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How to approach to paretic patients: part I

Weakness, ataxia, paresis, and paralysis

อ.น.สพ.ดร.นิรุตติ์ สุวรรณาศูนย์ระบบประสาท โรงพยาบาลสัตว์มหาวิทยาลัยเกษตรศาสตร์ บางเขน

และ

ภาควิชาเวชศาสตร์คลินิกสัตว์เลีย้ง คณะสัตวแพทยศาสตร์ มหาวิทยาลัยเกษตรศาสตร์

Weakness-Ataxia-Paresis-Paralysis• Weakness (อ่อนแรง): non-specific term referring to an inability to carry

out a desired movement with normal force • A reduction in the strength of the muscles necessary to carry out the

movement

• Ataxia (อาการเดนิเซ): lack of voluntary coordination of muscle movements

• Paresis (อัมพฤกษ์): reduced voluntary motor function

• Paralysis (อัมพาต): absence of voluntary motor function

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Voluntary motor function

•Purposeful movement• Control by upper motor neuron (UMN)

• Functions of UMN:

• Initiating voluntary motor functions

• Inhibitory action on spinal cord reflexes (LMN)

• Lesions of motor system produce clinical signs called paresis or paralysis, depending on the severity or completeness of lesions

UMN vs. LMN

• Upper motor neuron (UMN): From motor cortex to anterior horn cell of spinal cord

• Lower motor neuron (LMN): Starts from anterior horn cell and ends on muscle

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Motor Systems

• Pyramidal and extrapyramidalsystems

• Cerebral cortex: influence spinal cord both directly and through brain stem descending systems

• Subcortical system: basal ganglia and cerebellum

UMN

Pyramidal motor system

• Pyramidal tract or corticospinal tract

• Motor center of cerebral cortex

• Originates pyramidal cells of motor area (UMN of corticospinal tract)

• Corona radiata

• Internal capsule

• Midbrain

• Medulla oblongata

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Cerebral motor cortex

1. Postcruciate gyrusA. Pelvic limbB. Thoracic Limb

2. Rostral suprasylvian gyrusC. EarD. EyelidE. Masseter, temporal m.F. Lateral cervical m.

Extrapyramidal motor system

• Causing involuntary movements

• Found in reticular formation of pons and medulla

• Target neurons in spinal cord involved in reflexes, locomotion, complex movements, and postural control

• Modulated by nigrostriatal pathway, basal ganglia, cerebellum, vestibular nuclei, and different sensory areas of cerebral cortex

• Rubrospinal tract

• Pontine reticulospinal tract

• Medullary reticulospinal tract

• Lateral vestibulospinal tract

• Tectospinal tract

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Extrapyramidal pathways

CNS Control of Voluntary Movement

(Contralateral)

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Neuromuscular function

Somatosensory system

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Medial lemniscal pathway (conscious proprioception)

Medial lemniscal pathway (conscious proprioception)

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Spinothalamic pathway(pain perception)

Motor and sensory system

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Generalized weakness vs tetraparesis

• History, physical examination and observation of patient's gait

• Constant: anemia, hypoglycemia, muscle or neurological disease,

hypoperfusion, obesity

• Exercise induced: muscle disorders, neuromuscular junction disorders

(e.g. myasthenia gravis or MG), Addison's disease, cardiovascular,

respiratory, or orthopedic problems

• Paroxysmal: cardiac arrhythmias, splenic hemangiosarcoma or GI

hemorrhage, sporadic hypotension such as visceral mastocytosis with

concomitant sporadic histamine release, or endocrine disease such as

hypothyroidism

Problem-Oriented Approach (POA) to Neurological Patients

• Signalment and History taking

• Physical examination

• Neurological examination

• Differential diagnosis

• Diagnostic plan

• Treatment plan

• Client education and follow up (Prognosis)

