Incidence, severity and prognosis associated with hypernatremia in dogs and cats

International Renal Interest Society best practice consensus guidelines for the diagnosis and management of acute kidney injury in cats and dogs

Acute kidney injury (AKI) is defined as an injury to the renal parenchyma, with or without a decrease in kidney function, as reflected by accumulation of uremic toxins or altered urine production (i.e., increased or decreased). AKI might result from any of several factors, including ischemia, inflammation, nephrotoxins, and infectious diseases. AKI can be community- or hospital-acquired. The latter was not previously considered a common cause for AKI in animals; however, recent evidence suggests that the prevalence of hospital-acquired AKI is increasing in veterinary medicine. This is likely due to a combination of increased recognition and awareness of AKI, as well as increased treatment intensity (e.g., ventilation and prolonged hospitalization) in some veterinary patients and increased management of geriatric veterinary patients with multiple comorbidities. Advancements in the management of AKI, including the increased availability of renal replacement therapies, have been made; however, the overall mortality of animals with AKI remains high. Despite the high prevalence of AKI and the high mortality rate, the body of evidence regarding the diagnosis and the management of AKI in veterinary medicine is very limited. Consequently, the International Renal Interest Society (IRIS) constructed a working group to provide guidelines for animals with AKI. Recommendations are based on the available literature and the clinical experience of the members of the working group and reflect consensus of opinion. Fifty statements were generated and were voted on in all aspects of AKI and explanatory text can be found either before or after each statement.

Acid-base and electrolyte evaluation in dogs with upper GI obstruction: 115 dogs (2015-2021)

OBJECTIVES

Metabolic alkalosis, although uncommon in small animals, has been previously associated with gastrointestinal obstructions. Depending on the population and disease process evaluated, previous prevalence of metabolic alkalosis is reported as ranging from 2% to 45% in canine patients. The objective of this study was to determine the prevalence of metabolic alkalosis and other acid-base and electrolyte disorders in a cohort of dogs with a confirmed upper gastrointestinal obstruction.

MATERIALS AND METHODS

Electronic medical records were reviewed to identify dogs who presented for vomiting with evidence of an upper gastrointestinal obstruction from January 2015 to October 2021. Patients were enrolled only if a preoperative venous blood gas was obtained and analysed in house. Traditional acid-base analysis was utilised to determine an acid-base status before relieving the obstruction. When available, post-operative venous acid-base status was determined within 24 hours after surgery, and compared to preoperative results.

RESULTS

A total of 115 dogs were included in the study. Twenty-five out of 115 (22%) dogs displayed either a simple metabolic alkalosis or a mixed acid-base disturbance before surgery. Twenty-seven out of 115 dogs (37%) had a normal acid-base status at entry. Seventy-one dogs had pre- and post-operative venous blood gas results available. Metabolic alkalosis was resolved in nearly all patients post-operatively, with no patients displaying a simple metabolic alkalosis. A mixed metabolic acidosis and respiratory alkalosis was the most common condition post-operatively, found in 25 of 71 (35%) dogs. Severe derangements of electrolytes were infrequent preoperatively (3/115; 2.6%). A majority of patients in this study exhibited hypokalaemia (64.4%), hypochloraemia (72.8%) and hyponatraemia (77.4%) on preoperative venous blood gases. Venous pH, Pv CO2 , bicarbonate and base excess were significantly higher preoperatively when compared to the post-operative results.

CLINICAL SIGNIFICANCE

This study found the prevalence of pre-operative metabolic alkalosis in dogs with a documented upper gastrointestinal obstruction to be lower than previously reported. Surgical or endoscopic alleviation of the upper gastrointestinal obstruction resulted in resolution of metabolic alkalosis in nearly all patients.

Occurrence and clinical relevance of postoperative hypernatremia in dogs undergoing cholecystectomy

BACKGROUND

Patients undergoing cholecystectomy have not been reported previously to develop clinically relevant postoperative hypernatremia.

OBJECTIVES

Describe the frequency of postoperative hypernatremia in dogs undergoing cholecystectomy and its clinical relevance (duration of hospitalization and survival).

