While this blog usually focuses on new research in feline medicine, it is equally if not more important to take the time to review the state of veterinary medicine and discuss current standards of care. Consensus statements are recommendations made by panels of experts based on the best quality evidence in the literature. The International Society for Companion Animal Infectious Disease (ISCAID) has previously published consensus guidelines for the treatment of several classes of infection, and has recently updated their statement on the treatment of urinary tract infections. While the article focuses on dogs and cats, this blog will focus on the feline portion.  The statement classifies urinary tract infections into several categories based on history, clinical signs, and concurrent disease. These categories include:  Sporadic Bacterial Cystitis (Simple Uncomplicated UTI) - Healthy, non-pregnant females or neutered males without urinary tract abnormalities or relevant co-morbidities with less than 3 episodes of bacterial cystitis in the last 12 months. Animals must have clinical signs of lower urinary disease (ie pain, straining, inappropriate urination, etc), as well as a positive urine culture. As primary UTI is rare in cats, this should not be diagnosed without a positive culture.  Recurrent Bacterial Cystitis - Three or more episodes of bacterial cystitis in a 12 month period or two episodes in 6 months. Generally associated either with an underlying cause (stones, anatomical abnormalities, systemic disease, etc) or inappropriate treatment of a previous UTI. Upper Urinary Tract Infection (Pyelonephritis) - Infection of the kidney tissue either through ascending infection or bloodborne infection. Combination of positive urine culture and signs of renal pain, azotemia, lethargy, fever, casts, pelvic dilation, and other clinical and laboratory signs. Bacterial Prostatitis - This is extremely uncommon in cats and is not really discussed in this species. Subclinical Bacteriuria - A positive urine culture with no clinical signs of lower urinary disease. Blood and white blood cells may be present, but the animal has no signs of lower urinary disease, or signs attributable to a concurrent condition (ie increased urination may be due to diabetes and not bladder infection). Urinary catheters - Any patients with indwelling or temporary urinary catheters.  Urologic surgery and implants - Patients undergoing cystotomy, scoping, stent or SUB placement, or other urologic procedures. Medical dissolution of uroliths - Cats with struvite stones rarely have underlying infections, but if urine culture is positive, therapy may be indicated as for sporadic cystitis. Based on each of these categories, the panel made recommendations on the diagnostic path, treatment, and monitoring of animals with these conditions. While a full discussion of event he feline-relevant sections of this consensus statement would be beyond the scope of this blog, a few important points can be taken away. These include:  Don’t treat a UTI unless there are clinical signs - Subclinical bacteriuria should not be treated unless there is significant clinical risk for progression. Even in diabetic, cushingoid, or post-UTI treatment populations, the presence of bacteria or pyuria is not enough to justify therapy. In cats, treatment should always be based on culture and sensitivity (C&S). Samples should be collected by cystocentesis unless there are direct contraindications. NSAIDs or other pain control may be as effective as antibiotics and may be used in place of empirical therapy while awaiting culture results. Amoxicillin is the most reasonable empirical antibiotic choice. Amoxicillin with clavulanic acid is acceptable but rarely needed. TMS is another acceptable empirical choice. Other drugs should be based on culture results or significant clinical judgement. Duration of therapy should be 3-5 days. Post-treatment culture is not recommended for sporadic cystitis, and is of debatable utility for recurrent cystitis. Empirical therapy of pyelonephritis should involve a fluoroquinolone, cefotaxime or ceftazidime, or another broad spectrum antimicrobial with efficacy against Enterobacteriaceae. 10-14 days of treatment is recommended.  Urinary catheters should be placed and cared for aseptically and remain in place as short a time as possible. Prophylactic antimicrobials, culture of the catheter tip, and routine culture should be discouraged. Cats rarely have infection-associated struvite uroliths, and so antibiotic therapy is rarely indicated. Bacterial infection alongside struvite may be subclinical. A major limitation to these recommendations is the determination of whether clinical signs are present. While some cats present with typical hematuria, stranguria, and inappropriate urination, other animals with more mild signs and stoic demeanors may show limited indications of disease. This limits the ability of veterinarians to differentiate subclinical bacteriuria from bacterial cystitis. This is not a purely veterinary concern; a similar issue is encountered by physicians working with senile or non-verbal patients, many of whom may be predisposed to lower urinary infections.  