Page 993 - Cote clinical veterinary advisor dogs and cats 4th

488 Hyperadrenocorticism, Suspect/Conflicting Results

• The possibility that a patient has HAC is Advanced or Confirmatory Testing Possible Complications
based on history and physical exam findings. • If mild suspicion of HAC still exists, a urine • Complications of treatment for HAC with
VetBooks.ir when clinical signs consistent with HAC are help rule out the diagnosis (p. 1391). • Hypoadrenocorticism, if not recognized and
Endocrine tests should be performed only
mitotane or trilostane include gastrointestinal
cortisol/creatinine ratio can be measured to
signs and hypoadrenocorticism.
present.
○ Recently, sensitivity of this test has been
• Not all animals with an adrenal or pituitary
reassessed and may be as low as 70%.
mass have HAC. Tumors can be nonsecretory • If strong suspicion for HAC exists, consider addressed promptly, can be fatal.
or can secrete hormones unrelated to cortisol low-dose dexamethasone suppression test or Recommended Monitoring
production (p. 34). an ACTH stimulation test (pp. 1300 and • If the diagnosis of HAC is not clear, contin-
1360). ued monitoring is recommended. Owners
DIAGNOSIS • Liver aspirates and cytology are not helpful should be on the lookout for the common
for diagnosing HAC. Vacuolar hepatopathy clinical signs.
Diagnostic Overview is a nonspecific finding. • A physical exam should be repeated every
The primary indication for pursuing a diagnosis • When ACTH stimulation test and low-dose 3-4 months to identify new abnormalities.
of HAC is the presence of one or more of dexamethasone suppression test results are • Testing can be repeated if clinical signs and
the common clinical signs and physical exam normal physical changes progress.
findings. The more abnormalities identified, ○ If clinical signs are mild, wait and retest • Potential complications of HAC that can
the stronger the indication to pursue testing. for HAC if progression occurs. be damaging to the body (i.e., proteinuria
When only a single sign is present, it is ○ If clinical signs are moderate to severe and hypertension) should be monitored q
usually polyuria/polydipsia or dermatologic and bilateral adrenomegaly is present on 2-3 months.
abnormalities. abdominal ultrasound ○ Treatment of either may be required if
■ CT or MRI should be considered to they worsen (p. 501).
Differential Diagnosis identify a pituitary tumor causing early ○ Treatment for HAC is still not indicated
Differential diagnoses depend on the abnormali- HAC. if there are no clinical signs of it.
ties present: ■ Consider testing for occult hyperad-
• Polyuria/polydipsia (pp. 812 and 1271) renocorticism (p. 490) or food-related PROGNOSIS & OUTCOME
• Polyphagia (pp. 809 and 1270) HAC (p. 489).
• Panting (pp. 751 and 1263) ○ If clinical signs are moderate to severe Depend on the disease present
• Alopecia (pp. 47 and 1400) and the adrenal glands are normal on
• Proteinuria (p. 1272) abdominal ultrasound, reconsider dif- PEARLS & CONSIDERATIONS
• Hypertension (pp. 501 and 1238) ferential diagnoses.
• ALP elevation (p. 1304) Comments
TREATMENT • Diagnosis of HAC can be challenging. Because
Initial Database it is typically a slowly progressive disease, a
• Review the history and repeat exam to Treatment Overview wait and watch approach is an option.
ensure no details that could support or refute Treatment should be considered only if there are • No information exists that severe complica-
HAC are missed. Of particular importance clinical signs consistent with HAC. Laboratory tions (e.g., pulmonary thromboembolism)
are questions regarding exposure to exog- test abnormalities by themselves are insufficient occur before common clinical manifestations
enous glucocorticoids by any route, even grounds for treatment. No test for HAC is develop.
topical. 100% sensitive or specific. • If findings remain confusing, consultation
• CBC, biochemical profile, urinalysis, blood with a specialist in veterinary internal
pressure measurement, and urine protein/ Acute General Treatment medicine is indicated.
creatinine ratio should be obtained. See p. Acute treatment of HAC is not warranted.
485 for findings typical of HAC. Certain complications, such as pulmonary Technician Tips
○ No abnormality is pathognomonic for thromboembolism, may require immediate care. Signs of worsening include increased drink-
HAC. ing, urinating, appetite, and panting as well
○ Absence of abnormalities common in Chronic Treatment as reluctance to exercise (e.g., jump on furniture,
HAC (e.g., neutrophilic leukocytosis, • Treatment for HAC is warranted only when get in and out of vehicles).
thrombocytosis, increased ALP activity, there are clinical signs and positive tests for
dilute urine specific gravity, and pro- HAC. SUGGESTED READING
teinuria) should strongly decrease the • Trial therapy as a diagnostic test for HAC is Behrend EN, et al: Diagnosis of spontaneous canine
suspicion of HAC. not recommended because of the costs and hyperadrenocorticism: 2012 ACVIM consensus
• Abdominal ultrasound: if normal with potential side effects of treatment (p. 485). statement (Small animal). J Vet Intern Med
respect to adrenal gland size and shape, • If mild signs of HAC are present, treatment 27:1292-1304, 2013.
HAC is unlikely. A large liver is an extremely need not be pursued immediately. AUTHOR & EDITOR: Ellen N. Behrend, VMD, PhD,
nonspecific finding. • Therapeutic recommendations vary among DACVIM
classic, occult, and food-related HAC.

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