ANIMALS

Thirty-seven dogs undergoing cholecystectomy at 2 private referral hospitals.

METHODS

Retrospective study of dogs undergoing cholecystectomy with available preoperative and postoperative serum sodium concentrations.

RESULTS

Postoperative hypernatremia (>150 mEq/L) was common (56%; 95% confidence interval [CI], 40%-70%) and was associated with significantly higher mortality compared to nonhypernatremic patients (52%; 95% CI, 30%-70% vs 12.5%; 95% CI, 2%-40%; P = .02). Nonsurvivors had higher mean postoperative peak serum sodium concentrations (155 mEq/L; range, 146-172) than survivors (150 mEq/L; range, 142-156; P = .01). Dogs developing hypernatremia within 6 hours after surgery had 7.7 higher odds of nonsurvival (odds ratio [OR], 7.7; 95% CI, 5.9-9.4). A delta value (serum sodium concentration on admission [T0] - serum sodium concentration 6 hours postoperatively [T2]) of ≥10 mEq/L carried 3.3 higher odds of mortality (OR, 3.3; 95% CI, 1.6-5.1). All dogs with a postoperative peak sodium concentration >160 mEq/L did not survive. Admission acute patient physiologic laboratory evaluation fast (APPLEfast ) scores were not different between survivors and nonsurvivors or between postoperative hypernatremic and normonatremic patients. Hospitalization time was no different between hypernatremic and normonatremic patients (6 days vs 4.5 days; P = .15). Dogs with gallbladder mucocele were more likely to develop postoperative hypernatremia and have poorer outcomes.

CONCLUSIONS

Hypernatremia was a common and clinically relevant postoperative complication in dogs after cholecystectomy. Detection of hypernatremia within 6 hours after surgery may be associated with poorer outcomes.

Magnetic resonance imaging, clinicopathologic findings, and clinical progression of a puppy with confirmed Eastern equine encephalitis virus

A 5-month-old puppy was evaluated for rapidly progressive neurologic signs and pyrexia. Magnetic resonance imaging showed multifocal meningoencephalitis with transtentorial and foramen magnum herniation. A cerebrospinal fluid tap revealed highly cellular fluid, and the puppy was euthanized. Histopathology showed lymphoplasmacytic and neutrophilic meningoencephalitis. Viral polymerase chain reaction testing for Eastern equine encephalitis was positive. Rapid progression of neurologic signs and respiratory arrest necessitated mechanical ventilation. Severe hypernatremia, most consistent with central diabetes insipidus, developed. Key clinical message: Transtentorial and foramen magnum herniation and high cerebrospinal fluid cell counts may be indicators of poor prognosis. Brain death, respiratory arrest, and central diabetes insipidus may also ensue with Eastern equine encephalitis infection.

Effects of desmopressin acetate administration in healthy dogs receiving prednisolone

Background

Glucocorticoids are used for a variety of purposes in veterinary medicine but often are associated with clinically important adverse effects. Polyuria and polydipsia are the most frustrating adverse effects noted by owners.

Objective

To determine whether administration of desmopressin ameliorates polyuria and polydipsia associated with prednisolone administration.

Animals

Seven healthy adult Walker Hounds.

Methods

Prospective hypothesis testing study. Daily water intake and urine specific gravity (USG) were measured in dogs under 4 separate sequential conditions: no medications (C), prednisolone only (P), prednisolone and desmopressin (PD), and prednisolone after discontinuation of desmopressin (PAD).

Results

When compared to baseline, 6 of 7 dogs became polydipsic after administration of prednisolone (0.5 mg/kg PO q12h). When desmopressin (5 μg/dog SC q12h) was administered to dogs receiving prednisolone, significant decreases in water intake and serum sodium concentration occurred, and USG increased significantly.

Conclusions and Clinical Importance

Administration of desmopressin to dogs receiving prednisolone significantly decreased water intake and serum sodium concentration, and increased USG. Our results suggest that, in some dogs, desmopressin ameliorates the most important adverse effect of prednisolone noted by owners, but that hyponatremia is an important complication associated with desmopressin use.

