Prevalence and characterization of hypoadrenocorticism in dogs with signs of chronic gastrointestinal disease: A multicenter study

Comparison of prednisolone and alternative glucocorticoid dosing protocols for canine hypoadrenocorticism: insights from a survey-based study

Objectives

The aim of the study was to analyze glucocorticoid (GC) dosing protocols in dogs with hypoadrenocorticism (HA), and to identify predictors for optimal clinical outcomes during both the acute and chronic phases of the disease, as well as during long-term therapy.

Methods

This observational cross-sectional study utilized a case-based online questionnaire. Practicing veterinarians across Germany were invited to participate. The survey collected data in the disease course and follow-ups. Responses were analyzed using descriptive statistics, single and multiple comparisons, and a multivariable logistic regression model.

Results

For 103 dogs the questionnaire was fully completed and analyzed. Of these, 85 dogs (82.5%) were hospitalized, and they received either prednisolone (52.9%), dexamethasone (31.8%) or hydrocortisone (11.8%). Hydrocortisone therapy was associated with a shorter hospitalization time and faster normalization of electrolytes compared to prednisolone. Follow-up data were available for 85 dogs, with 82.35% (n = 70/85) achieving an optimal or well-adjusted clinical outcome. Multivariable logistic regression analysis indicated that the eukalemic and eunatremic form was significantly less associated with the presence of azotemia and the occurrence of an acute adrenal crisis. Dividing the daily GC dosage was associated with poorer clinical outcomes and a reduced likelihood of achieving optimal medication adjustment.

Conclusion

Our findings provide new, relevant recommendations for the therapeutic management of HA in dogs. Hydrocortisone appears to be a promising treatment for managing HA during hospitalization, highlighting its potential use in clinical practice. Once-daily administration of prednisolone is advisable for long-term therapy. To achieve the best possible outcome, implementing an optimal treatment protocol is essential, which veterinarians should tailor based on the needs of both owners and animals. The main limitations of the study include its retrospective nature and the limited number of participants. Future studies, particularly prospective ones, could further validate the beneficial effects of hydrocortisone and evaluate long-term therapy in comparison to prednisolone.

An extensively hydrolysed protein-based extruded diet in the treatment of dogs with chronic enteropathy and at least one previous diet-trial failure: a pilot uncontrolled open-label study

BACKGROUND

Canine chronic enteropathies (CE) are a group of disorders defined by persistent or recurrent clinical signs of gastrointestinal disease without a primary neoplastic, metabolic, parasitic, or other infectious cause. In this prospective, multicentre, uncontrolled, open-label study, a commercial dry diet with a protein source of extensively hydrolysed poultry feather was assessed in the management of dogs with CE that had not responded to previous dietary and antibacterial therapies. Dogs with moderate or marked protein-losing enteropathy were excluded. After screening, dogs entered stage 1 and started the test diet. Gastrointestinal endoscopy was performed, and only dogs with histopathological evidence of small intestinal inflammation confirming CE could continue to stage 2 of the trial. The test diet was fed for 10 weeks throughout stages 1 and 2, and the primary outcome measure was clinical success defined as a reduction in canine inflammatory bowel disease activity index (CIBDAI) of ≥ 75%. Secondary outcomes included body condition score (BCS, scale 1-9) and faecal consistency score (scale 1-5). Results (median [range]) for dogs with confirmed CE that participated in both study stages are reported.

RESULTS

A total of 15 dogs commenced stage 1, and 13 of these progressed to stage 2 (age 4.2 [1.1-7.1] years; BCS 3 (2-4); previous diet therapies 2 [1-3]) of which two were withdrawn at week 5 for protocol deviations. CIBDAI scores decreased from 9 (7-16; n = 13) at baseline to 2 (1-11; n = 13) at week 2 (P < 0.001), 2 (0-6; n = 13) at week 5 (P < 0.001), and 1 (0-3; n = 11) at week 10 (P < 0.001). Treatment success was achieved by 8/13 dogs at week 5 and 10/11 dogs at week 10. Faecal score (n = 11) and BCS (n = 11) improved between baseline (1 [1-3] and 3 [3-4], respectively; P < 0.001) and week 10 (4 [3-5] and 4 [3-5], respectively; P < 0.001).

