Hyperadrenocorticoism

Question 1

Causes

Answer 1

• 90% are spontaneous, of which 85% are pituitary dependant.

- 10% are iatrogenic

Question 2

Clinical Signs (14)

Answer 2

• allopecia
• change in coat colour
• skin becomes thin and inelastic
• abdominal distension (fat is redistributed dorsally)
• PU/PD
• lethargy
• polyphagia
• respiratory signs
• muscle weakness
• obesity
• haemostatic abnormalities: inelastic –> bleed everywhere!
• reproductive problems: small testes/stop cycling
• neurological
• myotonia

Question 3

serum biochem (6)

Answer 3

• increased AP
• increased cholesterol
• increased glucose
• increased liver enzymes
• increased bile acids
• decreased urea and creatinine

Question 4

haematology

Answer 4

stress leukogram:

• neutrophilia
• lymphopenia
• eosinopenia
• monocytosis
• erythrocytosis

Question 5

Urine analysis (4)

Answer 5

• low SG
• proteinurea
• glucosurea
• urinary tract infection

Question 6

Tests

Answer 6

• stim ACTH
• low dose dexamethasone suppression test
• basal ACTH

Question 7

Stim ACTH

• method
• results

Answer 7

Method:

• take blood
• give 0.2mg/kg ACTH
• take blood 30 mins-2 hours later
• judge maximal cortisol: in cushingoid will be very high
• iatrogenic will be the same
• normal will increase but only slightly

Question 8

LDDST

• why
• results
• method
• problems

Answer 8

• DXM suppresses ACTH
• cortisol will fall in normal animal
• harder to suppress/ won’t be suppressed for long in cushingoid animal
• adrenal dependent is especially not suppressed
  Method:
• blood sample
• give 0.015mg/kg of DXM
• blood sample 3-8 hours later

Problems:

• time consuming
• stress induced cortisol can affect it

Question 9

ACTH assay (4)

Answer 9

• can’t be used to Dx cushings but can tell you if adrenal or pituitary dependent.
• normal is between 20-120
• below is adrenal dependant
• above is pituitary dependant

Question 10

Treatment

Answer 10

Trilostane:

• synthetic steroid
• blocks steroid enzymes and has no intrinsic steroid activity itself
• blocks cortisol and aldosterone
• get dose right as aldosterone has severe effects!
• effects change over time so keep testing!

Question 11

Getting the right dose

Answer 11

ACTH:
 stop and restart at 50%
20-120 nmol.l --> no change
>120nmol/l --> increase by 50%
>200nmol/l --> increase by 100%

most effect in first 4-6 hours: if still seeing clinical signs but within range change to BID

Question 12

Surgery

Answer 12

• no trilostane on day of surgery/ill as needs cortisol to get through

Question 13

SE of trilostane

Answer 13

• electrolyte abnormalities
• diarrhoea, vomiting, lethargy, anorexia
• some dogs die within a few days but have no idea why

Question 14

Monitoring

Answer 14

CS!

• polyphagia/ PU/PD/lethargy should resolve within 2 weeks
• alopecia should resolve in 1 month