A 5 month old female Border collie presented with short-lived episodes (less than a couple of minutes) of profound hindlimb weakness, mildly exercise-induced and was perfectly normal in-between. The thoracic limbs were unaffected. The dog was a rescue and started showing 4 to 5 episodes within the first week of being adopted. Now she is having weekly episodes. Haematology and serum biochemistry (including CK) were normal.

 

The video on the left shows you this dog during one of these episodes which occurred with minimum activity. Return to normality was observed after 2 minutes. The selective involvement of the hind limbs would rule-out metabolic as well as generalised neuromuscular causes. Similarly, spinal cord disorders should not cause short-lived episodes of profound weakness.

 

The intermittent nature and selective involvement of the hind limbs should raise the suspicion of vascular disorder. Aortic thrombus would be a differential although the very young age would not be suggestive of that. Another possibility would be reverse patent ductus arteriosus (PDA) which is what this dog was diagnosed with contrast echography (assessed via the injection of agitated saline for a bubble study).

Courtesy of Dr. Karina Graham at Veterinary Specialists of Sydney.

You can read more about reverse PDA, presentation, diagnosis and management in a recently published study - click on the link below.

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