Hypocortisolaemia in a Labrador retriever

Veterinary clinicians often face challenges when diagnosing dogs presenting with vague signs like persistent fatigue. No prior work had fully characterized isolated primary adrenal insufficiency in young Labrador retrievers. That uncertainty drove the need for detailed endocrine profiling in such cases. It was already known that standard stimulation tests help identify adrenal dysfunction. However, distinguishing between various forms of hormonal failure remains complex. This gap motivated a closer look at atypical presentations of low cortisol levels. Prior research has shown that primary adrenal disease typically involves multiple hormone deficits. This report addresses a rare instance where only glucocorticoid production was impaired.

The study aimed to document a rare case of isolated primary adrenal insufficiency in a young dog. This report addresses the diagnostic challenges associated with non-specific clinical signs like exercise intolerance. The authors sought to clarify how primary adrenal failure presents when aldosterone production remains unaffected. This investigation was motivated by the need to improve recognition of atypical endocrine disorders. The researchers intended to demonstrate the utility of specific hormonal stimulation tests in clinical practice. They also aimed to show the effectiveness of low-dose glucocorticoid replacement therapy. This work provides a clear example of how to distinguish primary from secondary adrenal disease. The report serves as a guide for managing similar cases in veterinary settings.

The clinical team performed a comprehensive physical examination to evaluate the patient. They utilized standardized blood assays to measure hormone levels before and after stimulation. The diagnostic approach involved administering adrenocorticotrophin hormone to assess glandular capacity. Investigators compared the resulting cortisol concentrations against established assay detection limits. They also analyzed plasma aldosterone to determine if mineralocorticoid production remained intact. The team evaluated endogenous hormone levels to identify the anatomical origin of the failure. This systematic review of endocrine function guided the subsequent treatment plan. Clinicians monitored the response to replacement therapy to confirm the efficacy of the intervention.

The strongest finding was the complete absence of cortisol production during the stimulation test. Both pre-administration and post-administration plasma cortisol levels remained below the detection limit of the assay. The patient exhibited high endogenous plasma adrenocorticotrophin hormone concentrations, which pointed toward primary adrenal dysfunction. In contrast, plasma aldosterone levels stayed within the normal reference range throughout the evaluation. The dog showed a full clinical recovery following the initiation of glucocorticoid supplementation. The replacement dose of prednisolone was set at 0.1 mg/kg daily. These results confirmed that the animal suffered from isolated primary adrenal insufficiency. The clinical signs of lethargy and exercise intolerance resolved completely after the hormonal deficit was corrected.

The authors suggest that primary adrenal failure can manifest as an isolated deficiency in dogs. This case demonstrates that glucocorticoid replacement therapy effectively restores normal activity levels. Clinicians should consider this diagnosis even when aldosterone levels remain within reference ranges. The findings imply that high endogenous hormone levels confirm the primary nature of the glandular defect. Successful management requires careful titration of daily steroid supplementation. The report highlights the importance of thorough endocrine testing for lethargy. These observations provide a framework for treating similar cases of adrenal insufficiency. The authors propose that early intervention prevents severe clinical deterioration in affected animals.