Protein Deposits in Kidneys (Amyloidosis) in Horses
Key takeaways
Amyloidosis in horses is when amyloids, incorrectly formed proteins, deposit in the tissues due to chronic inflammation or cancers.
- Amyloids may be deposited in one location or affect multiple organs
- The most commonly affected organs are the liver, kidney, spleen, and lymph nodes
- Horses are particularly predisposed to nasal amyloidosis
- Symptoms depend on which organs are affected
- The most common form is found in the kidney and the symptoms are related to renal failure, such as lethargy, weight loss, abnormal urination, and fever
- The diagnosis, treatment, and prognosis depend on the type of amyloidosis and the areas affected
- Diagnosis commonly includes blood work, a physical exam, biopsy, and imaging
- Localized amyloidosis can be managed with ongoing treatment with a good prognosis
- Systemic amyloidosis is untreatable and the prognosis is poor
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A closer look: Protein Deposits in Kidneys (Amyloidosis) in Horses
Amyloidosis is rare in horses. The prognosis is good for localized amyloidosis, but in systemic cases affecting multiple organs the prognosis is poor.
Amyloidosis occurs in two different categorizations; primary and secondary.
Primary amyloidosis is referred to as immunoglobulin-derived amyloidosis. Secondary amyloidosis is called reactive amyloidosis.
Risk factors
The risk of amyloidosis is increased in horses who have repeatedly received an immunization for antiserum production.
No link has been found between occurrence rate and breed, sex, or age.
A form of amyloidosis particularly found in horses is localized nasal amyloidosis.
Amyloid depositing the liver may result in liver failure.
Possible causes
Causes of amyloidosis can be separated by the classification of primary vs secondary amyloidosis
The cause of primary amyloidosis is a tumor of the immunoglobulin-producing cells, called multiple myeloma.
There are numerous causes of secondary amyloidosis.
The chronic inflammation resulting from these conditions produces large amounts of inflammatory proteins, which accumulate in the tissues and form amyloid.
Main symptoms
Clinical symptoms vary depending on the deposition site. In horses, amyloidosis most commonly affects the kidneys.
The symptoms for kidney amyloidosis are related to kidney failure.
Another common form of amyloidosis in horses affects the spleen, which may not produce obvious symptoms.
Testing and diagnosis
The diagnostic procedure for amyloidosis includes:
- Physical examination
- Bloodwork
- Diagnostic imaging, including ultrasound
- Urinalysis
- Biopsy of affected tissues
Diagnosis of systemic amyloidosis can be difficult, as symptoms depend on the affected location and organs involved.
Steps to Recovery
Once amyloid is deposited it is not possible for the body to process them. The only option is to remove the affected tissue surgically, although this is not always a possibility. In systemic cases, the damage has spread through the body to the organs, making removal impossible. Treating the underlying cause in cases resulting from chronic inflammation can slow the deposition of amyloid, but does not reverse the damage to affected organs. There is no definitive treatment, and the focus is on symptom management. This differs depending on what organs are affected.
In localized cases such as nasal amyloidosis, surgery is the main method of treatment. Radiotherapy can be used to decrease the size of the deposits, but is not a truly effective treatment method. Even in cases where the amyloidosis has been removed, there is always a chance that it may reoccur.
As systemic amyloidosis has no treatment, prognosis is poor and in many cases the most humane option is euthanasia.
Conversely, the prognosis for localized amyloidosis, such as nasal amyloidosis is good, although deposits may continue to form requiring ongoing treatment.
Prevention
There is nothing that can prevent the development of this condition.
There are some conditions that can cause amyloidosis that can be transmitted between animals, such as internal parasites.
Is Protein Deposits in Kidneys (Amyloidosis) in Horses common?
Amyloidosis is rare in horses.
Typical Treatment
Symptom management, surgery, euthanasia