Clinicopathological factors associated with the presence of hypercapnia at admission in hospitalised cats with decompensated chronic kidney disease

AIMS

To evaluate associations between clinicopathological variables and hypercapnia measured in cats with decompensated chronic kidney disease (CKD) on admission to a veterinary hospital.

METHODS

This is a retrospective, cross-sectional study of cats (n = 39) that presented to a tertiary veterinary hospital in Argentina between June 2015 and December 2017 with blood creatinine concentrations >140 μmol/L, and abdominal ultrasound results consistent with CKD. Data recorded included venous partial pressure of CO₂ (PvCO₂), blood pH, haematocrit and concentrations of glucose, potassium, sodium, corrected sodium (Na⁺_c), and ionised calcium in blood. A logistic regression model was used to assess associations between the presence of hypercapnia (PvCO₂ ≥ 44.7 mmHg) and the other clinicopathologic variables. The duration of hospitalisation was compared in cats with and without hypercapnia using the Wilcoxon Rank Sum test.

RESULTS

The final study population comprised 39 cats. Eleven cats (28.2%) had hypercapnia. In the logistic regression model, two independent variables were associated with the presence of hypercapnia at admission in cats with CKD: the concentration of creatinine in blood (OR = 1.06 (95% CI = 1.016-1.108); p = 0.007) and Na⁺_c (OR = 1.33 (95% CI = 1.08-1.63); p = 0.005). There were no statistically significant differences in the length of hospital stay between the two groups.

CONCLUSIONS AND CLINICAL RELEVANCE

There appears to be an association between elevated concentrations of creatinine and Na⁺_c in blood, and hypercapnia in cats with CKD, suggesting careful assessment of blood gas and electrolyte parameters during hospitalisation is required. Further prospective studies are needed to evaluate the mechanisms behind this association and the association of hypercapnia with disease outcome including mortality.

Congenital pituitary cyst resulting in adipsic central diabetes insipidus and secondary hypernatremia in a cat

Case summary

A 9-month-old intact female domestic mediumhair cat presented with a 5-month history of obtundation, lethargy, hypernatremia (181 mmol/l; reference interval [RI] 151–158 mmol/l), hyperchloremia (142 mmol/l; RI 117–126 mmol/l), azotemia (blood urea nitrogen 51 mg/dl; RI 18–33 mg/dl), creatinine 3.0 mg/dl (RI 1.1–2.2 mg/dl), hyperphosphatemia (8.3 mg/dl; RI 3.2–6.3 mg/dl) and total hypercalcemia (11.4 mg/dl; RI 9–10.9 mg/dl), with concurrent polyuria with adipsia. Neurologic evaluation revealed proprioceptive deficits, and this finding paired with a history of focal seizure-like activity despite improving sodium concentrations suggested a cerebrothalamic lesion. For this reason, and historical and biochemical findings consistent with adipsic diabetes insipidus (DI), MRI of the brain was performed, which revealed a lesion of the hypophyseal fossa consistent with a pituitary cyst. Given the patient’s age and the timeline of clinical signs, a congenital pituitary cyst was strongly suspected. The patient was managed initially with intravenous fluids to correct the hypernatremia, then managed for more than 4 years with topical ocular desmopressin acetate administration and free water administered through a feeding tube. This cat’s clinical diagnosis included a congenital pituitary cyst with subsequent central DI and primary adipsia.

Relevance and novel information

The clinical presentations of primary adipsia or central DI are both rare in cats. This is the first report to describe these conditions occurring in a cat owing to a congenital pituitary cyst and describes successful long-term management of this condition.

