Peripheral Nerves and Neuropathies Flashcards
Functional Organization of PNS
PNS is divided into two divisions, what are they = ?
Peripheral Nerves & Neuropathies
Functional Organization of PNS:
- PNS is divided into two divisions:
- Sensory (afferent) Division
- Motor (efferent) Division
Functional Organization of PNS
PNS - Sensory (afferent) division relays what information ?
Peripheral Nerves & Neuropathies
Functional Organization of PNS:
- PNS - Sensory (afferent) division information;
(1) Somatic Sensory :
- General: Touch, pain, pressure, vibration, temp, and propriception in skin, body wall, and limbs.
- Special: Hearing, equilibrium, vision.
(2) Visceral Sensory :
- General: Stretch, pain, temp, chemical changes, and irratiation in viscera; nausea and hunger.
- Special: Taste, smell
Functional Organization of PNS
Motor (efferent) division relays what information ?
Functional Organization of PNS:
- Motor (efferent) division information;
(1) Somatic Nervous System:
- Motor innervation of all skeletal muscles.
(2) Autonomic Nervous System (ANS):
- Motor innervation of smooth muscle, cardiac muscle, and glands.
Functional Organization of PNS
Two divisions of ANS
Functional Organization of PNS:
- Two divisions of ANS =
- Sympathetic
- Parasympathetic
Peripheral Nervous System (PNS)
Includes = ?
3 things
Peripheral Nerves & Neuropathies
Peripheral Nervous System (PNS) includes:
- Cranial nerves
- Spinal nerves
- Peripheral nerves
Peripheral Nerves
Supply both the _ ? _ , and _ ? _ structures.
Peripheral Nerves & Neuropathies
Peripheral Nerves
Peripheral nerves are usually mixed: consisting of the _ ? _ , _ ? _ , and _ ? _ axons.
Peripheral Nerves & Neuropathies
Peripheral Nerves:
Peripheral nerves are usually mixed: consisting of the sensory , autonomic , and motor axons.
Peripheral Nerves
Peripheral axons are classified according to _ ? _ , and _ ? _ of conduction
Peripheral Nerves & Neuropathies
Peripheral Nerves:
Peripheral axons are classified according to diameter , and speed of conduction (e.g., Ia, Ib, II, Adelta, and C).
Plexus and nerves…
- The ventral rami innervates skin and muscles on the anterior aspect of the trunk, limbs, also provide the spinal contributions to all major neural plexuses.
- As such, they are responsible for the majority of the body’s sensorimotor innervation:
- Cervical region / Anterior (ventral) division = ?
Peripheral Nerves & Neuropathies
Plexus & Nerves:
- The ventral rami innervates skin and muscles on the anterior aspect of the trunk, limbs, also provide the spinal contributions to all major neural plexuses.
- As such, they are responsible for the majority of the body’s sensorimotor innervation:
- Cervical region / Anterior (ventral) division = Cervical plexus, brachial plexus
Plexus and nerves…
- The ventral rami innervates skin and muscles on the anterior aspect of the trunk, limbs, also provide the spinal contributions to all major neural plexuses.
- As such, they are responsible for the majority of the body’s sensorimotor innervation:
- Thoracic region /Anterior division = ?
Peripheral Nerves & Neuropathies
Plexus & Nerves:
- The ventral rami innervates skin and muscles on the anterior aspect of the trunk, limbs, also provide the spinal contributions to all major neural plexuses.
- As such, they are responsible for the majority of the body’s sensorimotor innervation:
- Thoracic region /Anterior division = Intercostal nerves
Plexus and nerves…
- The ventral rami innervates skin and muscles on the anterior aspect of the trunk, limbs, also provide the spinal contributions to all major neural plexuses.
- As such, they are responsible for the majority of the body’s sensorimotor innervation:
- Lumbar region / Anterior division = ?
Peripheral Nerves & Neuropathies
Plexus & Nerves:
- The ventral rami innervates skin and muscles on the anterior aspect of the trunk, limbs, also provide the spinal contributions to all major neural plexuses.
