Weakness in horses refers to a reduction in strength or power that can affect a horse's ability to perform normal activities. This condition can arise from various causes, including muscular, neurological, metabolic, or systemic issues. Common signs of weakness in horses may include difficulty in standing, a lack of coordination, or an inability to maintain usual activity levels. This page includes a collection of peer-reviewed research studies and scholarly articles that explore the causes, diagnostic approaches, and management strategies for weakness in equine patients.
Kutara K, Kadekaru S, Hisaeda K, Sugimoto K, Ono T, Inoue Y, Nakamura S, Yoshitake R, Ohzawa E, Goto A, Iwata E, Shibano K, Une Y, Kitagawa H.The necropsy of a 2-day-old Noma horse that died of weakness showed an enlarged cardiac base and a narrow cardiac apex, suggesting cardiac malformation. The excised heart underwent imaging to investigate its luminal structure. On three-dimensional magnetic resonance imaging, the right atrium and right ventricle were discontinuous. The right atrium communicated with the left atrium and the left ventricle communicated with the right ventricle. The lumen narrowed near the pulmonary artery valve. Since the same findings were observed on gross examination, the foal was diagnosed with tricuspid atre...
Zhang Z, Guo K, Chu X, Liu M, Du C, Hu Z, Wang X.Equine infectious anemia (EIA) is a contagious disease of horses caused by the equine infectious anemia virus (EIAV). The clinical signs at the acute phase include intermittent high fever, thrombocytopenia, hemorrhage, edema, and anemia. The clinical signs at chronic and relapsing subclinical levels include emaciation and progressive weakness. Surviving horses become lifelong carriers because of the integration of the viral genome into that of the host, and these horses can produce and transmit the virus to other animals. This increases the difficulty of imposing practical control measures to ...
van Spijk JN, Beckmann K, Wehrli Eser M, Stirn M, Steuer AE, Saleh L, Schoster A.Neuro- and nephrotoxicity of polymyxins are known but clinical studies in horses are lacking. The aim of this study was to describe neurogenic and nephrogenic side effects of hospitalized horses receiving Polymyxin B (PolyB) as part of their treatment plan. Twenty horses diagnosed with surgical colic ( = 11), peritonitis ( = 5), typhlocolitis ( = 2), pneumonia, and pyometra (each = 1) were included. Antimicrobial treatment was randomized to GENTA (gentamicin 10 mg/kg bwt q24 h IV, penicillin 30.000 IU/kg q6 h IV) or NO GENTA (marbofloxacin 2 mg/kg bwt q24 h IV, penicillin 30.000 IU/kg q6 h IV...
Steinfeld Y, Akian R, Rovitsky A, Puchkov N, Keren Y.In recent years, treatment for Achilles tendon rupture (ATR) went through radical changes: from the conservative non-weight bearing approach to a functional protocol. This functional protocol allows complete weight bearing after only 2 weeks by placing the foot in a plastic boot in tapered down equines and using interchangeable wedges under the heel. This change of approach has dramatically lowered the rate of re-rupture. Objective: To describe our preliminary results with this functional protocol and to assess outcome measures in the functional conservative treatment. Methods: The study compr...
Husulak ML, Lohmann KL, Gabadage K, Wojnarowicz C, Marqués FJ.Two horses from Saskatchewan were presented with signs of sweating, muscle fasciculations, weight loss, and generalized weakness. The horses were diagnosed with equine motor neuron disease (EMND), by histological assessment of a spinal accessory nerve or sacrocaudalis dorsalis medialis muscle biopsy. This is the first report of EMND in western Canada. Maladie équine des motoneurones chez 2 chevaux de la Saskatchewan. Deux chevaux de la Saskatchewan ont été présentés avec des signes de sudation, de fibrillations musculaires, de perte de poids et de faiblesse généralisée. On a diagnostiq...
Adaszek Ł, Winiarczyk S, Łukaszewska J.The study was aimed at determining the cause of a disease in a horse exhibiting symptoms of fever, joint effusion, weakness, and extravasations on the mucous membranes. Blood was drawn from the animal for haematological and biochemical molecular tests. The PCR technique revealed the presence of 16S RNA Ehrlichia spp. genetic material in the blood samples. DNA amplification by means of primers EHR 521 and EHR 747 gave a product with a volume of 247 bp.The sequence of the PCR product obtained showed a 97.6% similarity with a sequence of a fragment of 16S RNA Ehrlichia phagocytophila, gene number...
Salazar P, Traub-Dargatz JL, Morley PS, Wilmot DD, Steffen DJ, Cunningham WE, Salman MD.To determine outcome of equids in the western United States with clinical signs of West Nile virus (WNV) infection and identify factors associated with risk of death in infected equids. Methods: Cross-sectional study. Methods: 484 equids in Nebraska and Colorado. Methods: Owners of 484 equids with laboratory-confirmed West Nile virus infection in Nebraska and Colorado were contacted by telephone, and a questionnaire was used to obtain information on signalment, management, clinical signs, date of disease onset, duration of disease, WNV vaccination status, and health status at the time of the i...
Khan SA, Kuster DA, Hansen SR.Moxidectin is a macrolide endectocide available as a 2% equine oral gel in the US. This report presents clinical signs of moxidectin toxicosis and its treatment in equines as reported to the ASPCA Animal Poison Control Center (APCC) from January 1998 to December 2000. Nine cases of moxidectin overdose in equines occurred: 5 had signs of toxicosis such as coma, dyspnea, depression, ataxia, tremors, seizures, or weakness. The approximate dose of moxidectin at which these signs were observed ranged from 1.0 to 5.1 mg/kg. The 4 equines that ingested moxidectin between 0.9 mg/kg to 1.7 mg/kg did no...
Geelen SN, Sloet van Oldruitenborgh-Oosterbaan MM.A splenic hemangiosarcoma with multiple organ metastases in a pony is reported. Clinical signs included weakness and pallor. Abdominal paracentesis revealed haemorrhagic fluid. Laboratory data included anaemia, thrombocytopenia and hypoproteinaemia. Necropsy findings included a haemangiosarcoma in the spleen with metastases in the lung, liver, kidney and omentum.
Nelson KM, Darien BJ, Konkle DM, Hartmann FA.A 24-hour-old Hackney ony filly developed signs of weakness, depression and a poor suck reflex, with harsh lung sounds over both fields, and a 48-hour-old Arabian colt from a normal birth which had sucked vigorously developed loose stools and became depressed, weak and anorectic. Both foals had serum IgG concentrations greater than 800 mg/dl, but each had a severe neutropenia with a left shift, and blood cultures from both of them yielded Actinobacillus suis. The A suis isolates had different antimicrobial susceptibility patterns and, in the case of the Arabian, the isolate was resistant to co...
Zeilmann M.A literature review of the clinical syndrome HYPP (Hyperkalemic periodic paralysis) affecting Quarter Horses is given. HYPP is characterized by sporadic attacks of muscle tremors, weakness and/or collapse, lasting for variable periods of time. Diagnosis is based on physical findings in association with hyperkalemia. In horses with HYPP, the regulation of ion transport through the sodium channels in the muscle cells occasionally fails, causing uncontrollable muscle twitching. Further investigations into molecular genetics reveals a mutation in the gene responsible for sodium and potassium regul...
Mair TS, Yeo SP, Lucke VM.Two horses with deposits of lymphosarcoma, one in the spleen, the other in the mediastinum, several lymph nodes and kidneys, lost weight rapidly and became depressed and weak. They were hypercalcaemic and post mortem examination revealed extensive calcification of the heart and major vessels. There was no evidence of bone marrow metastases in the one horse whose marrow was examined, and the thyroid and parathyroid glands of both horses were grossly normal.
Salazar P, Traub-Dargatz JL, Morley PS, Wilmot DD, Steffen DJ, Cunningham WE, Salman MD.To determine outcome of equids in the western United States with clinical signs of West Nile virus (WNV) infection and identify factors associated with risk of death in infected equids. Methods: Cross-sectional study. Methods: 484 equids in Nebraska and Colorado. Methods: Owners of 484 equids with laboratory-confirmed West Nile virus infection in Nebraska and Colorado were contacted by telephone, and a questionnaire was used to obtain information on signalment, management, clinical signs, date of disease onset, duration of disease, WNV vaccination status, and health status at the time of the i...
Mair TS, Yeo SP, Lucke VM.Two horses with deposits of lymphosarcoma, one in the spleen, the other in the mediastinum, several lymph nodes and kidneys, lost weight rapidly and became depressed and weak. They were hypercalcaemic and post mortem examination revealed extensive calcification of the heart and major vessels. There was no evidence of bone marrow metastases in the one horse whose marrow was examined, and the thyroid and parathyroid glands of both horses were grossly normal.
Khan SA, Kuster DA, Hansen SR.Moxidectin is a macrolide endectocide available as a 2% equine oral gel in the US. This report presents clinical signs of moxidectin toxicosis and its treatment in equines as reported to the ASPCA Animal Poison Control Center (APCC) from January 1998 to December 2000. Nine cases of moxidectin overdose in equines occurred: 5 had signs of toxicosis such as coma, dyspnea, depression, ataxia, tremors, seizures, or weakness. The approximate dose of moxidectin at which these signs were observed ranged from 1.0 to 5.1 mg/kg. The 4 equines that ingested moxidectin between 0.9 mg/kg to 1.7 mg/kg did no...
Adaszek Ł, Winiarczyk S, Łukaszewska J.The study was aimed at determining the cause of a disease in a horse exhibiting symptoms of fever, joint effusion, weakness, and extravasations on the mucous membranes. Blood was drawn from the animal for haematological and biochemical molecular tests. The PCR technique revealed the presence of 16S RNA Ehrlichia spp. genetic material in the blood samples. DNA amplification by means of primers EHR 521 and EHR 747 gave a product with a volume of 247 bp.The sequence of the PCR product obtained showed a 97.6% similarity with a sequence of a fragment of 16S RNA Ehrlichia phagocytophila, gene number...
