Diagnostic efficacy of the leukogram and the chemiluminometric ACTH measurement to diagnose canine hypoadrenocorticism

Summary

Background and objective: The gold standard in the diagnosis of canine hypoadrenocorticism (HA) is the adrenocorticotropin (ACTH) response test. As synthetic ACTH (tetracosactide [Synacthen®]) is currently not available in the European Union, the evaluation of other diagnostic tests seemed warranted. The diagnostic efficacy of electrolytes, the leukogram and endogenous ACTH concentrations to diagnose HA was investigated. Material and methods: The medical records of 145 dogs with clinical signs suspect for spontaneous HA were included in a retrospective study. HA was diagnosed (n = 38) or ruled out (n = 84) by using an ACTH response test. In 23 patients HA was excluded by basal cortisol measurement. The diagnostic performance of various variables was assessed based on receiver operating characteristic (ROC) curves and by calculating differential positive rates. A decision tree (IBM SPSS Decision Trees 20, IBM Corporation) was constructed with the variables neutrophil to lymphocyte ratio (N/LR) and sodium to potassium ratio (Na/KR) to illustrate the diagnostic efficacy of the respective test results. Results: The best single variables to diagnose HA were the endogenous ACTH concentration (area under the ROC curve [ROC AUC] 0.97; cutoff > 50 pmol/l: sensitivity 96%, specificity 100%) and the Na/KR (ROC AUC 0.905; cutoff ≤ 22: sensitivity 92%, specificity 91%). The diagnostic performance of various variables of the leukogram was poor to moderate (ROC AUC 0.625–0.828). 68% of dogs with HA had a Na/KR ≤ 22 and a N/LR ≤ 2.3, a combination not observed in dogs with non-adrenal diseases. Conclusion and clinical relevance: As secondary HA is very rare, endogenous ACTH measurement is a very good alternative to the traditional ACTH response test. Data also suggest that the combination of a Na/KR ≤ 22 and a N/LR ≤ 2.3 is highly specific and can be used to rule in HA.

Zusammenfassung

Gegenstand und Ziel: Der ACTH-Stimulationstest ist der Goldstandard zur Diagnose des kaninen Hypoadrenokortizismus (HA). Da das dafür benötigte synthetische ACTH Tetracosactid (Synacthen®) derzeit in der Europäischen Union nicht erhältlich ist, wurde in dieser Studie die diagnostische Effizienz der Elektrolyte, des Leukogramms sowie der ACTH-Konzentration zur alternativen Diagnosesicherung des HA evaluiert. Material und Methode: Die Befunde von 145 Hunden mit für HA typischen klinischen Symptomen wurden retrospektiv ausgewertet. Das Vorliegen eines HA wurde bei 38 Patienten mittels ACTH-Stimulationstest bestätigt und bei 107 Tieren mittels ACTH-Stimulationstest (n = 84) oder aufgrund eines Kortisolbasalwerts > 55 nmol/l (n = 23) ausgeschlossen. Das Leukogramm wurde mit dem System ADVIA 120 erstellt und nach einem Algorithmus mikroskopisch kontrolliert. Zur ACTH-Messung diente ein validierter chemiluminometrischer Assay. Die Beurteilung der diagnostischen Effizienz der verschiedenen Labormesswerte erfolgte mithilfe von Receiver-Operating-Characteristic(ROC)-Kurven und Berechnung der Differential Positive Rate. Ergebnisse: Die besten alternativen Einzeltests zur Diagnose des HA waren die endogene ACTH-Konzentration (Fläche unter der ROC-Kurve [ROC AUC] 0,97; Cutoff-Wert > 50 pmol/l: Sensitivität 96%, Spezifität 100%) und der Natrium-Kalium-Quotient (Na/KR, ROC AUC 0,905; Cutoff-Wert ≤ 22: Sensitivität 92%, Spezifität 91%). Für das weiße Blutbild ergab sich eine moderate diagnostische Aussagekraft (ROC AUC 0,625–0,828). 68% der Hunde mit HA zeigten einen Neutrophilen-Lymphozyten-Quotienten ≤ 2,3 und einen Natrium-Kalium-Quotienten ≤ 22. Diese Kombination trat bei keinem Patienten auf, der nicht an HA litt. Schlussfolgerung und klinische Relevanz: Aufgrund der Seltenheit des sekundären HA stellt die Messung der endogenen ACTH-Konzentration eine sensitive und spezifische Alternative zum ACTH-Stimulationstest dar. Auch ein Neutrophilen-Lymphozyten-Quotient ≤ 2,3 in Kombination mit einem Natrium-Kalium-Quotienten ≤ 22 spricht für eine Unterfunktion der Nebennierenrinde.