- As such, they are responsible for the majority of the body’s sensorimotor innervation:
- Lumbar region / Anterior division = Lumbar plexus, Sacral plexus
Plexus and nerves…
- The ventral rami innervates skin and muscles on the anterior aspect of the trunk, limbs, also provide the spinal contributions to all major neural plexuses.
- As such, they are responsible for the majority of the body’s sensorimotor innervation:
- Sacral region = ?
Peripheral Nerves & Neuropathies
Plexus & Nerves:
- The ventral rami innervates skin and muscles on the anterior aspect of the trunk, limbs, also provide the spinal contributions to all major neural plexuses.
- As such, they are responsible for the majority of the body’s sensorimotor innervation:
- Sacral region = Sacral plexus, Lumbosacral plexus
Plexus and nerves…
- The ventral rami innervates skin and muscles on the anterior aspect of the trunk, limbs, also provide the spinal contributions to all major neural plexuses.
- As such, they are responsible for the majority of the body’s sensorimotor innervation:
- Coccygeal region = ?
Peripheral Nerves & Neuropathies
Plexus & Nerves:
- The ventral rami innervates skin and muscles on the anterior aspect of the trunk, limbs, also provide the spinal contributions to all major neural plexuses.
- As such, they are responsible for the majority of the body’s sensorimotor innervation:
- Coccygeal region = Coccygeal plexus
Cervical Plexus
- Anterior rami of = ?
- Provides cutaneous sensory information from the _ ? _ to the _ ? _.
- Innervates the _ ? _ muscles, and _ ? _.
Peripheral Nerves & Neuropathies
Cervical Plexus:
- Anterior rami of C1 - C4
- Provides cutaneous sensory information from the posterior scalp to the clavicle.
- Innervates the anterior neck muscles, and diaphragm .
Cutaneous Sensory Information
- The information that the skin sends to the central nervous system about touch , pressure , vibration , temperature , and pain .
Brachial Plexus
- Anterior rami of ? - T1
- Entire _ ? _ is innervated by the brachial plexus branches.
Peripheral Nerves & Neuropathies
Brachial Plexus:
- Anterior rami of C5 - T1
- Entire upper limb is innervated by the brachial plexus branches
Lumbar Plexus
- Branches innervate the skin and muscles of the _ ? _ and _ ? _ .
Peripheral Nerves & Neuropathies
Lumbar Plexus:
- Branches innervate the skin and muscles of the anterior and medial thigh .
Sacral Plexus
- Innervates the ? , as well as, most of the ? and ?.
Peripheral Nerves & Neuropathies
Sacral Plexus:
- Innervates the posterior thigh , and most of the leg & foot .
Peripheral Nerves
Consist of parallel bundles of axons (neurons) surrounded by three connective tissue sheaths:
- ? = Separates individual axons.
- ? = Surrounds bundles of axon (fascicles).
- ? = Encloses the entire nerve trunk.
Peripheral Nerves & Neuropathies
Peripheral Nerves:
- Consist of parallel bundles of axons (neurons) surrounded by three connective tissue sheaths:
- Endoneurium = Separates individual axons.
- Perineurium = Surrounds bundles of axon (fascicles).
- Epineurium = Encloses the entire nerve trunk.
Signs of peripheral damage
Include:
- = _ ? _ changes
- = _ ? _ changes
- _ ? _ changes
- = ?
Peripheral Nerves & Neuropathies
Signs of peripheral damage =
- Sensory changes
- Autonomic changes
- Motor changes
- Denervation : trophic changes
Trophic changes are abnormalities
that affect the area of pain, such as:
- Wasting of the skin, tissues, or muscle
- Thinning of the bones
- Changes in hair or nail growth
- Pitting of the nails
- Increased or decreased hair growth in the limb
- Changes in skin tone
- Changes in skin texture
Nerve Injury – What’s Happening?
Class I = ?
- Type A = ?
- Type B = ?
Peripheral Nerves & Neuropathies
Nerve Injury – What’s Happening?
- Class II = ?
Peripheral Nerves & Neuropathies
Nerve Injury – What’s Happening?
- Class III = ?
Peripheral Nerves & Neuropathies
Nerve Injury – What’s Happening:
- Class III
Nerve Injury – What’s Happening?
- Class IV = ?
Peripheral Nerves & Neuropathies
Nerve Injury – What’s Happening:
- Class IV
Nerve Injury – What’s Happening?
- Class V = ?
Peripheral Nerves & Neuropathies
Traumatic Injury to a Peripheral Nerve - Mononeuropathy
Depending on the severity of damage, traumatic injuries to peripheral nerves are classified into three categories:
- = ?
- = ?
- = ?
Peripheral Nerves & Neuropathies
Mononeuropathy:
- Traumatic myleinopathy
- Traumatic axonopathy
- Traumatic severance
Classification of Neuropathies - Mononeuropathy
- Neuropathy = Mononeuropathy (Traumatic myleinopathy )
- Usual Cause = ?
- Pathology = ?
- Typical Recovery = ?
Peripheral Nerves & Neuropathies
Neuropathy = Mononeuropathy (Traumatic myleinopathy )
- Usual Cause = Trauma
- Pathology = Demyelination
- Typical Recovery = Complete and rapid by remyelination
Classification of Neuropathies - Mononeuropathy
- Neuropathy = Mononeuropathy (Traumatic axonopathy )
- Usual Cause = ?
- Pathology = ?
- Typical Recovery = ?
Peripheral Nerves & Neuropathies
Neuropathy = Mononeuropathy (Traumatic axonopathy )
- Usual Cause = Trauma
- Pathology = Axonal damage
- Typical Recovery = Slow by regrowth of axons, complete because Schwann cells and connective tissue sheath remain intact.
Classification of Neuropathies - Mononeuropathy
- Neuropathy = Mononeuropathy (Traumatic severance )
- Usual Cause = Trauma
- Pathology = ?
- Typical Recovery = ?
Peripheral Nerves & Neuropathies
Neuropathy = Mononeuropathy (Traumatic severance )
- Usual Cause = Trauma
- Pathology = Axon and myelin degeneration
- Typical Recovery = Slow with poor results
Classification of Neuropathies
- Neuropathy = Multiple Mononeuropathy
- Usual Cause = ?
- Pathology = ?
- Typical Recovery = ?
Peripheral Nerves & Neuropathies
- Neuropathy = Multiple Mononeuropathy
- Usual Cause = Complication of blood vessel disease / inflammation / diabetes
- Pathology = Ischemia of neuron
- Typical Recovery = Slow by regrowth of axons
Classification of Neuropathies
- Neuropathy = Polyneuropathy
- Usual Cause = ?
- Pathology = ?
- Typical Recovery = ?
Peripheral Nerves & Neuropathies
- Neuropathy = Multiple Mononeuropathy
- Usual Cause = Complication of diabetes/ autoimmune disorder (GBS) or genetic.
- Pathology = Metabolic or inflammatory
- Typical Recovery = Diabetic neuropathy may be stable, progressive or improve with better blood glucose control; GBS improves gradually; hereditary is slow progressive.
Mononeuropathy
Focal neuropathies are conditions in which you typically have damage to a single nerve; most often in the…
- _ ? _ ,
- _ ? _ ,
- _ ? _ ,
- _ ? _
Peripheral Nerves & Neuropathies
Mononeuropathy:
- Focal neuropathies are conditions in which you typically have damage to a single nerve; most often in the hand , head , torso , or leg .
- This type of nerve damage is less common
Traumatic Myelinopathy
- Refers to the loss of myelin limited to the site of injury.
- Peripheral myelinopathy interferes with the function of _ ? _ .
Peripheral Nerves & Neuropathies
Mononeuropathy- Traumatic Myelinopathy:
- Refers to the loss of myelin limited to the site of injury.
- Peripheral myelinopathy interferes with the function of large-diameter axons (light touch / proprioceptive deficits ).
Focal compression of a peripheral nerve causes = _ ? _
Peripheral Nerves & Neuropathies
Mononeuropathy- Traumatic Myelinopathy:
- Focal compression of a peripheral nerve causes traumatic myelinopathy .
- Repeated mechanical stimuli may cause focal compression.
Myelinopathy Prognosis = ?
Peripheral Nerves & Neuropathies
Mononeuropathy- Traumatic Myelinopathy:
- Myelinopathy Prognosis = Good in cases of focal compression
- Schwann cells can remyelinate
Mononeuropathy
Traumatic _ ? _ ,
results in Wallerian degeneration.
Peripheral Nerves & Neuropathies
Mononeuropathy/ Traumatic Axonopathy - Axon Damage:
- Disrupts axons and results in Wallerian degeneration.
- Occurs distal to the lesion
Mononeuropathy
Axonopathies affect all sizes of axons; reflexes, somatosensorial, and motor functions are significantly _ ? _ .
Peripheral Nerves & Neuropathies
Mononeuropathy/ Traumatic Axonopathy - Axon Damage:
- Axonopathies affect all sizes of axons; reflexes, somatosensorial, and motor functions are significantly reduced or absent
- Regenerating axons (axon regrowth) may re-innervate targets
Axon Repair
- Prognosis improved if = ?
- Axonal regrowth, how much per day / month ?
Peripheral Nerves & Neuropathies
Axon Repair:
- Prognosis improved if support structures intact.
- Endoneurium , Perineurium , Epineurium
- Axonal regrowth: 1-2 mm / day , 1 inch / month .
- Axonal Sprouting : Intact axons take over, results in changes in motor unit morphology.
Traumatic Severance
_ ? _ , and _ ? _ are completely interrupted, causing immediate loss of sensation and/or muscle paralysis in the area supplied.
Peripheral Nerves & Neuropathies
Traumatic Severance:
- Occurs when nerves are physically divided by excessive stretching or a laceration.
- Axons and connective tissue are completely interrupted, causing immediate loss of sensation and/or muscle paralysis in the area supplied.
- Wallerian degeneration begins, later axons in the proximal stumps begin to sprout.
- Regeneration, however, may not always be functional, if the sprouts reach inappropriate targets or end-organs, resulting in poor recovery
Repair of Severance
- Requires = ?
- Prognosis typically = ?
- If no neurologic recovery, surgeries like = ?
Peripheral Nerves & Neuropathies
Repair of Severance:
- Requires surgical intervention
- Prognosis typically poor
- If no neurologic recovery, surgeries like tendon transfers may improve function.
_ ? _ neuropathy =
- Involves two or more nerves in different parts of the body; individual nerves are affected, producing a random, asymmetrical presentation of signs.
- Occurs when diabetes or vasculitis cause ischemia of the nerves.
Peripheral Nerves & Neuropathies
Multiple Mononeuropathy:
- Involves two or more nerves in different parts of the body; individual nerves are affected, producing a random, asymmetrical presentation of signs.
- Occurs when diabetes or vasculitis (inflammation of blood vessels) cause ischemia of the nerves
Multiple Mononeuropathy produces a random, _ ? _ presentation of signs.
Peripheral Nerves & Neuropathies
Multiple Mononeuropathy:
- Involves two or more nerves in different parts of the body; individual nerves are affected, producing a random , asymmetrical presentation of signs.
_ ? _ neuropathy =
Hallmark signs include symmetrical involvement of sensory, motor, and autonomic fibers, often progressing from distal to proximal .
Peripheral Nerves & Neuropathies
Polyneuropathy:
- Neuropathy involving multiple (poly) nerves in the body
- Hallmark signs include symmetrical involvement of sensory, motor, and autonomic fibers, often progressing from distal to proximal .
“ Distal symmetrical polyneuropathy ”
Polyneuropathy
- Symptoms typically begin in the (hands or feet) = ?
- Upper or Lower motor neuron = ?
Peripheral Nerves & Neuropathies
Polyneuropathy:
- Symptoms typically begin in the feet and then appear in the hands and areas of the body supplied by the longest axons ( length-dependent )
- Stocking and glove pattern
- Polyneuropathies are NOT the result of trauma.
- Multiple variants, but we will focus on most common presentations.
- Lower motor neuron
Stocking and glove pattern, makes you think ?
- (a) Traumatic myleinopathy
- (b) Traumatic axonopathy
- (c) Multiple mononeuropathy
- (d) Polyneuropathy
Peripheral Nerves & Neuropathies
- Stocking and glove pattern*** , makes you think ?
- (a) Traumatic myleinopathy
- (b) Traumatic axonopathy
- (c) Multiple mononeuropathy
- (d) Polyneuropathy
What kind of neuropathy…
A = ?
B = ?
Peripheral Nerves & Neuropathies
Mononeuropathy vs. Polyneuropathy:
- A = Multiple Mononeuropathy
- B = Polyneuropathy
Notes:
- Length-dependent
- Terminals of longest nerves affected, therefore:
- Distal symmetrical
- Distally affected first
- Motor loss, sensory loss, autonomic dysfunction
Diabetic Polyneuropathy
- Primary presenting factor = ?
- Can also lead to = ?
Can also lead to … (what impairments)
Peripheral Nerves & Neuropathies
Diabetic Polyneuropathy:
- Present in up to 90% of patients with DM
- Pathogenesis not fully understood, although hyperglycemia felt to be involved.
- Pain is primary presenting factor, often worse at night, burning to tingling like pins and needles.
- Presence of allodynia (pain response from non-painful stimulus).
- Can also lead to somatosensory impairments, loss / impaired sensation, sores / blisters, delayed wound healing, loss of toe / foot (Loss of balance/ falls).
Hallmark is midfoot collapse with “rocker-bottom” foot = ?
Peripheral Nerves & Neuropathies
- Interaction of multiple factors within DM polyneuropathy.
- Hallmark is midfoot collapse with “rocker-bottom” foot.
- High risk for breakdown, orthotics usually necessary.
Medications associated with the medical management of DM Polyneuropathy include = ?
Peripheral Nerves & Neuropathies
Medical Management of DM Polyneuropathy:
- Improve glycemic control
- Treatment of pain challenging, and pain management judged effective if 50% reduction in pain
- Medications:
- Anticonvulsants : Analgesia and improved sleep.
- Antidepressants : First line treatment.
- Opioids : 2nd or 3rd line treatment
- Topical agents : fewer side effects than medications and include capsaicin cream and lidocaine patches.
PT for DM Polyneuropathy should focus on = ?
Peripheral Nerves & Neuropathies
PT for DM Polyneuropathy:
- Exercise: Improve glycemic control, anti-depressive effects
- Address balance/gait impairments from proprioception deficits.
- Address strength deficits: according to prognosis and treatment goals
- Consider whether patient deconditioned
- Orthoses are frequently used to stabilize weight-bearing joints
- Prevent sprains and strains.
- Prevent dropping of the forefoot during gait in cases of paresis or paralysis of the tibialis anterior muscle
- Prevent deformities from paresis, paralysis, and lack of sensation.
- Sensory deficits
DM Polyneuropathy
Keys to foot care = ?
think shoes
Peripheral Nerves & Neuropathies
Foot Care:
- Wash your feet with soap in warm, NOT hot, water, 90° - 95° F is safe, or your elbow to test the warmth of the water.
- After washing and drying your feet, put talcum powder or cornstarch between your toes.
- Shoe Info:
- Wear shoes, that fit & protect your feet, and socks all the time.
- - Walking shoes and athletic shoes are good for daily wear.
- DO NOT wear vinyl or plastic shoes, because they do not stretch or “breathe.”
- Buy shoes at the end of the day, when your feet are the largest, so that you can find the best fit.
Alcoholic & Vitamin Deficiency Polyneuropathy
- Primary Treatment = ?
- Secondary Treatment = ?
Peripheral Nerves & Neuropathies
Alcoholic and Vitamin Deficiency Polyneuropathy:
- Primary Treatment : Abstain from alcohol, vitamin supplements, improve nutrition.
- Secondary Treatment : Medications and therapy similar to DM polyneuropathy.
- Notes:
- Vitamin deficiencies include B1 (thiamine), B6, B12, folate, niacin, and vitamin E.