CONCLUSIONS

Dogs with CE that had failed to respond to previous dietary and antibacterial therapy showed clinical improvement within 10 weeks when fed a dry extruded diet with a single protein source hydrolysed to amino acids and oligopeptides, without concurrent immunosuppressant treatment.

Clinical findings, treatment, and outcomes in cats with naturally occurring hypoadrenocorticism: 41 cases

BACKGROUND

Hypoadrenocorticism in cats is uncommonly reported. Most reports consist of cats with hyponatremia, hyperkalemia, or both.

HYPOTHESIS/OBJECTIVES

To describe clinical findings, treatment response, and outcome in cats diagnosed with hypoadrenocorticism, including cats with abnormal and normal serum sodium and potassium concentrations.

ANIMALS

Forty-one cats with hypoadrenocorticism; 36 with and 5 without abnormal serum sodium and potassium concentrations.

METHODS

Multicenter retrospective observational study. Data for the entire cohort were assessed using descriptive statistics and differences between cats with and without abnormal serum sodium and potassium concentrations were evaluated.

RESULTS

Median age was 5.7 years (range, 0.2-13.8). Twenty-three (56%) cats were male and 18 (44%) were female. Cats with hyponatremia, hyperkalemia, or both were less likely to have a history of vomiting (P = .01) but more likely to be hypothermic (P = .03), dehydrated (P = .04) or weak (P = .04) on examination, compared with nonhyponatremic and nonhyperkalemic cats. Frequency of hypercalcemia was 31.7%. Exocrine pancreatic insufficiency (EPI) was diagnosed in 4/7 cats tested; all 4 had concurrent cobalamin deficiency. Thirty-five (85.4%) cats survived to discharge. In 2 cats, hypoadrenocorticism occurred secondary to lymphoma. Median survival time (MST) for all-cause mortality was 2035 days (95% confidence interval [CI], 294-4380 days); MST for disease-specific mortality was not reached.

CONCLUSIONS AND CLINICAL IMPORTANCE

Approximately one-third of cats with hypoadrenocorticism had hypercalcemia. In some cases, hyponatremia and hyperkalemia were not observed. Cats with nonneoplastic associated hypoadrenocorticism that survive initial hospitalization can have a favorable long-term prognosis. Testing for EPI may be warranted in cats with hypoadrenocorticism.

Resting cortisol concentrations in dogs presenting to a university teaching hospital with collapse

BACKGROUND

The relationship between collapse and a diagnosis of hypoadrenocorticism is not well understood in dogs.

HYPOTHESIS

To assess the prevalence of episodes of collapse in dogs screened for hypoadrenocorticism, and to assess the prevalence of confirmed hypoadrenocorticism in dogs presenting with reported collapse.

ANIMALS

Seventy-three client-owned dogs with resting cortisol concentrations were measured and presented to a University teaching hospital for collapse.

METHODS

Retrospective review of medical records of dogs at a single center.

RESULTS

The prevalence of episodes of collapse in dogs that had a resting cortisol measurement was 73/856 (8.5%; 95% confidence interval [95% CI], 6.7%-10.6%). Resting cortisol concentration was <2 μg/dL (<55 nmol/L) in 19 dogs. Cortisol concentration after ACTH stimulation was <2 μg/dL (<55 nmol/L) in 1 of the 73 dogs in this cohort, consistent with a diagnosis of hypoadrenocorticism, giving a prevalence estimate of hypoadrenocorticism of 1.3% (95% CI, 0.15%-6.2%). In 8 dogs with an initial resting cortisol concentration <2 μg/dL (<55 nmol/L), hypoadrenocorticism was excluded based on a repeat resting cortisol concentration >2 μg/dL (>55 nmol/L). The most common diagnosis was vasovagal syncope (10/73), followed by sick sinus syndrome and third-degree atrioventricular block (2/73). The final diagnosis was unknown in 24/73 dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Hypoadrenocorticism was the final diagnosis in 1 of 73 dogs presented to a teaching hospital either in a collapsed state or with a previous history of episodes of collapse. No dog presenting as cardiovascularly stable for intermittent collapse was found to have hypoadrenocorticism.

European Network for Optimization of Veterinary Antimicrobial Therapy (ENOVAT) guidelines for antimicrobial use in canine acute diarrhoea

Acute diarrhoea is a common presentation in dogs, and a common reason for antimicrobial prescription and nutraceutical use. This evidence-based guideline provides recommendations for antimicrobial and probiotic treatment of canine acute diarrhoea (CAD). A multidisciplinary panel developed the recommendations by adhering to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. The opinions of stakeholders (general veterinary practitioners and dog owners) were collected and incorporated to ensure the applicability of this guideline. Four strong recommendations informed by high certainty evidence, and three conditional recommendations informed by very low or low certainty evidence, were drafted by the panel, along with an ungraded section on diagnostic work-up of dogs with acute diarrhoea. The ENOVAT guidelines initiative encourages national or regional guideline makers to use the evidence presented in this document, and the supporting systematic review, to draft national or local guidance documents.

Comparison between typical primary and eunatraemic, eukalaemic hypoadrenocorticism: 92 cases

BACKGROUND

Naturally occurring hypoadrenocorticism is an uncommon endocrine disorder in dogs but has significant morbidity and mortality. Some dogs present with apparent glucocorticoid deficiency alone as evidenced by eunatraemia and eukalaemia. Few studies have compared dogs with hypoadrenocorticism with or without electrolyte disturbances and there are no large case series of affected dogs from Ireland.

METHODS

Retrospective observational study.

RESULTS

Ninety-two cases diagnosed with hypoadrenocorticism subdivided into those with supportive electrolyte disturbances (Group 1; n = 72) and those without (Group 2; n = 20). Dogs in Group 1 were significantly (p = 0.001) younger (4.0 (3.0-6.0) years) than dogs in Group 2 (6.0 (4.75-8.25) years). Dogs in Group 1 presented significantly more commonly with vomiting (Group 1: 52/71 (73.2%), Group 2: 6/20 (30.0%); p < 0.001), total hyperproteinaemia (Group 1: 21/71 (29.6%), Group 2: 1/20 (5.0%); p = 0.023), increased urea (Group 1: 52/72 (72.2%), Group 2: 5/20 (25.0%); p < 0.001), increased creatinine (Group 1: 31/72 (43.1%), Group 2: 3/20 (15.0%); p = 0.021) and hyperphosphataemia (Group 1: 40/71 (56.3%), Group 2: 2/20 (10.0%); p < 0.001), and significantly less commonly with reticulocytosis (Group 1: 4/38 (10.5%), Group 2: 5/13 (38.5%), p = 0.023). An undetectable basal aldosterone concentration had a positive predictive value of 94.3% for diagnosing undetectable post-ACTH aldosterone concentration. Of the thirteen dogs in Group 2 that had aldosterone concentrations measured and secondary disease excluded, 7 (53.8%) had or subsequently developed evidence of aldosterone deficiency, although not always with electrolyte abnormalities.

CONCLUSIONS

Dogs with hypoadrenocorticism from Ireland are similar to other reported cases. An undetectable basal aldosterone concentration is highly predictive of mineralocorticoid deficiency. Dogs with apparent glucocorticoid deficiency alone can progress to more typical disease and should be monitored appropriately.

The effects of selected sedatives on basal and stimulated serum cortisol concentrations in healthy dogs

Background

Hormone assessment is typically recommended for awake, unsedated dogs. However, one of the most commonly asked questions from veterinary practitioners to the endocrinology laboratory is how sedation impacts cortisol concentrations and the adrenocorticotropic hormone (ACTH) stimulation test. Butorphanol, dexmedetomidine, and trazodone are common sedatives for dogs, but their impact on the hypothalamic-pituitary-adrenal axis (HPA) is unknown. The objective of this study was to evaluate the effects of butorphanol, dexmedetomidine, and trazodone on serum cortisol concentrations.

Methods

Twelve healthy beagles were included in a prospective, randomized, four-period crossover design study with a 7-day washout. ACTH stimulation test results were determined after saline (0.5 mL IV), butorphanol (0.3 mg/kg IV), dexmedetomidine (4 µg/kg IV), and trazodone (3-5 mg/kg PO) administration.

Results

Compared to saline, butorphanol increased basal (median 11.75 µg/dL (range 2.50-23.00) (324.13 nmol/L; range 68.97-634.48) vs 1.27 µg/dL (0.74-2.10) (35.03 nmol/L; 20.41-57.93); P < 0.0001) and post-ACTH cortisol concentrations (17.05 µg/dL (12.40-26.00) (470.34 nmol/L; 342.07-717.24) vs 13.75 µg/dL (10.00-18.90) (379.31 nmol/L; 275.96-521.38); P ≤ 0.0001). Dexmedetomidine and trazodone did not significantly affect basal (1.55 µg/dL (range 0.75-1.55) (42.76 nmol/L; 20.69-42.76); P = 0.33 and 0.79 µg/dL (range 0.69-1.89) (21.79 nmol/L; 19.03-52.14); P = 0.13, respectively, vs saline 1.27 (0.74-2.10) (35.03 nmol/L; 20.41-57.93)) or post-ACTH cortisol concentrations (14.35 µg/dL (range 10.70-18.00) (395.86 nmol/L; 295.17-496.55); (P = 0.98 and 12.90 µg/dL (range 8.94-17.40) (355.86 nmol/L; 246.62-480); P = 0.65), respectively, vs saline 13.75 µg/dL (10.00-18.60) (379.31 nmol/L; 275.86-513.10).

Conclusion

Butorphanol administration should be avoided prior to ACTH stimulation testing in dogs. Further evaluation of dexmedetomidine and trazodone's effects on adrenocortical hormone testing in dogs suspected of HPA derangements is warranted to confirm they do not impact clinical diagnosis.

Prevalence of eunatremic, eukalemic hypoadrenocorticism in dogs with signs of chronic gastrointestinal disease and risk of misdiagnosis after previous glucocorticoid administration

BACKGROUND

Dogs with eunatremic, eukalemic hypoadrenocorticism (EEH) typically show signs of chronic gastrointestinal disease (CGD). Previous glucocorticoid administration (PGA) can give false-positive results on the ACTH stimulation test (ACTHst).

HYPOTHESIS/OBJECTIVES

To determine the prevalence of EEH in dogs with signs of CGD, and to identify clinical and clinicopathological features for EEH and PGA.

ANIMALS

One hundred twelve dogs with CGD (101 non-PGA and 11 PGA), 20 dogs with EEH.

METHODS

Multicenter prospective cohort study. Basal serum cortisol (BSC) concentration was measured in dogs with signs of CGD. When BSC was <2 μg/dL and in PGA dogs, ACTHst plus measurement of endogenous ACTH (eACTH) were performed. Records of dogs with EEH from 2009 to 2021 were reviewed.

RESULTS

The BSC concentration was <2 μg/dL in 48/101 (47.5%) non-PGA and in 9/11 (82%) PGA dogs. EEH was diagnosed in 1/112 dog (prevalence 0.9%; 95% CI, 0.1%-4.8%); the ACTHst provided false-positive results in 2/11 PGA dogs. PGA dogs showed lower C-reactive protein-to-haptoglobin ratio (median 0.01, range 0.003-0.08; P = .01), and higher haptoglobin (140, 26-285 mg/dL; P = .002) than non-PGA dogs (0.04, 0.007-1.5; 38.5, 1-246 mg/dL, respectively). eACTH was higher (P = .03) in EEH (396, 5->1250 pg/mL) than in non-PGA dogs (13.5, 7.3-46.6 pg/mL). Cortisol-to-ACTH ratio was lower (P < .0001 and P = .01, respectively) in EEH (0.002, 0.0002-0.2) than in non-PGA (0.1, 0.02-0.2) and PGA dogs (0.1, 0.02-0.2).

CONCLUSIONS AND CLINICAL IMPORTANCE

The prevalence of EEH in dogs with signs of CGD was lower than previously reported. The clinical and clinicopathological features herein identified could increase the index of suspicion for EEH or PGA in dogs with an unclear history of glucocorticoid administration.

Prevalence of hypercalcemia in primary hypoadrenocorticism in dogs: Multicenter, retrospective study

BACKGROUND

Hypoadrenocorticism is an important differential for hypercalcemia. The etiology of hypercalcemia in hypoadrenocorticism in dogs is unclear.

OBJECTIVE

To review the prevalence of hypercalcemia and use statistical models to identify clinical, demographic, and biochemical variables associated with hypercalcemia in dogs with primary hypoadrenocorticism.

ANIMALS

One hundred ten dogs with primary hypoadrenocorticism; 107 with recorded total calcium (TCa), 43 recorded ionized calcium (iCa).

METHODS

Multicenter retrospective observational study at 4 UK referral hospitals. Univariable logistic regression analyses were performed to assess the association between independent variables of signalment, hypoadrenocorticism type (glucocorticoid only deficient hypoadrenocorticism [GHoC] vs glucocorticoid and mineralocorticoid deficient hypoadrenocorticism [GMHoC]), clinicopathological variables and hypercalcemia. Hypercalcemia was defined as elevated TCa, an elevated iCa, or both elevated TCa and iCa (Model 1) or as elevated iCa (Model 2).

RESULTS

Overall prevalence of hypercalcemia was 34.5% (38/110). The odds of hypercalcemia (Model 1) were increased (P < .05) in dogs with GMHoC ([vs GHoC], OR [odds ratio] = 3.86, 95% confidence interval [CI] 1.105-13.463), higher serum creatinine (OR = 1.512, 95% CI 1.041-2.197), and higher serum albumin (OR = 4.187, 95% CI 1.744-10.048). The odds of ionized hypercalcemia (Model 2) were increased (P < .05) with reduced serum potassium concentration (OR = 0.401, 95% CI 0.184-0.876) and younger age (OR = 0.737, 95% CI 0.558-0.974).

CONCLUSIONS AND CLINICAL IMPORTANCE

This study identified several key clinical and biochemical variables associated with hypercalcemia in dogs with primary hypoadrenocorticism. These findings aid understanding of the pathophysiology and etiology of hypercalcemia in dogs with primary hypoadrenocorticism.

Atypical hypoadrenocorticism with intact zona glomerulosa of the adrenal cortex after long-term observation: a case report of a dog

An 8-year-old intact male pointer presented with lethargy and hypoalbuminemia. On abdominal ultrasonography, both adrenal glands were reduced in thickness. Based on the ACTH stimulation test results and the absence of electrolyte abnormalities, the dog was diagnosed with atypical hypoadrenocorticism. After treatment with low-dose prednisolone, his general condition improved, and blood tests normalized. The dog died 818 days later, and a complete autopsy was performed. Histologically, the architecture of the zonae fasciculata and reticularis was disrupted in both adrenal glands; however, the zona glomerulosa remained relatively normal. In summary, in this study, we detailed the pathological presentation of atypical hypoadrenocorticism without electrolyte abnormalities.

Successful use of a benchtop fluorescent enzyme immunoassay analyzer to measure serum cortisol concentration as a screening test for hypoadrenocorticism in dogs

OBJECTIVE

To assess the diagnostic performance of a benchtop fluorescent enzyme immunoassay analyzer (AIA-360; Tosoh Bioscience Inc) for the measurement of serum cortisol concentration as a screening test for hypoadrenocorticism in dogs.

ANIMALS

173 client-owned dogs (20 with hypoadrenocorticism and 153 with nonadrenal illness).

PROCEDURES

Medical records of all dogs that underwent an ACTH stimulation test between June 2015 and October 2019 were reviewed retrospectively. Dogs were excluded if the ACTH stimulation test was performed on the basis of a suspicion of hypercortisolism, serum cortisol concentrations were measured using an analyzer other than the one assessed in the present study, or dogs had received medication known to affect the pituitary-adrenal axis in the 4 weeks1,2 preceding ACTH stimulation testing. The diagnostic performance of the benchtop analyzer was evaluated by calculating sensitivity, specificity, and likelihood ratios at various cutoff points.

