Tuesday, January 31, 2017

Preventing Infectious Kidney Failure

In the past few months I've seen two heartbreaking cases of dogs that were diagnosed with acute renal failure that probably could have been prevented.  But before we talk about failing kidneys, let's talk about what healthy kidneys do for our pets. (and us for that matter).

The major functions of the kidneys is to filter waste products of the blood into the urine, maintain a state of homeostasis (constant state in the body), and stimulate red blood cell production.  There are other hormonal functions but let's stick to the biggies here.  When we do a blood test and tell you that your pet's kidney function is good, we are actually measuring the levels of Urea Nitrogen and Creatinine (two toxic by products of protein metabolism).  these levels will be maintained within a narrow normal range until about 75% of the filtering units  (glomeruli) in the kidneys are damage.  Kidney function can also be evaluated by measuring the concentration of the urine as well as looking for things in the urine that shouldn't be there, such as protein and cells. When the filtering units are damaged, the waste products build up and the condition is called azotemia, or uremia.  hen the tubules ( different part of the kidneys) are damaged, we will see dilute urine or cast like structures in the urine.  Leaking membranes in the glomeruli may allow the filtering of wast products but facilitate the leakage of protein into the urine.  When caught early, the progressive nature of renal disease can often be mitigated.  However, once the glomeruli are damaged, they are gone, and no new ones will replace them.

We had a dog present to the clinic a few months ago.  It lived in Nassau county, never went out east, mostly lived in the yard in a suburban environment that was not particularly wooded.  This labrador was not feeling well and when blood work was performed, it was in azotemic (elevated BUN/Creatinine) renal failure with severe levels of protein in the urine.  It was also positive for exposure to Lyme disease.  The owners had not vaccinated it against Lyme disease because they did not think it was at risk for exposure.  Indeed it was at low risk based on life style assessment, but no dog on Long Island is at no risk.  They also were not using any flea or tick control.  Lyme nephritis is a kidney disease caused by the body's reaction to Borrelia burgdorferi, the bacteria that causes Lyme disease.  (Note Lyme not Lyme's).  Unfortunately for this dog, once the kidneys are involved, the prognosis is guarded.  In fact, this dog did not make it and was put to sleep after a week in the hospital receiving intensive care.  While we do not see a lot of dogs in our practice that are ill with Lyme disease, we do see many that are exposed to the bacteria and therefore at risk.  This is why we recommend testing every dog every year for heartworm and tick borne diseases.  we also recommend tick control for all dogs.

The second dog presented two weeks ago with a rapidly worsening, acute renal injury.  This young German Shepherd Dog was losing weight, not eating, and had decreased energy, His blood work showed a worsening azotemia, increased levels of protein in a dilute urine, and he tested positive for leptospirosis, a bacterial disease.  Leptospirosis is spread by the urine of infected animals, in our area, dogs, raccoons, mice and rats.  While usually more common in the summer, it is obviously around all year here on Long Island.  It's prevention is complicated by the fact that there are many serovars (types of Lepto bacteria), and the vaccination only covers the 4 most common and virulent.  Many clients are reluctant to vaccinate because they have read that the vaccine causes reactions, or is dangerous.  The truth is that while vaccine reactions do occur, most often, they are similar to the type of reaction we get when we get a flu vaccine or a tetanus shot. And while we hate our dogs to have any reaction, it is better than renal failure.  Lepto is also contagious to people so having a dog that is unknowingly shedding this bacteria in the urine puts all of us at risk.  This puppy (he is only 2 1/2 years old) is still undergoing treatment with antibiotics and Intravenous fluids.  It looks like he may make it but will most likely have permanent damage to it's kidneys.

We have to remember that there are many diseases that can affect our pets (and sometimes us).  prevention is always better than treatment.  While vaccination is not always a completely benign procedure, modern vaccine science has come a long way in our fight to protect our pets from infectious diseases.