Retrospective study of the diagnostic utility of Spec fPLin the assessment of 274 sick cats

Evaluation of Disease Spectrum in Hospitalized Cats with Hyperlipasemia: Pancreatitis Alone Is Rare, Hyperlipasemia without Suspected Pancreatitis Is Common

Histological evidence of pancreatitis is commonly found in necropsy studies in cats. A clinical diagnosis of pancreatitis is challenging due to nonspecific clinical signs, a lack of diagnostic lipase cutoffs, and frequent presence of multiple diseases. It is still unknown how often pancreatitis alone is found in sick cats and how often clinicopathological evidence of pancreatitis in sick cats does not lead to a clinical diagnosis of pancreatitis. Our aims were to evaluate the extent of comorbidities in cats with suspected pancreatitis, evaluate how often sick cats with hyperlipasemia are diagnosed only with non-pancreatic diseases, and compare their clinical findings. Medical records of 563 client-owned hospitalized cats with available lipase activity measurement (LIPC Roche) > 30 U/L (RI, 6-26) were searched and medical diagnoses recorded and grouped by organ system. Clinicopathological findings were compared between cats with pancreatitis alone (PA), pancreatitis with concurrent disease (PD), and no suspected pancreatitis (NP). We found that PA was present in 33 (6%) cats, 159 cats (28%) were in the PD group, and 371 cats (66%) had no suspected pancreatitis (NP). Clinical, laboratory, and ultrasonographic findings did not differ between PA and PD cats. Lipase activities did not differ between the three groups. The most common disease categories in PD and NP cats were gastrointestinal, hepatobiliary, renal/urinary, and endocrine, and renal/urinary, gastrointestinal, cardiac, and musculoskeletal, respectively. We conclude that cats are rarely hospitalized because of suspected pancreatitis alone, and PA cats did not differ clinically from PD cats. Hyperlipasemia in sick cats without a diagnosis of pancreatitis may be due to a reactive pancreatopathy or preexisting chronic pancreatitis.

Effects of prednisolone on 1,2-O-dilauryl-rac-glycero glutaric acid-(60-methylresorufin) ester-lipase activity and pancreatic lipase immunoreactivity in healthy cats

BACKGROUND

Corticosteroids are among the most commonly used drugs in cats and are increasingly discussed as a treatment for feline pancreatitis. However, its effects on serum lipase in healthy cats remain unknown.

OBJECTIVES

To evaluate the effects of prednisolone on serum lipase activity and pancreatic lipase immunoreactivity (PLI) in cats.

ANIMALS

Seven clinically healthy colony cats, aged 4 to 7 years, with unremarkable CBC/biochemistry panel were studied.

METHODS

Prospective study: Prednisolone (1.1-1.5 mg/kg, median 1.28 mg/kg PO) was given daily for 7 consecutive days. Lipase activity (LIPC Roche; RI, 8-26 U/L) and PLI (Spec fPL; RI, 0-3.5 μg/L) were determined at day 1 before first treatment and at days 2, 3, 8, 10, and 14. Cats were examined daily. An a priori power analysis indicated that 6 cats were needed to find a biological relevant effect at 1-β = 0.8. Statistical analyses comprised the Friedman test, random intercept regression, and repeated-measures linear regression.

RESULTS

Median (range) day 1 lipase activities and PLI were 22 U/L (14-52 U/L) and 3.2 μg/L (2.3-15.7 μg/L). One cat with abnormally high lipase activity (52 U/L) and PLI (15.7 μg/L) at day 1 continued having elevated lipase activities and PLI throughout the study. Lipase activities and PLI concentrations did not differ significantly among time points regardless of whether the cat with elevated values was included or not. All cats remained healthy throughout the study.

CONCLUSIONS AND CLINICAL IMPORTANCE

Administration of prednisolone in anti-inflammatory doses does not significantly increase serum lipase activity and PLI concentration.

Analytical validation of an ELISA for the measurement of feline pancreas-specific lipase and re-evaluation of the reference interval and decision threshold for diagnosing pancreatitis

BACKGROUND

The diagnosis of feline pancreatitis can be challenging. The clinical presentation often includes mild, nonspecific clinical signs, such as vomiting, anorexia, and weight loss. Measurement of feline pancreatic lipase immunoreactivity (fPLI) concentration in serum has been reported to be sensitive and specific for a diagnosis of pancreatitis in cats. However, analytical validation for a widely available commercial assay for the measurement of fPLI concentration has not been published.

OBJECTIVE

We aimed to analytically validate the Spec fPL assay (IDEXX Laboratories, Westbrook, ME), a commercial ELISA for the measurement of fPLI concentration, and re-evaluate its reference interval and decision threshold for diagnosing pancreatitis in cats.

METHODS

Dilutional linearity, accuracy, precision, and the effect of interfering substances were assessed. The upper limit of the reference interval was calculated based on the 95th percentile of results from clinically healthy cats (n = 107), and a decision threshold for diagnosing pancreatitis was calculated with an expected specificity of 99%.

RESULTS

Analytical validation demonstrated good linearity, accuracy, and precision, as well as the absence of interference from lipemia, hemolysis, or icterus. The upper limit of the reference interval for Spec fPL was determined to be 4.4 μg/L, and the decision threshold (a theoretical cut-off) for diagnosing pancreatitis was determined to be 8.8 μg/L based on a desired specificity of 99%.

CONCLUSIONS

The Spec fPL assay is analytically valid, and results suggest that a decision threshold of 8.8 μg/L would have high diagnostic specificity for excluding clinically healthy cats.

Specificity of a pancreatic lipase point-of-care test and agreement with pancreatic lipase immunoreactivity in cats without clinical evidence of pancreatitis

OBJECTIVES

The aim of this study was to determine the specificity of a rapid point-of-care test for the estimation of feline pancreatic lipase (SNAP fPL) in healthy and sick cats without clinical evidence of pancreatitis. A second objective was to evaluate the agreement between SNAP fPL and serum pancreatic lipase immunoreactivity (fPLI), as measured by Spec fPL.

METHODS

A total of 150 cats were prospectively enrolled into this study. Of them, 82 cats were healthy while 68 cats had various diseases but no clinical signs (eg, anorexia, depression, vomiting) raising a suspicion of pancreatitis.

RESULTS

SNAP fPL was normal in 133/150 cats (specificity 89%) without obvious clinical pancreatitis. SNAP fPL was normal in 74/82 healthy cats (specificity 90%) and in 59/68 cats that were sick but without typical signs of pancreatitis (specificity 87%). The agreement between SNAP fPL and Spec fPL was substantial (k = 0.64) in healthy cats and almost perfect (k = 0.93) in sick cats. The overall agreement between SNAP fPL and Spec fPL was almost perfect (k = 0.81).

CONCLUSIONS AND RELEVANCE

The specificity of SNAP fPL in this group of cats was high. There was a substantial and almost perfect agreement between the SNAP fPL and Spec fPL in healthy cats and sick cats without suspected pancreatitis, respectively. In the small percentage of cats with abnormal SNAP fPL and/or Spec fPL results, the possibility of subclinical pancreatitis cannot be excluded.

Serial Measurement of Serum Pancreatic Lipase Immunoreactivity, Feline Trypsin-like Immunoreactivity, and Cobalamin Concentrations in Kittens

Serum concentrations of feline pancreatic lipase immunoreactivity (fPLI), feline trypsin-like immunoreactivity (fTLI), and cobalamin are commonly used for the diagnostic investigation of cats with gastrointestinal signs. No information on these parameters in healthy cats less than 1 year of age exists. We aimed to evaluate serum concentrations of fPLI, fTLI, and cobalamin in healthy cats at different time-points during their first 12 months of life. Fourteen healthy 2-month-old kittens were included. Blood was collected at 2, 3, 4, 6, and 12 months of age, and serum concentrations of fPLI, fTLI, and cobalamin were measured. While there was a statistically significant difference in serum fPLI concentrations over time, there was no statistically significant difference between individual time-points. There was no significant difference in serum fTLI concentrations over time. Serum cobalamin concentrations were below the reference interval in 3/13 cats at 2 months of age and were significantly lower by 3 months, when 13/14 had hypocobalaminemia. By 12 months, serum cobalamin had significantly increased, yet 4/12 cats still had hypocobalaminemia. Serum fPLI and fTLI concentrations did not show any statistically or clinically significant differences in young kittens. In contrast, serum cobalamin concentrations were commonly below the reference interval in kittens. Serum fPLI and fTLI concentrations are not practically affected by age in kittens as young as 2 months of age and could be used for the investigation of pancreatic diseases.

Feline Comorbidities: Clinical perspective on diabetes mellitus and pancreatitis

PRACTICAL RELEVANCE

Diabetes mellitus (DM) is one of the most common feline endocrine disorders. It has been shown by several studies that DM in cats frequently coexists with pancreatitis.

CLINICAL CHALLENGES

It has not been definitively established what the exact pathogenetic association between DM and pancreatitis is in the cat. However, the association between these two conditions is most likely bidirectional, with DM predisposing cats to pancreatitis and vice versa. Diagnosis of pancreatitis in cats with DM is crucial because concurrent pancreatitis commonly leads to difficulties in the management of DM. When pancreatitis is associated with diabetic ketoacidosis (DKA), therapeutic management is even more challenging.

AIMS

This review focuses on the concurrent presence of DM or DKA and pancreatitis in cats, mainly focusing on their clinical management.

EVIDENCE BASE

Information provided in this review is based on feline-specific clinical research when available. In addition, comparative and human research, as well as clinical experience, has been used to enrich knowledge in areas where feline-specific research is not yet available.

Accuracy of acute-phase proteins in identifying lethargic and anorectic cats with increased serum feline pancreatic lipase immunoreactivity

The mainstay of laboratory diagnostics of feline pancreatitis (FP) is measuring serum feline pancreatic lipase immunoreactivity (fPLI). Thus far, several studies have investigated the relationship between acute-phase proteins (APPs) and the presence and severity of FP. Although changes in serum amyloid A (SAA) concentration have been linked with FP, its diagnostic accuracy remains unknown. We aimed to determine the accuracy of selected APPs in identifying cats with a high risk of FP based on increased fPLI. Serum fPLI was measured in cats (n = 52) that were presented to veterinary clinics with signs of lethargy and anorexia. The cats were divided into two groups (fPLI ≤3.5 μg/L; n = 27 and fPLI >3.5 μg/L, n = 25), corresponding to low and high risks of FP. Serum albumin, globulin, haptoglobin (Hp), and SAA concentrations, as well as the albumin-to-globulin ratio (A/G) and SAA-to-albumin (SAA/A) ratios, were determined and compared between groups. The accuracy of these measurements was examined using a multivariable logistic regression model and receiver operator characteristic (ROC) curve analysis. SAA concentrations and SAA/A ratios were significantly (P = .026 and P = .022) higher in cats with increased fPLI, with the area under ROC curve (AUROC) of 68.1% (CI 95%: 53.4%, 82.9%) and 68.6% (CI 95%: 54.0%, 83.2%), respectively. The logistic regression model combining SAA and A/G had AUROC of 75.2% (CI 95%: 62.0%, 88.4%) for identifying cats with increased fPLI. SAA as a sole analyte or combined with A/G had low to moderate accuracy in identifying anorexic, lethargic cats with increased fPLI. Serum albumin, globulin, and Hp concentrations had no discriminatory potential in these cats.

