or the reaction to a vitamin K administration helps to differentiate.

5. Vascular disorders

Some blood vessel diseases (such as vasculitis) can also cause bleeding, especially if the vessel walls themselves are damaged. However, this is rare and usually occurs secondary to inflammation or infection.

Diagnosis of von Willebrand disease requires careful clinical assessment combined with specific laboratory tests. Genetic testing is particularly useful for detecting predisposition and making a clear distinction between healthy, carrier and affected dogs. Since there are many other diseases that can lead to similar bleeding tendencies, differential diagnosis is crucial to find the right therapy and avoid unnecessary risks.

Dog breeds particularly affected

Some dog breeds are particularly frequently affected by von Willebrand disease. This includes:

• Doberman Pinscher : This breed is the most affected and often suffers from Type 1 of the disease.
• Shetland Sheepdog : These dogs also have a higher prevalence of vWD.
• Golden Retrievers and Labrador Retrievers : Although less common, these breeds can also be affected by the disease.
• German Shepherds , Poodles , Corgis , Manchester Terriers and Irish Terriers are also among the risk groups.
• Huskies

This genetic predisposition requires special attention when planning breeding.

Treatment of Willebrand disease

Treatment for von Willebrand disease (vWD) depends on the severity of symptoms and the type of disease. Because there is no cure, therapy is aimed at controlling bleeding symptoms and minimizing the risk of serious bleeding. Here are the main treatment options in detail:

1. Desmopressin (DDAVP)

Desmopressin is one of the most common drugs used to treat von Willebrand disease, especially type 1. It stimulates the release of stored von Willebrand factors from endothelial cells, which improves blood clotting. However, the effectiveness of this medication varies depending on the dog and is not suitable for all vWD types.

• Administration : Desmopressin can be administered either as a nasal spray or by injection.
• Use : It is often used before surgery or during acute bleeding to reduce the risk.
• Limitations : The effect of desmopressin is less pronounced in vWD type 2 and type 3, which is why it is less effective there.

2. Blood and plasma transfusions

In severe cases of vWD, particularly types 2 and 3, blood or plasma transfusions are necessary to compensate for the deficiency of von Willebrand factor. Transfusions can be life-saving when a dog suffers from severe bleeding, such as: B. after trauma or surgery.

• Fresh frozen plasma (FFP) : Plasma is rich in clotting factors and vWF, and it is often used to correct the deficiency.
• Cryoprecipitates : These are particularly rich in von Willebrand factor and factor VIII and provide a concentrated form of blood products that may be particularly helpful in severe bleeding.

3. Clotting factor concentrates

In some countries, commercial clotting factor concentrates are available that specifically contain von Willebrand factor. These products are particularly useful for dogs that do not respond to desmopressin or are scheduled for major surgery.

• Advantage : They offer a precise dosage of vWF and coagulation factor VIII and can be administered specifically as needed.

4. Operational precautions

Dogs with von Willebrand disease require special surgical planning to minimize the risk of postoperative bleeding. Desmopressin treatment or a transfusion is often given before surgery to increase vWF levels and shorten bleeding time.

• Secure blood supply : It should be ensured in advance that blood products or plasma are available in case of an emergency.
• Follow-up care : Dogs should be monitored closely after surgery to ensure there is no post-operative bleeding.

5. Medications to control bleeding

In addition to specific vWD therapies, other medications can help control bleeding. This includes:

• Antifibrinolytics : These medications, such as tranexamic acid or aminocaproic acid, prevent the breakdown of blood clots and may be helpful in controlling postoperative bleeding or during tooth extractions.
• Local hemostatic measures : If a dog is bleeding locally, hemostatic agents such as collagen or gelatin sponges can be used to stop the bleeding.

6. Preventive action

Since vWD is genetic, there is no preventative cure, but targeted prevention is essential:

• Avoiding Injury : Dogs with vWD should be protected from potential sources of injury. This includes avoiding rough play or situations where they could cut themselves.
• Regular check-ups : Regular visits to the vet help keep an eye on the dog's health and respond to bleeding symptoms early.
• Breeding management : Pre-breeding genetic testing is critical to ensure that dogs with vWD are not used for breeding and to reduce the spread of the disease in the population.

7. Long-term management

Long-term management of von Willebrand disease requires close collaboration between dog owners and veterinarians. This includes:

• Individual treatment plans : Depending on the severity of the disease, an individual plan is developed that is tailored to the dog's needs.
• Be careful with medications : Certain medications, such as aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs), can further impair blood clotting and should be avoided.
• Diet and general care : A healthy diet and general care contribute to the dog's overall health, which is important for keeping the immune system and blood clotting stable.

Treating von Willebrand disease requires a holistic approach that both treats acute bleeding and uses preventive measures to avoid long-term complications. Modern medications, blood products and genetic tests now offer many options to enable affected dogs to lead a normal and active life. With proper care, medical support, and careful monitoring, dogs with vWD can live well.

Here are five frequently asked questions (FAQ) about von Willebrand disease/Willebrand disease in dogs, with very detailed answers:

Summary of Willebrand disease

Willebrand disease is a common blood clotting disorder in dogs caused by a deficiency or malfunction of von Willebrand factor (vWF). 's disease is particularly common in breeds such as Dobermans and Golden Retrievers. Dogs with Willebrand disease often have prolonged bleeding after injuries or surgeries. Willebrand disease is inherited genetically and can be diagnosed with blood tests and genetic analysis.

Early detection of Willebrand disease helps prevent complications. Treatments for Willebrand disease include desmopressin and blood transfusions. Willebrand disease can be minimized through genetic testing in breeding dogs. Dogs with Willebrand disease should be monitored carefully to prevent bleeding complications. Willebrand disease is not curable, but can be easily controlled. Platelets and von Willebrand factor play a central role Willebrand disease Early diagnosis of Willebrand disease improves the quality of life of dogs.

Willebrand disease requires comprehensive management to prevent bleeding and ensure the dog's health. Regular veterinary visits are crucial to monitoring the condition of a dog with Willebrand's disease. Veterinarians should be prepared for Willebrand disease, especially during surgery or dental treatment, to minimize the risk of bleeding. Preventative measures such as genetic testing are particularly important for breeders to reduce the spread of Willebrand disease in certain dog breeds. With proper care, dogs with Willebrand disease can lead largely normal lives.

Willebrand disease should also be taken into account in everyday life for affected dogs. Dog owners must be particularly careful to avoid injury, as even small wounds in dogs with Willebrand disease can cause significant bleeding. Regular check-ups at the vet are important to keep an eye on blood clotting levels and to monitor the progress of Willebrand's disease . Genetic avoidance of Willebrand disease an important role in breeding planning in order to protect future generations from this disorder.

Further information:

https://www.cliniciansbrief.com/article/understanding-bleeding-disorders

https://www.cliniciansbrief.com/article/laparoscopic-spay-dogs-von-willebrand-disease