Hydrocortisone in the management of acute hypoadrenocorticism in dogs: a retrospective series of 30 cases

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.

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.

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.

A retrospective study of hydrocortisone continuous rate infusion compared with administration of dexamethasone boluses in dogs with adrenal crisis

BACKGROUND

Evidence indicating the optimal treatment protocol for dogs in adrenal crisis is lacking.

OBJECTIVES

Compare outcomes of dogs presented in adrenal crisis treated with either hydrocortisone (HC) continuous rate infusion (CRI) or intermittent dexamethasone (DEX) administration.

ANIMALS

Thirty-nine client-owned dogs.

METHODS

Multi-institutional retrospective observational study (July 2016-May 2022) including dogs diagnosed with adrenal crisis and with available sequential blood work during hospitalization. Dogs were excluded if already on treatment with exogenous corticosteroids. Outcomes assessed included duration of hospitalization, survival, number of repeat measurements of electrolyte concentrations, and time to normalization of electrolyte and acid-base status.

RESULTS

No significant difference was found between the groups for hospitalization time (P = .41; HC median [range] 48 h [19-105 h]; DEX 57 h [17-167 h]) nor case fatality rate 2/28 in the DEX group and 0/11 in the HC group (P = 1), nor in number of measurements of electrolyte concentrations (P = .90; HC 4 [2-10]; DEX 4.5 [2-15]). No significant differences were found between the 2 treatment groups in time to normalization of serum Na (P = .30; HC 33 h [7-66 h]; DEX 16 h [1.5-48 h]), K (P = .92; HC 17 h [4-48 h]; DEX 16 h [1.25-60 h]) or Na/K ratio (P = .08; HC 17 h [8-48 h]; DEX 26 h [1.5-60 h]).

CONCLUSIONS

This study detected no difference in outcomes for dogs in adrenal crisis treated with either DEX boluses or HC CRIs.

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.

Comparison of Hydrocortisone Continuous Rate Infusion and Prednisolone or Dexamethasone Administration for Treatment of Acute Hypoadrenocortical (Addisonian) Crisis in Dogs

Objectives

To determine whether administration of intravenous hydrocortisone is a safe and effective alternative treatment in comparison to the traditional treatment with prednisolone/dexamethasone in dogs presenting with Addisonian crisis; and to assess if there is any advantage of the former over the latter in normalisation of electrolyte imbalances and in hospitalisation length in these dogs.

Methods

Medical records of client-owned dogs with hypoadrenocorticism were retrospectively reviewed. Time until normalisation of sodium and potassium concentration, intravenous fluid needs over the first 24 h and hospitalisation length were compared between hydrocortisone and prednisolone/dexamethasone treated dogs.

Results

Twenty-five dogs met the inclusion criteria; 13 received hydrocortisone and 12 prednisolone/dexamethasone. Intravenous hydrocortisone was well-tolerated but failed to prove superiority in terms of time to normalisation of sodium and potassium concentration. Interestingly, potassium normalised in all dogs prior to discharge, but sodium did not in 1/11 hydrocortisone and 5/9 prednisolone/dexamethasone treated dogs with initial hyponatraemia (p = 0.05). Hydrocortisone treated dogs, however, had more electrolyte re-checks [hydrocortisone treated dogs, median (range): 4 (2–16); prednisolone/dexamethasone treated dogs: 2 (0–6); p = 0.001]. There was no difference in intravenous fluid needs over the first 24 h but hydrocortisone treated dogs had longer hospitalisation [hydrocortisone: 81 (45–309) h; prednisolone/dexamethasone: 52 (22–138) h; p = 0.01].

Clinical Significance

Intravenous hydrocortisone is well-tolerated and safe, but no clear additional benefit over traditional glucocorticoid replacement could be identified. Also, it might result in longer hospitalisation time and more intensive monitoring.

Crystalloid and Colloid Compositions and Their Impact

This manuscript will review crystalloid (hypo-, iso-, and hyper-tonic) and colloid (synthetic and natural) fluids that are available for intravenous administration with a focus on their electrolyte, acid-base, colligative, and rheological effects as they relate to each solution's efficacy and safety. The goal is for the reader to better understand the differences between each fluid and the influence on plasma composition, key organ systems, and their implications when used therapeutically in animals with critical illness.

Addison's Disease Secondary to Bilateral Adrenal Gland Metastatic Mammary Carcinoma in a Dog

A 12 yr old intact female Siberian husky was referred with a 2 wk history of progressive weakness, paraparesis, anorexia, and panting. A 4 cm diameter grade 3 mammary solid carcinoma involving the fifth right mammary gland had been removed 2 days prior to the current visit. While hospitalized, the dog was diagnosed with Addison's disease based on electrolyte disturbances and low serum cortisol levels following adrenocorticotropic hormone stimulation test. An abdominal ultrasound revealed adrenal glands at the upper limit of normal size. Despite treatment, the dog deteriorated and died 4 days after presentation. A postmortem examination revealed a neoplastic infiltrate of epithelial malignant cells in both adrenal glands, popliteal lymph nodes, vertebral bodies, and paralumbar musculature, compatible with metastasis from mammary carcinoma. To our knowledge, this is the first reported case of Addison's disease secondary to metastatic mammary carcinoma in a dog.

Management of hypoadrenocorticism (Addison's disease) in dogs

Hypoadrenocorticism (HOAC; Addison’s disease) is an endocrine condition seen in small animal practice. Dogs with this disease can present in a variety of ways from acute hypovolemic collapse to vague, chronic, waxing, and waning clinical signs. In the most common form of this disease, animals have both mineralocorticoid and glucocorticoid deficiency, resulting in hyponatremia and hyperkalemia, and signs of cortisol deficiency. The etiology may be immune-mediated destruction of the adrenal cortex, drug-induced adrenocortical necrosis (mitotane), enzyme inhibition (trilostane), or infiltrative processes such as neoplastic or fungal disease. Much less commonly, dogs have signs of cortisol deficiency, but no electrolyte changes. This is referred to as atypical HOAC. The veterinarian needs to have a clinical suspicion for HOAC to make a diagnosis in a timely manner. Treatment of dogs with an acute presentation prioritizes correcting the hypovolemia, hyperkalemia, acidosis, and hypoglycemia. Fluid therapy addresses most of these issues, but other directed therapies may be required in the most severe cases. For chronic management, all patients with Addison’s disease will require replacement of glucocorticoids (usually prednisone), and most patients require replacement of mineralocorticoids with either desoxycorticosterone pivalate or fludrocortisone. Atypical Addisonians do not require mineralocorticoid supplementation, but electrolytes should be monitored in case the need arises in the future. The prognosis for dogs treated for HOAC promptly and appropriately is excellent; most patients die from other diseases. However, if the diagnosis is missed, patients may die as a consequence of HOAC. Thus, knowledge of the hallmarks of Addison’s disease is imperative.