30. Diseases of the adrenal glands in dogs and cats

Question 1

Hypoadrenocorticism =

Answer 1

addisons

Question 2

Primary addisons show:

Answer 2

decreased cortisol, decreased aldeosterone, but high ACTH

Question 3

Causes of primary addisons

Answer 3

bilateral adrenal tumor, amyloidosis, infection

Question 4

Secondary addisons show

Answer 4

decreased ACTH, cortisol , but aldosterone is the same

Question 5

Causes of secondary addiosons:

Answer 5

• Unprofessional glucocorticoid therapy – leading to ACTH deficiency
• (Hypophysis tumor, trauma, inflammation)

Question 6

Who gets addisons?

Answer 6

• Young and middle-aged
• in bitches
• Great Dane, Rottweiler, Poodle, Schnauzer, Westie, Bearded collie, English cocker spaniel (most common in hungary)
• (Very rare in cats)

Question 7

Clinical signs of addisons

Answer 7

Aldosterone decreased which leads to dehydration and can cause Addisonian-crisis.

-Due to cortisol deficiency : Depression, weakness, tremor, weight loss, hypothermia, anorexia, no stress response

GI symptoms like: Vomiting/diarrhea (+/- bloody), abdominal pain, PD/PU

Shock, CRT increase, bradycardia (can also have severe K+ with it), weak pulse
- When these signs are present, include Addison’s disease in differential diagnosis!

Question 8

Lab findings in addisons:

Answer 8

-Normocytic normochromic anaemia
(dehydration/hypocolemia can mask the anaemia!)
-Lack of „stress leukogram”:
-Hyponatremia
-Hyperkalaemia
-hypochloraemia,
- hypoglycaemia
-albumin decreased (after vomit, diarrhea),
-prerenal azotaemia (nitrogen, creatinine)
-bradycardia
-Abdominal US: „thinner” adrenals

Question 9

Diagnosis of addisons:

Answer 9

ACTH-stimulation test

• Blood sampling: t0, t1
• Positive: t0 cortisol < 28nmol/l, t1 cortisol <100 nmol/l
• On the morning of the test the hydrocortisone injection should be postponed
• Single cortisol >55 nmol/l: Addison’s unlikely

Question 10

Differential diagnosis of addisons

Answer 10

Differential diagnosis

• Renal failure
• Gastroenteritis
• Acute pancreatitis, (Ileus)

Question 11

Treatment of addisonian crisis:

Answer 11

Addisonian-crisis
normal saline for 2 hours
hydrocortisone with the first infusion.

Thereafter: normal saline
-hydrocortisone SC – single injection
Then : Maintenance therapy

Question 12

Treatment of addisons

Answer 12

Fludrocortisone (mineralcorticoid replacement)

-often started with prednisolone, but after a while we lower the admin of prednisolone and change the dose.

Question 13

Hypercortisolism =

Answer 13

cushing

Question 14

the types of cushing

Answer 14

Pituitary dependent (PDH)
Adrenocortical tumors : ADH
Iatrogenic form

Question 15

Who gets cushing?

Answer 15

• Middle-aged and old dogs
• Poodle, Dachshund, Yorkshire terrier, Hungarian vizsla, Boxer
• PDH: small dogs
• AC tumors: large dogs

Question 16

Clinical signs of cushing:

Answer 16

• Glucocorticoids increase, so will lipogenesis, GNG
• PD/PU
• PP, centripetal obesity, abdominal enlargement, muscle wasting, pot
• Thin, atrophic skin, keratin plugs, alopecia, hyperpigmentation, calcinosis cutis
• Hepatomegaly
• Testicular atrophy, anoestrus
• Secondary infections (skin, urinary tract)
• (Cerebral signs)

Question 17

Diagnostics of cushing:

Answer 17

-Leukocytosis, neutrophilia

• Increased: Cholesterol , lipemia, blood glucose and AP.
• Low specific gravity of urine
• Ultrasound: enlargement of adrenal gland(s), metastases (liver, vessels)
• X-ray: hepatomegaly, osteoporosis, calcinosis cutis, lung metastasis
• CT: pituitary tumor
• Blood pressure measurement: hypertension +/-
• Measurement of urinary corticoid/creatinine ratios

-LDDS test

Question 18

Explain the LDDS test

Answer 18

• LDDS test
• In the morning: 0,01 mg/kg dexamethasone IV
• Blood sampling: t0, t4, t8
• Positive: t8 cortisol >40 nmol/l
• If t4 cortisol <0,5 X t0: PDH
• ACTH-stimulation test: if iatrogenic ~ is suspected

Question 19

Diagnosis – distinguishing PDH and AC tumor

Answer 19

• Abdominal US
• HDDS test
• In the morning: 0,1 mg/kg dexamethasone IV
• Blood sampling: t0, t4, t8
• If t4 or t8 cortisol < 0,5 X t0: PDH
• If t4 or t8 cortisol < 40 nmol/l: PDH

Question 20

Treatment of cushing:

Answer 20

Mitotane - selective destruction of AC
Trilostane - reduces cortisol synthesis

Surgery:
Adrenalectomy or hypophysectomy