Lecture 24 4/24/24

Question 1

What is the primary goal of glucocorticoid therapy?

Answer 1

reduce the processes that are activated in response to a disease

Question 2

Why is it important to frequently reevaluate patients undergoing GC therapy?

Answer 2

GC sensitivity differs greatly between individuals

Question 3

How do physiological, anti-inflammatory, and immunosuppressive doses of GCs relate?

Answer 3

-anti-inflammatory dose is roughly 10 times the physiological dose
-immunosuppressive dose is roughly 2 times the anti-inflammatory dose

Question 4

What is physiological replacement therapy?

Answer 4

providing GCs in amounts similar to those naturally produced

Question 5

What is the ideal for replacement therapy?

Answer 5

mimicking the hormonal output of the adrenal gland under basal conditions

Question 6

Why is it difficult to achieve perfect replacement with GCs?

Answer 6

under normal function, the adrenal gland is able to make minute-to-minute adaptations based on cortisol secretion

Question 7

Which patients receiving GC replacement therapy typically require mineralocorticoid replacement as well?

Answer 7

those with primary disease, such as Addison’s

Question 8

What are the characteristics of primary hypoadrenocorticism?

Answer 8

-can be caused by autoimmune adrenal destruction, trauma, neoplasia, or coagulopathy
-GC and MC deficiency

Question 9

What are the characteristics of atypical hypoadrenocorticism?

Answer 9

-minority of patients with normal serum electrolytes at initial diagnosis
-occurs secondary to gradual loss of adrenocortical tissue
-GC-secreting portion is lost before mineralocorticoid-secreting layer

Question 10

What are the characteristics of iatrogenic hypoadrenocorticism?

Answer 10

-results from drugs that cause destruction of adrenal cortices
-can cause development of Addison’s secondary to unintentional, non-selective loss of entire adrenal cortex

Question 11

What are the characteristics of secondary hypoadrenocorticism?

Answer 11

-lack of ACTH synthesis in the pituitary due to neoplasia, inflammation, or trauma
-typically only see a GC deficiency
-can be iatrogenic due to exogenous GC admin. and rapid withdrawal

Question 12

What are the characteristics of tertiary hypoadrenocorticism?

Answer 12

-lack of CRH
-very rare
-only GC deficiency

Question 13

What are the characteristics of anti-inflammatory GC therapy?

Answer 13

-typically used for inflammatory and allergic disorders
-must first check for infectious disease; otherwise could kill patient
-once clinical signs are under control, dose should be reduced to lowest necessary concentration

Question 14

What are the characteristics of immunosuppressive GC therapy?

Answer 14

-GCs are considered initial first-line therapy for many immune-mediated diseases
-used to prevent organ rejection after transplantation
-used to reduce immunological reactions associated with some infectious diseases
-goal is to use higher doses to achieve remission quickly, and then taper dose slowly to the lowest level that maintains remission

Question 15

What are the goals of giving prednisolone in combination with chemotherapy?

Answer 15

-reduce edema and inflammation
-stimulate appetite
-decrease nausea and vomiting
-alleviate chronic cancer pain

Question 16

What are the characteristics of prednisolone as the sole treatment in lymphoma cases?

Answer 16

-controls tumor short term; 1-2 months
-side effects include multidrug resistance; cannot choose to start chemo after GC use
-must diagnose before starting GCs, because they can induce apoptosis of neoplastic lymphocytes and complicate diagnosis

Question 17

How are GCs used in patients with other cancer-like diseases?

Answer 17

-used in patients with hypercalcemia of malignancy
-used to increase blood glucose conc. in patients with insulinoma

Question 18

What are the characteristics of GC use in shock?

Answer 18

-sometimes used in addition to epinephrine when treating anaphylactic shock, but no studies support benefits
-can be used at a low does for a few days when treating septic shock if necessary for treatment of other conditions

Question 19

What is the connection between GCs and neurological treatment?

Answer 19

GCs are no longer used in the treatment of brain and spinal cord injuries in animals

Question 20

What are the characteristics of iatrogenic hyperadrenocorticism?

