title: A retrospective study of dogs with atypical hypoadrenocorticism: a diagnostic cut-off or continuum?
abstract: OBJECTIVE
  To describe the clinicopathologic findings and outcome in dogs with atypical hypoadrenocorticism (Group 1) and dogs with suspected atypical hypoadrenocorticism whose post-adrenocorticotropic hormone stimulation cortisol concentrations were greater than 55 nmol/L but below the laboratory reference interval (Group 2).
  
  
  METHODS
  Medical records were searched to identify dogs diagnosed with hypoadrenocorticism between January 2004 and June 2014. Dogs were excluded if their Na:K ratio was less than 27 or if they had received prior therapy that could interfere with adrenocorticotropic hormone stimulation testing.
  
  
  RESULTS
  Forty dogs were included in Group 1 and nine dogs in Group 2. In Group 1, the most common biochemical abnormalities were hypoalbuminaemia (87%) and hypocholesterolaemia (76%). Of 35 dogs in Group 1 with follow-up biochemistry results, five (14%) developed electrolyte abnormalities at 2 to 51 months post diagnosis. Of seven dogs in Group 2 with follow-up, glucocorticoid therapy was discontinued in two dogs without return of clinical signs, four dogs were subsequently diagnosed with inflammatory bowel disease and one dog continued to have clinical signs despite glucocorticoid treatment.
  
  
  CONCLUSIONS
  Dogs with gastrointestinal signs and hypoalbuminaemia and, or, hypocholesterolaemia should be evaluated for atypical hypoadrenocorticism. Follow-up electrolyte monitoring is recommended because some will develop electrolyte abnormalities. Although dogs in Group 2 had a clinical presentation compatible with atypical hypoadrenocorticism, the diagnosis appears unlikely based on review of follow-up data. Dogs with equivocal adrenocorticotropic hormone stimulation results should be evaluated for other underlying diseases such as inflammatory bowel disease. The use of endogenous adrenocorticotropic hormone measurements in these dogs warrants investigation.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Wakayama
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA.
authors.forename: E
authors.initials: E
authors.lastname: Furrow
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA.
authors.forename: L K
authors.initials: LK
authors.lastname: Merkel
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Armstrong
mesh_terms: D000309:Adrenal Insufficiency / Q000097:blood / Q000175:diagnosis / Q000662:veterinary*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000818:Animals; D004283:Dog Diseases / Q000097:blood / Q000175:diagnosis*; D004285:Dogs; D004573:Electrolytes / Q000097:blood; D005938:Glucocorticoids / Q000627:therapeutic use; D006854:Hydrocortisone; D012189:Retrospective Studies
chemical_list: D004573:Electrolytes; D005938:Glucocorticoids; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone