Peripheral Nerve Lesions - Trigeminal Neuralgia - Intercostal Neuralgia Flashcards
What is a Peripheral Nerve Lesion?
A peripheral nerve lesion is an injury to a peripheral nerve which, depending on the severity, results in:
- motor loss (flaccidity)
- weakness (paresis)
- sensory loss (anesthesia)
- sensory impairment (paresthesia)
- pain (dysesthesia)
- as well as autonomic dysfunction
The Peripheral Nervous System
The PNS refers to the portion of the nervous system that lies outside the brain and spinal cord and includes the spinal nerves and cranial nerves
Individual fibres can be myelinated, they have an insulating layer that speeds nerve impulse conduction or unmyelinated
The epineurium provides a protective barrier around fascicles which make up the nerve
Fascicles are groups of fibres that are contained within the mechanically strong epineurium
The endoneurium surrounds individual fibres
The fibres that make up each individual nerve have different functions. Some conduct information to (via afferent fibres) or from (via efferent fibres)
The afferent fibres, or sensory neurons convey sensory stimuli from the skin and deeper structures to the CNS
The somatic efferent fibres, also known as motor neurons, their cell bodies are found in the brainstem and spinal cord. Their axons innervate skeletal muscle cells, referred to as motor end organs
When firing, these motor neurons lead to muscular contractions
A combination of these fibers is known as a mixed nerve
Autonomic fibres which influence vasomotor function, sweating and skin, hair and nail health as well as neuropathic pain usually travel with these nerves or along the walls of arteries
Causes of Peripheral Nerve Lesions
- Compression
- Either internally (from a bony callus, hypertonic muscle) or externally (from crutches or prolonged leaning)
- Trauma
- Such as crushing or severance wounds
- Systemic disorders
- Leprosy
- Systemic edematous conditions
- Pregnancy, hypothyroidism, diabetes, kidney and heart conditions
Classification of Nerve Injuries
- Neuropraxia
- Axonotmesis
- Neurotmesis
Nerve lesions may be:
complete-all fibres within the nerve are affected or
partial-only some fibres are affected
In terms of the healing process,
the lesion may be regenerating-repairing itself or
permanent-the nerve is unable to regrow
- Neuropraxia
- First degree:
Compression of a nerve causing a local conduction block with no structural damage to the axon or to tissue distal to the lesion
The conduction block is caused by a local demyelination of nerve fibres
Recovery occurs as the damaged area is repaired, which may require weeks or months
This type of injury involves loss of motor function but sensory and autonomic fibres are unaffected
Prognosis is good
- Axonotmesis
- Second degree:
Prolonged, severe compression of a nerve
Causes a lesion at the site of the compression, followed by degeneration of the axons distal to the injury
The endoneurial tube remains intact
Sensory, motor and autonomic losses occur
Regeneration of the axons to the peripheral end organs results in functional recovery
Prognosis is good since the endoneurial tube provides an appropriate pathway through which the axons can regenerate to the correct end organ
- Neurotmesis
- Third degree to fifth degree:
An injury to the nerve as a result of severance of part or all of the nerve trunk, including the endoneurial tube
This category of injury results in degeneration of the nerve
Axons may have difficulty regenerating to distal end organs because of scar tissue at the lesion site from local edema and bleeding
The same losses occur as with axonotmesis
The prognosis for recovery is poor because there is no clear pathway to orient the regenerating axons
Surgical repair is usually required to ensure some functional recovery
Peripheral Nerve Pain
Peripheral nerve pain can be due to:
- Neuritis
- Neuralgia
- Causaliga
- Reflex sympathetic dystrophy (RSD)
- Neuromas
Neuritis
Inflammation of the nerve
Primarily the sheath and CT are affected, usually the axon is not affected
Characterized by constant dull pain, paresthesia or dysesthesia may be present
In cases of long duration, there may be motor and sensory deficit
Causes of neuritis are:
Secondary to a pathology such as diabetes, leprosy or TB
Trauma to the nerve
Chronic exposure to a toxin such as lead, drugs or alcohol
Massage is ideally contraindicated
Neuralgia
+ Nerve pain:
Characterized by recurrent attacks of sudden, paroxysmal (excruciating) pain along the distribution of the affected nerve
Described as “lightning like” and often throbbing
No appreciable pathological change in the nerve
Characterized by a “trigger zone”, an area that causes an attack when stimulated. The trigger zone is often the cutaneous region supplied by the nerve. Movement of the affected area increases pain
Commonly affected are the trigeminal and intercostal nerves
+ Causes of neuralgia are:
Local compression from a trauma with inflammation leading to scar tissue, a subluxation of the vertebrae or a bony callus
Prolonged exposure to cold
Massage therapy can play a significant role in alleviating the discomfort of neuralgia, in particular, managing those cases caused by pressure from soft tissue or local swelling
Trigeminal Neuralgia
Also known as tic douloureux or painful tic.
