Lesson 12: Adrenals (mineralocorticoid) lab evaluation

What are the 4 causes of Primary Addison’s?

Neoplasia

Medications

Auto-immune disease

Surgical removal

Primary Addisons causes a deficiency in what two things?

Cortisol and Mineralcorticoids

What happens to electrolytes in primary addisons?

Electrolytes are excreted through the urine causing hyponatremia and hyperkalemia/metabolic acidosis

What are the two causes of secondary addisons?

Pituitary lesions

Trauma or chronic suppression

Secondary addison’s causes a deficiency in what hormone?

Cortisol

What are the CBC findings in Addison’s?

• Lack of Stress leukogram

• Mild non-regenerative anemia

• Lymphocytosis or eosinophilia

What are the Chemistry findings in Addison’s?

• Hyperkalemia

• Hyponatremia

• Hypochloremia

What Na:K ratio is virtually diagnostic for addison’s?

<15:1

What Na:K ratio makes one suspicious of addison’s?

<23:1

What causes pseudo-addisons?

Trichuris vulpis (whipworms)

What are artifacts that can cause an elevated K?

Thrombocytosis or hemolysis

If hypoadrenocorticism leads to decreased cortisol production, how would this be reflected in basal cortisol levels?

Decreased levels

Can you use basal cortisol to screen for addisons or cushings?

Addisons because if cortisol is low it is most likely Addisons

Cushings is not reliable due to pulsatile secretion, it can be high/normal or even overlap with stressed but otherwise healthy dogs.

What is the test of choice for addison’s?

ACTH stim

How does an ACTH stim test diagnose addison’s?

If post cortisol levels fails to double or increase above 2, its diagnostic for addison’s.