Correlation between metabolomic profile constituents and feline pancreatic lipase immunoreactivity

Background

Feline pancreatic lipase immunoreactivity (fPLI) is commonly used to diagnose pancreatitis in cats (FP). Untargeted metabolomics has been extensively applied in human and veterinary medicine, but no metabolomic studies regarding FP have been conducted.

Objectives

To identify metabolites significantly associated with increased fPLI.

Animals

Forty‐nine client‐owned cats: 11 clinically healthy and 38 with various clinical conditions.

Methods

Analytical cross‐sectional study with convenience sampling. A panel of 630 metabolites belonging to 26 biochemical classes was quantified in plasma using a commercial metabolomic assay. The correlation between plasma metabolite concentrations and serum fPLI was evaluated using Spearman's rank correlation coefficient (R_s) with Bonferroni correction. Multivariable analysis then was performed to control for glomerular filtration rate, liver damage, and blood glucose concentration. The accuracy of selected metabolites in discriminating between cats with normal (≤3.5 μg/L) and increased (>5.3 μg/L) fPLI was estimated using the area under the receiver operating characteristic curve (AUROC).

Results

Four hundred and seven of 630 metabolites (64.6%) were quantified in all cats. When controlled for potential confounders only 3 sphingolipids were significantly positively correlated with fPLI: 2 cerebrosides: HexCer(d18:1/24:0); (R_s = .56), and HexCer(d18:1/24:1); (R_s = .58) and 1 sphingomyelin: SM C18:0 (R_s = .55). Their AUROCs in identifying cats with increased fPLI were 82% (95% confidence interval [CI 95%], 70%‐94%), 84% (CI 95%, 72%‐96%), and 78% (CI 95%, 65%‐92%), respectively.

Conclusions and Clinical Importance

Selected sphingolipids are moderately positively correlated with fPLI and appear to have fair to moderate diagnostic accuracy in discriminating between cats with normal and increased fPLI.

Serum feline pancreatic lipase immunoreactivity and trypsin-like immunoreactivity concentrations in cats with experimentally induced chronic kidney disease

Background

Serum feline pancreatic lipase immunoreactivity (fPLI) and trypsin‐like immunoreactivity (fTLI) concentrations are commonly used in cats for the evaluation of pancreatic disease. The effect of kidney disease on these tests in cats are unknown.

Objective

To investigate the effect of experimentally induced chronic kidney disease (CKD) on serum fPLI and fTLI concentrations.

Animals

Surplus serum samples from 20 cats with CKD experimentally induced for an unrelated project and a group of healthy control cats.

Methods

Serum fTLI and fPLI concentrations were compared between groups.

Results

Mean (±SD) serum fTLI concentrations in 20 cats with CKD (117.8 ± 63.6 μg/L) were significantly higher than those in healthy cats (n = 32; 46.9 ± 17.5 μg/L; P < .0001). Serum fTLI concentrations in cats with CKD were above the upper limit of the reference interval in 13 of 20 cats (65%). Serum fPLI concentrations were not significantly different between cats with induced CKD (n = 18; 8.6 μg/L; range, 5.4‐9.9 μg/L) and healthy cats (n = 41; 7.4 μg/L; range, 5.0‐15.2 μg/L; P = .12). All cats with experimentally induced CKD had serum fPLI concentrations within the reference interval.

Conclusions and Clinical Importance

Decreased renal function has a clinically relevant impact on serum fTLI concentrations and potentially could interfere with a diagnosis of exocrine pancreatic insufficiency (EPI). Serum fPLI concentration was not affected by experimentally induced CKD and thus serum fPLI may be used for the diagnosis of pancreatitis in cats with kidney disease. Additional studies are needed to verify these results in cats with naturally occurring CKD.

