How I approach cats with lower urinary tract signs
Lower urinary tract signs (LUTS) in cats include variable combinations of frequent attempts to urinate, straining to urinate, urinating in inappropriate places in the house (periuria), crying out during attempts to urinate, and blood tinged urine. These signs are not specific for any particular disease; they can be seen in cats that have bladder stones (cystic calculi), bacterial urinary tract infections, cancer, or other mass lesions in the bladder. In approximately two thirds of these cases, clinicians are unable to find a specific cause for the clinical signs, and therefore refer to this syndrome as Feline Idiopathic Cystitis (FIC) (1).
History and physical examination
A complete history can be very important to ascertain whether the cat is polyuric, polydipsic, pollakiuric (urinating small amounts frequently), stranguric, hematuric, or a combination of these signs. The history will help decide which diagnostics are most important. An environmental history should also be obtained, particularly for those cats where FIC is probable. A thorough physical examination should always be performed with careful attention to the lower urinary tract and surrounding perineal region.
Urinalysis and culture:
One can see various results in the urinalysis (abnormalities in hematuria, proteinuria, pyuria, crystalluria and specific gravity) from cats with LUTS, few of which are specific for any particular bladder disease. For example, both hematuria and proteinuria, evidence of suburethral vasodilation and vascular leakage regardless ofetiology, can be transient; present in one urination and not the next. When a true urinary tract infection is present, one can see pyuria, however pyuria (usually minimal amounts) can also be present in sterile cystitis. Moreover, fewer than 2% of cats less than 10 years of age have a true bacterialcystitis, urine culture also usually is a low yield test.
The likelihood of a urinary tract infection does increase with age, the presence of cystic calculi, perineal urethrostomies (2), and dilute urine (3). Crystalluria, too, can be found in many cats with no signs referable to the lower urinary tract, but may be important in cats prone to recurrent urinary calculi. Because FIC is a diagnosis of exclusion, a urinalysis and culture should be recommended for any cat presenting with recurrent LUTS that has not been evaluated previously. The urine specific gravity should be closely evaluated, particularly in older cats, to be certain that there is adequate concentration, recognizing that the form of the diet (dry >1.040 vs. canned >1.030), can influence the result. Therefore the clinician should more strongly recommend a urinalysis in older cats, or if the cat has other disorders where isosthenuria is present (e.g. hyperthyroidism, renal insufficiency), or has had previous surgeries.
A plain abdominal radiograph that includes the entire urinary tract (including the urethra) can be a useful diagnostic tool in cats with LUTS. It is helpful to perform a warm water enema prior to imaging to fully evaluate the urethra. Approximately 15-20% of cats that present with LUTS will have radiographic evidence of cystic calculi (4). In some circumstances, a contrast cystogram can be helpful to reveal lesions such as non-radiopaque calculi, masses and blood clots. Contrast studies are especially indicated in elderly cats, when FIC is not as likely.
If the cat has had recurrent bouts of LUTS and the above diagnostics have already been performed, cystoscopy can be considered. This tool allows one to visualize the urethra and bladder at low and high pressures. Small cystic calculi, diverticula, ectopic ureters, and small polyps can all be visualized. If none of these are seen, the severity of edema, glomerulations (small pinpoint hemorrhages), friability and fibrosis can be evaluated. I will occasionally biopsy the bladder for histopathology and possibly culture if the cystoscopic picture warrants it. The examples listed below are cases that have presented to our clinics or composites of several cases to illustrate various diagnostics and therapeutic strategies for cats with LUTS.
Onion is a 3-year-old female spayed DSH. She presented for her first episode of periuria, stranguria and hematuria which had occurred over the past 1.5 days.
Pertinent past history: She was obtained from a shelter at 2 years of age, and the owners had noted no problems with her in the past. The owners reported no polyuria or polydipsia. She lives strictly indoors with no other pets. She eats a commercial dry cat food.
Physical examination: The exam was essentially unremarkable except for bilateral inguinal hair loss and obvious self excoriations in the same area (Figure 1). The bladder was small and the cat resented bladder palpation. Body score (BCS) =6/9.
