Addisonian Crisis in a Young Standard Poodle

This presentation is classic for an acute Addisonian crisis. The low Na:K ratio, hyperkalemia, hyponatremia, hypoglycemia, bradycardia, and hypothermia paint a clear picture. This dog is in hypovolemic shock complicated by severe electrolyte derangements.

My immediate focus is on life-threatening issues, primarily the hyperkalemia and shock.

Acute Crisis Management:

Immediate IV Access & Fluids:

* Place a large bore IV catheter.
* Start 0.9% NaCl. This is critical for hyperkalemia (dilutes K+ and promotes renal excretion), hyponatremia (corrects sodium deficit), and hypovolemic shock resuscitation.
* Administer a 20 ml/kg bolus of 0.9% NaCl over 10-15 minutes. Reassess cardiovascular parameters (HR, pulse quality, CRT, mentation, blood pressure) and electrolytes. Repeat boluses (10-20 ml/kg) as needed until perfusion improves. Expect to give significant volumes.

Hyperkalemia Management (ECG changes & bradycardia are indications):

* Cardioprotection: Calcium gluconate 10% solution, 0.5-1 ml/kg IV slowly over 10-15 minutes, while monitoring ECG for improvement in bradycardia and QRS duration. Stop if HR increases significantly or rhythm disturbances occur. This does not lower K+, it stabilizes the myocardium.
* K+ Shift Intracellularly:
* Dextrose 50% solution, 0.5-1 ml/kg IV bolus, then start a Dextrose CRI (2.5-5% final concentration) if hypoglycemia persists or for further K+ shifting. Consider adding regular insulin (0.1-0.2 U/kg IV) if hyperkalemia is severe and refractory, but monitor glucose closely.
* Sodium Bicarbonate (8.4% solution), 1-2 mEq/kg IV slowly over 15-20 minutes, if severe metabolic acidosis is present (though 0.9% NaCl will help correct acidosis from hypovolemia).

Hypoglycemia Management:

* Dextrose 50% solution, 0.5 ml/kg IV bolus.
* Continue with a Dextrose CRI (2.5-5% final concentration) to maintain normoglycemia.

Presumptive Addison's Treatment:

* Dexamethasone Sodium Phosphate (Dexamethasone SP) 0.15 mg/kg IV. This provides necessary glucocorticoid supplementation and does not interfere with a subsequent ACTH stimulation test, which is important for definitive diagnosis.
* Do NOT give prednisolone or hydrocortisone prior to ACTH stim.

Hypothermia:

* Active external warming measures (forced air warming, warm IV fluids).

Monitoring:

* Continuous ECG for changes in heart rate and rhythm.
* Serial electrolytes (Na, K, glucose) every 1-2 hours until stable.
* Blood pressure (indirect or direct) and urine output (via catheter).
* Lactate to assess perfusion.

Long-Term Plan (Once Stable):

Definitive Diagnosis: Perform an ACTH stimulation test once the patient is stable and on dexamethasone (which won't interfere).

Maintenance Therapy:

* Mineralocorticoid replacement: Percorten-V (DOCP) IM every 25 days or oral fludrocortisone acetate daily.
* Glucocorticoid replacement: Prednisone at a physiologic dose (0.1-0.2 mg/kg/day orally), adjusting based on stress and clinical signs.

This dog needs aggressive, immediate resuscitation targeting the hyperkalemia and shock. Stabilize the patient first, then confirm the Addison's diagnosis.

This is an addisonian crisis. Na:K of 17, bradycardia, weak pulses, hypothermia, and hypoglycemia are textbook. Get aggressive now.

Acute Crisis Management:

* IV Fluids: Immediately start rapid IV crystalloids (LRS is fine). Give 60-90 mL/kg over the first 15-30 minutes, then reassess. Combat shock, improve perfusion, and start diluting that potassium.
* Hyperkalemia Management:
* Calcium Gluconate: 0.5-1.0 mL/kg of 10% calcium gluconate IV slowly over 10-15 minutes, while monitoring ECG. This protects the heart from the K+ effects; it won't lower K+ itself.
* Dextrose: Give 1-2 mL/kg of 50% dextrose IV slowly, or add 2.5-5% dextrose to your maintenance fluids. This addresses hypoglycemia and drives K+ intracellularly. If hyperkalemia persists, 0.1-0.2 U/kg regular insulin IV with concurrent dextrose (2 grams dextrose per unit insulin) can be used, but usually the fluid bolus and dextrose are enough initially.
* Glucocorticoid: Administer Dexamethasone sodium phosphate (DexSP) at 0.1-0.2 mg/kg IV. Do NOT use prednisone or prednisolone, as they will interfere with an ACTH stimulation test later.

Diagnosis:

* Once the dog is stable and out of immediate danger, perform an ACTH stimulation test. Draw a pre-sample, administer synthetic ACTH (e.g., cosyntropin 5 mcg/kg IV, maximum 250 mcg total), and draw a post-sample 60 minutes later. This is the only definitive way to diagnose Addison's. I'd draw the pre-sample after the DexSP, as DexSP will not interfere with the cortisol assay.

Long-Term Management:

* If the ACTH stim confirms Addison's:
* Mineralocorticoid Replacement: I prefer DOCP (desoxycorticosterone pivalate, Percorten-V or Zycortal). Administer 2.2 mg/kg SC or IM every 25-30 days. It's more expensive upfront but superior for compliance and stable electrolyte control compared to daily pills. Owners usually find it worth it.
* Glucocorticoid Replacement: Start Prednisone at a physiologic dose, typically 0.1-0.2 mg/kg PO SID. Adjust to the lowest effective dose, sometimes every other day. This is crucial for managing stress. Owners should have extra prednisone on hand to double the dose during stressful events (travel, boarding, illness).
* Monitoring: Recheck electrolytes (Na, K) and renal values (BUN, Creatinine) 10-14 days after the first DOCP injection, then prior to subsequent injections. Once stable, monitor every 3-6 months.
* Client Education: Emphasize that this is a lifelong condition requiring consistent medication and careful monitoring. Teach them to recognize signs of recurrence and the importance of increasing prednisone during stress.