Answer 20

-typically seen within first 2 weeks of therapy
-signs include polyuria, polydipsia, polyphagia, panting
-more severe signs develop after weeks/months of therapy
-large individual variation
-cats more resistant than dogs
-cats can have severe unique signs such as tearing/sloughing of skin and curling of pinnae
-treatment is cessation of GC therapy

Question 21

What are the characteristics of HPA axis alteration?

Answer 21

-all GCs suppress CRH and ACTH secretion
-greater suppression and adrenal cortex atrophy occurs with greater anti-inflammatory potency
-usually reversible; full recovery depends on duration, dose, preparation, and application frequency
-abrupt cessation of treatment can result in GC withdrawal syndrome

Question 22

What are the characteristics of diabetes mellitus with GC use?

Answer 22

-increased insulin resistance
-increased hepatic glucose production
-inhibition of insulin release from beta cells
-cats more susceptible than dogs
-likely to go into remission if steroid-induced
-administration of GCs will typically worsen glycemic control

Question 23

What are the characteristics of GI ulcerations and hemorrhage with GC use?

Answer 23

-decreased or altered mucus
-decreased mucosal cell turnover
-increased acidic output
-impaired mucosal blood flow
-decreased healing rate
-promotion of bacterial colonization

Question 24

What are the characteristics of neurological disease and GC use?

Answer 24

-use less potent GCs in these patients
-use lowest possible dose and duration
-no concurrent or successive use of NSAIDs

Question 25

Which lab abnormalities can be seen with GC use?

Answer 25

-elevation of liver enzymes
-increased glucose and lipase
- increased serum lipids
-increased neutrophils and monocytes
-decreased lymphocytes and eosinophils

Question 26

What are the characteristics of pancreatitis and GC use?

Answer 26

-previous concern that GCs caused pancreatitis; now dismissed
-possible that GCs could contribute to pancreatitis in sick animals/in a specific subset of animals
-use caution if animal has pancreatitis; avoid GCs

Question 27

When should tapering of GCs be done?

Answer 27

-therapy that lasts 2 weeks or more
-if high doses were used
-if disease has resolved

Question 28

What is the general rule for GC tapering?

Answer 28

the longer the induction phase and/or the greater the induction dose, the more stepwise and longer the period between dose reductions

Question 29

What is the initial dose reduction step taken with GCs?

Answer 29

consolidating the dose, which achieves longer dosing intervals

Question 30

How many days of therapy are typically required when treating with GCs?

Answer 30

-5 to 7 days for inflammatory diseases
-10 to 28 days for immune-mediated diseases

Question 31

What are the characteristics of prednisone in horses?

Answer 31

-poor oral bioavailability
-low conversion in the liver

Question 32

What are the characteristics of prednisolone in horses?

Answer 32

-moderately potent GC with minimal MC activity
-used for lots of inflammatory and immune-mediated diseases

Question 33

What are the characteristics of dexamethasone in horses?

Answer 33

-admin. IV, IM, or oral
-high vol. of dist.
-treats many inflammatory and immune-mediated diseases

Question 34

What are the characteristics of fluticasone propionate in horses?

Answer 34

-potent GC
-administered via facemask and inhaler
-used for inflammatory resp. diseases

Question 35

What are the characteristics of beclomethasone dipropionate in horses?

Answer 35

-administered via inhaler
-very potent

Question 36

What are the characteristics of methylprednisolone in horses?

Answer 36

-long-acting GC for IA injection
-reduces pain and inhibits joint inflammation

Question 37

What are the characteristics of betamethasone in horses?

Answer 37

-potent GC with virtually no MC activity
-administered via IA injection
-treats sterile synovitis

Question 38

What are the characteristics of triamcinolone acetonide in horses?

Answer 38

-potent GC
-intermediate duration of action
-low volume IA injection

Question 39

What are the potential GC adverse effects in horses?

Answer 39

-laminitis (no evidence)
-gastric ulcers (poor evidence)
-birth defects (poor evidence)