1. Dayna Ryan, PT, DPT Winter 2012
Extra Information!
Dayna Ryan, PT, DPT
Winter 2012

2. Classification of Nerve Injuries
Neurapraxia = segmental demyelination, which slows/blocks conduction of the action potential
Axonotmesis = when axon is damaged but the connective tissue coverings that support and protect the nerve remain intact
Neurotmesis = complete severance of the axon and supporting connective tissues
These injuries typically occur from mechanical compression/entrapment
Neurapraxias: often occur after nerve compression injuries that induce mild ischemia
-nerve conduction is normal above and below the point of compression because the axon remains intact and the muscle does not atrophy
Axonotmesis: can be caused by prolonged compression that produces an area of infarction and necrosis
Neurotmesis: causes axons distal to injury to degenerate (because no stimulation) and least likely to recover and re-innervate the correct muscles (because no pathway)
LML
**will get muscle atrophy with both axonotmesis and neurotmesis

3. Classification of Neuropathy
Mononeuropathy: single peripheral nerve affected (i.e. CTS)
Polyneuropathy: multiple peripheral nerves involved (i.e. DM) glove/sock
Radiculoneuropathy: involvement of the nerve root as it emerges from the spinal cord (dermatome/myotome)
Myopathy: muscle involved, typically at NMJ
When nerve involved starting at the spinal nerve root, see patterns of weakness in myotomes

4. Saturday Night Palsy/Sleep Palsy
Radial nerve compression (typically is spiral groove of the humerus)
Compression causes segmental demyelination
Radial nerve compression in the axilla: crutch palsy
Clinical presentation: weakness in triceps, brachioradialis, and supinators, wrist extensors, and grip; paresthesias in the radial nerve distribution
This is why it is important to know your peripheral nerve distributions!!

5. Erb’s Palsy = traction injury to the brachial plexus at birth
Erb-Duchenne Palsy: C5-C6 nerve roots
Klumpke’s Palsy: C8-T1 nerve roots
Whole Arm Palsy: C5-T1 nerve roots
You will learn more about this in Peds course

6. Morton’s Neuroma Entrapment of the common digital nerve
Most often occurs in the third toe space
Symptoms: burning/tingling/sharp pain, always want to massage foot
Bilateral involvement uncommon
Occurs from wearing high heels, too tight of shoes, and thin-soled shoes—increased pressure on the ball of foot
Confined space around the transverse metatarsal ligamentincreased compression forces causes an acute inflammatory response

7. Carpal Tunnel Syndrome
Impingement of the median nerve AT THE WRIST (carpal tunnel)
Cubital tunnel syndrome = ulnar nerve impingement at the elbow
Commonly mis-diagnosedlook at MOI and clear neck/shoulder/elbow
will talk more about in orthopedic course!

8. Referred Pain from Internal Organs
a.k.a. Visceral Pain
Need to know these patterns so can rule out musculoskeletal and neuromuscular disorders
Note kidneys, heart, liver/gallbladder, and lungs
Radiation is different than referred pain – radiating is from nerves and follows a distinct pattern from the site of disfunction
You will learn more about this in future courses

9. Referred Pain Patterns
Just in case you like this picture better…

10. Thalamic Pain Syndrome
= results when a stroke occurs in the thalamus
Initial Symptom: numbness on the opposite side of the body
Later develops into burning/tingling sensation
Allodynia (hypersensitivity to pain)
Pain can increase from ambient temperatures (heat or cold) or emotional distress
SENSORY affected!
a.k.a. Dejerine-Roussy Syndrome
The thalamus is generally believed to relay sensory information between a variety of subcortical areas and the cerebral cortex

11. Reye’s Syndrome Exact cause is unknown
Seems to be triggered by using aspirin to treat a viral illness or infection (flu, chicken pox) in children/teens who have an underlying fatty acid oxidation disorder
Exposure to certain toxins: insecticides, herbicides, paint thinner
Blood glucose drops while levels of ammonia (acidity) rise
Liver swells and develops fatty deposits
Brain may swell  seizures, convulsions, LOC
Fatty acid oxidation disorders are a group of inherited metabolic disorders in which the body is unable to break down fatty acids because an enzyme is missing or not working properly. A screening test is needed to determine if your child has a fatty acid oxidation disorder.
LOC = loss of consciousness

12. Reye’s Syndrome Initial signs/symptoms Additional signs/symptoms
Children <2 y.o.: diahrrea, rapid breathing
Older children/teens: persistent vomiting, lethargy/unusual sleepiness
Additional signs/symptoms
Irritability; aggressive/irrational behavior
Confusion, disorientation, or hallucinations
Weakness or paralysis in the arms/legs
Seizures
Excessive lethargy
Decreased level of consciousness
The signs and symptoms of Reye's syndrome typically appear about three to five days after a viral infection, such as the flu (influenza) or chickenpox, or an upper respiratory infection, such as a cold.
Diagnosed by ruling out neurological conditions: spinal tap, CT scan, liver biopsy, urine testing
Tested with drugs: diuretics, IV fluids, anti-seizure meds, medications to prevent bleeding in the liver, ventilator is breathing affected

13. Spinal Muscular Atrophy
Lesion site = anterior horn cells and motor nuclei of the brainstem
Etiology: autosomal-recessive inheritance
Signs/Symptoms:
Hypotonia
Weakness
Cranial nerve palsies

14. Spinal Muscular Atrophy
Proximal muscles are weaker than distal
Good fine motor control
Legs weaken before arms
Only motor system affected
Decreased DTRs
Hypotonia
Weakness/atrophy

15. Spinal Muscular Atrophy
SMA Type I (Werdnig-Hoffman Disease) = floppy baby syndrome
Never sit, roll, walk
Death by 3 y.o. from respiratory failure
SMA Type II
Onset before 18 months of age
May sit but never walk
Death by 7 y.o.
With Type I, mother may report decreased activity in utero in the later weeks of pregnancy
“onset” Is time of diagnosis—are not able to diagnose until baby does not reach their motor milestones

16. Spinal Muscular Atrophy
SMA Type III (Kugelberg-Welander Disease)
Onset after age 2
Difficulty walking, running, jumping
Half of these children lose the ability to walk by age 10  WC dependent as adults
Proximal muscle weakness but affects UE more
Can have either hyporeflexia or hyperreflexia
PT Considerations:
Intellect is NOT affected
Try to prevent scoliosis to preserve respiratory function
Postural control also important to prevent feeding problems

17. Blood-Brain Barrier
= specialized, permeable barrier between the capillary endothelium of the CNS and extracellular space
Exclude large molecules (FFA, proteins, specific amino acids)
Prevents many pathogens from entering CNS

18. Spinal Tracts – know where they cross!
Left: spinothalamic: pain, temp, crude touch
Center: corticospinal: voluntary motor
Right: medial lemniscal, fine touch, vibration, propreiception
MCA=lateral brian.
PCA=occipital
Expressive aphsia= broca’s
Receptive=wernickies
Ischemic and Hemerrogic (intracranial, subdural)