Lecture 22: Addison’s

• Why is hypoadrenocorticism hard to diagnose?

  -Uncommon disease with common symptoms

  -Usually looking for more common diagnoses for those symptoms

  -Test for it any or most vague

  -Pay attention to the owner and prep then for a normal ACTH stim
• What animals should you test the most?

  Renal failure patients
• Adenocortical deficiency resulting in low glucocorticoid (cortisol) +/- aldosterone

  Hypoadrenocorticism
• ____% of adrenal cortex destroyed when CS develop

  90%
• Low glucocorticoid and mineralcorticoid, most common presentation


  Typical Addison's disease
• Can get glucocorticoid-only deficiency


  Atypical/secondary Addison's disease
• Pathology of hypoadrenocorticism


  -Suspect idiopathic, immune-mediated destruction

  -Lymphocytic inflammation with fibrosis on necropsy

  -Performed years after diagnosis so histopathology at time of diagnosis is not known
• What is typical hypoadrenocorticism?

  -Deficiency of both glucocorticoid and mineralcorticoid

  -Most common

  -Severe illness but could have early stages with milder illness and less severe mineralcorticoid deficiency
• What is atypical hypoadrenocorticism?

  -Low coritsol and high ACTH

  -Glucocorticoid deficiency only

  -May become typical

  -Less severe disease since aldosterone present
• What is atypical hypoadrenocorticism?

  -Pitutary dependent (decreased ACTH)

  -Looks like atypical because of aldosterone/lytes ok

  -Exogenous glucocorticoids can cause it as well
• What are the functions of cortisol?

  -Metabolism, BP, blood glucose

  -Response to stress

  -GI health

  -Control inflammation and manage immune response
• What CS are seen with lack of cortisol?

  GI signs, mentation, lack of ability to handle stress
• What is the primary cause of hypoadrenocorticism (Addison's Disease)?

  
  

  a. Excess cortisol in the body

  b. Deficiency in glucocorticoid and mineralocorticoid hormones

  c. Lack of aldosterone alone

  d. Pituitary malfunction

  b. Deficiency in glucocorticoid and mineralocorticoid hormones
• Which of the following is NOT a common presentation of hypoadrenocorticism?

  
  

  a. Vomiting and diarrhea

  b. Sudden increase in energy levels

  c. Weight loss

  d. Lethargy

  b. Sudden increase in energy levels
• What is the function of aldosterone?

  -Sodium and potassium balance

  -Water balance
• What the CS that seen with lack of aldosterone?

  Hyponatremia, hyperkalemia, hypovolemia, hypotension, reduced cardiac output, reduced renal perfusion (decreased GFR0
• What kind of deficiency is seen in Atypical Addison's Disease?

  
  

  a. Glucocorticoid only

  b. Mineralocorticoid only

  c. Both glucocorticoid and mineralocorticoid

  d. Excessive cortisol

  a. Glucocorticoid only
• Which breed is commonly associated with hypoadrenocorticism?

  
  

  a. Labrador Retriever

  b. Beagle

  c. Standard Poodle

  d. Siberian Husky

  c. Standard Poodle
• Common signalment of hypoadrenocorticism?

  Young to middle aged (2 months-14 years) female (spayed) dog
• What breeds are predisposed to hypoadrenocorticism?

  Standard poodle, Great Dane, Westie

  
• What animals should you consider having Addison's?

  -Renal failure

  -Unspecified, vague illness

  -Waxing/waning or any sick animal
• CS of atypical Addison's

  -Lethargy

  -Decreased appetite

  -Vomiting

  -Diarrhea

  -WL

  -Other unresolving problems (pneumonia, other infections)

  -Illness when stressed

  -Often improves with symptomatic treatments
• CS of typical Addison's

  -All of those seen with atypical Addison's

  -Progressive or more severe

  -PU/PD

  -Bradycardia

  -Dehydration

  -Weak pulses

  -Hypovolemia

  -Hypotension

  -Lethargy and weakness to point of collapse

  -Abdominal pain (?)
• What is the role of cortisol in the body?

  
  

  a. Regulating water balance

  b. Controlling inflammation

  c. Maintaining sodium balance

  d. Managing potassium levels

  b. Controlling inflammation
• What are typical electrolyte imbalances seen in hypoadrenocorticism?

  
  

  a. Hypernatremia

  b. Hypokalemia

  c. Hypocalcemia

  d. Hyponatremia

  d. Hyponatremia
• What tests can we use to diagnose Addison's?

  -CBC/Chemistry/UA

  -ECG

  -Chest radiographs

  -ACTH stimulation test
• CBC findings with Addison's disease

  -Nonregenerative anemia (usually mild)

  -Anti-stress leukogram (but can have neutrophilia)
• Chemistry findings with Addison's disease

  -Unlikely to have all these

  -Hyponatremia

  -Hyperkalemia

  -Hypercalcemia

  -Azotemia (pre-renal but looks renal)

  -Hyperphosphatemia

  -low albumin, cholesterol, BG

  -Na:K <27
• UA findings with Addison's disease

  USG <1.030, often isothenuria
• ECG findings with Addison's disease

  -Small to absent p-waves

  -Bradycardia- prolonged QRS interval, P-R interval

  -Tall, narrow t-waves
• Chest radiograph findings with Addison's disease

  -Microcardia

  -Flattened, thinner descending aorta

  -Thinner CVC

  -Megaesophagus (?)
• Which test is recommended for diagnosing hypoadrenocorticism?

  
  

  a. LDDS test

  b. Urine cortisol:creatinine ratio

  c. ACTH stimulation test

  d. Aldosterone level measurement

  c. ACTH stimulation test
• How is an Addisonian Crisis managed?

  
  

  a. Fluid therapy

  b. Antibiotics only

  c. Anti-inflammatory drugs

  d. Antifungal medications

  a. Fluid therapy
• Hypoadrenocorticism radiographs

  
• Hypoadrenocorticism ECG

  
• What are you measuring with an ACTH test?

  Cortisol!
• What tests should you use to diagnose Addison's?

  NOT LDDS or urine coritsol:creatine
• True or false, can you differentiate between typical/atypical/secondary Addison's with ACTH alone?

  False
• Plan for differentiating primary/ atypical/secondary Addison's disease

  -Need glucocorticoid regardless of diagnosis

  -Monitor electrolytes

  -Secondary should be identified from history, taper steroids to slowly regain adrenal function
• What is the treatment for typical Addison's disease during an Addisonian Crisis?

  
  

  a. Prednisone and fludrocortisone

  b. Dexamethasone

  c. Metronidazole

  d. Famotidine

  a. Prednisone and fludrocortisone