The acute form of lymphocytic leukemia is called acute lymphoblastic leukemia, or ALL. This form is more common in German shepherds
and large breed dogs of any age. Pets with ALL are generally very ill, and begin to show clinical signs of illness fairly suddenly. Patients with ALL will often have a fever.
The chronic form of lymphocytic leukemia is called chronic lymphocytic leukemia, or CLL. This disease is usually seen in dogs older than 10 years, with no breed predisposition. Pets with CLL often have vague signs of illness that can be present for months to years before a diagnosis is made. The most common complaints include weight loss and lethargy, although the aforementioned signs can also be present.
Based on the clinical signs alone, leukemia can mimic a multitude of disease processes. The appropriate laboratory findings are crucial to making a diagnosis. However, other conditions that may cause similar clinical signs include: Neoplasia (cancer), especially lymphoma. Lymphoma is another form cancer that is quite similar to leukemia and involves cancerous lymphocytes.
Autoimmine disease. Autoimmune or immune-mediated diseases occur when the body destroys its own cells. This often results in severe anemia and/or thrombocytopenia, which is a decrease in the number of platelets, cells that aid in blood clotting. Clinical signs of pale gums and bleeding or bruising can often be seen in autoimmune disease and leukemia.
Severe bacterial infection/sepsis. Sepsis is a disorder that occurs secondary to uncontrolled infection within the body. Sepsis can be associated with a variety of conditions, including ALL.
Severe inflammatory conditions such as pancreatitis or pneumonia. Inflammation of the pancreas, lungs, or other organs can also cause clinical signs similar to leukemia.