Peripheral Nerve Lesions, Muscle Tone, UMN and LMN injuries Flashcards
What is double crush syndrome?
Existence of two separate lesions along the same nerve that create more severe symptoms than if only one existed
What is a mononeuropathy?
An isolated nerve lesion, often associated with trauma and entrapment
What is a neuroma?
Abnormal growth of nerve cells
What is a polyneuropathy? What conditions are associated with this dysfunction?
Diffuse nerve dysfunction that is symmetrical and typically secondary to pathology and not trauma
Associated conditions include GBS, peripheral neuropathy, use of neurotoxic drugs and HIV
What is Wallerian degeneration?
Degeneration that occurs distally, specifically to the myelin sheath and axon
List 3 classifications of acute nerve injuries in order of severity (least to most).
Neurapraxia
Axonotmesis
Neurotmesis
Describe neuropraxia. What is the most common example of neurapraxia?
Injury to nerve that causes a transient block of function (conduction block ischemia)
Never dysfunction may be rapidly reversed or persist a few weeks
Pressure injuries are the most common
Describe axonotmesis. What is the most common examples of axonotmesis?
Injury to nerve interrupting the axon and causing loss of function and Wallerian degeneration distal to the lesion
With no disruption to the endoneurium, regeneration is possible
Traction, compression and crush injuries are most common
Describe neurotmesis. What is the most common example of neurotmesis?
Cutting of the nerve with severance of all structures, complete loss of nerve function, and Wallerian degeneration
Surgical intervention needed for regeneration to occur
Complete transection of the nerve trunk leads to neurotmesis
What is an UMN disease?
Characterized by a lesion found in descending motor tracts within the cerebral motor cortex, internal capsule, brainstem or spinal cord
List 5 symptoms associated with UMN disease/injury.
- Weakness of involved muscles
- Hypertonicity
- Hyperreflexia
- Mild disuse atrophy
- Abnormal reflexes
List 6 examples of UMN lesions.
Cerebral palsy Hydrocephalus TBI ALS Huntington's chorea Multiple sclerosis
What is a LMN disease?
Characterized by a lesion that affects nerves or their axons at or below the level of the brainstem
List 5 symptoms associated with LMN disease/injury.
- Flaccidity or weakness of involved muscles
- Decreased tone
- Fasciculations
- Muscle atrophy
- Decreased or absent reflexes
List 7 examples of LMN lesions.
Poliomyelitis ALS GBS Muscular dystrophy Spinal muscular atrophy Bell's palsy Carpal tunnel syndrome
What condition is considered to be an example of an UMN and LMN lesions?
ALS
Compare and contrast reflexes in UMN vs LMN lesions.
UMN = hyperactive LMN = Diminished or absent
Compare and contrast atrophy in UMN vs LMN lesions.
UMN = mild from disuse LMN = present
Compare and contrast fasciculations in UMN vs LMN lesions.
UMN = absent LMN= present
Compare and contrast tone in UMN vs LMN lesions.
UMN = hypertonic LMN= hypotonic to flaccid
What is a clasp knife response?
Marked resistance to PROM suddenly gives way
What is clonus?
Characteristic of an UMN lesion; involuntary alternating spasmodic contraction of a muscle precipitated by a quick stretch reflex
What is spasticity?
Velocity dependent increased resistance to PROM
What tool is used to determine the different grades of spasticity?
Modified Ashworth Scale
Describe the different spasticity grades on the Modified Ashworth Scale.
0: No increase in muscle tone
1: Slight increase in muscle tone, minimal resistance at end of ROM
1+: Slight increase in muscle tone, minimal resistance through less than half of ROM
2: More marked increase in muscle tone, through most of ROM, affected part easily moved
3: Considerable increase in muscle tone, passive movement difficult
4: Affected part rigid into flexion or extension
What is rigidity?
Increased resistance to PROM that is independent of the velocity of movement
Describe the 2 different types of rigidity.
Lead pipe = rigidity that is uniform throughout the range (associated with basal ganglia lesions)
Cogwheel = rigidity that is interrupted by a series of jerks (associated with Parkinson’s disease)
What is decerebrate rigidity?
A characteristic of a corticospinal lesion at the level of the brainstem that results in extension of the trunk and all extremities.
What is decorticate rigidity?
A characteristic of a corticospinal lesion at the level of diencephalon where the trunk and LEs are positioned in extension and the UEs are positioned in flexion
What is opisthotonos?
Prolonged, severe spasm of muscles, causing the head, back, an heels to arch backward; arms and hands are held rigidly flexed
What 4 conditions is opisthotnos seen in?
Meningitis
Tetanus
Epilepsy
Strychnine poisoning
What is athetosis?
Movement disorder that presents with slow, twisting and writhing movements that are large in amplitude.
Primarily seen in the face, tongue and extremities
Commonly seen in those with cerebral palsy
What is Chorea?
A form of hyperkinesia that presents with brief, irregular, contractions that are rapid.
Chorea occurs secondary to damage to the _____.
Caudate nucleus
What is ballism?
A form of chorea that includes choreic jerks of large amplitude producing flailing movements of the limbs
Ballism occurs secondary to damage to the _______.
Subthalamic nucleus
What is dystonia?
A syndrome of sustained muscle twitching, abnormal postures and repetitive movements.
Often increased with volitional movement, and with progression, can produce overflow
List 3 conditions associated with dystonia.
Parkinson’s disease
Cerebral palsy
Encephalitis
What are tics?
Sudden, brief, repetitive, coordinated movements that will usually occur at irregular intervals.
What are tremors? Describe 3 different types of tremors.
Involuntary, rhythmic, oscillatory movements that are classified into three groupings:
- Resting = tremors are observable at rest and may or may not disappear with movement; may increase with mental stress.
- Postural = tremors are observable during a voluntary contraction to maintain a posture
- Intention (kinetic) = tremors are absent at rest, but observable with activity and typically increase as the target approaches
What is akinesia?
Inability to initiate movement
What is asthenia?
Generalized weakness typically secondary to cerebellar pathology
What is ataxia?
Inability to perform coordinated movements
What is bradykinesia?
Movement that is very slow
What is dysmetria?
Inability to control the range of a movement and force of muscular activity
