Particles in the Urine in Cats

Particles in the urine of cats can be an indication of degeneration, inflammation, epithelial irritation, or renal tubular irritation of the kidneys. A hypothesis of the cause of the systemic disorder can be determined through a urinalysis, as structures are often embedded into the cast at the time they are formed. There are five types of urine casts a cat could have and each one links the cats to an underlying condition.

Particles in the urine in cats can appear on a urinalysis, or exam of the urine, in almost non-existent numbers, which is normal. However, when there is more than just one or two particles in a single field of view (under a microscope), particles in the urine of your cat is the indication of a pathological problem. Veterinarians refer to urinary particles as casts. When the urine contains an abnormally high number of these casts, the term cylindruria is used. Cylindruria is a clinical indication that your cat is having problems with her kidneys, as casts take the form of the kidney’s collective tubes before they reach the bladder. 

The symptoms associated with particles in the urine in cats depends on the underlying cause of the urine casts. Symptoms may increase in severity as this condition worsens.

• Dark, cloudy urine
• Reduced volume of urine
• Fever
• Abdominal pain
• Lethargy
• Weakness
• Excessive drinking (polydipsia)
• Frequent urination (polyuria)
• Diarrhea
• Vomiting
• Irregular heartbeat
• Shock

Types

Hyaline Casts

Hyaline casts are composed of mucoprotein and plasma protein that indicates a mild form of renal irritation. 

Cellular Casts

Cellular casts are subcategorized into tubular epithelial casts, red blood cell casts, and white blood cell casts. Epithelial casts contain cells from renal epithelium and are seen in acute nephritis and renal tubule degeneration. Red blood cells casts are an indication of a hemorrhage to the tubules. White blood cell casts are due to an infectious or inflammatory process causing a degeneration of the tubular cells. 

Granular Casts

Granular casts contain pieces of granules and indicate acute nephritis or severe kidney disease.  

Fatty Lipid Casts

Fatty lipid casts contain refractive fat droplets and indicate renal disease. 

Waxy Casts

Waxy casts are rare but indicate a cat has chronic to severe tubular degeneration. 

The potential causes of particles in the urine in cats are numerous. The condition can be due to any of the following: 

• Trauma to the renal organ
• Glomerular disease 
• Infectious disease (Leptospira spp., Ehrlichiosis, FIP) 
• Renal Inflammation 
• Myoglobulinuria (rhabdomyolysis) 
• Hemoglobinuria (intravascular hemolysis) 
• Renal vessel thrombosis 
• Low cardiac output 
• Hypovolemia 
• Dehydration 
• Renal Ischemia 
• Nephrotoxic drug 
• Toxin 

Particles in the urine in cats can be found on a urinalysis and is part of a diagnostic plan the veterinarian previously set for the symptoms a cat is displaying. A urinalysis is the examination of urine. Your veterinarian will likely collect a sample from your pet in the veterinary clinic. Casts dissolve in alkaline urine within two hours, so a fresh sample is important. If your cat is unable to give a sample on her own, the bladder may be palpated with pressure applied or a catheter may be placed. The sample will then be placed in the centrifuge to separate the sediment from the fluid and the veterinarian will take a dropper full of sediment to be examined under the microscope. 

The doctor will be able to detect which type of cast your cat has by the shape and color of the particle. The type of cast identified, number, and additional abnormalities found in the urine sample will clue the veterinarian in to the cause of your cat’s symptoms. 

Treatment of particles in the urine in cats includes restoring hydration and administration of medication required for the underlying condition. Most cats are treated as an outpatient, but if the pet is severely dehydrated, intravenous fluid therapy may be needed. Antibiotics are also a common choice of treatment for urine casts, as infection is not unusual.

Your cat should be able to continue with her regular diet and activities during treatment, unless otherwise instructed by your veterinarian. A feline with a history of urinary particles should have access to water 24/7 and keeping the feline hydrated should be the owner’s number one priority. The prognosis for cylindruria is very good for felines who receive adequate veterinary care and treatment.