Taken together, the recommendations from this guideline detail a plan for more responsible, targeted, and effective antimicrobial use in lower urinary disease. There is a general trend towards shorter courses of therapy, basing therapy on culture and sensitivity results, treating only the animals that need treatment, and using antimicrobials of least concern as first line choices.  While there may be practical and financial difficulties associated with following these recommendations in some situations, striving to practice according to the consensus described will help provide the best medicine to individual patients and minimize antimicrobial resistance in the future. Reference: International Society for Companion Animal Infectious Diseases (ISCAID) guidelines for the diagnosis and management of bacterial urinary tract infections in dogs and cats. Vet J. 2019 May;247:8-25. doi: 10.1016/j.tvjl.2019.02.008. Epub 2019 Feb 26. PubMed PMID: 30971357

Researchers around the world are working intensively to find a safe and effective treatment for feline infectious peritonitis (FIP), a highly lethal systemic disease, but to date no such treatment has become available for practical use. The etiologic agent in FIP is a coronavirus, an enveloped, single-stranded positive-sense RNA virus. Not all feline coronaviruses, however, cause FIP; only the feline infectious peritonitis virus (FIPV) biotype is the agent involved in FIP. The other feline coronavirus biotype, feline enteric coronavirus (FECV), causes a mild, often subclinical, enteritis. Both feline coronavirus (FCoV) biotypes exist as two serotypes, type I and II; therefore, there are FECV types I and II and FIPV types I and II. The majority of FCoVs worldwide, approximately 70-90%, belong to type I.  Previously these authors determined that type I FCoV has a close association with cholesterol throughout its life cycle, and that itraconazole, a highly lipophlic, triazole antifungal drug often used to treat dermatophytosis and other fungal infections in cats, inhibits FCoV infection. Itraconazole has been reported to inhibit intracellular cholesterol transport, and the authors wanted to determine if this drug would inhibit intracellular cholesterol transport in feline cells. In the present study, the antiviral effects of itraconazole on FCoV were studied in cell cultures of feline cells found to be sensitive to types I and II FIPV and type II FECV. Three strains of type I FIPV and one strain of type II FIPV were used in the study. Results of the study showed that itraconazole inhibits type I FCoV infection in feline cells, but had no effect on Type II FCoV infection. Based on the known pharmacokinetics of itraconazole in cats, and the results obtained with various concentrations of the drug in cell cultures evaluated in the present study, the authors recommend using itraconazole for treatment of FIP following the currently recommended fungal infection treatment protocol in cats. The authors plan to perform a clinical trial of itraconazole in cats diagnosed with FIP, and also investigate combinations of itraconazole with other drugs in treatment of FIP. Reference: Antiviral activity of itraconazole against type I feline coronavirus infection. Vet Res 2019;50:5

Damage to the Cranial Cruciate Ligament (CCL; analogous to the ACL in humans) is among to most common disorders of the knee in veterinary medicine. While more common in dogs, it is also seen in cats. In dogs, especially large breed dogs, surgical correction of CCL rupture is recommended in order to improve return to function and long term prognosis and decrease the future development of arthritis. In cats, the benefit of surgical correction is less clear as they are smaller animals with different weight-bearing patterns than dogs. The purpose of this study was to determine the long term prognosis of cats with conservative management of their ruptured CCL compared to cats that are surgically corrected.  The study was designed as a retrospective cohort study of cats presenting to two university hospitals over a 6 year period. Medical records were examined for cats presenting with a ruptured CCL diagnosed by a positive cranial drawer test where follow up was available. Signalment information, medical records, surgical logs, and follow up information were obtained. Cats that were alive at the time of data collection had their owners contacted and asked to complete the Feline Muscluloskeletal Pain Index (FMPI) questionnaire.  