Hydrocortisone therapy in a cat with vasopressor-refractory septic shock and suspected critical illness-related corticosteroid insufficiency

Pisano, Simone R. R.; Howard, Judith; Posthaus, Horst; Kovacevic, Alan; Yozova, Ivayla D.

Although reports on histopathologic findings in CIRCI patients are rare, severe adrenal hemorrhage secondary to bacterial infection (Waterhouse-Friderichsen syndrome), most commonly to meningococcal sepsis, is described in humans and has been associated with the development of CIRCI [43, 44] . In the case described herein, necropsy revealed bilateral diffuse adrenocortical hyperplasia and hypertrophy, which has previously been associated with chronic stress [45] , pituitary hyperadrenocorticism [46, 47] , hyperaldosteronism [48] , and congenital adrenal hyperplasia [49] . Although ACTH-stimulation testing is not considered useful during initial shock management, a convalescent ACTH-stimulation test may, therefore, have been of benefit to investigate adrenal function in this case. The failure to perform an ACTH-stimulation test when the cat presented for follow-up examination is, therefore, a limitation of this report. Necropsy also revealed adrenocortical cytoplasmic vacuolization, which has been described in association with toxicosis [50] and MA administration [34] . However, reversible adrenocortical atrophy rather than hyperplasia would be expected if vacuolization was due to MA or hydrocortisone administration [34] . Whether the observed histopathologic changes were secondary to CIRCI or an underlying disease predisposing to CIRCI in this case remains unclear. Furthermore, as necropsy was performed 2 months after initial presentation, the observed histopathologic findings may be unrelated to the presenting sepsis, shock, or CIRCI. Indeed, no macroscopic adrenal changes were observed during laparotomy, although abdominal exploration may have been limited due to hypotension and the desire to curtail the duration of anesthesia. To the authors' knowledge, necropsy findings of adrenal glands of animals with suspected CIRCI have not been previously reported.