Novel Diagnostic Tools for Identifying Cognitive Impairment in Dogs: Behavior, Biomarkers, and Pathology

Canine cognitive dysfunction syndrome (CCDS) is a progressive neurodegenerative disorder in senior dogs that is mainly associated with decreased ability to learn and respond to stimuli. It is commonly under-diagnosed because behavioral changes are often attributed to the natural process of aging. In the present study, we used for the first time a comprehensive approach enabling early diagnosis of canine patients with mild cognitive disorders (MiCI). We included CAnine DEmentia Scale (CADES) questionnaires, biochemical parameters, and biomarkers in blood serum, and correlated them with post-mortem histopathological changes. The CADES questionnaires enabled us to identify MiCI dogs developing changes mainly in domains corresponding to social interaction and spatial orientation, which seems to be crucial for delineating early cognitive disorders. Biochemical analyses in these dogs showed slightly elevated liver enzyme parameters (AST and ALT) and significantly decreased sodium and chloride levels in blood serum. Furthermore, we describe for the first time a significant increase of neurofilament light chain (NFL) in blood serum of MiCI dogs, compared to normal aging seniors and young controls, but no changes in TAU protein and amyloid-β (Aβ42) peptide levels. In canine brains with cognitive impairment, amyloid plaques of mainly diffuse and dense types were detected. Furthermore, activated microglia with amoeboid body and dystrophic processes occurred, in some cases with spheroidal and bulbous swellings. On the other hand, no TAU pathology or neurofibrillary tangles were detected. These results suggest that a combination of CADES questionnaire mainly with CNS injury biomarker (NFL) and with biochemical parameters (ALT, AST, Na, and Cl) in blood serum may predict CCDS in senior dogs.

Effect of 7.5% hypertonic saline solution on whole blood coagulation in healthy dogs using thromboelastography

Objective

To evaluate the effects of 7.5% hypertonic saline solution (HSS) on whole blood coagulation in healthy dogs and to compare electrolyte and osmolality measurements between in vivo and in vitro dilution with HSS.

Design

Experimental study.

Setting

University teaching hospital.

Animals

Twelve adult purpose‐bred Beagles.

Interventions

All 12 dogs received 5 mL/kg 7.5% HSS at 1 mL/kg/min. After a 14‐day washout period, 5 of these dogs were randomly selected and received the same volume of 0.9% NaCl. Blood samples were collected before infusion, immediately after infusion, and at 30, 60, and 90 minutes after infusion for the measurement of coagulation using thromboelastography. For comparison of electrolyte concentrations and osmolality between in vitro dilution and in vivo dilution of HSS, 6‐mL blood samples were diluted with 7.5% HSS (1:18 ratio) at baseline.

Measurements and Main Results

None of the thromboelastography variables differed significantly between the 7.5% HSS group and the 0.9% NaCl group. The sodium and chloride levels, and the osmolality, were significantly increased at all postinfusion time points compared to baseline, while those levels were significantly higher with in vitro dilution than all postinfusion time points. However, almost all the values gradually decreased and became similar to baseline values in case of in vivo dilution.

Conclusions

The clinically relevant dose of 7.5% HSS (5 mL/kg) did not affect whole blood coagulation significantly in healthy Beagles. Further studies are necessary to assess the effect of HSS on blood coagulation in canine patients with shock.

Multi-Level Safety Studies of Anti Fel d 1 IgY Ingredient in Cat Food

Chickens exposed to antigens produce IgY antibodies, similar in structure to mammalian IgG. Hens exposed with an allergen produced by cats (Fel d 1) results in production of anti-Fel d 1 specific IgY (AFD1), which is naturally concentrated in egg yolk. A chicken egg product ingredient containing AFD1 was evaluated for safety in a 26-week randomized, controlled, blinded tolerance study in cats and in vitro for mutagenic and genotoxic effects. The in vivo study was conducted with groups fed kibble containing 0, 7, 39, or 66 ppm AFD1. Parameters examined included: clinical observations, body weights, food consumption, serum chemistry, hematology, blood coagulation, urinalyses, and mortality and morbidity checks. AFD1 was evaluated for potential mutagenic effects utilizing the bacterial reverse mutation assay at concentrations of up to 2.78 ppm and for potential structural chromosomal aberrations at up to 3 ppm using human peripheral blood lymphocytes (HPBL). After 6-months of feeding to cats, there were no significant differences between control and any test groups in any parameters analyzed. No significant increases in mutations or chromosomal aberrations were observed in tests with or without metabolic activation (S9). These studies show AFD1 was well-tolerated in cats at levels tested and does not induce mutagenic or chromosomal aberrations under study conditions.