60 cats had a diagnosis of CCL rupture during the time period, of which 50 had complete follow up information available. There was an even sex distribution and a median age of 9years. Presenting complaints were usually acute onset lameness.  28 cats were treated conservatively, and 22 received surgical intervention. The lateral fabellotibial suture technique was used in all cats. Arthrotomy was performed in 19 of the 22 cats and complete rupture of the CCL confirmed. Of these cats, 9 had concurrent meniscal injury, 4 had collateral ligament injury, and 3 had rupture of the caudal cruciate ligament. No cat treated conservatively required conversion to surgery. 6 of the surgical group cats had post-operative complications, 3 of which required a second surgery. 29 cats were alive at the time of follow up, of whom 24 (83%) had the FMPI questionnaire completed. The FMPI is scored on a numerical scale, with higher numbers representing more severe pain. The surgically treated cats reported a median score of 5, while conservatively treated cats were 0.5. This was a statistically significant difference, and significance was maintained even when cats with multi-ligament injuries were excluded.  Two of the conservatively treated and 5 surgically treated cats developed CCL rupture of the contralateral limb.  The retrospective nature and lack of complete follow up represent limitations to this study. Further, while long term pain was assessed, no data was collected on shorter term return to functionality and pain scoring.  The authors conclude that, based on the results of this study, surgical repair of CCL rupture in cats is of no benefit and may actually worsen long term arthritis. While prospective studies are indicated to investigate this in more detail, it would appear that surgical intervention may not be indicated in cats with CCL rupture, and that conservative management may be the preferred option.  Reference: Cranial cruciate ligament disease in cats: an epidemiological retrospective study of 50 cats (2011-2016). J Feline Med Surg. 2019 Mar

Multimodal analgesia is an essential part of a modern, balanced anesthetic technique. Local anesthetics are effective tools in the management and prevention of surgical pain. Bupivacaine is a long acting local anesthetic that has been shown to be effective in controlling surgical pain in cats. It must be administered at the source of pain, and so intraoperative administration is required.  The purpose of this study was to determine the efficacy of bupivacaine for postoperative pain control in cats undergoing ovariohysterectomy. This study was designed as a prospective double blinded case control trial.  267 female cats presenting for routine, elective OHE to a high volume spay-neuter practice were recruited into the study. Cats were >2m age and 0.9kg body weight. Cats that were pregnant, in heat, or had an intraoperative complication were excluded from the study. Cats were block randomized by day to receive either bupivacaine, placebo, or sham.  Cats were premedicated with buprenorphine, ketamine, and dexmedetomidine, intubated and maintained on isoflurane. OHE was performed by experienced high-volume surgeons via a midline approach. Two of the surgeons utilized a pedicle ligation technique and one used a pedicle tie. The times to administer interventions were recorded. Cats in the treatment group received bupivacaine 2mg/kg total dose divided into the left and right suspensory ligaments and mesovarium of the ovary, the uterine body just caudal to the bifurcation, and the SQ tissue between the closed linea and skin using a 25g needle. The placebo group received saline at these sites, and in the sham group the sites were simply identified. Pain was assessed by a veterinary technician trained in pain scoring techniques. Pain was scored at 1h post op and just before discharge (<7h postop). Initially, a modified UNESP Botucatu multidimensional composite pain scale (MCPS) was used to score cats pain, in conjunction with a 0-10 numerical scale. As the study progressed, the MCPS was replaced with a modified version of the Colorado scale due to difficulty and time constraints performing the MCPS.  A total of 267 cats were enrolled in the study, of which 212 met all inclusion criteria. 71 cats were included in the bupivacaine group, 58 in the saline group, and 83 in the sham group.  Cats were stratified by weight into 0.9–1.5 kg, >1.5–2.7 kg and >2.7 kg groups for the purposes of analysis.  In the lower two weight categories there was no significant difference in pain score at both time points between groups (while the pain scores were numerically lower in the other groups this did not attain statistical significance). In the higher weight class, the bupivacaine group had lower pain scores at both time points. No cat included in the study required rescue analgesia.  