Fluid and Electrolyte Therapy in Endocrine Disorders: Diabetes Mellitus and Hypoadrenocorticism

Semiquantitative acid-base analysis in dogs with typical hypoadrenocorticism

OBJECTIVE

To describe the semiquantitative acid-base status of dogs with untreated naturally occurring typical hypoadrenocorticism and to compare this to the status determined by traditional acid-base analysis.

DESIGN

Retrospective study.

SETTING

University teaching hospital.

ANIMALS

Thirty-three dogs with newly diagnosed typical hypoadrenocorticism between 2000 and 2017.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Dogs were included if they had newly diagnosed hypoadrenocorticism, post-ACTH stimulation serum cortisol concentration <2 μg/dL, and blood collected within 6 hours of presentation for acid-base, electrolyte, and serum biochemical assays. Dogs were excluded if the Na⁺ :K⁺ ratio was ≥28 or the dog had received a mineralocorticoid-containing corticosteroid medication within the preceding month. Traditional acid-base analysis identified normal acid-base status in 1 dog, simple respiratory acid-base abnormalities in 2 of 33 dogs, and simple metabolic acidosis in 14 of 33 dogs. A mixed disorder was most common, noted in 16 of 33 dogs. The semiquantitative approach identified metabolic abnormalities in all cases. All dogs had ≥1 acidifying process, and 29 of 33 had both acidifying and alkalinizing processes. Acidosis attributable to excess free water was present in all dogs, and an acidifying phosphate effect was present in 27 of 33. Hyperlactatemia contributed to the acidosis in 8 of 33 dogs, with a median (range) lactate concentration of 1.5 mmol/L (13.5 mg/dL) (0.3-4.2 mmol/L [2.7-37.8 mg/dL]).

CONCLUSIONS

Dogs with untreated Addison's disease have complex acid-base derangements. The semiquantitative approach to acid-base analysis provides greater insight into the underlying mechanisms of metabolic acid-base abnormalities in these dogs, particularly because lactic acidosis appears to be a minor influence in most cases.

Accuracy of a flash glucose monitoring system in dogs with diabetic ketoacidosis

Background

A factory‐calibrated flash glucose monitoring system (FGMS; FreeStyle Libre) recently was evaluated in dogs with uncomplicated diabetes mellitus. It is not known if this system is reliable during diabetic ketoacidosis (DKA).

Objectives

To assess the performance of the FGMS in dogs with DKA and to determine the effect of severity of ketosis and acidosis, lactate concentration, body condition score (BCS), and time wearing the sensor on the accuracy of the device.

Animals

Fourteen client‐owned dogs with DKA.

Methods

The interstitial glucose (IG) measurements were compared with blood glucose (BG) measurements obtained using a validated portable glucometer. The influence of changes in metabolic variables (β‐hydroxybutyrate, pH, bicarbonate, and lactate) and the effect of BCS and time wearing on sensor performance were evaluated. Accuracy was determined by fulfillment of ISO15197:2013 criteria.

Results

Metabolic variables, BCS, and time wearing were not associated with the accuracy of the sensor. Good agreement between IG measurements and BG was obtained both before and after DKA resolution (r = .88 and r = .93, respectively). Analytical accuracy was not achieved, whereas clinical accuracy was demonstrated with 100% and 99.6% of results in zones A + B of the Parkes consensus error grid analysis before and after DKA resolution, respectively.

Conclusions and Clinical Importance

Changes in metabolic variables, BCS, and time wearing do not seem to affect agreement between IG and BG. Despite not fulfilling the ISO requirements, the FGMS provides clinically accurate estimates of BG in dogs with DKA.

Retrospective comparison of early- versus late-insulin therapy regarding effect on time to resolution of diabetic ketosis and ketoacidosis in dogs and cats: 60 cases (2003-2013)

OBJECTIVE

To determine whether early insulin administration (≤6 h after admission) results in more rapid resolution of diabetic ketosis (DK) and ketoacidosis (DKA), shorter duration of hospitalization, and higher incidence of complications, and whether more severe ketonuria is associated with longer time to resolution of DK/DKA.

DESIGN

Retrospective study (January 1, 2003-March 1, 2013).

SETTING

University teaching hospital.

ANIMALS

Sixty dogs and cats with DK or DKA receiving short-acting insulin therapy.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Medical records were reviewed and data recorded including signalment; previous history of diabetes; intake temperature, blood pressure, blood glucose, pH, base excess, and degree of ketonuria; time to short-acting insulin therapy and resolution of DK/DKA; length of hospitalization; and complications. Insulin was initiated ≤6 hours in the early group and >6 hours in the late group after hospital admission. Early group patients had more rapid resolution of DK/DKA after starting short-acting insulin therapy (36.4 ± 22.6 vs. 55.4 ± 26.6 h, P = 0.014). There was no difference in duration of hospitalization or complications. More severe ketonuria resulted in longer time to resolution of DK/DKA after initiation of short-acting insulin (severe: 50.9 ± 24.2; moderate: 29.6 ± 19; mild: 23.4 ± 21.9 h, P = 0.005, all individual pairwise comparisons P < 0.05).

CONCLUSIONS

Early insulin administration is associated with more rapid resolution of DK/DKA without an associated increase in complication rates. DK/DKA took longer to resolve with more severe ketonuria. Prospective studies are warranted to identify specific time targets for insulin administration in DK/DKA patients.

The effect of experimentally induced chronic hyperglycaemia on serum and pancreatic insulin, pancreatic islet IGF-I and plasma and urinary ketones in the domestic cat (Felis felis)

Like in humans, diabetes mellitus is on the rise in cats. Feline diabetes is a suitable model for human type-2 diabetes. We investigated magnitude and timing of insulin suppression with induced hyperglycaemia and its relationship to plasma and urinary ketones and to pancreatic islet insulin. IGF-I is under discussion as a protective mechanism but little is known about its role in diabetes in general and its distinct localisation in feline pancreatic islets in particular. Thirteen healthy, adult cats were allocated to 2 groups and infused with glucose to maintain their blood glucose at a high or moderate concentration for 42 days resulting in insulin secretion suppression. After initial increase, insulin levels declined to baseline but were still detectable in the blood at a very low level after 6 weeks of glucose infusion and then increased after a 3 week recovery period. While IGF-I in healthy cats was primarily located in glucagon cells, in hyperglycaemia-challenge IGF-I was pronounced in the β-cells 3 weeks after ceasation of infusion. Six/8 cats developing glucose toxicity became ketonuric after 3-4 weeks. Gross lipaemia occurred approx 1 week prior to ketonuria. Ketonuric cats required 1-2 weeks of insulin therapy after-infusion until β-cell recovery. In conclusion, ketosis and hyperlipidaemia are likely to occur in diabetic cats with glucose at 30 mmol/L, especially after ≥2 weeks. Three weeks after ceasation of infusions, clinical and morphological recovery occurred. We propose a local protective effect of IGF-I to support survival and insulin production in the hyperglycaemic state and recovery period.

Diabetic emergencies in small animals

Diabetic ketoacidosis and hyperglycemic hyperosmolar syndrome are two serious and potentially life-threatening complications of diabetes mellitus. Understanding pathophysiology is crucial to the proper management of veterinary patients with these disorders. This article reviews the biochemical alterations contributing to these conditions, and discusses traditional and controversial management strategies.