Key words

White blood cell count - neutrophil to lymphocyte ratio - sodium to potassium ratio - adrenocorticotropin - Addison’s disease - dog

Schlüsselwörter

Weißes Blutbild - Neutrophilen-Lymphozyten-Quotient - Natrium-Kalium-Quotient - adrenokortikotropes Hormon - Morbus Addison - Hund

• References

• 1 Adler JA, Drobatz KJ, Hess RS. Abnormalities in serum electrolyte concentrations in dogs with hypoadrenocorticism. J Vet Int Med 2007; 21: 1168-1173.
• 2 Arlt W, Allolio B. Adrenal insufficiency. Lancet 2003; 361: 1881-1893.
• 3 Baker PR, Nanduri P, Gottlieb PA, Yu L, Klingensmith GJ, Eisenbarth GS, Barker JM. Predicting the onset of Addison’s disease: ACTH, renin, cortisol and 21-hydroxylase autoantibodies. Clin Endocrinol 2012; 76: 617-624.
• 4 Beerda B, Schilder MBH, vanHoff JARAM, deVries HW. Manifestation of chronic and acute stress in dogs. Appl Anim Behav Sci 1997; 52: 307-319.
• 5 Church DB. Canine Hypoadrenocorticism. In: BSAVA Manual of Canine and Feline Endocrinology. 4th edn. Mooney CT, Peterson ME. eds. Gloucester: BSAVA; 2012: 156-166.
• 6 Cohen S, Janicki-Deverts D, Miller GE, Frank E, Rabin BS. Chronic stress, glucocorticoid receptor resistance inflammation, and disease risk. PNAS 2012; 109: 5995-5999.
• 7 Cole SW, Mendoza SP, Capitanio JP. Social stress desensitizes lymphocytes to regulation by endogenous glucocorticoids: insights from in vivo cell trafficking dynamics in rhesus macaques. Psychosomatic Med 2009; 71: 591-597.
• 8 Dhabhar FS, Miller AH, McEwen BS, Spencer RL. Stress-induced changes in blood leucocyte distribution. Role of adrenal steroid hormones. J Immunol 1996; 157: 1638-1644.
• 9 DiBartola SP, Johnson SE, Davenport DJ, Prueter JC, Chew DC, Sherding RG. Clinicopathologic findings resembling hypoadrenocorticism in dogs with primary gastrointestinal disease. J Am Vet Med Assoc 1985; 187: 60-63.
• 10 Feldman EC, Nelson RW. Canine and Feline Endocrinology and Reproduction. 3rd ed. St. Louis: Saunders; 2004
• 11 Gates MC, Nolan TJ. Risk factors for endoparasitism in dogs: retrospective case-control study of 6578 veterinary teaching hospital cases. J Small Anim Pract 2009; 50: 636-640.
• 12 Gilor S, Gilor C. Common laboratory artifacts caused by inappropriate sample collection and transport: How to get the most out of a sample. Top Companion Anim Med 2011; 26: 109-118.
• 13 Graves TK. When normal is abnormal: keys to laboratory diagnosis of hidden endocrine disease. Top Companion Anim Med 2011; 26: 45-50.
• 14 Javadi S, Galac S, Boer P, Robben JH, Teske E, Kooistra HS. Aldosterone-torenin and cortisol-to-adrenocorticotropic hormone ratios in healthy dogs and dogs with primary hypoadrenocotrticism. J Vet Int Med 2006; 20: 556-561.
• 15 Kipperman BS, Feldman EC, Dybdal NO, Nelson RW. Pituitary tumor size, neurologic signs, and relation to endocrine test results in dogs with pituitary dependent hyperadrenocorticism: 43 cases (1980-1990). JAVMA 1992; 201: 762-767.
• 16 Klein SC, Peterson ME. Canine hypoadrenocorticism: Part 1. CVJ 2010; 51: 63-69.
• 17 Lennon EM, Boyle TE, Hutchins RG, Friedenthal A, Correa MT, Bissett SA, Moses LS, Papich MG, Birkenheuer AJ. Use of basal serum or plasma cortisol concentrations to rule out a diagnosis of hypoadrenocorticism in dogs: 123 cases (2000-2005). JAVMA 2007; 231: 413-416.