Retrospective evaluation of the association between hyponatremia and neurological dysfunction in hospitalized foals (2012-2016): 109 cases

OBJECTIVE

Hyponatremia and rapid correction of hyponatremia can lead to neurological abnormalities. The objective of the study was to determine whether plasma sodium concentrations (Na⁺ ) and speed of correction of hyponatremia are significantly associated with neurological abnormalities in foals.

DESIGN

Retrospective cohort study 2012 to 2016.

SETTING

Equine hospital.

ANIMALS

One hundred and nine foals <6 months old with hyponatremia (Na⁺ concentration ≤125 mmol/L).

INTERVENTIONS

Case records were reviewed for any foal with hyponatremia. Clinicopathological findings, presence or absence of neurological signs on the day of the lowest Na⁺ concentration measured and the following 5 days, diagnosis and outcome were recorded, and changes in Na⁺ concentration per hour were calculated for up to 5 subsequent days. Logistic regression was used to assess the association between presence or absence of neurological signs, Na⁺ concentration, other known risk factors for neurological dysfunction in foals, and possible confounders.

MEASUREMENTS AND MAIN RESULTS

In the final multivariable model, only Na⁺ (odds ratio [OR]: 0.86; 95% CI 0.79-0.95; P = 0.002) and BUN concentrations (OR: 1.04; 95% CI: 1.02-1.06; P = 0.001) were significantly associated with neurological signs. Changes in Na⁺ concentrations per hour were not associated with neurological signs on any day after the lowest Na⁺ concentration had been measured (P = 0.18-0.82), and development of new neurological signs following correction of hyponatremia was not reported in any foal.

CONCLUSIONS

Na⁺ concentrations were associated with the development of neurological signs in hyponatremic foals. Increased BUN concentrations might contribute to neurological dysfunction, but further studies are necessary to confirm or refute these findings.

Of Mice and Men-The Physiology, Psychology, and Pathology of Overhydration

The detrimental effects of dehydration, to both mental and physical health, are well-described. The potential adverse consequences of overhydration, however, are less understood. The difficulty for most humans to routinely ingest ≥2 liters (L)-or "eight glasses"-of water per day highlights the likely presence of an inhibitory neural circuit which limits the deleterious consequences of overdrinking in mammals but can be consciously overridden in humans. This review summarizes the existing data obtained from both animal (mostly rodent) and human studies regarding the physiology, psychology, and pathology of overhydration. The physiology section will highlight the molecular strength and significance of aquaporin-2 (AQP2) water channel downregulation, in response to chronic anti-diuretic hormone suppression. Absence of the anti-diuretic hormone, arginine vasopressin (AVP), facilitates copious free water urinary excretion (polyuria) in equal volumes to polydipsia to maintain plasma tonicity within normal physiological limits. The psychology section will highlight reasons why humans and rodents may volitionally overdrink, likely in response to anxiety or social isolation whereas polydipsia triggers mesolimbic reward pathways. Lastly, the potential acute (water intoxication) and chronic (urinary bladder distension, ureter dilation and hydronephrosis) pathologies associated with overhydration will be examined largely from the perspective of human case reports and early animal trials.

An online survey of small animal veterinarians regarding current fluid therapy practices in dogs and cats

OBJECTIVE To determine common fluid therapy practices of small animal practitioners and identify fluid therapy-related knowledge gaps that may benefit from improved educational efforts, targeted research, or both. DESIGN Online survey. SAMPLE 1,496 small animal veterinarians PROCEDURES An online survey was provided to members of the Veterinary Information Network between December 23, 2013, and January 30, 2014. The survey consisted of 24 questions investigating the administration of crystalloid and synthetic colloid solutions, but not blood products, and focused primarily on the choice of fluid type, frequency of administration, type of patient treated with fluids, treatment with fluids subcutaneously versus IV, and potassium supplementation of fluids. Only responses from practicing small animal veterinarians were included. Not all respondents answered every question, and some questions allowed > 1 answer. RESULTS Balanced crystalloid solutions were the most common fluid type in all clinical scenarios described. The most common maintenance IV fluid rate reported by respondents (762/1,333 [57%]) was 60 mL/kg/d (27 mL/lb/d); calculation of fluid administration rate by means of body surface area was infrequent. Challenges of fluid therapy included determining the appropriate rate (572/1,496 [38%]) and fluid type (497/1,496 [33%]) and determining the need for potassium supplementation (229/1,496 [15%]). CONCLUSIONS AND CLINICAL RELEVANCE Small animal veterinarians tended to favor isotonic balanced crystalloid solutions for IV fluid therapy, compared with other common choices such as isotonic saline (0.9% NaCl) solution. Despite its ubiquity, respondents found many aspects of fluid therapy to be challenging, suggesting the need for easy to use, evidence-based guidelines.

Hypernatremia and Coagulopathy May or May Not Be Useful Clinical Biomarkers in Dogs with Head Trauma: A Retrospective Study

This study was performed to evaluate clinical biomarkers as prognostic values in dogs with traumatic brain injury (TBI) based on findings in human patients. Sodium levels of 158 dogs with TBI and 169 patients with trauma without involvement of the head except head trauma (EHT) were examined. TBI patients with hypernatremia had a slightly higher risk of dying (22.03 %) than dogs with normal sodium levels (19.76%). However, there was no significant correlation between sodium levels and outcome in TBI patients (p = 0.6357). Dogs with sodium levels >160 mmol/L were non-survivors. In dogs with late-onset post-traumatic epilepsy (PTE) more often hyponatremia was measured, and in dogs with immediate PTE mild hypernatremia or normal sodium levels were measured after the trauma. Evaluation of coagulation parameters in a subpopulation of dogs showed a strong correlation between partial thromboplastin time/prothrombin time (PTT/PT) and the Modified Glasgow Coma Scale (MGCS) (p = 0.0006; p = 0.0306). In conclusion, unlike in human patients, sodium levels displayed no significant correlation with survival in dogs with TBI in the current study. However, in cases with severe TBI, dog owners often elect euthanasia before severe hypernatremia can be measured. Late PTE was observed in cases with initial hyponatremia. Because of a significant correlation between PTT/PT and MGCS, coagulopathy might be considered as a prognostic clinical biomarker in canine TBI patients.

Hypernatraemia in 39 hospitalised foals: clinical findings, primary diagnosis and outcome

OBJECTIVE

To evaluate hypernatraemia in foals presenting as medical emergencies to an intensive care unit (ICU) to determine the prevalence, clinical findings, primary diagnosis and outcome.

METHODS

Retrospective case study of records from Thoroughbred foals aged less than 3 months that presented to an ICU as medical emergencies in 2002-12. Data retrieved included signalment, clinical findings, laboratory results, primary diagnosis and outcome. Foals with hypernatraemia (serum sodium > 145 mmol/L) on admission laboratory data were identified and further evaluated.

RESULTS

A total of 39 of 1718 foals (2.3%) were diagnosed with hypernatraemia; all foals were less than 7 days of age. The most common primary diagnoses in the foals with hypernatraemia were neonatal syndrome (19/39, 48.7%) and sepsis (15/39, 38.5%). Foals with hypernatraemia at presentation were more likely to die or be euthanased during their hospitalisation than foals with a normal serum sodium concentration on ICU admission (33.3% vs 16.1%; odds ratio, 2.3; 95% confidence interval, 1.2-4.6; P = 0.02).

CONCLUSION

Admission hypernatraemia was an uncommon but important electrolyte abnormality in this population of hospitalised foals. Although the short-term outcome in survivors was most likely dependent on the underlying disease process, hypernatraemia was negatively associated with outcome in hospitalised foals.

Multivariable analysis of the association between electrolyte disturbances and mortality in cats

OBJECTIVES

Electrolyte disorders have been individually associated with mortality in small populations of cats with specific conditions, but the associations and interactions between electrolyte disturbances and outcome have not been evaluated in a large, heterogeneous population. It was hypothesized that abnormalities of sodium, chloride, potassium and calcium concentrations would be independently and proportionately associated with death from natural causes and with all-cause mortality in cats.

