Changes

Spinal cord:

Spinal cord:

*Ataxia and paresis

*Ataxia, paresis or spastcity of one or more limbs, often asymmetrical, signs usually worse in hindlimbs, may see stumbling, falling, knuckling, toe dragging, circumduction, crossing over, tetraparesis - areflexia, hyporeflexia (LMN) or hyperreflexia (UMN) depending on site of lesion

 

*Loss of reflexes or cutaneous anaesthesia

Ataxia or paresis of one or more limbs: stumbling, falling, knuckling and toe dragging.

*Apparent lameness, particularly atypical or slight gait asymmetry of hindlimbs (not alleviated by local anesthesia)

*Abnormal placing reactions  

Cranial nerve signs: loss of tongue tone, loss of sensation to the face and unilateral facial paralysis. Brain involvement: dysphagia, circling, head tilt or recumbency(EPM3)

*Focal muscle atrophy of individual muscle grps (Pasq), especially gluteal muscles, often asymmetrical  

 

*Generalized muscle atrophy or loss of condition

Signs: asymmetrical weakness, ataxia, vestibular disease (peripheral or central) peripheral neuropathy, ill-defined hindlimb lameness, asymmetric muscle atrophy. (Vetstream)

 

 

*Upward fixation of the patella

*Ataxia and weakness (hindlimbs > forelimbs) - often asymmetrical.

*Apparent lameness, particularly atypical or slight gait asymmetry of hindlimbs (not alleviated by local anesthesia).

*Abnormal placing reactions.

*Focal muscle atrophy (individual muscle grps (Pasq)- evident anywhere especially gluteal muscles - often asymmetrical.

Brainstem (cranial nerve signs, <5% cases):

*Generalized muscle atrophy/loss of condition

*Atrophy of temporalis and masseter muscles, loss of sensation to the face (V)

Lesions of the brainstem, cerebrum or cerebellum are less frequently recognized:

*Abnormalities of facial (VII) and vestibulocochlear (VIII) nerves often observed together:  

Cranial nerve dysfunction (<5% of cases) - any can be affected:  

**VIII - vestibular signs of nystagmus, head tilt, base-wide stance (peripheral or central vestibular disease)

*Atrophy of temporalis/masseter muscles (V)

**VII - unilateral facial paralysis - muzzle deviation, ptosis, ear droop

*Abnormalities of facial (VII)   and vestibulocochlear (VIII) nerves often observed together:  

*VIII - vestibular signs of nystagmus, head tilt, base-wide stance  

*VII - muzzle deviation, ptosis, ear droop

*Dorsal displacement of soft palate (IX, X)  

*Dorsal displacement of soft palate (IX, X)  

*Laryngeal hemiplegia (X)  

*Laryngeal hemiplegia (X)

*Inability to stand.

*Headshaking(EPM 7)

*Inability to swallow.

*Blindness with or without abnormal pupillary reflexes (Pasq)

Infection of cerebrum, basal nuclei, cerebellum:  

Cerebrum, basal nuclei, cerebellum:

*Seizures (may be the only clinical sign)(82 in Furr)

*Seizures (may be the only clinical sign)(82 in Furr)

*Abnormal EEG.  

*Abnormal EEG.  

*Asymmetrical central blindness

*Asymmetrical central blindness

*Facial hypalgesia

*Facial hypoalgesia

*Cerebellar ataxia

*Cerebellar ataxia

*Altered behavior  

*Altered behavior  

*Depression

*Depression

*Narcolepsy-like syndrome  

*Narcolepsy-like syndrome  

Headshaking(EPM 7)

*Untreated progressive to recumbency in 14days to 6mths (Pasq)

Without treatment, progression to recumbency and death is likely.  This deterioration may occur smoothly or spasmodically over hours to years. (Merck)

Gait abnormality (peracute or acute) - 1 or all 4 limbs depending on where migrates, asymmetrical (because multifocal), ataxia, paresis & spasticity - knuckling, circumduction, crossing over, tetraparesis - areflexia, hyporeflexia (LMN) or hyperreflexia (UMN) depending on site of lesion, localized areas of sensory deficits, 'strip sweating' localized areas (dermatomes, sympathetic white matter tracts), cerebellar, brain stem (less common) or cerebral signs, cranial nn - head tilt, facial paralysis, circling, nystagmus, dysphagia, blindness with or without abnormal pupillary reflexes, untreated progressive to recumbency in 14days to 6mths (Pasq)

Any gait abnormality in galloping/trotting race/dressage horses while in training which cannot be attributed to musculoskeletal abnormality may result from EPM and requires careful neurologic evaluation.(V)

The three characteristic 'As' of EPM (ataxia, asymmetry, atrophy) suggest multifocal or diffuse disease, but are not pathognomonic.  It has been suggested that rapidly progressive presentations reflect brainstem lesions. Spinal cord signs are most commonly seen and may include:

Lesions of the brainstem, cerebrum or cerebellum are less frequently recognized.The three characteristic 'As' of EPM (ataxia, asymmetry, atrophy) suggest multifocal or diffuse disease, but are not pathognomonic.  It has been suggested that rapidly progressive presentations reflect brainstem lesions.

====Diagnosis====

====Diagnosis====