• 18 Lifton SJ, King LG, Zerbe CA. Glucocorticoid deficient hypoadrenocorticism in dogs: 18 cases (1986–1995). JAVMA 1996; 209: 2076-2081.
• 19 McGonigle KM, Randolph JF, Goldstein RE. Mineralocorticoid before glucocorticoid deficiency in a dog with primary hypoadrenocorticism and hypothyroidism. JAAHA 2013; 49: 54-57.
• 20 Melian C, Peterson E. Diagnosis and treatment of naturally occurring hypoadrenocorticism in 42 dogs. J Small Anim Pract 1996; 37: 268-275.
• 21 Müller C, Boretti FS, Wenger M, Sieber-Ruckstuhl N, Reusch C. Untersuchung der Aldosteronkonzentration vor und nach ACTH-Applikation bei 44 Hunden mit Hypoadrenokortizismus. Kleintierprax 2007; 52: 216-224.
• 22 Nielsen L, Bell R, Zoia A, Mellor DJ, Neiger R, Ramsey I. Low ratios of sodium to potassium in the serum of 238 dogs. Vet Rec 2008; 162: 431-435.
• 23 Oelkers W, Diederich S, Bähr V. Diagnosis and therapy surveillance in Addison’s disease: rapid adrenocorticotropin (ACTH) test and measurement of plasma ACTH, renin activity, and aldosterone. J Clin Endocrinol Metab 1992; 75: 259-264.
• 24 Osbaldiston GW, Greve T. Estimating adrenal cortical function in dogs with ACTH. Cornell Vet 1978; 68: 308-316.
• 25 Peterson ME, Kintzer PP, Kass PH. Pretreatment clinical and laboratory findings in dogs with hypoadrenocorticism: 225 cases (1979–1993). JAVMA 1996; 208: 85-91.
• 26 Podell Ml. Canine hypoadrenocorticism. Diagnostic dilemmas associated with the “great pretender”. Probl Vet Med 1990; 02: 717-737.
• 27 Reimers TJ, Salerno VJ, lamb SV. Validation and application of solid-phase chemiluminescent immunoassays for diagnosis of endocrine diseases in animals. Comp Haematol Int 1996; 06: 170-175.
• 28 Richartz J, Neiger R. Hypoadrenocorticism without classic electrolyte abnormalities in seven dogs. Tierärztl Prax 2011; 39 (K): 163-169.
• 29 Rodriguez MIPineiro, Benchekroun G, de Fornel-Thibaud P, Maurey-Guenec C, Garnier F, Rosenberg D. Accuracy of an adrenocorticotropic hormone (ACTH) immunoluminometric assay for differentiating ACTHdependent from ACTH-independent hyperadrenocorticism in dogs. J Vet Intern Med 2009; 23: 850-855.
• 30 Ruckstuhl N, Hoerauf A, Tomsa K, Reusch C. Pseudohypoadrenocorticism in two Sibirian huskies with intestinal parasitism. Schweiz Arch Tierheilk 2002; 144: 75-81.
• 31 Schwedes C, Müller W. Determination of endogenous ACTH in dogs. Validation of a chemiluminometric assay and preanalytic stabilisation. Tierärztl Prax 2000; 28 (K): 65-70.
• 32 Scott-Moncrieff JC, Koshko MA, Brown JA, Hill K, Refsal KR. Validation of a chemiluminescent enzyme immunometric assay for plasma adrenocorticotropic hormone in the dog. Vet Clin Pathol 2003; 32: 180-187.
• 33 Seth M, Drobatz KJ, Church DB, Hess RS. White blood cell count and the sodium to potassium ratio to screen for hypoadrenocorticism in dogs. J Vet Int Med 2011; 25: 1351-1356.
• 34 Swets JA. Measuring the accuracy of diagnostic systems. Science 1988; 240: 1285-1293.
• 35 Wolfesberger B, Fuchs-Baumgartinger A, Schwendenwein I, Zeugswetter F, Shibly S. Sudden death in a dog with lymphoplasmacytic hypophysitis. J Comp Path 2011; 145: 231-234.
• 36 Zeugswetter FK, Pagitz M, Hittmair K, Schwendenwein I. Diagnostic efficacy of plasma ACTH measurement by a chemiluminometric assay in canine hyperadrenocorticism. Schweiz Arch Tierheilk 2011; 153: 111-116.