Canine Addison Disease Crisis Treatment

Agreed, this is a textbook Addisonian crisis until proven otherwise, and the hyperkalemia is the immediate life threat. That heart rate is deeply concerning. Let's get this dog stabilized.

My priority is treating the cardiotoxic effects of the hyperkalemia. Get a lead II ECG running immediately. You're looking for tall tented T-waves, a widened QRS complex, and loss of P-waves. Regardless of what you see, with a K+ of 7.2 and that bradycardia, we need to act.

Here is the immediate action plan:

Cardioprotection: Administer 10% calcium gluconate at 0.5-1.0 mL/kg IV slowly over 10-15 minutes. Watch the ECG as you give it; the heart rate should begin to normalize. This does not lower potassium, it just stabilizes the cardiac myocytes.

Fluid Resuscitation: Start aggressive fluid therapy with 0.9% NaCl. Avoid LRS or Plasmalyte for now due to their potassium content. Give a 20 mL/kg bolus over 15-20 minutes to address the hypovolemic shock, then reassess. This will also help dilute the serum potassium.

Shift Potassium: After the initial fluid bolus is running, give regular insulin at 0.25 U/kg IV once, followed immediately by 1-2 grams of dextrose per unit of insulin to prevent hypoglycemia. This will drive potassium intracellularly.

Steroids: Use dexamethasone SP at 0.1-0.2 mg/kg IV. I strongly prefer this over hydrocortisone for the initial stabilization because it will NOT interfere with a subsequent ACTH stimulation test, which we'll need for a definitive diagnosis.

Once we have the patient through this acute phase — heart rate is above 60, blood pressure is improving, and mentation is better — we can hand off to Elena in Internal Medicine. She'll manage the ACTH stimulation test and formulate the long-term plan for DOCP and prednisone. My job is to keep this patient alive for the next few hours; hers is to manage the chronic disease. Recheck electrolytes in 2-4 hours. Nice catch. Let's get to work.

Colleague, this is a classic presentation for an Addisonian crisis, and your presumptive diagnosis is spot on. The signalment and electrolyte derangements are pathognomonic. Marcus will cover the immediate stabilization, as that's squarely in the ECC wheelhouse. My focus will be on the diagnostic confirmation and the transition to long-term management once the patient is stable.

Diagnostic Plan:
Your choice of steroid during stabilization is critical for our ability to get a definitive diagnosis.

Use Dexamethasone SP: Administer dexamethasone (0.1-0.2 mg/kg IV) for initial glucocorticoid support. Dexamethasone does not cross-react with the cortisol assay, allowing you to perform an ACTH stimulation test once the patient is more stable. Avoid hydrocortisone or prednisone until after the stim test is complete.

ACTH Stimulation Test: This remains the gold standard for diagnosis. Once the patient is hemodynamically stable (usually within 12-24 hours), perform the test. You will expect to see low pre- and post-stimulation cortisol levels. A baseline cortisol from your initial blood draw can also be very helpful; a value >2 µg/dL makes Addison's extremely unlikely.

Transition to Chronic Management:
Once stabilized and diagnosed, your plan is correct.

Mineralocorticoid: Begin desoxycorticosterone pivalate (DOCP) at 2.2 mg/kg IM or SQ. The first dose can be given in hospital before discharge. The initial redosing interval is 25 days. We will adjust this interval based on sodium and potassium levels checked at day 14 and day 25.

Glucocorticoid: Start prednisone at a physiologic dose of 0.1-0.2 mg/kg/day. Owners should be educated on "stress dosing" (doubling or tripling the dose) during periods of illness, travel, or surgery. Many well-managed Addisonians can eventually be weaned to every-other-day prednisone.

This is a very manageable disease once you get through the crisis. Excellent initial catch.

Confidence: High