Immune Mediated Thrombocytopenia
Immune Mediated Thrombocytopenia is known as IMTP or ITP. We use the term IMTP throughout the website.
Who can get IMTP?
Primary IMTP is more commonly seen in middle aged female dogs, especially Cocker Spaniels, German Shepherds, Poodles, and Old English Sheepdogs. Unfortunately, although it is more common in these breeds, it can happen at any age, any sex, and any breed.
Secondary IMTP can occur in any pet as there is a secondary condition like infection, cancer, or sepsis causing the IMTP.
There have been cases reported of breed-specific asymptomatic thrombocytopenia, meaning they have a lower platelet count that is ‘normal’ for them.
Greyhounds have been reported to have a lower ‘normal’ at 150,000/mcL.
Cavalier King Charles Spaniels can have hereditary macrothrombocytopenia. This means the platelet cell numbers are decreased, but the size of these platelets are much larger than platelets are in other breeds. Dogs with this condition can have platelet counts of 25,000/mcL to 100,000/mcL and not have any symptoms. It is recommended to work with a specialist to determine if these pets have IMTP, or this hereditary disease.
Secondary IMTP can occur in any pet as there is a secondary condition like infection, cancer, or sepsis causing the IMTP.
There have been cases reported of breed-specific asymptomatic thrombocytopenia, meaning they have a lower platelet count that is ‘normal’ for them.
Greyhounds have been reported to have a lower ‘normal’ at 150,000/mcL.
Cavalier King Charles Spaniels can have hereditary macrothrombocytopenia. This means the platelet cell numbers are decreased, but the size of these platelets are much larger than platelets are in other breeds. Dogs with this condition can have platelet counts of 25,000/mcL to 100,000/mcL and not have any symptoms. It is recommended to work with a specialist to determine if these pets have IMTP, or this hereditary disease.
How Do IMTP Pets Look?
IMTP patients present with bruising, either small pin point spots (pettechia) or large bruising. They can have spontaneous bleeding such as nose bleeds (epistaxis), bloody urine (hematuria) or stool (hematochezia), bloody vomit (hematemesis), or other random bleeding. These patients may also be anemic, pale, lethargic, or not eating because they may have had excessive bleeding from not being able to clot appropriately.
What is IMTP?
Immune Mediated Thrombocytopenia (IMTP) involves the immune system attacking the platelets (the cells that make clots). Thrombo- is platelet; -cyto- is cell; and -penia means lack or deficiency. So, thrombocytopenia literally means the deficiency of platelet cells.
In the case of IMTP, the body’s immune system sees platelets as a foreign invader needing to be destroyed. The immune system no longer recognizes the platelets as belonging to the animal and starts breaking down the cells. This can cause severe bruising or spontaneous bleeding as the pet can no longer form clots.
Platelets are crucial for clot formation. Throughout the course of a regular day a normal, healthy pet will have small capillary bleeds when they move, bump into things, chew on kibble, chew on sticks, and so on. Normally we don’t see these small cuts or bruises because the body quickly creates a small clot repairing the capillaries (the smallest blood vessel) before blood can leak out. The problem is when there are not enough platelets circulating in the blood stream to form the clot needed. This causes small pin point bruises called petechiae. Common places for these to be seen are on the gums, groin, and abdomen.
There are a large number of platelets circulating around in the blood. Typically there are 175,000-500,000 platelets in every microliter of blood (175k-500k/mcL). We get extremely concerned when numbers fall below 50k-75k/mcL and monitor very closely.
Spontaneous bleeding can occur when the platelets are less than 20,000 per microliter (20k/mcL). Depending on the severity of the thrombocytopenia, the pet can become anemic. We discuss blood transfusions in the hematology section here.
Handling these patients extremely carefully is crucial. When venipuncture is performed to obtain blood, it is crucial for it to be from a periphreal spot like the arms or legs, and a pressure wrap is suggested for a minimum of 30 minutes with close monitoring of the site once the bandage is removed for continued bleeding/bruising. It is important to not do jugular venipuncture (the neck is the common place to get blood from animals) as it can cause large bruises and as you can imagine is a difficult place to bandage.
These patients should only eat soft or wet food until their platelet numbers are above 75k/mcL or the veterinarian gives the okay to feed kibble again. During this time, your pet should not chew on toys, bones, or other rough objects. Do not let them run, or play rough. I also recommend to not use a neck collar during this time, just use a harness to prevent bruising on the neck.
Unlike pets with IMHA, IMTP patients typically do not act as sick or lethargic, so they may want to do more than they are allowed to do. It’s our job to keep them from hurting themselves.
Close monitoring of platelet cell counts are done by manual platelet counts in the hospital or sent out to the lab. These pets may present with no platelets on a blood smear (or 0k/mcL), and it can take several days for the body to start producing enough platelets for your veterinarian to send the pet home.
Due to the risk of bleeding close monitoring of PCVs are also done to ensure the pet does not need a blood transfusion from anemia.
In the case of IMTP, the body’s immune system sees platelets as a foreign invader needing to be destroyed. The immune system no longer recognizes the platelets as belonging to the animal and starts breaking down the cells. This can cause severe bruising or spontaneous bleeding as the pet can no longer form clots.
Platelets are crucial for clot formation. Throughout the course of a regular day a normal, healthy pet will have small capillary bleeds when they move, bump into things, chew on kibble, chew on sticks, and so on. Normally we don’t see these small cuts or bruises because the body quickly creates a small clot repairing the capillaries (the smallest blood vessel) before blood can leak out. The problem is when there are not enough platelets circulating in the blood stream to form the clot needed. This causes small pin point bruises called petechiae. Common places for these to be seen are on the gums, groin, and abdomen.
There are a large number of platelets circulating around in the blood. Typically there are 175,000-500,000 platelets in every microliter of blood (175k-500k/mcL). We get extremely concerned when numbers fall below 50k-75k/mcL and monitor very closely.
Spontaneous bleeding can occur when the platelets are less than 20,000 per microliter (20k/mcL). Depending on the severity of the thrombocytopenia, the pet can become anemic. We discuss blood transfusions in the hematology section here.
Handling these patients extremely carefully is crucial. When venipuncture is performed to obtain blood, it is crucial for it to be from a periphreal spot like the arms or legs, and a pressure wrap is suggested for a minimum of 30 minutes with close monitoring of the site once the bandage is removed for continued bleeding/bruising. It is important to not do jugular venipuncture (the neck is the common place to get blood from animals) as it can cause large bruises and as you can imagine is a difficult place to bandage.
These patients should only eat soft or wet food until their platelet numbers are above 75k/mcL or the veterinarian gives the okay to feed kibble again. During this time, your pet should not chew on toys, bones, or other rough objects. Do not let them run, or play rough. I also recommend to not use a neck collar during this time, just use a harness to prevent bruising on the neck.
Unlike pets with IMHA, IMTP patients typically do not act as sick or lethargic, so they may want to do more than they are allowed to do. It’s our job to keep them from hurting themselves.
Close monitoring of platelet cell counts are done by manual platelet counts in the hospital or sent out to the lab. These pets may present with no platelets on a blood smear (or 0k/mcL), and it can take several days for the body to start producing enough platelets for your veterinarian to send the pet home.
Due to the risk of bleeding close monitoring of PCVs are also done to ensure the pet does not need a blood transfusion from anemia.
What happens after diagnosis?
Handling these patients extremely carefully is crucial. When venipuncture is performed to obtain blood, it is crucial for it to be from a periphreal spot like the arms or legs, and a pressure wrap is suggested for a minimum of 30 minutes with close monitoring of the site once the bandage is removed for continued bleeding/bruising. It is important to not do jugular venipuncture (the neck is the common place to get blood from animals) as it can cause large bruises and as you can imagine is a difficult place to bandage.
These patients should only eat soft or wet food until their platelet numbers are above 75k/mcL or the veterinarian gives the okay to feed kibble again. During this time, your pet should not chew on toys, bones, or other rough objects. Do not let them run, or play rough. I also recommend to not use a neck collar during this time, just use a harness to prevent bruising on the neck.
Another concern is gastrointestinal bleeding. It is normal for microscopic tears to happen in the mucosa of the intestines in normal patients and platelets easily fix those tears. But, if there are no platelets to fix it, then hemorrhaging can occur through the guts.
Unlike pets with IMHA, IMTP patients typically do not act as sick or lethargic, so they may want to do more than they are allowed to do. It’s our job to keep them from hurting themselves.
Close monitoring of platelet cell counts are done by manual platelet counts in the hospital or sent out to the lab. These pets may present with no platelets on a blood smear (or 0k/mcL), and it can take several days for the body to start producing enough platelets for your veterinarian to send the pet home.
Due to the risk of bleeding close monitoring of PCVs are also done to ensure the pet does not need a blood transfusion from anemia.
These patients should only eat soft or wet food until their platelet numbers are above 75k/mcL or the veterinarian gives the okay to feed kibble again. During this time, your pet should not chew on toys, bones, or other rough objects. Do not let them run, or play rough. I also recommend to not use a neck collar during this time, just use a harness to prevent bruising on the neck.
Another concern is gastrointestinal bleeding. It is normal for microscopic tears to happen in the mucosa of the intestines in normal patients and platelets easily fix those tears. But, if there are no platelets to fix it, then hemorrhaging can occur through the guts.
Unlike pets with IMHA, IMTP patients typically do not act as sick or lethargic, so they may want to do more than they are allowed to do. It’s our job to keep them from hurting themselves.
Close monitoring of platelet cell counts are done by manual platelet counts in the hospital or sent out to the lab. These pets may present with no platelets on a blood smear (or 0k/mcL), and it can take several days for the body to start producing enough platelets for your veterinarian to send the pet home.
Due to the risk of bleeding close monitoring of PCVs are also done to ensure the pet does not need a blood transfusion from anemia.
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You just got the call that your precious fur-baby is coming home! Yay!!
Now the long battle begins. Unless your pet was diagnosed with a tick borne disease, your pet may be on life-long medications and need close monitoring. It is common to have recheck CBC and manual platelet counts every 1-2 weeks initially and then as your pet stays in remission and is weaned off of medications the rechecks can be as infrequent as once a month to once every few months. Your veterinarian will work with you closely to develop your pets individual treatment plan. If keeping track of medications is a struggle, we have a journal to track medication that can help you. Check out how to get your own copy of the One Month Pet Health Journal from Amazon here. |
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What complications do you watch for?
- Secondary infections:
- Immunosuppressive drugs suppress the immune system for everything not just auto-immune issues, so these pets can pick up infections very easily.
- Development of other allergies:
- The immune system is ramped up and can easily redirect to other things like food, environmental, or medications. Keep a close eye out for anything unusual and talk to your veterinarian.
- Steroid related side effects:
- Garbage diving, aggression, severe muscle wasting, increased drinking, and increased urination.
- Changes in hair coat or skin pigmentation have been noted from medications.
Want to know more?
We hope this helps with this confusing and overwhelming disease. Please feel free to email at [email protected] and I'll be happy to talk to help if I can.
Learn more about IMTP and related subjects by checking out the hematology and immunology sections of the website.
Also visit the other blog posts related to the immune system and IMTP here.
Learn more about IMTP and related subjects by checking out the hematology and immunology sections of the website.
Also visit the other blog posts related to the immune system and IMTP here.