Lesions, injuries, disorders, pathology; some terminology

P. 240-243

What is a lesion?

can occur through many mechanisms of injury

etiologies: compression injuries, fracture/compartment syndrome, laceration, penetrating trauma, stretch, high velocity trauma, cold

results in total loss of muscle over time w/ replacement by fibrous tissue

Mononeuropathy

isolated nerve lesion

trauma and entrapment

Neuroma

abnormal growth of nerve cells

vasculitis, AIDS, amyloidosis

Peripheral neuropathy

impairment/dysfunction of peripheral nerves

diabetic neuropathy, trauma, alcoholism

Polyneuropathy

diffuse nerve dysfunction that is symmetrical and typically secondary to pathology and not trauma

Gillian-barre syndrome, peripheral neuropathy, use of neurotoxic drugs, HIV

Neurapraxia

mildest

conduction block due to myelination dysfunction

axonal continuity preserved

axons, epineurium, perineurium, endoneurium intact

nerve conduction is preserved proximal and distal to lesion

nerve fibers are not damaged

symptoms: pain, minimal muscle atrophy, numbness or greater loss of sensory and motor function, diminished proprioception

recovery is rapid and complete and will occur w/in 4-6 wks

pressure injuries are most common

Axonotmesis

more severe to peripheral nerve

reversible injury to damaged fibers

damage occurs to axons with preservation of endoneurium, epineurium, Schwann cells, supporting structure

distal Wallerian degeneration

nerve regeneration distal to lesion (1mm per day)

recovery is spontaneous and varies from spotty to no recovery; surgery may be required for repair

traction, compression, and crush injuries are most common

Neurotmesis

most severe injury to peripheral nerve

axon, myelin, connective tissue components are all damaged or transected

irreversible injury

flaccid paralysis and wasting muscle; total loss of sensation to area supplied by nerve

all motor and sensory loss distal to lesion becomes permanently impaired

no spontaneous recovery; w. surgical reattachment, potential regenerating axons regenerate 1mm per day w/ proximal recovery first; sensory recovers sooner than motor fibers

complete transection of nerve trunk

Pathology present in anterior horn cell presentation

sensory component intact

motor weakness and atrophy

fasciculations

dec DTR

example: ALS, poliomyelitis

Pathology to a muscle presentation

sensory component intact

motor weakness; fasciculations are rare

normal/dec DTR

example: muscular dystrophy

Pathology to neuromuscular junction presentation

sensory component intact

motor fatigue > actual weakness

normal DTR

example: myasthenia gravis

pathology to Peripheral nerve (mononeuropathy) presentation

sensory loss along nerve root

motor weakness and atrophy in peripheral distributions; may have fasciculations

example: trauma

pathology to peripheral polyneuropathy presentation

sensory impairments; “stocking glove” distribution

motor weakness and atrophy; weaker distal than proximal; may have fasciculations

example: diabetic peripheral polyneuropathy

pathology in spinal roots and nerves presentation

sensory components will have corresponding dermatomal deficits

motor weakness is dermatome pattern; may have fasciculations

dec DTR

example: herniated disk

UMN disease

lesion found in descending motor tracts w/in cerebral motor cortex, internal capsule, brainstem or spinal cord

symptom: weakness, hypertonicity, hyperreflexia, mild disease atrophy, abnormal reflexes

damage tracts: lateral white column of spinal cord

UMN lesions includes:

CP

hydrocephalus

ALS

CVA

birth injuries

MS

Huntington’s

TBI

pseudobulbar palsy

brain tumors

LMN disease

lesion that affects nerves/axons at or below level of brainstem; usually w/in “final common pathway”

ventral grey column of sc may be affected

symptoms: flaccidity or weakness of involved muscles, dec tone, fasciculations, muscle atrophy, dec/absent reflexes

LMN lesions include:

poliomyelitis

ALS

Gillian-barre

tumors involving sc

trauma

progressive muscular atrophy

infection

Bell’s palsy

CTS

muscular dystrophy

spinal muscular atrophy

Common forms of hypokinesia

apraxia, rigidity, bradykinesia

Common forms of hyperkinesia

ataxia, athetosis, chorea, tics, tremors, dysmetria

Athetosis

slow, twisting, and writhing mvmnts large in amplitude

associated with spasticity

seen in pts with CP secondary to basal ganglia pathology

Chorea

form of hyperkinesia

brief, irregular contractions that are rapid, but not to the degree of myoclonic jerks

ballism is a form of this

Huntington’s disease is an example

Dystonia p242

sustained muscle contractions that causes twisting, abnormal postures, and repetitive movements

Parkinson’s, CP, and encephalitis is seen with this disorder

Tics

sudden, brief, repetitive coordination movements at irregular intervals

Tourette syndrome is an example that presents with this disorder

Tremors

involuntary, rhythmic, oscillatory movements that are classified in 3 groups p.243

1. resting

2. postural

3. intention (kinetic)

Akinesia

inability to initiate mvmnt

Athenia

generalized weakness secondary to cerebellar pathology

Ataxia

inability to perform coordinated movments

Athetosis

involuntary movements occur without central stability

Bradykinesia

slow movement

Clasp-knife response

resistance during ROM of hypertonic jt where greatest resistance is at initiation of range that lessens w/ mvmnt through ROM

Clonus

UMN lesion

involuntary alt spasmodic contraction of a muscle precipitated by quick stretch

cogwheel rigidity

resistance mvmnt has a phasic quality to it

dysdiadochokinesia

inability to perform rapid alt movmnt

dysmetria

inability to control range of movement and force of muscle activity

dystonia

closely related to athetosis, but there is larger axis of muscle involvement

fasciculation

muscle twitch caused by random discharge of LMN and muscle fibers

Hemiballism

involuntary and violent movement

lead pipe rigidity

constant resistant to ROM

rigidity

severe hypotonicity where sustained muscle contraction does not allow movement