METHODS

An electronic database containing 7064 electrolyte profiles was constructed to assess the association between disorders of sodium, potassium, corrected-chloride and ionized calcium concentrations with non-survival by multivariable modelling. A second database containing 2388 records was used to validate the models constructed from the first database.

RESULTS

All four electrolytes assessed had non-linear U-shaped associations with case fatality rates, wherein concentrations clustered around the reference interval had the lowest case fatality rates, while progressively abnormal concentrations were associated with proportionately increased risk of non-survival (area under the receiver operator characteristic curve [AUROC] 0.689) or death (AUROC 0.750).

CONCLUSIONS AND RELEVANCE

Multivariable modelling suggested that these electrolyte disturbances were associated with non-survival and with death from natural causes independent of each other. The present study suggests that measurement of electrolyte concentrations is an important component of the assessment of cats in emergency rooms or intensive care units. Future studies should focus on confirming these associations in a prospective manner accounting for disease severity.

Food engorgement in 35 dogs (2009-2013) compared with 36 dogs with gastric dilation and volvulus

The clinical features and management of food engorgement (FE) in dogs have not been previously described. This retrospective observational study describes characteristics and outcome of 35 dogs with FE, and compares features on presentation to 36 dogs with gastric dilation and volvulus (GDV). Cases were retrospectively reviewed for history, clinical findings and outcome. Gastric distension was measured by caudal gastric margin (CGM), level with lumbar vertebrae, on a lateral abdominal radiograph. Frequent characteristics of dogs with FE included tachycardia, tachypnoea, hyperproteinaemia, increased base excess (BE), mild hypernatraemia and hyperlactataemia. There was overlap in CGM between dogs with GDV (CGM range L3 to >L6) and dogs with FE (CGM range <L2 to L5-L6). In contrast to dogs with GDV, lactate concentration in dogs with FE was not associated with CGM or BE. Dogs with FE mostly received medical intervention consisting of fluid therapy and analgesia, and all dogs survived to discharge. In conclusion, dogs with FE frequently presented with acid-base and electrolyte derangements, including hyperlactataemia. While dogs with FE can have gastric distension as severe as that seen with GDV, outcome with supportive care only is excellent.

Desoxycorticosterone Pivalate Duration of Action and Individualized Dosing Intervals in Dogs with Primary Hypoadrenocorticism

Background

Clinicians alter dosing for desoxycorticosterone pivalate (DOCP) to mitigate costs, but this practice has not been critically evaluated in a prospective clinical trial.

Hypothesis/Objectives

The duration of action of DOCP is longer than 30 days in dogs with primary hypoadrenocorticism (PH).

Animals

A total of 53 client‐owned dogs with PH. Twenty‐four dogs with newly diagnosed PH (Group 1) and 29 dogs with treated PH (Group 2).

Methods

Prospective, multicenter, clinical trial. For phase I, DOCP was administered and plasma sodium and potassium concentrations were measured until the dog developed hyponatremia or hyperkalemia at a planned evaluation, or displayed clinical signs with plasma electrolyte concentrations outside of the reference interval independent of a planned evaluation, thus defining DOCP duration of action. Plasma electrolyte concentrations then were assessed at the end of the individualized dosing interval (IDI; i.e., DOCP duration of action minus 7 days, phase II and at least 3 months after concluding phase II, phase III).

Results

The duration of action of DOCP in dogs in phase I with naïve PH (n = 24) ranged from 32 to 94 days (median, 62 days; 95% confidence interval [CI], 57, 65) and previously treated PH (n = 29) from 41 to 124 days (median, 67 days; CI, 56, 72). Overall, the final DOCP dosing interval for all dogs that completed phase II (n = 36) ranged from 38 days to 90 days (median, 58 days; CI, 53, 61). No dog that completed phase III (n = 15) required reduction in the IDI. The DOCP duration of action, independent of group, was not significantly associated with several baseline variables. The median drug cost reduction using IDI was approximately 57.5% per year.

Conclusion and Clinical Importance

The duration of action of DOCP in dogs with PH is >30 days, and plasma sodium and potassium concentrations can be maintained with an IDI >30 days long term.

