Having last week discussed what the spleen is, the important functions it performs and what happens when it ruptures, we conclude the topic today by looking at a few of the more common conditions that are seen in the dog and cat.
Mentioned last week was that one of the causes of bleeding from the spleen was when a mass on it ruptures. With that in mind, we start by looking at two common masses that can have very different prognoses.
The first is called a haematoma and is actually the most common localised mass found on the spleen. In simple terms this is purely a swelling containing blood; it is not malignant in any way. Although it can be potentially dangerous if it ruptures, once removed the problem is solved.
Unfortunately, the second type of mass affecting the spleen that we are discussing today is not benign. It is called a haemangiosarcoma and is fast growing, very invasive and will commonly spread elsewhere.
These tumours are common and usually found in middle-aged or old medium to large breed dogs, especially German Shepherds. Often the first anyone knows about the tumour is when the dog becomes very weak and lethargic or even just collapses due to a large internal bleed. Sometimes a more chronic progressive in-appetence, tiredness and weight loss can be seen, usually caused by anaemia.
Diagnosis may involve palpating the abdomen, blood tests, ultrasound examination, abdominocentesis (sticking a needle with syringe into the belly and seeing if there is any blood to suck back) and possibly x-rays. From this, enough evidence is gathered to justify the surgical treatment required which is total removal of the spleen.
Definitive diagnosis is only achieved by sending the mass for analysis at a laboratory after surgery. This is one of the few tumours that would not be considered for ultrasound guided biopsy (to confirm diagnosis prior to surgery).
This is because not only is surgery often needed immediately and there being high risk of haemorrhage but also because of the chance of spreading the tumour through the act of biopsying.
It’s worth mentioning that removing the spleen is usually only a palliative measure as there is a high likelihood it will have already spread elsewhere, and pre-op X-rays of the chest may be done to see how advanced the condition is and to assess whether the surgery is really in the patient’s best interest. Chemotherapy can be used to try increase survival time.
A much less common problem that is again primarily of larger, and in this case deep-chested dogs, is splenic torsion (twisting). This can occur with or without the stomach dilating and twisting as well. Either way, it’s life-threatening and needs to be rapidly diagnosed and corrected. Once the dog is medically stabilised (and if stomach dilation has occurred it is decompressed) the spleen is assessed for the presence of clotting. Depending on the severity of damage it may just be untwisted or removed.
Cats, in contrast to dogs, are more likely to have a generalised enlargement of the spleen rather than just a localised one due to a mass. There are a number of reasons for this including: congestion (an abnormal accumulation of blood in the spleen), infections or inflammation. Any condition which results in the spleen having to work much harder can also cause overall enlargement.
This increased workload may be due to either blood cells being destroyed so the spleen has to replace them, an increased demand for certain types of antibody or more abnormal cells needing removed from the blood circulation.