HAC

1. Jade Webster

2. Hyperadrenocorticism
 Common endocrine condition
 Overproduction of cortisol
 Results in signs of:
 PUPD
 Polyphagia
 Alopecia
 Abdominal distension

4. Types
 Categorised into 2 types:
 Pituitary Dependent
 Adrenal Dependent

5. Pituitary Dependent (PDH)
 Overproduction of ACTH = Increased cortisol
 Majority of HAC dogs (85%)
 Mainly small breeds
 Middle aged – older (7-9yrs)

6. PDH
 Radiotherapy
 Progression of disease : can form a
pituitary macroadenoma
 Neurological signs
 Median survival time = 662-900 days (tx
with trilostane)

7. Adrenal Dependent
 Tumour of the Adrenal cortex produces
excessive cortisol
 Less common (15%)
 Large breeds
 Older dogs (11yrs)
 Median survival time = 353 days

8. ADH
 50% benign and 50% malignant
 Surgery: Adrenalectomy
 Progression of disease:
 Malignancy is a possibility in 50% of these
cases

9. Study
 Involved 57 dogs from both first opinion
(32 dogs) and referral hospitals (25
dogs)
 All diagnosed with HAC
 Age Range = 4 – 17 years old
 Weight range = 2.3 - 38.5kg

10. Breeds involved
 Cross-breed (20)
 Jack Russell (7)
 Cocker Sp. (4)
 YRT (3)
 Shih-Tzu (3)
 WHWT (2)
 Springer Sp. (2)
 Bichon Frise (2)
 Schnauzer (2)
 Patterdale (1)
 Scottish Terrier (1)
 Collie (2)
 SBT (1)
 Shetland Sheepdog (1)
 Affenpinscher (1)
 Beagle (1)
 Hungarian Viszla (1)
 CKCS (1)
 Flatcoat Ret. (1)
 Border Terrier (1)
 Red Setter (1)
 Shar Pei (1)

11.  What tests were used to diagnose HAC?
 Were the patients differentiated into
PDH or ADH?
 And if so, How were they differentiated?

12. Diagnostic tests
 Cannot use basal cortisol
 Non-adrenal illness (NAI) can cause a high
circulating cortisol level
 Pulsatile action of ACTH
 Therefore diagnosis of HAC based on
other tests

13. Tests performed
ACTH LDDST 17-OH Urine Cortisol:Creatinine
 ACTH Stimulation Test
 LDDST
 17-OH Progesterone
 Urine Cortisol:Creatinine

14. ACTH stimulation test
 HAC = exaggerated response
 Post ACTH cortisol >600nmol/l
 Sensitivity = 57-83%
 Specificity = 59-93%

15. ACTH Stimulation Test
 ACTH Stim was performed on 45 dogs
in the study
 31 recorded as a positive result
 Positive Post ACTH ranged from 618-
1443 (mean 926)
 Negative Post ACTH ranged from 218-
651 (median 427)

16. LDDST
 HAC response: either no suppression or
suppression and then escape at 8h
 8 hour >40nmol/l
 Sensitivity: 85-100%
 Specificity: 44-73%

17.  LDDST performed in 20 dogs in study
 Of these 14 produced positive result

18. 17-OH Progesterone
 Precursor for
cortisol
 Increased in HAC
and “atypical
HAC”
 Performed in 4
dogs in study

19. Urine cortisol:creatinine
 Cortisol excreted in urine – reflection of
cortisol release
 Very sensitive (92%)
 Non-specific (21%)
 Used in one case in the study as ACTH,
LDDST and 17-OH were all negative but
clinical signs strongly suggested HAC.

20. First Line Test
84%
16%
ACTH Stim Test LDDST

21. Test that confirmed
diagnosis
67%
29%
2%2%
ACTH LDDST 17-OH TRILOSTANE

22. Differentiation
 Ultrasound
 Endogenous ACTH
 LDDST

23. Differentiated
 54% were differentiated
 PDH = 25 cases (89%)
 ADH = 3 cases (11%)
 29% cases in 1st opinion practice
 90% cases in referral hospital

24. Ultrasound
 PDH = Bilateral adrenomegaly
 ADH = Mass on adrenal gland
 Ultrasound of adrenals performed in
24/53 dogs in study
 95% of referral cases had adrenal
ultrasound
 15% of first opinion cases

25. Endogenous ACTH
 PDH = high ACTH (>28pg/ml)
 ADH = low ACTH (<5pg/ml)
 Used in 5 cases
 All in referral centres
 Used alone in 2 of these
 Rest were used in conjunction with
ultrasound

26. LDDST
 Suppression at 4hours and then escape
suggest PDH
 No suppression – either ADH or PDH
 Suggestive results were used to
differentiate alone in 7 cases
 6 in First opinion
 1 in Referral
 Used in conjunction with ultrasound and
endogenous ACTH

27. MRI
 Used to diagnose PDH or following PDH
diagnosis for planning of radiotherapy
 Used in one case in the study as
showed neuro signs and was diagnosed
with a macroadenoma

28. Conclusions
 ACTH was the most popular test of
choice for diagnosing HAC
 LDDST suggested as test of choice
 Higher Sensitivity
 Confusion over interpretation

29. UCCR
LDDST
17-OH
ACTH
Decreasing
Sensitivity

30.  Only 54% of dogs were differentiated
 Simple test that can be performed in first
opinion practice

31. Case Example - Sammy
 Diagnosed in first opinion practice with
HAC and was not differentiated
 The year following diagnosis
 More PUPD
 Dx: diabetes insipidus. Responded to tx
 6 months later represented for PUPD,
weight loss and lethargy
 Believed to be due to an over suppression
(Addisons) therefore decreased dose of
trilostane
 2 months later – presented for lying in
lateral recumbency and head banging

33. Limitations of Study
 Assumptions of correct diagnosis
 History availability
 Information on diagnosis
 Absent values for Post ACTH/8hr
LDDST
 Assumptions of ultrasound
measurements made by first opinion
vets

34.  Important to differentiate
 Not being done as often in first opinion
practice as in referral hospitals
 Endogenous ACTH – very simple

35. References
 Gould S.M, Baines E.A, Mannion P.A, Evans H and Herrtage M.E. (2001)
Use of endogenous ACTH concentration and adrenal ultrasonography to
distinguish the cause of canine hyperadreocorticism. Journal of Small
Animal Practice 42, 113-121
 Behrend et al. (2012) Diagnosis of Spontaneous Canine
Hyperadrenocorticism:ACVIM Consensus Statement (Small Animal). J Vet
Intern Med 2013;27:1292–1304
 Mooney C.T, Peterson M.E (2012) BSAVA Manual of Canine and Feline
Endocrinology 4th ed.
 Helm et al. (2011) A Comparison of Factors that Influence Survival in Dogs
with Adrenal-Dependent Hyperadrenocorticism Treated with Mitotane or
Trilostane. J Vet Intern Med 2011;25:251–260.
 Chapman, P.S. et al (2003) Evaluation of the basal and post
adrenocorticotrophic hormone serum concentrations of 17-
hydroxyprogesterone for the diagnosis of hyperadrenocorticism in dogs.
Veterinary Record 153, 77-775
 Smiley L.E, Peterson M.E (1993) Evaluation of a urine cortisol:creatinine
ratio as a screening test for hyperadrenocorticism in dogs. JVIM 7, 163-8
 Ramsey I, Ristic J (2007) Diagnosis of canine hyperadrenocorticism. In
Practice 2007;29:446-454

36. Acknowledgements
Thanks to Laura Cosgrove

37. Questions?