1. LUTS primarily characterized by periuria, hematuria and stranguria.
2. Inguinal hair loss and self excoriations.
Assessments: Differential diagnoses for the LUTS in a cat this age include: FIC, urolithiasis, behavioral problem, and urinary tract infection. Other differentials such as neoplasia, bladder diverticulum or other anatomic abnormality, or urethral stricture are less likely in cats with this signalment and history. The alopecia is likely self induced, and could be due to referred pain from the underlying bladder condition. Consideration of primary dermatologic disorders may be appropriate in individual cases.
Diagnostic plan: Although this was the initial occurrence of LUTS, the owner elected to pursue additional diagnostic procedures. An abdominal radiograph was performed, with care taken to include the entire lower urinary tract; no abnormalities were detected, and the bladder was small. A urinalysis and culture revealed a urine specific gravity of 1.049 with >100 RBC/hpf. The urine culture was negative.
Diagnosis: Most likely FIC.
Recommendations for Onion: The causes of FIC are not yet fully understood. Fortunately, approximately 85% of cats with FIC will not have a subsequent recurrence of clinical signs. In my experience, educating the owners about the disease and what we know appears to be helpful for clients to gain an understanding about their cat’s clinical signs.
An overarching premise is that FIC is not just a bladder disorder but involves complex interactions of the two main arms of the body’s stress response system: the sympathetic nervous and endocrine systems. A similar disease occurs in humans called interstitial cystitis and both disorders appear to have a waxing and waning course that is exacerbated by stressors (5). The sympathetic nervous system acts through release of catecholamines such as norepinephrine (NE) and epinephrine, while the adrenal glands release cortisol and a plethora of other steroids. FIC appears to be characterized by an exaggerated sympathetic nervous system (6) and a blunted endocrine response (7) to stressors that do not seem to affect healthy cats. Studies have shown increased NE and other catecholamine metabolites in cats with FIC during a mild stressor as compared to healthy cats (Figure 2). Any treatment strategy to decrease sympathetic nervous system outflow may be important in reducing clinical signs. Reducing the noxiousness of the urine to the damaged bladder wall and normalizing bladder permeability may also prove useful.
In addition to the sympathetic nervous system, abnormalities in the hypothalamic - pituitaryadrenal axis (HPA) have also been observed in cats with FIC. After a high dose (125 μg) of synthetic ACTH was administered, cats with FIC had significantly decreased serum cortisol responses as compared to healthy cats (8). Although no obvious histological abnormalities were identified, the areas consisting of the zonae fasciculata and reticularis were significantly smaller in sections of glands from cats with FIC than in sections of glands from healthy cats. Therefore, it appears that while the sympathoneural system is fully activated in this disorder, the HPA axis is not. The pathophysiology of FIC likely involves complex interactions between a number of body systems. Abnormalities are not localized just to the bladder, but are present in the nervous, endocrine, gastrointestinal, behavioral and even cardiovascular systems (9). How these systems manifest as FIC in some cats but not in others remains to be determined, but the unpredictable pattern supports the presence of a common underlying abnormality being expressed differently based on individual susceptibilities. In order to better treat these patients, it is important for clinicians to understand that this syndrome is not just a “bladder disease” amenable to simple diet or drug therapies. From what we have observed in research studies of cats with FIC, it appears to be a painful syndrome. During acute episodes, analgesic therapy should be prescribed. A mild sedative also may be beneficial to help decrease the anxiety that can be seen during acute flare-ups. This therapy is generally prescribed for 4-6 days, paying close attention that at least small amounts of urine are passed, especially in male cats. Onion was prescribed buprenorphine (0.03 mg/kg PO BID for 4 days). Although we prefer buprenorphine, alternative analgesic strategies could have included: fentanyl patches, butorphanol, oxymorphone, or, possibly, non steroidal anti-inflammatory drugs such as meloxicam. Onion’s home environment also was addressed because we have found that providing an “enriched” environment for these cats helps to decrease the sympathetic “overdrive” and prolong the inter-episode interval (10). We made the following recommendations for Onion:
Addendum: Onion’s owners were contacted 3 days after their appointment and the cat was clinically normal. Subsequent follow-up at 3 weeks and 3 months revealed that the cat had remained asymptomatic.
Note: In Onion’s case, diagnostics were performed at the owner’s request to help elucidate a cause for her LUTS. If the owners had not requested further testing, or if financial concerns had been present, beginning therapy with analgesics and educating the clients would have been sufficient. Most cats concentrated urine specific gravity would have ruled out underlying renal disease. However, if clinical signs persisted or relapsed, diagnostics should be strongly encouraged.
Casey is a 6-year-old MC Himalayan who presented to our clinic for recurrent LUTS and a history of a urethral blockage 6 months ago.
Pertinent past history: Casey presented to his referring veterinarian approximately 2 years ago for a history of stranguria, pollakiuria and hematuria which would last approximately 3-4 days and recur every 2-3 months. A CBC and biochemical profile performed one year ago revealed no abnormalities. Abdominal radiographs, revealed no evidence of calculi within the urinary tract. Several urine cultures over the past two years were negative. All the urinalyses had urine specific gravities greater than 1.035 and urine sediments revealed only hematuria and occasionally small amounts of pyuria (5-7/hpf). He had been given several different antibiotics over the past 2 years, including amoxicillin with clavulanic acid and baytril, with no consistent improvement. Approximately six months ago, the cat went to an emergency service for persistent stranguria and Casey was diagnosed with a urethral obstruction. He was treated and released after 3 days in the hospital. The cat’s diet consisted of various dry commercial cat foods. The litter boxes are scooped daily and cleaned regularly. He has window perches and many toys that were recommended by the referring veterinarian. Casey lives strictly indoors with two other cats.
Physical examination: Casey’s physical exam revealed no abnormalities BCS=5/9.
Problem list: Waxing and waning LUTS for the past 2 years and historical urethral blockage six months ago.
Assessments: Because the referring veterinarian has ruled out several causes of LUTS in cats such as cystic calculi and urinary tract infections, the most likely differential for Casey is FIC. However, Casey’s signs have continued, so other differentials such as neoplasia, diverticula, and blood clots should be reconsidered. I consider the urethral blockage a manifestation of FIC that can occasionally occur in male cats. It is possible that serum proteins, crystals (usually struvite), cells and debris can be trapped and form a mucous plug (Figure 3).
Plan: Advanced diagnostics were considered in Casey because of the lack of response to therapy and persistent clinical signs.
Diagnosis: FIC and historical urethral obstruction.
Recommendations for Casey: After the diagnostics, a separate appointment was made with Casey’s owner to discuss his condition and provide the owners with as much information as possible about what might help improve Casey’s clinical signs and prolong his inter-episode interval. An environmental resource checklist was discussed with the owners and the following details obtained:
More Recommendations for Casey:
1. Analgesic therapy was prescribed for Casey. Although Casey was not symptomatic at the time of the appointment, the owners were supplied with butorphanol and instructed to give (1mg orally 2-3 times per day for no more than 3 days) if clinical signs developed. He was also sent home with the non-selective alpha adrenoceptor antagonist, phenoxybenzamine to use if needed. Phenoxybenzamine may help relax the urethra, which can be important in male cats. Alternatively, we could have prescribed the more selective alpha-1 adrenoceptor antagonist prazosin (CoVM1). The alpha antagonists also have a sedative effect. By having these medications at home, the owners would not have to return Casey for care in the event of another episode. Casey does not do well in the car and because further diagnostics are not warranted, it is usually better to help reduce the stress associated with a trip to the veterinary hospital whenever possible.
2. On the basis of previous studies done in cats with recurrent chronic FIC we have demonstrated elevated catecholamines, and a blunted hypothalamic pituitary axis during a moderate stressor. Furthermore we have documented a functional deficit in the alpha-2 adrenoceptor function in cats with FIC as compared to healthy cats under similar stressful circumstances (13). Based on these data, treatment strategies aimed at decreasing sympathetic tone in hopes of improving these abnormalities have been published (10). In this study, owners of 46 indoor-housed cats with FIC were offered recommendations for multimodal environmental enrichment methods (MEMO) based on a detailed environmental history, such as the one obtained in Casey. Cases were followed for 10 months by client contact to determine the effect of MEMO on LUT and other signs. Significant (P<0.05) reductions in LUTS, fearfulness, nervousness, signs referable to the respiratory tract, and a trend (P<0.1) toward reduced aggressive behavior and signs referable to the lower intestinal tract were identified. These results suggest that MEMO may be a useful adjunctive approach to therapy for indoor-housed cats with FIC due to decrements in noradrenergic outflow. I strongly encourage implementing MEMO, particularly for cats with recurrent FIC. We implemented a similar MEMO strategy for Casey with the following guidelines:
By three weeks, they had slowly implemented the changes we prescribed and Casey was doing well. Our technician called them at 3 months; they reported that Casey had “bloody urine” 2 weeks ago and that they treated him with the medications we prescribed. The episode lasted only 36 hours, and they did not seek veterinary attention for it. If Casey’s FIC continued to progress, we informed the owners that, in addition to other MEMO therapy, we could prescribe a tricyclic antidepressant such as amitryptiline or clomipramine. These drugs are sometimes used in chronic, severe cases of FIC after all efforts at environmental enrichment have been implemented (16).
