June 2022

In this VETgirl online veterinary continuing education blog sponsored by Royal Canin, Dr. Margie Scherk, DVM, DABVP (Feline) will review what’s new with Feline Lower Urinary Tract Disease. She’ll review how we can use hematuria as a tool in management of this frustrating disease in our feline patients! Please note the opinions in this blog are the expressed opinion of the author and not directly endorsed by VETgirl.

Feline lower urinary tract disorders…again. What’s new? Using hematuria as a tool in management

By Dr. Margie Scherk, DVM, DABVP (Feline)

Have you ever been unsure of whether hematuria is real vs iatrogenic?

Cats are generally pretty stoic so clients frequently misinterpret voiding in inappropriate locations/periuria as a signal that their cat is upset with them. As inappropriate elimination is the top reason people give for relinquishing their cats to shelters, where a cat urinates is critical for their survival (1). When a client brings their “accident-prone” cat to the veterinary clinic, we are talking with a person who feels disheartened, angry, and guilty. So we need to help them (and their cat) quickly…and hopefully permanently. Along with collecting a urine sample, we have to inquire how many boxes there are, where they are located in the home, how often they are cleaned, how large the box is, how deep the litter is, etc., in hopes that the problem is one of correcting poor toilet care. If that isn’t the case, we delve deeper looking for anything else that could be causing stress for the cat. Indeed, idiopathic cystitis is the number one cause (65%) for a cat to present with lower urinary tract signs (LUTS), followed by urolithiasis, urethral plug or obstruction, and urinary tract infection (UTI).

Signs of lower urinary tract disorders are pollakiuria, hematuria, stranguria and periuria. These are associated with the bladder essentially being a urine reservoir that, under normal circumstances, is emptied when full. However, when the “reservoir” becomes inflamed for any reason and the wall is stretched as urine enters from the ureters, it hurts, so the cat voids smaller amounts, more frequently (pollakiuria), to reduce the stretch. The pain may also result in periuria should the cat need to pee before getting to the appropriate litterbox or if they associate the box with the pain they are experiencing. Stretching of the inflamed bladder wall causes bleeding. In fact, any disorder causing damage to the mucosal surface or vasculature of any part of the urogenital tract can result in leakage of red blood cells (RBC) into urine.

As a consequence, hematuria is a common finding regardless of the cause of the LUTS. The red or pink tinged urine we see with gross/macroscopic hematuria occurs when there are > 2500 RBC/ μL of urine (TNTC RBC/HPF). However, hematuria, reflecting inflammation, is present before we can see it. In fact, over 90% of cats with lower urinary tract disease have microscopic hematuria present (2) but owners are able to appreciate gross hematuria only 42% of the time (3). Being able to detect microscopic hematuria is beneficial in many ways to monitoring healing as well as recurrence of chronic problems in patients with disorders affecting the urinary tract.

In cases of idiopathic cystitis, we can assess whether an individual is suffering from recurrence as well as assess how well environmental and other stress-alleviating methods (including pharmacological aids) are working by checking for the presence of hematuria. In cats predisposed to crystalluria or urinary tract infection (lower and upper), finding hematuria at home may enable earlier intervention by alerting the client to bring their cat in to see us. In cats who are recovering from obstruction or urinary tract surgery (e.g., cystotomy for stone removal), finding resolution of hematuria over the first two weeks helps monitor progress of healing. In those with urinary tract neoplasia, increasing hematuria can aid in making decisions around palliative care.

Patients with LUTS frequently have tiny bladders when presented to the veterinary clinic. This makes it difficult to collect a urine sample. While performing cystocentesis (with or without the aid of ultrasound), we can inadvertently cause hematuria. Additionally, in cats with existing hematuria, when we note a swirl of blood while collecting the urine sample, it is impossible to know whether the hematuria is “real”, iatrogenic, or both. When this happens, we can ask the client to syringe-collect a urine sample from the litterbox using a non-absorbent litter, however it is important to note that this process can be cumbersome and time-consuming for the owner, and disruptive to the cat. We can also ask the owner to bring the cat back to the clinic for a repeat cystocentesis, or we can use scientifically validated litter granules, sprinkled on top of the litter the cat is already familiar with, to detect hematuria. These granules (Royal Canin Hematuria Detection, technology by Blücare) are able to detect even microscopic levels of hematuria. With these hematuria granules (Blücare), a readily visualized blue colorimetric change occurs in the granules quickly – in under a minute – and that lasts 2 days, meaning that the client doesn’t have to be watching the cat.

Royal Canin Hematuria litter box image

At-home identification and monitoring of hematuria is useful in cases where the client is busy and/or in families who are reluctant to bring their cat in for regular veterinary preventive veterinary care. Relative to dogs, cats do not receive necessary regular veterinary care as frequently, and novel approaches to improve access to care are needed. Screening can also be part of semi-annual assessment of the senior cat who lives with a person who is reluctant to bring them in for routine screening or because they don’t recognize the subtle signs of illness.

As with so many things, early detection is key. The sooner we can determine that a cat is distressed, the sooner we can help improve their circumstances and help them relax. When the blood is due to crystals or uroliths, we can make appropriate changes in diet and hydration to dissolve or reduce the chance of further stone formation. Monitoring hematuria every 2-4 months allows us to detect recurrence of crystalluria/urolithiasis, infection, or idiopathic cystitis. In the case of idiopathic cystitis, it also makes sense to preemptively screen for hematuria when stress is anticipated (renovations, moving, visitors, holidays, etc.). During the first five months of the Covid-19 pandemic when people shifted to working from home, there was a significant increase in male cats being presented to emergency departments of two veterinary teaching hospitals (paper under review). It is not a stretch to think that there may have been have been a similar increase in unobstructive presentations of idiopathic cystitis as well, that didn’t require emergency visits.

By encouraging clients to monitor hematuria at times appropriate for the underlying condition, clients are motivated to seek veterinary care. We can give them peace of mind and help them be proactive in their cat’s welfare.

References:
1. Salman MD, Hutchison J, Ruch-gallie R, Kogan L, Kass PH, Scarlett JM. Behavioral Reasons for Relinquishment of Dogs and Cats to 12 Shelters. J Appl Anim Welf Sci.2000; 3(2):93-106.
2. Kaul E, Hartmann K, Reese S, Dorsch R. Recurrence rate and long-term course of cats with feline lower urinary tract disease. J Feline Med Surg. 2020 Jun;22(6):544-56.
3. Dorsch R, Remer C, Sauter-Louis C, Hartmann K. Feline lower urinary tract disease in a German cat population. A retrospective analysis of demographic data, causes and clinical signs. Tierarztl Prax Ausg K Kleintiere Heimtiere. 2014;42(4):231-239.

Footnote:
a. Personal communication, Joanna Finstad

Recommended reading:
• 2014 AAFP and ISFM Guidelines for Diagnosing and Solving House-Soiling Behavior in Cats (https://catvets.com/guidelines/practice-guidelines/house-soiling)
• Blücare® Granules: A Novel Tool for the Early Detection and Monitoring of Urinary Tract Disorders in Cats

Today’s VETgirl blog is sponsored by Royal Canin. Recommend multifunction Royal Canin Urinary SO (plus) CALM complete and balanced adult cat food to help support a healthy urinary tract while providing calming nutrients for cats facing stress. Learn more at my.royalcanin.com.

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  1. I have had some colleagues suggest placing a urinary catheter and “washing out” male cats with hematuria prior to them blocking. My understanding has been that introducing something like a catheter could cause more inflammation and should only be done if they are already obstructed?

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