RESULTS

Serum resting cortisol cutoff point concentrations of 0.8 μg/dL (22 nmol/L), 1 μg/dL (28 nmol/L), and 2 μg/dL (55 nmol/L) had a sensitivity of 100%. An optimal serum resting cortisol cutoff point of 0.58 μg/dL (16 nmol/L) had a sensitivity, specificity, and positive and negative likelihood ratios of 100%, 97%, and 30.6 and 0.0, respectively.

CLINICAL RELEVANCE

Findings indicated that previously derived cutoff points could be used with excellent sensitivity to exclude hypoadrenocorticism in this population of dogs when serum cortisol concentration was measured with the evaluated benchtop analyzer. An ACTH stimulation test may need to only be performed to diagnose hypoadrenocorticism if resting serum cortisol concentration is ≤ 0.58 μg/dL when measured with the evaluated benchtop analyzer.

Evaluation of a machine learning tool to screen for hypoadrenocorticism in dogs presenting to a teaching hospital

BACKGROUND

Dogs with hypoadrenocorticism (HA) have clinical signs and clinicopathologic abnormalities that can be mistaken as other diseases. In dogs with a differential diagnosis of HA, a machine learning model (MLM) has been validated to discriminate between HA and other diseases. This MLM has not been evaluated as a screening tool for a broader group of dogs.

HYPOTHESIS

An MLM can accurately screen dogs for HA.

ANIMALS

Dogs (n = 1025) examined at a veterinary hospital.

METHODS

Dogs that presented to a tertiary referral hospital that had a CBC and serum chemistry panel were enrolled. A trained MLM was applied to clinicopathologic data and in dogs that were MLM positive for HA, diagnosis was confirmed by measurement of serum cortisol.

RESULTS

Twelve dogs were MLM positive for HA and had further cortisol testing. Five had HA confirmed (true positive), 4 of which were treated for mineralocorticoid and glucocorticoid deficiency, and 1 was treated for glucocorticoid deficiency alone. Three MLM positive dogs had baseline cortisol ≤2 μg/dL but were euthanized or administered glucocorticoid treatment without confirming the diagnosis with an ACTH-stimulation test (classified as "undetermined"), and in 4, HA was ruled out (false positives). The positive likelihood ratio of the MLM was 145 to 254. All dogs diagnosed with HA by attending clinicians tested positive by the MLM.

CONCLUSIONS AND CLINICAL IMPORTANCE

This MLM can robustly predict HA status when indiscriminately screening all dogs with blood work. In this group of dogs with a low prevalence of HA, the false positive rates were clinically acceptable.

Effect of long-term management of hypoadrenocorticism on the quality of life of affected dogs and their owners

BACKGROUND

The treatment of canine adrenal insufficiency consists of hormone substitution and requires high owner compliance and intense human-dog interaction. This might affect the quality of life (QoL) of owners and their pets. The aim of the study was to evaluate the impact of hypoadrenocorticism and its treatment on the QoL of dogs and their owners.

METHODS

Owners completed a web-based survey that contained items concerning signalment, owner QoL, dog QoL and long-term therapy.

RESULTS

Three hundred and twenty-two owners participated. Most owners feared an adrenal crisis. Approximately half of the participants reported that the bond between them and their pet increased after diagnosis. Although many participants felt that their own QoL was not affected by their dog's disease, worries about costs and leaving their dog unsupervised were frequently reported. Half of the study participants increased their dog's glucocorticoid doses when a stressful situation was foreseeable ('boosting' of therapy). Some administered hydrocortisone, mostly switched from prednisolone, resulting in a reduction in side effects.

CONCLUSIONS

Special attention should be given to glucocorticoid therapy and owner's QoL. The overall worry of an adrenal crisis might increase caregivers' burden, reducing their overall QoL. Hydrocortisone might be a safe alternative to prednisolone, but further research is necessary to evaluate its long-term efficacy and safety in dogs.

