spinal cord diseases - members.cvma.net · • innervate muscle (lmn) • ... paraparesis 4-mo amh...

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Spinal Cord Diseases Relevant Examination Techniques

Rob MacKayAlec P. and Louise H. Courtelis

Equine Teaching HospitalUniversity of Florida

Functions of the Spinal Cord

• ProprioceptionFunction Cardinal Sign

• Ataxia• Relay motor commands (UMN)

• Trunk and limb weakness

• Relay long spinal reflexes

• Abnormal long spinal reflexes

•  Innervate muscle (LMN) •  Limb weakness, muscle atrophy, abnormal limb reflexes

• Relay sensation • Reduced sensation

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CNS Anatomy

Brachial intumesence

L3 L4 L5

L6 S1 S2

Lumbosacral intumesence

C6

C7 C8 T1

T2

Modified from: Mayhew IG. Large Animal Neurology. A handbook for veterinary clinicians. 1989

Spinal cord Anatomy

Lower motor neuron

Dorsal root ganglion

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• Proprioception

Function Cardinal Sign

• Ataxia

• Transmission of sensory information about the position and movement of muscles, tendons, and joints • Cerebellum • Forebrain

• Lack of awareness of the position of the neck, trunk, and limbs in space

De Lahunta & Glass. Veterinary Neuroantatomy and Clinical Neurology, ed 3, 2009

Ataxia

Lower motor neuron


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Neuroanatomic Localization

C1-T2 Ataxia in all 4 limbs

Signs of Ataxia

•  Abnormal limb positions•  Abnormal stride from the side•  Abnormal movements pelvis/pelvic

limbs from behind•  Circling errors•  Pacing•  Lead change errors

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Abnormal Limb Positions

3-yo TB fillyWest Nile encephalomyelitis

2-yo TB coltWobbler

Abnormal Stride

22-yo Morgan stallionEPM

2-yo Thoroughbred coltWobbler

Asymmetric stride length Hypometria/floating

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Pelvis/Pelvic Limb Movements

3-yo QH fillyWest Nile encephalomyelitis

2-yo TB coltWobbler

Pelvic Movements

• Yaw • Swivel • Sway

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Pelvis/Pelvic Limb Movements


2-yo TB coltWobbler

Circling Errors


Circumduction Interference/pivotting

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2-Beat (“Pacing”) Gait at Walk

1-yo Tennessee Walking Horse fillyC7-T1 facet fracture

5-yo Paso Fino stallionEquine degenerative myeloencephalopathy

Lead-Change errors

Respository videosBarrett’s sale, California

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Lead-Change Errors

Respository videosBarrett’s sale, California

Normal EPM





• Maintenance of muscle tone and posture; initiation of voluntary activity • UMN entirely within CNS

• Spastic sparesis • Contrast flaccid paralysis – LMN • No muscle atrophy

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Upper Motor Neuron Paresis

Lower motor neuron


Tail-pull

At rest At the walk


26-yo QH geldingEPM

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Neuroanatomic Localization Tailpull Interpretation

L3-S2 standing tail-pull

C1-S2 walking tail-pull

Hopping Responses

Normal Abnormal

13-yo QH geldingNormal

15-yo QH geldingEPM

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Neuroanatomic localization Hopping responses

C1-T2 Hopping responses

Quadriparesis & Ataxia in all 4 Limbs Focal Lesion


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C1-T2 Quadriparesis & ataxia

Neuroanatomic Localization Quadriparesis & Ataxia in all 4 Limbs

Ataxia in all 4 Limbs Diffuse/Multifocal

8-mo Andalusian geldingEquine degenerative myeloencephalopathy

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EDM Lesions

Lower motor neuron


Paraparesis

4-mo AMH fillyEpidural mass T9

7-yo TB mareWest Nile encephalomyelitis

Focal Multifocal

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Neuroanatomic Localization Paraparesis

