Immune mediated haemolytic anaemia or IMHA is an immune-mediated health condition in which the body’s own immune system attacks its own red blood cells, leading to the development of anaemia.
The condition might develop without any obvious root cause or reason, but may also be triggered by another underlying health condition or problem that affects the dog’s immune system or red blood cells. In rare cases, immune mediated haemolytic anaemia can develop as an adverse vaccine reaction, although this is very uncommon.
Immune mediated haemolytic anaemia in dogs can be acute and serious, and it is a good idea to learn the basics of the condition and what it means if your dog has bee diagnosed with IMHA, or if your vet is considering this as a potential diagnosis. In this article we will look at immune mediated haemolytic anaemia in dogs in more detail, explaining the condition’s symptoms, effects and treatment options. Read on to learn more.
In order to understand IMHA, it is first necessary to understand the basics of the role that red blood cells play in the body of the healthy dog. Red blood cells carry oxygen to the body’s cells and remove carbon dioxide from the bloodstream, which are vital functions of the healthy body.
However, anaemia results when the dog’s red blood cell count drops below their normal, healthy levels, or when their red blood cells don’t work properly. This can be caused by loss of blood, an underlying disease or health condition, or because the body simply doesn’t produce enough red blood cells in the first place.
In dogs with immune mediated haemolytic anaemia, the condition arises because the dog’s own immune system wrongly identifies red blood cells as a threat, and destroys them when they are released from the bone marrow into the bloodstream.
There are two different types of immune mediated haemolytic anaemia, called primary and secondary respectively. Primary IMHA occurs when the dog’s immune system creates antibodies to destroy red blood cells, and secondary IMHA occurs when an external factor such as a toxin or health condition alters the structure and makeup of the dog’s red blood cells, again causing their immune systems to turn on them.
Any dog can develop immune mediated haemolytic anaemia, although the primary form of the condition is more common in certain breeds and types of dogs than others, including the Basenji and some Cocker spaniel breed lines, although for the latter breed, the condition is not very common within UK breed lines.
Male and female dogs are equally likely to be affected, and the age of onset of IMHA can be very variable.
IMHA produces a number of different symptoms in affected dogs, and which can be quite variable in terms of their presentation from dog to dog, and not all dogs will display all of them. Some of the main symptoms you might identify at home as a warning that something is amiss include:
In order to formally diagnose immune mediated haemolytic anaemia, your vet will need to run a range of different tests and examinations to get to the bottom of the problem. Blood tests will help to identify if your dog’s red blood cell count is lower than it should be, and from there, your vet will work to determine why this is and work out the underlying cause of the problem.
Generally, dogs exhibiting the primary form of immune mediated haemolytic anaemia will be treated with a type of immunosuppressive therapy, which uses medications to supress the body’s immune reaction and prevent it from attacking the red blood cells. This is often achieved with steroids, although in some cases this is not enough in and of itself.
In dogs who are suffering from very acute anaemia, a blood transfusion or platelet transfusion may be required, to help to keep the dog stable whilst the underlying cause is identified and addressed.
If there is an underlying trigger or cause that led to the onset of IMHA, this must be treated or brought under control too in order to allow for recovery.
Immune mediated haemolytic anaemia is a serious condition that can be challenging to treat, and the faster that a diagnosis is made and treatment begun, the greater your dog’s ultimate chances of survival and a full recovery.
If you have any concerns, speak to your vet as soon as possible and ask them to investigate your dog’s symptoms.