By altering pre-glomerular resistance, healthy kidneys can maintain relatively stable glomerular capillary pressures despite variations in systemic blood pressure. This process is termed "renal autoregulation". Autoregulation can be reduced when renal disease results in loss of nephrons.
Over the last several years, there has been a shift in the mineral content of uroliths in cats from predominantly magnesium-ammonium phosphate (MAP) to calcium oxalate (CaOx). Of the nephroliths and ureteroliths analyzed by the Minnesota Urolith Center in 2002, 70% of 170 renolith submissions and 98% of ureterolith submissions were CaOx.
Persistent proteinuria of renal origin is an important marker of chronic kidney disease (CKD) in dogs and cats. Unfortunately, due to the high incidence of false-positive results for proteinuria on the urine dipstick screening test and proteinuria associated with lower urinary tract inflammation, positive reactions for urine protein are quite common and therefore often disregarded.
Urinary incontinence is a common problem affecting up to 20% of spayed female dogs and 30% of those > 20 kg. In most of these patients it occurs within 3 years of spaying, although in many it may not become a major problem until later in life when it can be complicated by diseases that increase water intake and urine production.
Dogs and cats frequently present for signs related to the urinary tract. These signs may be due to inappropriate urination (house soiling or urinary incontinence) or may relate to the act of voiding itself.
One of the simplest and most cost effective diagnostic tools is at our disposal every day in practice, however we often overlook it and the large amount of data that it provides us. Urinalysis, including fresh sediment examination, can provide additional important information that complements and enhances the diagnostic information we gain from other diagnostic modalities such as serum chemistry, CBC, and the all-important physical examination.