October 23, 2012

The full name for Lupus is Systemic Lupus Erythematosus, or SLE for short.  This disease affects a number of species including dogs, cats and humans. It is classed as an autoimmune disorder, which means that the body has identified a part of itself as foreign, and attacks that part as if it was an invader. This results in severe tissue reactions in many body systems in SLE because in this condition, the body sees nucleus, cytoplasm, and cell surface components as “foreign”. Because of this widespread reaction to self, there is significant immune system activation.

One of the harmful effects of the immune system reaction is the accumulation of clumps of antibody-cell complexes which we term immune complexes. Many of these get stuck in the microcirculation or capillaries, especially in the kidneys, skin, and joints. This interferes with normal organ function and signs vary, depending on where the tissue reactions occur.

On the outside, an owner may notice general signs of malaise such as lethargy, behavioural changes, reduced mobility or shifting lameness, reduced appetite, and skin lesions.  Often the skin lesions localize to margins between skin and mucous membranes. 

The reason for SLE development is poorly understood, but certain viral infections and drug exposures are thought to act as triggers for the condition. There may be an inherited component to the illness as well.

Laboratory blood tests such as the antinuclear antibody test (ANA) or Lupus Erythematosus (LE prep) test are needed to confirm the illness, and frequently, other diagnostic procedures such as joint tap, X-rays, biopsy, and urine analysis will be performed.

Lupus is an unpredictable disease, and variable response to treatment is seen. Long term therapy is needed. To bring the immune system back under control, powerful chemotherapy-class drugs are selected. Management of secondary problems like kidney failure and arthritis often requires considerable additional therapy, so this is not an easy disease to control. It does not carry a good prognosis.

This condition starts out with very vague symptoms, and should remind an owner that if their pet is showing any signs of ill health, a visit to the veterinarian is warranted so that early intervention can be undertaken since those waxing and waning symptoms may reflect a more serious internal medicine disease such as lupus.