Hypoadrenocorticism Flashcards
(31 cards)
Disease name in primary hypoadrenocorticism
Addison disease
What hormones are lacking in hypoadrenocoriticism?
Adrenocortical hormones: lack of glucocorticoids, mineralocorticoids, or both.
Hypoadrenocorticism vs Addison disease difference
Hypoadrenocorticism = adrenocortical insufficiency
Addison disease = Primary hypoadrenocorticism
What does aldosterone do?
-Maintains water and electrolyte balance
-Conservation of Na+ and water
-Excretion of K+
What three things will deficiency of aldosterone cause?
-Dehydration
-Hyponatremia
-Hyperkalemia
Some clinical signs in case of aldosterone deficiency
-Weakness
-Polydipsia
-Polyurea
-Hypovolemic shock
-Cardiac arrhythmias
Some functions of glucocorticoids
-Glucose metabolism and gluconeogenesis
-Immune system
-Inflammatory response
-Integrity of GI-mucosa
-Stress tolerance
Some effects of glucocorticoid deficiency
-Waxing and waning clinical signs
-Impaired gluconeogenesis and glucogenolysis
-Stress and excercise intolerance
-GI disturbances
-Lethargy, weakness
What is primary hypoadrenocorticism?
Destruction of adrenal glands (>90%)
–> deficiencies of mineralocorticoids and glucocorticoids
Causes of primary hypoadrenocorticism:
-Immune-mediated destruction of adrenal cortex (most common; Addison disease)
-Iatrogenic: drug induced lysis
-Neoplasia, infection, infarction of adrenal glands
What is secondary hypoadrenocorticism? Causes?
Decreased ACTH secretion.
-Iatrogenic: exogenous glucocorticoid administration –> inhibits release of ACTH
-Pituitary lesions
What is “atypical” hypoadrenocorticism?
Deficiency of glucocorticoids (aldosterone) but mineralocorticods are normal. Symptoms are still similar but hyperkalemia and hyponatremia do not occur. Hypoglycemia might cause seizures.
Which is more common: Cushing or Addison disease?
Cushing (hyperadrenocorticism) is significantly more common.
Do cats have primary hypoadrenocorticism/Addison?
Very rarely, fewer than 40 cases described
If happens, it’s similar to canine Addison. Cats need double doses of glucocorticoids per kg of body weight compared to dogs.
What are clinical signs in Addison?
Often not very specific. Symptoms might be related to stress (e.g. “stress colitis”)
-Recurrent episodes of gastroenteritis
-progressive loss of body condition
-failure to respond to stress
-lethargy
-anorexia
-GI-signs
-Polyuria
-Polydipsia
-Bradycardia
-Abdominal pain
What happens in acute hypoadrenocorticism?
~30% of dogs go into hypovolemic shock
-Bradycardia, weak pulse, pale mucous membranes, increased CRT
-Vomiting and diarrhea
-Dehydration
-Abdominal pain
Usually hypovolemic shock causes tachycardia but in acute hypoadrenocorticism we will see bradycardia. Why?
It’s called “relative bradycardia” and is caused by hyperkalemia - animal is not able to become tachycardic
Hematology findings in hypoadrenocorticism?
Absence of stress leukogram!
-Eosinophilia
-Lymphocytosis
-Mild anemia that might be masked by hypvolemia
Biochemistry findings in hypoadrenocorticism
-Hyponatremia
-Hyperkalemia
-Hypochloremia
(because of lack of aldosterone)
Also prerenal azotemia (hypoperfusion in kidneys)
Urinalysis findings in hypoadrenocorticism
-Specific gravity usually low or might be isosthenuric. This is contradictory in dehydration.
-Might be difficult to differentiate from renal diseases
What happens to the cortisol levels in ACTH-stimulation test in case of hypoadrenocorticism?
The levels do not rise, but stay low.
Can ACTH-stimulation test differenciate between primary and secondary hypoadrenocorticism?
No
What might give a false negative result in ACTH-stimulation test?
Cross reactions if patient has been given synthetic glucocorticoids
Treatment of chronic hypoadrenocorticism?
Life-long supplementation of mineralocorticoids (e.g. fludrocortisone acetate) and glucocorticoids (e.g. prednisolone)
