Concerning Dr. Brown's comments on polycystic kidneys:
 
        Polycystic kidneys are a different problem entirely than cystic kidneys
(or renal cysts, which is a more appropriate appelation.)
 
        One or two cysts in the kidneys, unless extremely large and prone to
rupture, as I said in an earlier post - are very common and most likely have
little effect on the animal's renal status.
 
        Polycystic kidneys, on the other hand, is a very rare (in my experience)
finding in ferrets, although I have seen one case.  Generally polycystic kidneys
arise from a genetic defect in which the various parts of the kidney's filtering
system are not properly hooked up together, and the plumbing simply doesn't
work.  These animals tend to die withint he first year of life.  This finding is
seen in all species, including man.
 
        Hydronephrosis is an ACQUIRED phenomenon - either as a resultof surgical
intervention (such as a bad spay), or anything else that blocks up the ureter.
I have also seen several cases of hydronephrosis as a result of severe urinary
tract infection (once again, the aggregate of inflammatory material blocked the
ureter).  When there is no outflow, urine builds up, causing pressure inside the
kidney.  It's like filling up a water balloon - eventually the kidney becomes a
big urine filled bag.
 
        But of course, the most common presentation is one or two cysts in a
kidney, and I generally don't worry about that at all...
 
       Bruce Williams, DVM                 Department of Veterinary Pathology
       [log in to unmask]         Armed Forces Institute of Pathology
       (202) 576-2453/2454                 Washington, D.C.  20306-6000
 
 
[Posted in FML issue 0808]