Cyclosporine Treatment in Cats with Presumed Chronic Pancreatitis-A Retrospective Study

Simple Summary

Chronic pancreatitis (CP) is a common disease in middle-aged to older cats. Cyclosporine, an immunosuppressive drug, has been suggested as an alternative treatment when other drugs that suppress inflammation are ineffective or unsuitable. However, no published studies have investigated its efficacy in cats with CP. The aim of this retrospective study was to evaluate the efficacy of cyclosporine as a treatment for pancreatitis in cats with presumed CP. All cats had a history and clinical signs suggestive of CP and blood samples showed abnormally high concentrations of feline pancreas-specific lipase (Spec fPL) on at least two occasions. This is common in CP. All cats were treated with cyclosporine for at least three weeks. Nineteen cats, aged 6.9–17.5 years, were included. Daily treatment with cyclosporine resulted in an improvement of serum Spec fPL concentrations which indicates that the pancreatic inflammation likely had improved. The study has several limitations, including different treatment durations and doses, lack of biopsies to confirm CP and the treatment effect was not compared with an untreated control group. Despite the limitations, our results suggest that cyclosporine treatment decreases serum Spec fPL concentrations and may be effective in the management of feline chronic pancreatitis.

Abstract

Chronic pancreatitis (CP) is a common disease in middle-aged to older cats. Cyclosporine has been suggested as an alternative treatment when other immunosuppressive treatments are insufficient or contraindicated. However, no published studies have investigated its efficacy on feline CP. The aim of this retrospective study was to evaluate the efficacy of cyclosporine on supranormal serum feline pancreas-specific lipase (Spec fPL) concentrations in cats with presumed CP. Inclusion criteria were history and clinical signs suggestive of CP, serum Spec fPL concentrations above 5.3 μg/L (reference range 0–3.5 μg/L, equivocal range 3.6–5.3 μg/L) on at least two occasions and treatment with cyclosporine for at least three weeks. Serum Spec fPL was analyzed at Idexx Laboratories, Kornwestheim, Germany. Nineteen cats, aged 6.9–17.5 years (median 11.6), were included. No pancreatic biopsies were available. Median (range) serum Spec fPL concentration was 14.2 μg/L (6.1–43.3) at baseline and 6.7 μg/L (0.9–23.6) at follow-up. Cyclosporine treatment (5.0–7.9 mg/kg orally SID) was associated with a significant reduction in serum Spec fPL concentrations (p < 0.001) at follow-up after 23–206 days (median 35). Body weight decreased significantly between inclusion and follow-up (p = 0.013). Significant improvement of clinical signs could not be measured (p = 0.781). This study has several limitations, including unstandardized treatment length and dose, no control group and lack of pancreatic biopsies. Despite the limitations, our results suggest that cyclosporine treatment reduces supranormal serum Spec fPL concentrations in cats with presumed CP.

ACVIM consensus statement on pancreatitis in cats

Background

Pancreatitis in cats, although commonly diagnosed, still presents many diagnostic and management challenges.

Objective

To summarize the current literature as it relates to etiology, pathogenesis, diagnosis, and management of pancreatitis in cats and to arrive at clinically relevant suggestions for veterinary clinicians that are based on evidence, and where such evidence is lacking, based on consensus of experts in the field.

Animals

None.

Methods

A panel of 8 experts in the field (5 internists, 1 radiologist, 1 clinical pathologist, and 1 anatomic pathologist), with support from a librarian, was formed to assess and summarize evidence in the peer reviewed literature and complement it with consensus clinical recommendations.

Results

There was little literature on the etiology and pathogenesis of spontaneous pancreatitis in cats, but there was much in the literature about the disease in humans, along with some experimental evidence in cats and nonfeline species. Most evidence was in the area of diagnosis of pancreatitis in cats, which was summarized carefully. In contrast, there was little evidence on the management of pancreatitis in cats.

Conclusions and Clinical Importance

Pancreatitis is amenable to antemortem diagnosis by integrating all clinical and diagnostic information available, and recognizing that acute pancreatitis is far easier to diagnose than chronic pancreatitis. Although both forms of pancreatitis can be managed successfully in many cats, management measures are far less clearly defined for chronic pancreatitis.