It affects the trigeminal nerve, which is cranial nerve V (CNV)
This nerve supplies sensory awareness to the face and motor function to the muscles of mastication and the tensor tympani of the middle ear
The nerve consists of three divisions:
- The ophthalmic
- The maxillary
- The mandibular
The primary causes of trigeminal neuralgia are:
Local compression such as that caused by a neuroma
Demyelinating conditions with subsequent scarring, such as MS
Sudden painful attacks occur unilaterally, along one or more divisions of the nerve
Facial tics or spasms are observed, often resembling grimaces
The “trigger zone” may be the lips, face or tongue
Medical treatment consists of antiseizure medication
Local massage over the trigger zone is contraindicated. A full body relaxation massage is appropriate between attacks
Intercostal Neuralgia
Affects the intercostal nerve that travels between the internal and innermost intercostal muscles
The nerve travels as a neurovascular bundle from the spine to the sternum for ribs 1-6 and from the spine to abdomen for ribs 7-11. Below the 12th rib there is no intercostal muscle
Causes
Diabetes, due in part to metabolic changes. Attacks may recur at different areas of the trunk or they may remain localized
Post-herpes zoster (shingles). When first contracting the virus, the person gets chicken pox. The virus then invades the dorsal root ganglion of the intercostal
This condition consists of intermittent attacks of deep, burning, sharp pain shooting along the affected intercostal nerve
Pain is especially intense where the cutaneous branches emerge at the spine, at the lateral axillary line and at the sternum
The trigger is often light touch and movement over the affected area
Local massage over the trigger zone is contraindicated
Causalgia
Considered a severe pain syndrome
Characterized by the sudden onset of an intense, persistent, usually burning pain, most often associated with a traumatic injury to a peripheral nerve
The lesion to the nerve is often incomplete and there may be accompanying arterial injuries
Causes:
- Gunshot wounds
Iatrogenic nerve injuries, secondary to surgery - Electrocution
- Amputations
- Injuries from high velocity sharp objects
Accompanying the pain are severe autonomic and trophic disturbances such as poor vasomotor control, swelling and dystrophic skin changes
Aggravating factors include emotional stress loud or sudden noises and tactile stimulation
A relaxation massage can be given to decrease SNS firing and to alleviate the client’s pain, as well as provide emotional support
RSD
Reflex Sympathetic Dystrophy is considered a pain syndrome
The term is often used interchangeably with causalgia, it actually refers to a different pain syndrome
It is thought that an abnormal sympathetic reflex results in arterial spasm which causes a spontaneous burning pain in the limb beyond the area of a nerve injury
Onset of pain may be immediately following an injury or within a few weeks of a trauma
Pain is often out of proportion to the injury
Edema is present, accompanied by dystrophic tissue
Tissue may be warm and hyperemic or cool and pale
Sweating is usually increased but may also be decreased and muscular wasting often occurs
Pain is aggravated by movement and emotional excitation
The person often immobilizes the area in an attempt to stop the pain but unfortunately this leads to increased edema and ischemia in the tissue which then cause more pain
A vicious pain cycle develops
After 3-6 months after injury, constant pain affects the limb distal to the injury site
Joints become stiff and the tissue is cool and cyanotic
Causes of RSD
Trauma, often from relatively minor injuries which may be followed by prolonged immobilization
Surgery, involving the wrist, hand ankle or foot which may be followed by prolonged immobilization
Massage is used to control edema, maintain joint ROM and heat applications are applied unless there is tissue dystrophy or lack of vasomotor control
Neuromas
A tumour composed of nerve cells
After the partial or complete severance of a peripheral nerve, the proximal nerve stump responds by sending nerve sprouts towards the distal endoneurial tube stump
These sprouted fires often grow indiscriminately until some of them attach to the distal rube and that provides a pathway for other fibres to follow
A neuroma can develop at this site
The regenerating nerve fibres grow randomly and often into a clumped mass because they cannot penetrate the dense scar tissue that forms at the site of an injury
A neuroma at the end of the proximal nerve stump is referred to as a terminal bulb
This type is associated with amputations or complete severance injuries
In the case of a partial lesion, a neuroma can develop within the nerve itself
May or may not be symptomatic
Small fibre, compact neuromas are less sensitive than large, soft ones
When the neuroma is is symptomatic, the area over the neuroma is extremely sensitive
The client experiences continuous, poorly localized pain, as well as altered sensation in some of the area supplied by the nerve
Painful neuromas are often surgically treated in order to restore continuity to the nerve and give it a chance to regenerate
Treatment generally includes a relaxation massage to decrease SNS firing and to provide emotional support to the client
If compression of the neuroma is painful, massage is locally CI’d
AF and active assisted movements of proximal and distal joints are encouraged to maintain joint motion and health