Diagnosis of canine spontaneous hypoadrenocorticism

Hypoadrenocorticism is characterized by a reduction in mineralocorticoid and/or glucocorticoid production by the adrenal glands. Several subtypes have been described with different clinical and clinicopathological consequences. Most affected dogs have vague and non-specific signs that precede an eventual life-threatening crisis. This review aims to appraise classification, the available data on epidemiology and the clinical and laboratory features of naturally occurring canine hypoadrenocorticism.

Canine hypoadrenocorticism is a relatively uncommon endocrine disease that can present with a wide variety of clinical signs resulting from cortisol or aldosterone deficiency or both. Hypoadrenocorticism should be considered in all dogs with severe illness and typical electrolyte abnormalities but also in those with waxing and waning clinical signs. Multiple clinical and laboratory features are suggestive of the disease and should prompt evaluation of adrenal function. The ACTH stimulation test is the best test for diagnosing hypoadrenocorticism but, in those cases without the typical presentation, evaluation of aldosterone secretory capacity and endogenous ACTH concentrations should be performed to distinguish primary from secondary disease. In this review we discuss the pathophysiology of the disease, the clinical signs and laboratory features that should raise suspicion of hypoadrenocorticism and the performance of the different diagnostic tests.

Investigation of the urine cortisol to creatinine ratio for the diagnosis of hypoadrenocorticism in dogs

OBJECTIVE

To evaluate the urine cortisol-to-creatinine ratio (UCCR) for the diagnosis of hypoadrenocorticism (HA) in dogs and to determine whether the method of urine cortisol measurement affects results.

ANIMALS

41 dogs with naturally occurring HA and 107 dogs with nonadrenal illness.

PROCEDURES

Urine samples were prospectively collected from dogs undergoing testing for HA. Urine cortisol concentrations were measured at a veterinary diagnostic laboratory using either a radioimmunoassay (RIA) or a chemiluminescent immunoassay (CLIA). Receiver operating characteristic (ROC) curves were constructed to assess UCCR performance by both methods for HA diagnosis. Sensitivities, specificities, accuracies, and predictive values were calculated for various cutpoints.

RESULTS

The areas under the ROC curves for UCCR diagnosis of HA were 0.99 (95% CI, 0.98 to 1.00) and 1.00 (95% CI, 1.00 to 1.00) when urine cortisol was determined by RIA and CLIA, respectively. An RIA UCCR of ≤ 2 was 97.2% sensitive, 93.6% specific, and 94.7% accurate for HA diagnosis, whereas a CLIA UCCR of ≤ 10 was 100% sensitive, specific, and accurate. An RIA UCCR > 4 and a CLIA UCCR of > 10 had negative predictive values of 100%.

CLINICAL RELEVANCE

The UCCR was an accurate diagnostic test for HA in this study population, although equivocal results are possible. Case characteristics, method of cortisol measurement, and laboratory-specific cutpoints must be considered when interpreting results.

Urinary cortisol-creatinine ratio in dogs with hypoadrenocorticism

Background

Basal serum cortisol (BSC) ≥2 μg/dL (>55 nmol/L) has high sensitivity but low specificity for hypoadrenocorticism (HA).

Objective

To determine whether the urinary corticoid:creatinine ratio (UCCR) can be used to differentiate dogs with HA from healthy dogs and those with diseases mimicking HA (DMHA).

Animals

Nineteen healthy dogs, 18 dogs with DMHA, and 10 dogs with HA.

Methods

Retrospective study. The UCCR was determined on urine samples from healthy dogs, dogs with DMHA, and dogs with HA. The diagnostic performance of the UCCR was assessed based on receiver operating characteristics (ROC) curves, calculating the area under the ROC curve.

Results

The UCCR was significantly lower in dogs with HA (0.65 × 10⁻⁶; range, 0.33‐1.22 × 10⁻⁶) as compared to healthy dogs (3.38 × 10⁻⁶; range, 1.11‐17.32 × 10⁻⁶) and those with DMHA (10.28 × 10⁻⁶; range, 2.46‐78.65 × 10⁻⁶) (P < .0001). There was no overlap between dogs with HA and dogs with DMHA. In contrast, 1 healthy dog had a UCCR value in the range of dogs with HA. The area under the ROC curve was 0.99. A UCCR cut‐off value of <1.4 yielded 100% sensitivity and 97.3% specificity in diagnosing HA.