Correlation of thyroid hormone measurements with thyroid stimulating hormone stimulation test results in radioiodine-treated cats

Background

Iatrogenic hypothyroidism can develop after radioiodine‐I¹³¹ (RAI) treatment of hyperthyroid cats and can be diagnosed using the thyroid stimulating hormone (TSH) stimulation test.

Objectives

To assess the effect of noncritical illness on TSH stimulation test results in euthyroid and RAI‐treated cats. To assess the correlation of low total‐thyroxine (tT4), low free‐thyroxine (fT4), and high TSH concentrations with TSH stimulation test results.

Animals

Thirty‐three euthyroid adult cats and 118 client‐owned cats previously treated with RAI.

Methods

Total‐thyroxine, fT4, and TSH were measured, and a TSH stimulation test was performed in all cats. Euthyroid control cats were divided into apparently healthy and noncritical illness groups. RAI‐treated cats were divided into RAI‐hypothyroid (after‐stimulation tT4 ≤ 1.5 μg/dL), RAI‐euthyroid (after‐stimulation tT4 ≥ 2.3 μg/dL OR after‐stimulation tT4 1.5‐2.3 μg/dL and before : after tT4 ratio > 1.5), and RAI‐equivocal (after stimulation tT4 1.5‐2.3 μg/dL and tT4 ratio < 1.5) groups.

Results

Noncritical illness did not significantly affect the tT4 following TSH stimulation in euthyroid (P = .38) or RAI‐treated cats (P = .54). There were 21 cats in the RAI‐equivocal group. Twenty‐two (85%) RAI‐hypothyroid cats (n = 26) and 10/71 (14%) of RAI‐euthyroid cats had high TSH (≥0.3 ng/mL). Twenty‐three (88%) RAI‐hypothyroid cats had low fT4 (<0.70 ng/dL). Of the 5 (7%) RAI‐euthyroid cats with low fT4, only one also had high TSH. Only 5/26 (19%) RAI‐hypothyroid cats had tT4 below the laboratory reference interval (<0.78 μg/dL).

Conclusions and Clinical Relevance

The veterinary‐specific chemiluminescent fT4 immunoassay and canine‐specific TSH immunoassay can be used to aid in the diagnosis of iatrogenic hypothyroidism in cats.

Retrospective study of the diagnostic utility of Spec fPLin the assessment of 274 sick cats

Background

Serum feline pancreatic lipase immunoreactivity (fPL) commonly is used in the assessment of sick cats suspected to have pancreatitis but its diagnostic utility is debated.

Objectives

To evaluate the diagnostic utility of the Spec fPL test and selected serum biochemistry tests in the diagnosis of pancreatitis in cats.

Animals

Two hundred seventy‐four client‐owned cats presented to a university teaching hospital in the United Kingdom, from April 2013 to May 2017, in which Spec fPL was measured.

Methods

Cats were classified into 1 of 4 groups based on clinical signs (all cats), ultrasonographic findings (all cats) and histopathological or cytological assessment of the pancreas where available (9 cats) regardless of Spec fPL concentration. The groups were (a) definite pancreatitis (n = 9), (b) probable pancreatitis (n = 49), (c) possible pancreatitis (n = 139), and (d) unlikely pancreatitis (n = 77). Spec fPL and selected serum biochemistry test results were compared among groups.

Results

Serum fPL concentrations >5.3 μg/L were classified as positive and concentrations <3.5 μg/L were classified as negative. There was a significantly (P = .03) lower proportion of false‐positive results (cats unlikely to have pancreatitis, n = 77, with a positive fPL, n = 8, 10%) than false‐negative results (cats with definite or probable pancreatitis, n = 58, with a negative fPL result, n = 14, 24%). None of the selected biochemical tests were helpful diagnostically.

Conclusion and Clinical Importance

A positive Spec fPL result indicates that pancreatitis is a probable diagnosis, but the test cannot be used to rule the diagnosis out.