Polymyositis in Het Nederlandse Kooikerhondje

Yvet Opmeer
BVM (PhD student)
Dr. Paul J.J. Mandigers
Clinical Associate Professor in Neurology
Evidensia Dierenziekenhuizen Arnhem
Meander 10, 6825 MB Arnhem, The Netherlands


Polymyositis in the Kooikerhondje appears to present in two forms that can either present themselves separately or combined.

The first type is marked by abnormal locomotion and locomotion problems due to general weakness, muscle weakness or stiffness. Most dogs presented with a stiff gait although the exact presentation varies based on which muscle groups are affected. The second type is marked by drinking, eating and swallowing problems. Both types may be present in the same dog. Other clinical signs are lethargy, weight loss, dyspnoea, general weakness, and/or exercise intolerance. Most of the symptoms present between one year and two years of age and there is no apparent predilection for age. Male dogs might be more likely to suffer from the disease than female dogs however.

Diagnosis is made based on the clinical symptoms, blood examination (elevated CPK), an electromyogram and histopathology. The latter is of the utmost importance.

As this disease is most likely immune mediated the basis of the treatment consists of corticosteroids in combination with oral supplements. The response to this treatment varies.

Currently we are investigating this disease (Paul Mandigers: p.j.j.mandigers@veterinair-neuroloog.nl). As it is most likely hereditary we seek DNA samples of affected Kooikerhondjes. As written above the disease has to be confirmed with histopathology.

How can we help each other?
  1. If you have a Kooikerdog under treatment with clinical signs that may fit a polymyositis please notify us. We would like to receive a copy of the patient record including blood test results and of the pedigree.
  2. If the CK (or CPK) level is clearly elevated it is most likely a polymyositis case. The next step is to make an EMG (electromyogram) and/or sample muscle tissue. We are happy to get them examined for you. Ideally, we would like to receive a small sample (1 cm by 1 cm by 0.5 cm) of the triceps muscle and of the femoral biceps. Please put the two samples in a 4 to 10% buffered formalin container. You can send it to: Dr. P. Mandigers, EDZ Arnhem, Meander 10, 6825 MB Arnhem (+31 26 3333730).
  3. If the CK level is not clearly elevated please consider testing for myasthenia gravis as this is a disorder that occurs in this breed as well.
  4. In all cases: if possible, make a video of the moving dog or when the dog is eating/swallowing. Videos can be sent in any format using www.wetransfer.com to p.j.j.mandigers@veterinair-neuroloog.nl
  5. In all cases we would like to get a DNA sample. We need 4 ml of EDTA blood. Please send it together with a copy of the pedigree to: Dr. P. Mandigers, EDZ Arnhem, Meander 10, 6825 MB Arnhem (+31 26 3333730).
    Based on the diagnosis we can advise you or your veterinarian on the treatment of your dog.

Best wishes

Yvet Opmeer and Paul Mandigers