Mischa is an 11-year-old FS Siamese Mix that presented to our hospital for evaluation of periuria and hematuria of 2 weeks duration. Upon further questioning, the owners did not think that Mischa was straining to urinate, but they did note that the puddles of urine found on the carpet were quite small (suggesting to us that the cat was possibly pollakiuric). She does lick her perineal area quite often. Mischa had not had any health problems until this time. The owners were unsure of her food and water intake because they have 2 other cats and all the cats share the same bowls. They eat a dry commercial cat food ad libitum. Mischa is occasionally allowed out in the back yard only.
Physical examination: No abnormalities were detected, except that she was uncomfortable on caudal abdominal palpation. The bladder was moderately full. BCS= 5/9.
Problems: Hematuria, periuria and possible pollakiuria.
Assessments: The differentials are similar to those discussed in the two previous cases, however, most cats with FIC are generally younger and do have distinct LUTS. Therefore diagnostics should be encouraged in cases such as this because one is less likely to diagnose FIC.
Plan: A CBC, biochemical profile, urinalysis with culture, and abdominal radiographs were performed. The CBC and biochemical profile were normal (BUN=25 mg/dL (8.9 mmol/L), creatinine = 1.5 mg/dL (134 mmol/L)). The urine specific gravity was 1.049. Urine sediment revealed >100 RBC/hpf, no evidence of pyuria and the culture was negative. Abdominal radiographs showed moderate renal mineralization and a ureterolith was suspected in the left ureter (Figure 5). A scant amount of “crystalline debris” was noted in the bladder, but no true calculi could be identified. To further characterize the bladder sediment, renal mineralization and ureteral stone, an abdominal ultrasound was recommended. This test revealed only mild dilation of the left ureter. The kidneys had a slight decrease in corticomedullary definition and the left renal pelvis was mildly distended. The stone in the ureter was approximately 3 cm from the bladder. No bladder stones were noted. Mischa’s urinations were monitored in the hospital over the next 24 hours. It can be very helpful to watch urination habits and evaluate for LUTS whenever possible in animals that present for urinary disorders. We were fortunate and discovered that Mischa urinated without any stranguria or pollakiuria. However, gross hematuria was present.
Diagnosis: Renal mineralization and ureteral calculi.
Plan: A CT scan with contrast was suggested to help delineate how much of the left ureter was occluded, but the owners declined. Surgery for the stone was not recommended at this time due to the invasiveness of the procedure, the cat was stable and doing well, as well as financial limitations for the clients. Ureteral stones in cats are quite frustrating and often, we reserve surgery for cases where renal function is severely compromised. Clinicopathologic features and case management of ureteral obstruction is well described in the literature (17,18). Most stones in the upper urinary tract in cats are composed of calcium oxalate (19,20). Occasionally calcium phosphate or dried solidified blood stones have been reported (21). No dissolution protocol is available for calcium oxalate urolithiasis and Mischa was placed on a canned, prescription, nonacidifying diet to help prevent recurrence of calcium oxalate formation. Canned diets appear to be the easiest method of increasing water intake, which is beneficial to help reduce the solute load and prevent stone formation (22). A non-acidifying diet was chosen due to the presumed calcium oxalate component of the stone. Periodic CBC’s and evaluation of renal function were recommended. We also monitored the cat by ultrasound for progressive worsening of the ureteral obstruction. This case was presented to illustrate the importance of the signalment, history, and physical exam when evaluating cats with LUTS. Although over two thirds of cats that present with LUTS will not have an identifiable cause and will be diagnosed with FIC, these cats are usually younger to middle-aged cats. Cats with FIC usually have a one or more of the signs mentioned in the first two cases.
This article was kindly provided by Royal Canin, makers of a range of both wet and dry urinary diets for cats and dogs, for the full range please visit www.RoyalCanin.co.uk or speak to your Veterinary Business Manager:
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