Addisons and Cushings Flashcards
What are Addisons and Cushings and what is the difference?
Addisons = HYPOadrenocorticisom - Not enough cortisol and aldosterone produced.
Cushings = HYPERadrenocorticisom - Too much cortisol produced.
What are the possible causes of Cushings?
Ususally a pituitary tumour (85%) causing excess production of ACTH, which stimulates release of cortisol from the adrenal cortex.
Or an adrenal tumour (15%)
What are some actions of increased cortisol production seen with Cushings?
Cortisol promotes gluconeogenesis and catabolism of proteins and fat stores.
Cushings can lead to hyperglycaemia - why?
Cortisol promotes gluconeogenesis
Cushings is characterised by muscle weakness (pot belly, weakened resp muscles) - why?
Protein catabolism promoted by increased levels of cortisol.
PU/PD is seen with Cushings - why?
Increased cortisol causes inhibition of antidiuretic hormone (ADH)
Decreased hepatic function is seen with Cushings, what effects can this have?
Prolonged recoveries and hyper coagulation leading to possible pulmonary thromboembolism. Hepatomegaly also contributes to pot belly appearence.
What is the cause of hypercholesterolaemia in dogs with Cushings?
Lipid catabolism by increased production of cortisol
What are the treatments for Cushings?
Trilostane (aka Vetoryl) blocks adrenal synthesis of glucocorticoids (cortisol).
Hypophysectomy is surgical removal of the pituitary gland.
What are the general signs of Cushings in dogs?
Increased appetite (excess cortisol), weight gain, alopecia, thin skin, skin/UTIs (decr immune system - cortisol), muscle weakness (protein catabolism), panting (respiratory muscle weakness, hepatomegaly, stress), PU/PD (inhibition of ADH), hypertension (excess cortisol - SNS), anxiety, lethargy, facial nerve damage - facial drooping.
Prior to GA, should trilostane (Vetoryl) be administered in a patient with Cushings?
NO - Trilostane should be withheld the previous 24 hrs to avoid risk of HYPOcortisolaemia under GA leading to hypotension and the inability of the body to react to stressors under GA.
What are some anaesthetic considerations for dogs with Cushings?
Hypertension, hypoventilation (hypoxaemia/hypercapnia), thromboembolism, further SNS stimulation, prolonged recovery.
What are the anaesthesia drug considerations for dogs with Cushings?
Avoid long acting drugs such as ACP. Avoid SNS stimulating drugs such as ketamine, anticholinergics, alpha-2 agonists. Avoid heavily hepatically metabolised drugs such as diazepam (less so midazolam). Avoid NSAIDs. Avoid etomidate. Propofol is good for induction - less hepatic metabolism. Avoid etomidate as it may ‘go the other way’ and cause a significant drop in cortisol.
What causes Addisons?
Primarily due to immune destruction of adrenal cortex. Secondary hypoadrenocorticism is reduced production of ACTH from the pituitary - this effects cortisol production primarily.
Common signs of Addisons in dogs?
PU/PD, V+ & D+, anorexia, weight loss, impaired renal perfusion, anaemia, lethargy, muscle weakness, electrolyte imbalances (incr K+/decr Na+), hyperchloraemic acidosis.