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Neurological Examination

1. Observation

- Mental status

- Posture

- Gait

2. Postural reaction

3. Cranial nerve examination

4. Spinal reflexes

5. Palpation

6. Pain perception

Postural reaction

• Proprioceptive positioning

• Evaluate the conscious awareness of limb position and movement in space

• Hopping

• Wheelbarrowing

• Extensor postural thrust

• Placing response

Paresis: Partial loss of the capacity to carry out a voluntary movement

Paralysis: Total loss of the capacity to carry out a voluntary movement

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Proprioceptive positioning response

Grading• 0 = None• 1 = Decrease• 2 = Normal

2 2 2 2

2 2 2 2

2 2 2 2

2 2

2 22 2

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Grading: 0 = negative / 1 = deficit / 2 = normal

Spinal reflexes

• Thoracic limbs

- Flexor reflex (C6-T2)

- Extensor carpi radialis reflex (C7-T1)

• Pelvic limbs

- Patellar reflex (L4-L6)

- Flexor reflex (L6-S1)

• Cutaneous trunci (panniculus) reflex (T3-L3)

Green = sensoryRed = motor

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ECR (C7-T1)

Flexor FL (C6-T2)

Patellar (L4-6)

Flexor HL (L6-S1)

Perineal (S1-3)

Grading0 = Areflexia1 = Hyporeflexia2 = Normal (Normoreflexia)3 = Hyperreflexia4 = Spasticity

Grades based on neurological deficit

• Grade 1: Normal gait with pain

(paresthesia/hyperesthesia), may

show kyphosis

• Grade 2: Ambulatory paresis/ataxia

• Grade 3: Non-ambulatory paresis

(inability to bear weight and walk)

• Grade 4: Paralysis with urinary incontinence and intact nociception (deep pain +ve)

• Grade 5: Paralysis with absent deep nociception (deep pain -ve)

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Observation: posture and gait

Kyphosis

Normal

spine

Kyphotic

spine

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Cerebellar lesion

• Cerebellar ataxia

• Intention tremor

• Hypermetria / dysmetria

Proprioceptive ataxia

• Loss of general proprioception and incoordination

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Localization of lesion

• Forebrain (Cerebral cortex and diencephalon)

• Brainstem

• Cerebellum

• Spinal cord: C1-C5, C6-T2, T3-L3, L4-S1

• Neuromuscular junction

Forebrain lesion

• Altered mental status (Consciousness)

• Behavioral change

• Circling

• Visual impairment (Contralateral)

• Postural reaction deficit

- Hemiparesis (Contralateral)

- Tetraparesis

• Head turn/Pleurothotonus

• Seizures

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Brainstem lesion

• CN 3-12 deficit

• Altered mental status

• Postural deficit

- Hemiparesis (Ipsilateral)

- Tetraparesis

Vestibular lesion

• Head tilt

• Positional strabismus

• Nystagmus

• Falling / Rolling

• Wide-based stance

• Hemiparesis (ipsilateral)

• Tetraparesis

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Cerebellar lesion

• Intention tremor

• Dysmetria

- Hypermetria

- Hypometria

• Cerebellar ataxia

LMN and UMN signs

LMN UMN

Motor function Paralysis of muscle group

Paralysis of part of body

Reflexes Hyporeflexia / Areflexia Normal / Hyperreflexia

Muscle tone Decreased Normal

Muscle atrophy Early and severe (neurogenic)

Late and mild

(non-used)

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Signs of lesion in spinal cord

Location Clinical signs

C1-C5 Tetraparesis, UMN all 4 limbs

C6-T2 Tetraparesis, LMN forelimbs,

UMN hindlimbs

T3-L3 Normal forelimbs, UMN hindlimbs

L4-S1 Normal forelimbs, LMN hindlimbs

S1-S3 LMN bladder and sphincters

Neuromuscular lesion

• LMN signs (local / general)

• Monoparesis / Tetraparesis

• Decrease motor function / tone