Electrolyte Disturbances Are Associated with Non-Survival in Dogs-A Multivariable Analysis

Electrolyte disorders have been individually associated with mortality in small populations of dogs and cats with specific conditions, but the associations and interactions between electrolyte disturbances and outcome have not been evaluated in a large, heterogeneous population. It was hypothesized that abnormalities of sodium, chloride, potassium, and calcium concentrations would be independently and proportionately associated with death from natural causes and with all-cause mortality in dogs. An electronic database containing 33,117 electrolyte profiles was constructed to retrospectively assess the association between disorders of sodium, potassium, corrected chloride, and ionized calcium concentrations with non-survival and with death excluding euthanasia by multivariable modeling. A second database containing 11,249 records was used to validate the models constructed from the first database. All four electrolytes assessed had non-linear U-shaped associations with case fatality rates, wherein concentrations clustered around the reference interval had the lowest case fatality rates, while progressively abnormal concentrations were associated with proportionately increased risk of non-survival (AUROC 0.624) or death (AUROC 0.678). Multivariable modeling suggested that these electrolyte disturbances were associated with non-survival and with death from natural causes independent of each other. This study suggests that measurement of electrolyte concentrations is an important component of the assessment of dogs in emergency rooms or intensive care units. Future studies should focus on confirming these associations in a prospective manner accounting for disease severity.

A Quick Reference on Hypernatremia

Hypernatremia most commonly is associated with water loss in excess of sodium or salt gain (typically associated with restriction of access to water). Most of the signs of hypernatremia arise from the central nervous system; the more rapid the development of hypernatremia, the more severe the neurologic signs are likely to be. Anorexia, lethargy, vomiting, muscular weakness, behavioral changes, disorientation, ataxia, seizures, coma, and death have been identified in dogs and cats with hypernatremia and hypertonicity.

Is Bicarbonate Therapy Useful?

Despite concerns about the negative effects of metabolic acidosis, there is minimal evidence that sodium bicarbonate administration is an effective treatment. In addition, sodium bicarbonate therapy is associated with many adverse effects, including paradoxic intracellular acidosis, hypokalemia, hypocalcemia, hypernatremia, and hyperosmolality. Definitive recommendations regarding bicarbonate therapy are challenging as there is little high-quality evidence available. In most clinical scenarios of metabolic acidosis, treatment efforts should focus on resolution of the underlying cause, and sodium bicarbonate therapy should be used with caution, if at all. An exception to this is kidney disease, wherein sodium bicarbonate therapy may have a valuable role.

Incidence, severity and prognosis associated with hypernatremia in dogs and cats

Background

Hypernatremia has been associated with substantial morbidity and death in human patients. The incidence and importance of hypernatremia in dogs and cats has not been determined.

Hypothesis/Objectives

To describe the incidence of and prognosis associated with hypernatremia in dogs and cats at a university teaching hospital.

Animals

A total of 16,691 dogs and 4,211 cats with measured blood or serum sodium concentration.

Methods

Retrospective study. Medical records of animals with a blood or serum sodium concentration measured during a 60‐month period were reviewed to determine the severity of hypernatremia and its associated case fatality rate. Cases with moderate (11–15 mmol/L above the reference range) or severe hypernatremia (≥16 mmol/L above the reference range) were further reviewed.

Results

A total of 957 dogs (5.7%) and 338 cats (8.0%) were diagnosed with hypernatremia. Case fatality rates of dogs and cats with hypernatremia was 20.6 and 28.1%, respectively compared to 4.4 and 4.5% with a normal blood or serum sodium concentration (P < .0001). The magnitude of hypernatremia was linearly associated with a higher case fatality rate (P < .0001). Hypernatremia was associated with a higher case fatality rate than hyponatremia. Among the animals with moderate or severe hypernatremia, 50% of dogs and 38.5% of cats presented with community‐acquired hypernatremia, and 50% of dogs and 61.5% of cats developed hospital‐acquired hypernatremia.

Conclusions and clinical importance

Hypernatremia was found infrequently in this population but was associated with increased case fatality rates in dogs and cats. Presence and severity of hypernatremia might be useful as a prognostic indicator.