This presentation is classic for an acute Addisonian crisis in a young Standard Poodle. The severe bradycardia, hypothermia, hyponatremia, profound hyperkalemia with a low Na:K ratio (17), and hypoglycemia are all hallmarks. The ECG changes (tall T waves) directly reflect the severe hyperkalemia impacting cardiac conduction. The owner's history of "off" for months with intermittent vomiting, appetite changes, and trembling is also typical for chronic hypoadrenocorticism before the crisis stage.

My primary focus as a Fear Free DVM is typically on preventing these crises by recognizing subtle behavioral cues, but in this case, we're already there. Our immediate goal is stabilization while minimizing additional stress.

Acute Crisis Management:

Establish IV Access & Fluids: Immediately place an IV catheter. Given the severe hyponatremia and hyperkalemia, 0.9% Sodium Chloride (NaCl) is the fluid of choice. Administer a shock bolus (e.g., 20-30 mL/kg over 15-20 minutes, then reassess and repeat as needed) to address hypovolemic shock, restore perfusion, and start diluting hyperkalemia and hyponatremia. Avoid LRS as it contains potassium.

Glucocorticoids: Administer Dexamethasone Sodium Phosphate (0.1-0.2 mg/kg IV) immediately. This provides rapid glucocorticoid replacement without mineralocorticoid activity, so it won't interfere with the ACTH stimulation test. Do NOT use prednisone or prednisolone until after the ACTH stim test has been completed, as they will interfere with cortisol measurements.

Hyperkalemia Management (if severe ECG changes persist after initial fluids):

* Calcium Gluconate (10% solution, 0.5-1.5 mL/kg slow IV over 10-20 minutes, with continuous ECG monitoring): This is a cardioprotective measure, immediately stabilizing myocardial cell membranes against the effects of hyperkalemia. It does not lower potassium itself.
* Dextrose (50% solution, 0.5-1 g/kg IV bolus) +/- Regular Insulin (0.2-0.5 U/kg IV): Dextrose alone can drive potassium into cells, and if hypoglycemia is present (as it is here at 52 mg/dL), it's essential. If hyperkalemia is severe and persistent after fluids, regular insulin given with dextrose will actively shift potassium intracellularly. Monitor glucose closely.

Hypoglycemia: Address immediately with a Dextrose 50% bolus (0.5-1 mL/kg slow IV push), then add dextrose to IV fluids as a CRI if needed.

Diagnostics: Once initial stabilization is underway, perform an ACTH Stimulation Test. Collect a pre-ACTH cortisol sample, administer 5 mcg/kg (max 250 mcg total) of synthetic ACTH (cosyntropin) IV, and collect a post-ACTH cortisol sample 1 hour later. This is the gold standard for diagnosis.

Long-Term Management:

Mineralocorticoid Replacement:

* Desoxycorticosterone Pivalate (DOCP, e.g., Percorten-V): My preferred method for owner compliance due to its monthly injection schedule. Initial dose is typically 2.2 mg/kg SC every 25-30 days. Electrolytes (Na, K) should be rechecked 10-14 days post-initial injection, and then again just before the next scheduled injection to ensure proper dosing and interval.
* Fludrocortisone Acetate (Florinef): Oral alternative, typically dosed at 0.01 mg/kg PO once daily. Requires daily administration and dose adjustments based on electrolytes.

Glucocorticoid Replacement: Administer Prednisone (0.1-0.2 mg/kg PO once daily). Once stable, I aim for the lowest effective dose, often every other day, as physiologic replacement. This dose may need to be increased temporarily during stressful events (e.g., surgery, travel, boarding).

Monitoring: Monitor electrolytes and clinical signs closely. Initially, every few weeks, then monthly until stable, then every 3-6 months.

Fear Free & Behavioral Wellness Integration:

This is where my 16 years of experience, including 10 years "pre-Fear Free," really comes into play. The owner reported "occasional trembling" for months. This could have been a sign of generalized anxiety, a physiological response to feeling unwell, or both. Addisonian dogs often present with lethargy, weakness, and gastrointestinal upset, but can also show signs of generalized anxiety, especially if their symptoms are ignored or they are forced into stressful situations.

* Pre-Visit Pharmaceuticals (PVPs): For all future visits (monthly injections, blood draws, regular exams), I would routinely prescribe PVPs. My protocol would be Trazodone (5-7 mg/kg PO) + Gabapentin (10-20 mg/kg PO) 2-3 hours prior to the appointment. This will dramatically reduce stress and improve the dog's ability to cope with necessary veterinary care, turning potentially traumatic monthly injections into positive experiences.
* Cooperative Care: Teach the owner to train the dog to voluntarily offer a limb for injection or blood draw. Use high-value treats and positive reinforcement. This empowers the dog with choice and control, which significantly reduces fear and anxiety.
* Low-Stress Environment: Ensure injections are given in a calm, quiet room. Use pheromone diffusers (Adaptil), non-slip mats, and allow the dog to stay on the floor or a comfortable mat.
* Client Education: Emphasize that managing the dog's overall stress response is critical, not just for quality of life, but also for preventing recurrence of crisis signs (as stress can exacerbate the need for glucocorticoids). Educate the owner on recognizing subtle signs of stress or impending crisis.

By managing both the medical disease and the patient's emotional well-being, we set this Standard Poodle up for a long, happy, and stress-free life.