Use of electromyography for the diagnosis of equine hyperkalemic periodic paresis.
Abstract: The use of electromyography (EMG) as a diagnostic aid for equine hyperkalemic periodic paresis (EHPP) was investigated in seven affected and seven control horses. Affected horses were confirmed positive for EHPP either by elevated serum potassium concentration with clinical signs of myotonia, or by inducing hyperkalemia and clinical signs using oral potassium chloride challenge. All horses were asymptomatic at the time EMG was performed, using bipolar fine wire needle electrodes. The myopotentials were recorded on magnetic tape and displayed on paper charts for analysis. Insertional and resting activity were recorded from the right supraspinatus, triceps, extensor carpi radialis and gluteal muscles in standing horses. Myotonic discharges were seen in six of seven affected horses but not in any of the controls. All seven affected horses and two control horses had prolonged insertional activity. Five out of seven affected horses and one control horse displayed spontaneous motor unit discharges unrelated to recording electrode movement. Myoelectrical potentials containing closely timed muscle potentials, i.e. doublets, were found in all affected horses, with four of seven affected horses also showing triplets. These potentials were not observed in any of the controls. No obvious difference in activity was observed among the four muscle sites tested. It is concluded that EMG is a safe and useful tool for diagnosing EHPP in horses not currently displaying clinical signs. Myotonic discharges and doublets appear to be the most diagnostically significant electromyographic abnormalities in EHPP affected horses.
Publication Date: 1990-10-01 PubMed ID: 2249182PubMed Central: PMC1255699
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research paper focuses on the application of electromyography (EMG) to identify equine hyperkalemic periodic paresis (EHPP) in horses, an affliction that could remain undetected due to the absence of clinical symptoms, but identifiable via EMG tools.
Methodology
- The study was conducted on a sample of 14 horses, seven of whom were confirmed to be affected by EHPP, either through elevated serum potassium concentration accompanied by symptoms of myotonia, or by eliciting hyperkalemia and clinical signs using an oral potassium chloride challenge.
- All horses were asymptomatic at the time of the EMG procedure, which used bipolar fine wire needle electrodes.
- The myopotentials, electric potentials resulting from muscle activity, were documented on magnetic tape and represented on paper charts to facilitate analysis.
- Different types of muscle activity – insertional (occurring when the needle electrode is inserted into a muscle) and resting – were registered from multiple muscle sites, namely the supraspinatus, triceps, extensor carpi radialis, and gluteal muscles, while the horses were standing.
Findings
- It was found that myotonic discharges – a specific pattern of electrical discharge – were visible in six out of seven EHPP-affected horses but not in any of the control horses.
- All the affected horses exhibited prolonged insertional activity, a characteristic also seen in two of the control horses.
- Half of the affected horses and one control horse exhibited spontaneous motor unit discharges, not related to any movement of the recording electrode.
- All affected horses displayed myoelectrical potentials containing closely timed muscle potentials, specifically, doublets and in some cases, triplets. These potentials were absent in the control group.
- There was no noticeable variance in the activity recorded from the four muscle sites tested.
Conclusion
- The researchers concluded that EMG is a safe and effective tool for diagnosing EHPP in horses, even without overt clinical signs.
- Myotonic discharges and doublets are the most significant EMG abnormalities in identifying EHPP in horses.
Cite This Article
APA
Robinson JA, Naylor JM, Crichlow EC.
(1990).
Use of electromyography for the diagnosis of equine hyperkalemic periodic paresis.
Can J Vet Res, 54(4), 495-500.
Publication
Researcher Affiliations
- Department of Veterinary Internal Medicine, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon.
MeSH Terms
- Animals
- Electromyography / veterinary
- Female
- Horse Diseases / diagnosis
- Horse Diseases / physiopathology
- Horses
- Hyperkalemia / complications
- Hyperkalemia / diagnosis
- Hyperkalemia / physiopathology
- Hyperkalemia / veterinary
- Male
- Paresis / complications
- Paresis / diagnosis
- Paresis / physiopathology
- Paresis / veterinary
References
This article includes 13 references
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Citations
This article has been cited 2 times.- Naylor JM. Equine hyperkalemic periodic paralysis: review and implications.. Can Vet J 1994 May;35(5):279-85.
- Naylor JM, Robinson JA, Crichlow EC, Steiss JE. Inheritance of myotonic discharges in American quarter horses and the relationship to hyperkalemic periodic paralysis.. Can J Vet Res 1992 Jan;56(1):62-6.
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