T3-S2 Paraparesis







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Long Spinal Reflexes

•  Cervicofacial•  Laryngeal adductor “slap” test•  Cutaneous trunci•  Dorsal reflexes

8-yo TB geldingEPM

1-yo TB fillyEDM

Cervicofacial Reflex

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Laryngeal Adductor “Slap” Test

Laryngeal adductor “slap” test

Vagus - CN X

Recurrent Laryngeal nerve

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Cutaneous Trunci Reflex

2-yo TB coltEPM

15-yo QH geldingEPM

Abnormal

Dorsal Reflexes

Normal

13-yo QH geldingNormal

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• Flaccid paralysis

Thoracic Limb Weakness/Atrophy

4-yo Paint geldingEPM

4-yo TB coltWest Nile encephalomyelitis

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Neuroanatomic Localization Thoracic Limb Weakness/Atrophy

C6-T2 gray matter thoracic limb weakness

OR Spinal roots

Spinal nerves Brachial plexus

Peripheral nerves

Pelvic limb Atrophy/Weakness

3-yo TB fillyEPM

4-yo TB stallionEPM

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Pelvic limb Atrophy/Weakness

6-wo TB fillyT12,L3 fractures


Patella reflex L3-L6 NEG Flexor reflex L6-S2 POS

Equine Motor Neuron Disease

13-yo Quarter Horse Equine motor neuron disease

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Flexor Reflexes

Thoracic Pelvic

8-mo Paso Fino fillySpinal cord trauma








• Relay sensation • Reduced sensation

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Deep Pain Sensation

•  Bilateral polysynaptic tracts (redundant)

•  Distinguish from withdrawal (unconscious sensation)

•  Must see behavioral response to assess

•  Indicates catastrophic injury

Absence of deep pain Loss of Deep Pain Sensation

1-mo Paint coltVertebral osteomyelitis

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Cauda equina syndrome

Cauda equina syndrome

• A group of neurologic clinical signs referable to dysfunction of the cauda equina

• S2-S5 and caudal (coccygeal) segments and nerve roots

• S1-S5 segments within L6-S1 vertebrae

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CES signs

•  Motor and sensory•  Mild hindlimb signs (rare)•  Urinary and fecal incontinence•  Anesthesia of caudal structures

•  Penis, not prepuce•  Breeding issues

•  Tail, anal, rectal, penile paralysis•  Tail atrophy

CES of foals

5-week-old TB fillyR equi osteomyelitis

Paint and TB foalsMyelodysplasia

Chaffin MK et al. JAVMA 1995;206:215

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5-yo mixed breed marePolyneuritis equi

CES - NCE/PNE

20-yo Welsh cross geldingNeuritis of the cauda equina

CES – Equine herpesvirus-1 Myeloencephalopathy

8-yo Thoroughbred mare5-yo Thoroughbred mare

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CES – Traumatic/Toxic Injury

8-yo Thoroughbred mareSacral fracture

3-yo Quarter Horse mareAlcohol tail block

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CES - Mild

Third presentation for small colon impaction Failure to ejaculate

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C1-C2 injury

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C7 osteomyelitis

Neuroanatomic localization Postural responses

T3-S2 postural responses & rump pressure

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Neuroanatomic localization Hopping responses

C1-T2 Hopping responses

Neuroanatomic localization Thoracic limb weakness/atrophy

L3-S2 gray matter pelvic limb weakness

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Equine Motor Neuron Disease

• world-wide, mostly NY state•  risk factors

•  dirt lots•  lack of green forage

• adult horses• single cases• associated with low serum vitamin E• possible link to high Cu in feed?

Diagnostic Keys

•  limb, neck weakness•  normal head•  elevated tail•  retinal pigment•  dental tartar•  increased serum CK •  coccygeal muscle

biopsy

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Treatment

•  good-quality forage•  vitamin E•  stabilize•  usually remain

exercise intolerant

spinal cord diseases - members.cvma.net · • innervate muscle (lmn) • ... paraparesis 4-mo amh...

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