- Nutrition usually poor
- Symptoms similar to DM polyneuropathy
_ ? _ neuropathy =
Can be caused by the neurotoxic effects of many cancer agents, and has symptoms similar to DM polyneuropathy.
Peripheral Nerves & Neuropathies
Chemotherapy Induced Polyneuropathy:
- Also called Chemo-induced peripheral neuropathy (CIPN).
- Neurotoxic effects of many cancer agents.
- Symptoms similar to DM polyneuropathy.
- Treated medically similar to DM polyneuropathy.
? Syndrome =
- Involves acute inflammation and demyelination of peripheral sensory and motor fibers.
- In 2/3 of cases it is preceded by an intestinal infection.
- Symmetrical motor loss in legs, then in trunk and arms, motor involvement is more severe.
- Absent/ diminished reflexes
- In severe cases, respiratory involvement.
Peripheral Nerves & Neuropathies
Guillain-Barré Syndrome:
- Involves acute inflammation and demyelination of peripheral sensory and motor fibers.
- Occurs 2-3 weeks after a mild infection.
- In 2/3 of cases it is preceded by an intestinal infection that activates the immune system causing production of an antibody that mistakenly cross-reacts with the myelin sheath.
- Dysfunction of peripheral nerves and the muscles they innervate can be evaluated by _ ? _ .
BONUS = What information does this give us ?
Peripheral Nerves & Neuropathies
Electrodiagnostic Studies:
- Dysfunction of peripheral nerves and the muscles they innervate can be evaluated by electrodiagnostic studies.
- BONUS = Recording electrical activity from nerves and muscles by nerve conduction and EMG studies reveal the pathologic location & are often diagnostic.
- Studies can be diagnostic as well as prognostic
Nerve Conduction Studies =
- The application of external current and record response from large diameter, myelinated axons.
- What does a segment with slow nerve conduction indicate = ?
- Three key parameters = ?
Peripheral Nerves & Neuropathies
Nerve Conduction Studies = The application of external current and record response from large diameter, myelinated axons.
- Response depends upon site of stimulation and location of recording electrodes.
- Slow nerve conduction across the site of damage w/ normal conduction in the axon segment proximal and distal to the injury.
- Key parameters:
- Latency : Time from stimulus to response.
- Velocity : Speed of conduction across segment.
- Amplitude
Electromyography
- What is it = ?
- What are these used to investigate = ?
- Two key parameters = ?
Peripheral Nerves & Neuropathies
Electromyography:
- Insertion of recording electrode (needle) into muscle, view and listen to electrical activity of muscle.
- Generally investigates axonal & muscular integrity.
- Key parameters :
- Insertional and rest activity
- Recruitment activity
In patients 50 y/o or older, the presence of two or three signs correlate highly with peripheral neuropathy.
- What are the three signs = ?
Peripheral Nerves & Neuropathies
Clinical Testing:
- Presence of two or three signs correlate highly with electrodiagnostic evidence of peripheral neuropathy.
- Absence of ankle jerk reflex
- Impaired vibration
- Impaired position sense of the great toe
Distinguising Peripheral F/ Central Nervous System
- Distribution of signs & symptoms :
- PNS = ?
- CNS = ?
- Nerve conduction study :
- PNS = ?
- CNS = ?
- Muscle tone :
- PNS = ?
- CNS = ?
- Muscle atrophy :
- PNS = ?
- CNS = ?
- Phasic stretch reflex :
- PNS = ?
- CNS = ?
Peripheral Nerves & Neuropathies
- Distribution of signs & symptoms :
- PNS = Peripheral nerve pattern
- CNS = Dermatomal or myotomal pattern
- Nerve conduction study :
- PNS = Slowed or blocked conduction; decreased amplitude or recorded potentials
- CNS = Normal
- Muscle tone :
- PNS = Lower motor neuron involvement; hypo-tonia
- CNS = Upper motor neuron involvement; hyper-tonia
- Muscle atrophy :
- PNS = Rapid muscle atrophy indicates denervation
- CNS = Muscle atrophy progresses slowly
- Phasic stretch reflex :
- PNS = Reduced or absent
- CNS = Hyperactive or normal