Surgical times were measured and averaged 5.5 minutes. The median time to administer bupivacaine was 69s, of which 30s was due to calculating dose and drawing up the drug.  Some drawbacks to this study were present. One of these was the change in pain scoring technique partway through the study, with the use of a non-verified pain scale limiting interpretation of results. Rescue analgesia was given to any cat with moderate to severe pain.  The authors of this study concluded that a targeted bupivacaine block reduced postoperative pain in cats. This block may provide a safe and inexpensive option for pain control in cats presenting for routine spay. The authors also concluded that the MCPS was not an ideal pain scoring system for a high volume spay setting. Reference: Fudge JM, Page B, Mackrell A, Lee I. Evaluation of targeted bupivacaine for reducing acute postoperative pain in cats undergoing routine ovariohysterectomy. J Feline Med Surg. 2019 Feb 5

Lower urinary obstruction is a common occurrence in domestic cats. It occurs most commonly in male cats and is a complication of any form of feline lower urinary tract disease (FLUTD). Underlying causes of lower urinary obstruction may include bladder crystals and stones, urinary tract infections, idiopathic cystitis, or other causes. It is characterized by an inability to urinate due to an obstructed and spasmodic urethra due resulting in pain, azotemia, and hyperkalemia. Untreated, it will result in death. Treatment involves catheterization to relieve the obstruction, fluid therapy, pain control, and other symptomatic care.  It has been theorized by many clinicians that lavage of the bladder with sterile saline at the time of catheterization could be helpful, under the assumption that this will allow dilution of the urine and removal of crystals, mucous, and debris that may be associated with obstruction. It may, however, lead to increased time under sedation/anesthesia which may be detrimental, especially in unstable cats. The purpose of this study was to determine if there is an effect of bladder lavage on rate of urinary re-obstruction after catheterization. The study was designed as a prospective, unblinded, controlled trial. The primary outcome was re-obstruction after urethral catheterization.  One hundred thirty-seven cats were recruited to the study, 69 in the flush group and 68 in the no-flush group; based on an analysis for sample size. All cats were male. Age, weight, history of obstruction, and presence of crystals did not differ between groups.  All cats were de-obstructed with a rigid open-ended polypropylene catheter using sterile 0.9% saline for retropulsion.  After successful catheterization this was replaced with a 3.5 or 5 Fr red rubber catheter and sutured into place. Cats in the flush group received a bladder lavage with a volume of saline between 50 and 500mL (average 240mL) until the fluid was clear, and then attached to a closed collection system. Cats in the no-flush group were connected directly to a closed system. Difficulty of catheterization did not differ between groups.  Clinicians scored the difficulty of catheterization on a subjective 1-4 system. Care after catheterization was not standardized and included combinations of fluid therapy, analgesia, antispasmodics (prazosin), and a quiet environment.  The in-hospital recurrence rate was 13% for “flush” group cats, and 19% for “no-flush” cats. These values were not statistically different. Limiting analysis to cats with crystalluria, recurrence rates were 22% for both groups. Median time of catheterization was 37 hours for the flushed cats and 36h for the no flush, a non-significant difference. Duration of hospitalization was 3 days for both groups. These findings indicate that bladder lavage had no effect or rate of re-obstruction.  Several limitations to this study were present. The study was underpowered to detect small differences in outcome, however the authors correctly state that larger samples sizes may be impractical. There was also a lack of standardization in treatment protocols, which may have led to some degree of variation. Finally the lack of blinding is a major limitation, though this may be difficult to accomplish given the nature of the intervention.   The author’s conclude that there was no effect of bladder lavage on the rate of re-obstruction in catheterized cats with lower urinary obstruction. However, as a non-statistically significant difference was present and treatments were not blinded or standardized, they suggest that further research is needed to determine the true effect of bladder lavage in blocked cats.   Reference: Effect of urinary bladder lavage on in-hospital recurrence of urethral obstruction and durations of urinary catheter retention and hospitalization for male cats.