Clinical History
A six-year old male castrated Llewelyn Setter was examined by the CSU Emergency Service for an acute onset of myalgia and respiratory distress.  Intense hunting activity was previously performed without problems. That last hunting trip had been a few months prior to onset of clinical signs. Two days prior to presentation the dog had scavenged beef bones from the garbage.

Physical and Neurological Examination
The dog appeared anxious and painful with an elevated respiratory rate. Pain was elicited upon extension of the shoulders bilaterally and upon cervical manipulation. Gait evaluation showed that the dog was lethargic but could ambulate. All spinal reflexes were decreased.  A full bladder was noted. Over the course of the day, the weakness and myalgia progressed.  By day 2 of hospitalization the dog became non-ambulatory to the point where respiratory weakness was such that ventilatory assistance was required (Figure 1). A urinary catheter was placed as the dog did not urinate and could not be easily expressed. It was noted at that time that the urine was “coca-cola” colored consistent with myoglobinuria (Figure 2).

Figure 1	Figure 2

Diagnostic Tests on Day 1 of Hospitalization
CBC - Mild lymphopenia
Chemistry Profile –
Creatine kinase (CK) 116,419 U/L (reference 5-275)
Alanine transaminase (ALT) 658 U/L (reference 10-110)

Aspartate aminotransferase (AST) 561 U/L (reference 16-50)

Diagnostic Tests on Day 2 of Hospitalization
Creatine kinase (CK) 939,950 U/L
Cardiac troponin-I 12.0 ng/ml (reference <0.06)

Muscle biopsy performed under sedation and local anesthesia – Severe necrotizing myopathy of undetermined cause.  Since the dog did not have a past history of similar episodes and the onset was acute, most likely causes for rhabdomyolysis and myoglobinuria include a toxic exposure or an infectious disease.

Echocardiography – Moderate to severe dilatation of the left ventricle and atrium, marked systolic dysfunction of the left ventricle consistent with myocardial failure.

Clinical Course and Long-term Follow-up
For a complete description of supportive care administered during hospitalization and the clinical course, refer to Wells et al. J Am Vet Med Assoc 2009;234:1049-1054.  By day 3 the dog was weaned from mechanical ventilation and was ambulatory when assisted with sling support (Go to video clip). By day 7 the CK activity was only mildly elevated and the cardiac troponin-I was within the reference range with improved cardiac function. The dog responded well to supportive care and was discharged 13 days after admission with almost complete return of normal function and activity. In a follow-up 3 months later, the owner stated that his dog was “better than ever and had already been out hunting blue grouse 4 times” (Figure 3). The owner was happy to have his dog back.

Figure 3

Conclusion
Although a specific cause was not determined for the clinical presentation of severe rhabdomyolysis and myoglobinuria with myocardial and respiratory failure, the clinical course of this syndrome rapidly reversed with only intensive supportive care.  It is important that clinicians recognize this syndrome as the clinical severity in the early stages of the disease could have resulted in euthanasia. For a review of necrotizing myopathies and myoglobinuria in dogs, refer to Shelton GD. Rhabdomyolysis, myoglobinuria and necrotizing myopathies. Vet Clin North Am Small Anim Pract 2004;34:1469-1482.