The Canine Spleen

Full Title: The Canine Spleen

Author: Betsy Marsted

Date of Publication: February 9, 2015


Research Paper Text:

History of the Spleen

Metaphorically, the spleen is often referred to as a “venting spleen” as it was considered to have a close relationship to our emotions in the medieval times. People thought that “venting” their spleens would remove excess anger because many thought it was the literal, physical source of a hot temper. We have learned a lot since then about the spleen’s purpose in our bodies.

Function of the Spleen

The spleen is the “front lines” of the canine body; it is a very busy organ considering its small size. Although it is an integral organ of the immune system, it is not vital to the species. Its purpose is to transform raw materials from the stomach into usable forms, distributing them throughout the body via the blood. It also forms red blood cells in the fetus. The spleen is also closely related to the immune and pancreas function.

  1. Immune system function
    The spleen also acts as a filter for the blood by recognizing and eliminating toxic, old, malformed or damaged red blood cells and harmful elements. Similar to its role in detecting unhealthy red blood cells, the spleen can identify unwanted bacteria or viruses. When blood flows into the dog’s spleen, it performs a quality check, as the red blood cells must pass through a network of narrow passages. Healthy blood cells will pass through the spleen and continue to circulate throughout the bloodstream. When the spleen and lymph nodes detect unhealthy blood cells in the bloodstream, they create defender cells called lymphocytes which destruct the old and unhealthy red blood cells. Lymphocytes are large white blood cells that produce antibodies; unique proteins that weaken or kill bacteria, viruses, and other organisms that cause infection. Lymphocytes purify the blood by increasing the power of the white blood cells, which helps to fight infections from spreading through the body by trapping germs and destroying them.
  2. Pancreas function
    The spleen metabolizes sugar and overall digestion by breaking food down into manageable parts. Because the spleen is an extremely vascular organ, it contains many vessels that carry and circulate fluids in the dog’s body.

The spleen is very economical, in that it saves any useful components, such as iron, from the old cells. It stores iron, eventually returning it to the bone marrow, where it makes hemoglobin. Hemoglobin is a protein in the blood that transports oxygen from the dog’s lungs to all the parts of its body that require it.

Another function of the spleen is to store blood. The blood vessels contract and expand, depending upon the need of the canine body. When vessels expand, the spleen holds (reserves) blood. When the body calls for the stored blood to move into circulation, the contraction of the smooth muscle occurs. If trauma causes the dog to lose blood, the spleen will respond by releasing that reserve blood back into the system.


The dog’s spleen is located in the left side of the abdominal cavity and is attached to the stomach. It is purple, soft and smooth with notches on its upper front edge. It will change shape, mirroring the stomach’s changes and will swell when the storage of blood increases. Size and weight vary according to each dog, but it can grow larger with adverse medical conditions.


Adverse Conditions

Because the spleen works in close collaboration with the dog’s blood and lymph, it can be affected by infection, liver disease and other conditions that may compromise the health of the dog.

If you suspect your dog might have spleen cancer symptoms include severe abdominal pain, anemia, weakness, sudden collapse and loss of appetite. The two types of spleen cancer are as follows:

  1. Hemangiosarcoma
    A type of cancer or mass that forms on the soft tissues of the blood vessels of the spleen and is the most common form of cancer in dogs. The mass resembles a raised blister, which then interrupts normal organ function. It is aggressive; often spreading rapidly to other organs within the body. Surgery to remove the spleen caused by this deadly form of cancer is possible in the first two stages of development and don’t involve other organs. While all dogs are subject to Hemangiosarcoma, German Shepherds, Golden Retrievers and Labrador Retrievers (dogs or larger breeds) and middle-aged or older dogs are more prone to this form of cancer.
  2. Hemangioma
    Similar to Hemangiosarcoma, it is not malignant and does not spread to other parts of the body.

The biggest hurdle with spleen cancer is that the symptoms do not appear until it has progressed to the advanced stages, when immediate veterinary care is imperative. Symptoms will also vary depending upon the location of the tumor.

Splenic torsion occurs when there is trauma or damage and is more common in dogs that also suffer from gastric dilation. It involves the twisting of the blood vessels that carry blood to the spleen. If this occurs, the spleen may enlarge, which will most likely increase the chances for the spleen to rupture. Dogs may experience shock with a cold body and pale gums if a tumor ruptures in the spleen, resulting in an internal hemorrhage, and can be fatal if excessive blood loss occurs. Possible car accidents or dog fights are common causes of splenic torsion.

Diagnosis and Treatment

The diagnosis will usually discover that a tumor has ruptured which has caused bleeding. Once the spleen has ruptured, due to the presence of a tumor, prognosis is not favorable. Emergency care should be immediate, as soon as symptoms appear. Due to blood loss and the possibility of shock, intravenous fluids may be administered, as well as blood transfusions. Once stabilized, the vet will examine the dog to establish if surgery is necessary and possible. Such tests will include:

  • Blood Count: A complete blood count, which can indicate if the pet is affected by a tumor
  • X-rays: X-rays of the abdominal area to determinate if there is a tumor, a rupture of the spleen or splenic torsion
  • Chest X-rays: X-rays of the chest if the vet suspects a tumor, which may quickly spread to the lungs
  • Biopsy: If tests indicate there is a tumor
  • Abdominocentesis: Extraction of fluids from the dog’s abdominal cavity for further diagnosis if there is a suspected rupture.

Blood tests check the function of the kidneys and the liver, as well as to determine if the surgery and anesthesia are safe for the dog.

Surgical Procedure

If the dog is healthy enough for a splenectomy, which removes the entire spleen, it can be performed without adverse effects on the dog’s health, as it is a simple surgery. Anesthesia is given prior to the splenectomy procedure, which will require a small incision in the abdominal cavity, and should take approximately one hour. The surgery will require stitches. Once stabilized, other organs can be checked for the spread of the disease. If the dog has a malignant tumor, which is removed together with the spleen, the dog will need additional treatment in the form of chemo drugs and radiation therapy.

Risks and Side Effects

Surgery may present side effects such as swelling and redness at the incision site. Owners should know that there is always a possibility of complications with any surgical procedure, which include infection, excessive bleeding during surgery or abnormal heart rhythm.

In conclusion, medication will be required for the life of the dog to help fight off infections, as the loss of the spleen with compromise the body’s immune system. Although the spleen plays a significant role in both the human and canine species, our bodies do not require it for survival.


  • Evans, Howard E., Ph.D. and Alexander de Lahunta, DVM, Ph.D. Guide to the Dissection of the Dog. St. Louis: Saunders, 2010.
  • Kainer, Robert A., DVM, MS and McCracken, Thomas O., MS. Dog Anatomy A Coloring Atlas. Jackson: Teton NewMedia, 2003.
  • O’Malley, Dennis. Atlas of Spleen Pathology. New York: Springer, 2013.
  • Thie, John, DC and Thie, Matthew, M.Ed. Touch For Health. Camarillo: DeVorss, 2006.

Leave a Reply