Acute myopathy in horses at grass in east and south east Scotland.

The research article discusses a study about an instance of muscle disease (myopathy) that occurred in horses in east and south east Scotland between autumn 1984 and spring 1985. This myopathy showed similar clinical signs to paralytic myoglobinuria, but had some distinct differences which are explored in the paper.

Study background

• The research was prompted by an observed outbreak of a previously unrecognized muscle disease (myopathy) in horses pastured in east and south east Scotland in the period between autumn 1984 and spring 1985.
• The clinical presentations observed in the affected horses were similar to the ones seen in cases of paralytic myoglobinuria, a condition characterized by muscle weakness and the release of a protein called myoglobin into the urine.

Clinical and hematological findings

• The main symptoms of this myopathy were greatly increased levels of creatine kinase (an enzyme that indicates muscle damage when found in high levels in the blood) and dark brown urine which suggests muscle breakdown.
• However, unlike paralytic myoglobinuria which is often observed in heavily-worked horses, these horses were not in training.
• Another difference was that the most affected muscles were not the ones related to movement (as expected in cases of paralytic myoglobinuria) but rather the muscles of posture and respiration.

Nutritional aspects

• The study found that the observed myopathy might not be related to nutritional myopathy, an illness that occurs due to vitamin E and selenium deficiencies, as the horses had sufficient levels of alpha-tocopherol (a form of vitamin E).
• However, their selenium levels varied from normal to deficient, indicating the need for further exploration in this aspect.

Clinical and pathological presentations

• The researchers present the clinical and pathological findings from 12 observed cases.
• They discuss the differential diagnoses and potential causes of the observed myopathy.