Conclusions and Clinical Importance

The UCCR seems to be a valuable and reliable screening test for HA in dogs. The greatest advantage of this test is the need for only a single urine sample.

Evaluation of resting cortisol concentration testing in dogs with chronic gastrointestinal signs

Background

Resting cortisol concentrations are routinely measured in dogs with chronic gastrointestinal signs to rule out hypoadrenocorticism based on a concentration >2 μg/dL (>55 nmol/L).

Hypothesis/Objectives

To assess the cross‐sectional prevalence of hypoadrenocorticism in a group of dogs with chronic gastrointestinal signs presented to a referral internal medicine service.

Animals

Two‐hundred and eighty‐two client‐owned dogs with chronic gastrointestinal signs and with resting cortisol concentration testing performed.

Methods

Retrospective review of medical records (final diagnosis, resting cortisol concentration, and adenocorticotropic hormone [ACTH] stimulation test results) of a referral population of dogs between May 2013 and September 2017.

Results

Resting cortisol concentration was <2 μg/dL (<55 nmol/L) in 79 patients (28%). Repeated resting cortisol concentration measurements were performed in 28 dogs, and in 8, resting cortisol concentrations remained <2 μg/dL (<55 nmol/L). Post‐ACTH cortisol concentration was <2 μg/dL (<55 nmol/L) in 1 dog, consistent with a diagnosis of hypoadrenocorticism and giving a prevalence estimate of hypoadrenocorticism in this population of dogs of 0.3% (95% confidence interval [95CI], 0.03‐1.5%). In 19 dogs with an initial resting cortisol concentration <2 μg/dL (<55 nmol/L), hypoadrenocorticism was excluded based on a repeat resting cortisol concentration >2 μg/dL (>55 nmol/L). Overall, the most common diagnosis was chronic primary inflammatory enteropathy (176/282, 62.4%), followed by extragastrointestinal neoplasia (17/282, 6%), protein‐losing enteropathy, pancreatitis and megaesophagus (10/282, 3.5% each).

Conclusions and Clinical Importance

Although dogs with hypoadrenocorticism can present with chronic gastrointestinal signs, it was the final diagnosis in only 1 of 282 dogs presenting to a referral internal medicine service for signs of chronic enteropathy. Repeated resting cortisol concentration may be considered as a test to try and exclude hypoadrenocorticism.

Prevalence and characterization of hypoadrenocorticism in dogs with signs of chronic gastrointestinal disease: A multicenter study

Background

Dogs with hypoadrenocorticism (HA) frequently show signs of gastrointestinal disease (SGD). The prevalence of dogs presented for chronic SGD with HA is unknown.

Objectives

The aims of this study were to determine the prevalence of HA in dogs with chronic SGD and to identify clinical and laboratory variables for HA in this population.

Animals

One hundred fifty‐one dogs with chronic SGD.

Methods

In this multicentered prevalence study a standardized workup was performed in prospectively enrolled dogs with SGD > 3 weeks duration. Basal serum cortisol concentration was measured in every dog with ACTH stimulation test (ACTHST) if basal serum cortisol concentration was <3 μg/dL.

Results

Basal serum cortisol concentration was <3 μg/dL in 80/151 (53%) dogs, <2 μg/dL in 42/151 (28%) dogs, and < 1 μg/dL in 9/151 (6%) dogs. In 6/151 dogs HA was diagnosed based on ACTHST (stimulated serum cortisol concentration < 2 μg/dL), a prevalence of 4%. There was no difference in history, physical examination, and laboratory variables between dogs with HA and those with other causes of chronic SGD. In 4/6 dogs with HA, there was melena or hematochezia indicating gastrointestinal blood loss. Hyperkalemia, hyponatremia, or both was not observed in any dog.

Conclusion and Clinical Importance

The prevalence of HA among dogs with chronic SGD is higher than in the general population. Based on these results, testing adrenal function should be performed as a standard screening test in dogs with chronic SGD to differentiate between HA and chronic enteropathies.