Lymphoscintigraphy of draught horses with chronic progressive lymphoedema

Reasons for performing study: Early diagnosis of chronic progressive lymphoedema (CPL) may result in more effective interventions and provide a basis for further investigation of whether early diagnosis could be used as a means of eliminating potential genetic influences by cessation of breeding from affected individuals. Hypothesis: Lymphoscintigraphy may be useful in draught horses to differentiate early lesions of CPL from other conditions in the pastern region. Methods: Forelimbs of 2 normal and 5 CPL-affected draught horses were evaluated with lymphoscintigraphy. Results: Lymphoscintigraphy showed clearly the presence of interstitial fluid stasis and delayed lymphatic drainage in the affected extremities of diseased animals in contrast to normal animals of these breeds. The rate of decreased clearance of a particulate radiopharmaceutical from the tissues was related positively to the severity of clinical signs. Conclusions and potential relevance: Our findings support the hypothesis that lymph stasis is probably responsible for the progressive swelling and concurrent skin lesions observed in association with CPL in draught horses. Lymphoscintigraphy should also prove useful in diagnosis of CPL in draught horses, even in the mild stages of the disease; such early diagnosis may result in more effective intervention.