Changes

Depending on the clinical signs, differential diagnoses may include cervical stenotic myelopathy, trauma, aberrant metazoan parasite migration, equine degenerative myeloencephalopathy, myeloencephalopathy caused by equine herpesvirus 1, equine motor neuron disease, neuritis of the cauda equina, arboviral (Eastern or Western equine, West Nile) encephalomyelitis, rabies, bacterial meningitis, and leukoencephalomalacia.  

Depending on the clinical signs, differential diagnoses may include cervical stenotic myelopathy, trauma, aberrant metazoan parasite migration, equine degenerative myeloencephalopathy, myeloencephalopathy caused by equine herpesvirus 1, equine motor neuron disease, neuritis of the cauda equina, arboviral (Eastern or Western equine, West Nile) encephalomyelitis, rabies, bacterial meningitis, and leukoencephalomalacia.  

====Clinical Signs====

====Clinical Signs====

Clinical Findings:  

Clinical Findings:  

Because the protozoa may infect any part of the CNS, almost any neurologic sign is possible. The disease usually begins insidiously but may present acutely and be severe at onset. Signs of spinal cord involvement are more common than signs of brain disease. Horses with EPM involving the spinal cord have asymmetric or symmetric weakness and ataxia of one to all limbs, sometimes with obvious muscle atrophy. When the caudal spinal cord is involved, there are signs of cauda equina syndrome. EPM lesions in the spinal cord also may result in demarcated areas of spontaneous sweating or loss of reflexes and cutaneous sensation. The most common signs of brain disease in horses with EPM are depression, head tilt, and facial paralysis. Any cranial nerve nucleus may be involved, and there may be seizures, visual deficits including abnormal menace response, or behavioral abnormalities. Without treatment, EPM often progresses to cause recumbency and death. Progression to recumbency occurs over hours to years and may occur steadily or in a stop-start fashion.  

Because the protozoa may infect any part of the CNS, almost any neurologic sign is possible. The disease usually begins insidiously but may present acutely and be severe at onset. Signs of spinal cord involvement are more common than signs of brain disease. Horses with EPM involving the spinal cord have asymmetric or symmetric weakness and ataxia of one to all limbs, sometimes with obvious muscle atrophy. When the caudal spinal cord is involved, there are signs of cauda equina syndrome. EPM lesions in the spinal cord also may result in demarcated areas of spontaneous sweating or loss of reflexes and cutaneous sensation. The most common signs of brain disease in horses with EPM are depression, head tilt, and facial paralysis. Any cranial nerve nucleus may be involved, Without treatment, EPM often progresses to cause recumbency and death. Progression to recumbency occurs over hours to years and may occur steadily or in a stop-start fashion.  

 

 

The neurologic signs that EPM causes are most commonly asymmetric incoordination (ataxia), weakness and spasticity, although they may mimic almost any neurologic disorder. Clinical signs among horses with EPM include a wide array of symptoms that may result from primary or secondary problems. Some of the signs cannot be distinguished from other problems, such as lameness, which can be attributed to many different causes. Airway abnormalities, such as laryngeal hemiplegia (paralyzed flaps), dorsal displacement of the soft palate (snoring), or airway noise of undetermined origin may result from protozoa infecting the nerves which innervate the throat. Apparent lameness, particularly atypical lameness or slight gait asymmetry of the rear limbs are commonly caused by EPM. Focal muscle atrophy, or even generalized muscle atrophy or loss of condition may result. Secondary signs also occur with neurologic disease. Upward fixation of the patella (locking up of the stifle joint) is among the most common findings among horses with neurologic disease. Another common side effect of EPM is back soreness, which can be severe. The actual method by which the Sarcocystis neurona infects a horse is still unknown, however it is thought to preferentially infect leukocytes (white blood cells) in order to cross the blood brain barrier.

The neurologic signs that EPM causes are most commonly asymmetric incoordination (ataxia), weakness and spasticity, although they may mimic almost any neurologic disorder. Clinical signs among horses with EPM include a wide array of symptoms that may result from primary or secondary problems. Some of the signs cannot be distinguished from other problems, such as lameness, which can be attributed to many different causes. Airway abnormalities, such as laryngeal hemiplegia (paralyzed flaps), dorsal displacement of the soft palate (snoring), or airway noise of undetermined origin may result from protozoa infecting the nerves which innervate the throat. Apparent lameness, particularly atypical lameness or slight gait asymmetry of the rear limbs are commonly caused by EPM. Focal muscle atrophy, or even generalized muscle atrophy or loss of condition may result. Secondary signs also occur with neurologic disease. Upward fixation of the patella (locking up of the stifle joint) is among the most common findings among horses with neurologic disease. Another common side effect of EPM is back soreness, which can be severe. The actual method by which the Sarcocystis neurona infects a horse is still unknown, however it is thought to preferentially infect leukocytes (white blood cells) in order to cross the blood brain barrier.

====Laboratory tests====

====Laboratory tests====

====Radiography====

====Radiography====