Nelson KM, Darien BJ, Konkle DM, Hartmann FA.A 24-hour-old Hackney ony filly developed signs of weakness, depression and a poor suck reflex, with harsh lung sounds over both fields, and a 48-hour-old Arabian colt from a normal birth which had sucked vigorously developed loose stools and became depressed, weak and anorectic. Both foals had serum IgG concentrations greater than 800 mg/dl, but each had a severe neutropenia with a left shift, and blood cultures from both of them yielded Actinobacillus suis. The A suis isolates had different antimicrobial susceptibility patterns and, in the case of the Arabian, the isolate was resistant to co...
van Spijk JN, Beckmann K, Wehrli Eser M, Stirn M, Steuer AE, Saleh L, Schoster A.Neuro- and nephrotoxicity of polymyxins are known but clinical studies in horses are lacking. The aim of this study was to describe neurogenic and nephrogenic side effects of hospitalized horses receiving Polymyxin B (PolyB) as part of their treatment plan. Twenty horses diagnosed with surgical colic ( = 11), peritonitis ( = 5), typhlocolitis ( = 2), pneumonia, and pyometra (each = 1) were included. Antimicrobial treatment was randomized to GENTA (gentamicin 10 mg/kg bwt q24 h IV, penicillin 30.000 IU/kg q6 h IV) or NO GENTA (marbofloxacin 2 mg/kg bwt q24 h IV, penicillin 30.000 IU/kg q6 h IV...
Geelen SN, Sloet van Oldruitenborgh-Oosterbaan MM.A splenic hemangiosarcoma with multiple organ metastases in a pony is reported. Clinical signs included weakness and pallor. Abdominal paracentesis revealed haemorrhagic fluid. Laboratory data included anaemia, thrombocytopenia and hypoproteinaemia. Necropsy findings included a haemangiosarcoma in the spleen with metastases in the lung, liver, kidney and omentum.
Husulak ML, Lohmann KL, Gabadage K, Wojnarowicz C, Marqués FJ.Two horses from Saskatchewan were presented with signs of sweating, muscle fasciculations, weight loss, and generalized weakness. The horses were diagnosed with equine motor neuron disease (EMND), by histological assessment of a spinal accessory nerve or sacrocaudalis dorsalis medialis muscle biopsy. This is the first report of EMND in western Canada. Maladie équine des motoneurones chez 2 chevaux de la Saskatchewan. Deux chevaux de la Saskatchewan ont été présentés avec des signes de sudation, de fibrillations musculaires, de perte de poids et de faiblesse généralisée. On a diagnostiq...
Zeilmann M.A literature review of the clinical syndrome HYPP (Hyperkalemic periodic paralysis) affecting Quarter Horses is given. HYPP is characterized by sporadic attacks of muscle tremors, weakness and/or collapse, lasting for variable periods of time. Diagnosis is based on physical findings in association with hyperkalemia. In horses with HYPP, the regulation of ion transport through the sodium channels in the muscle cells occasionally fails, causing uncontrollable muscle twitching. Further investigations into molecular genetics reveals a mutation in the gene responsible for sodium and potassium regul...
Steinfeld Y, Akian R, Rovitsky A, Puchkov N, Keren Y.In recent years, treatment for Achilles tendon rupture (ATR) went through radical changes: from the conservative non-weight bearing approach to a functional protocol. This functional protocol allows complete weight bearing after only 2 weeks by placing the foot in a plastic boot in tapered down equines and using interchangeable wedges under the heel. This change of approach has dramatically lowered the rate of re-rupture. Objective: To describe our preliminary results with this functional protocol and to assess outcome measures in the functional conservative treatment. Methods: The study compr...
Zhang Z, Guo K, Chu X, Liu M, Du C, Hu Z, Wang X.Equine infectious anemia (EIA) is a contagious disease of horses caused by the equine infectious anemia virus (EIAV). The clinical signs at the acute phase include intermittent high fever, thrombocytopenia, hemorrhage, edema, and anemia. The clinical signs at chronic and relapsing subclinical levels include emaciation and progressive weakness. Surviving horses become lifelong carriers because of the integration of the viral genome into that of the host, and these horses can produce and transmit the virus to other animals. This increases the difficulty of imposing practical control measures to ...
Kutara K, Kadekaru S, Hisaeda K, Sugimoto K, Ono T, Inoue Y, Nakamura S, Yoshitake R, Ohzawa E, Goto A, Iwata E, Shibano K, Une Y, Kitagawa H.The necropsy of a 2-day-old Noma horse that died of weakness showed an enlarged cardiac base and a narrow cardiac apex, suggesting cardiac malformation. The excised heart underwent imaging to investigate its luminal structure. On three-dimensional magnetic resonance imaging, the right atrium and right ventricle were discontinuous. The right atrium communicated with the left atrium and the left ventricle communicated with the right ventricle. The lumen narrowed near the pulmonary artery valve. Since the same findings were observed on gross examination, the foal was diagnosed with tricuspid atre...
