Extra Information!Dayna Ryan, PT, DPTWinter 2012

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

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

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

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

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

Carpal Tunnel Syndrome

• Impingement of the median nerve AT THE WRIST (carpal tunnel)• Cubital tunnel syndrome = ulnar nerve

impingement at the elbow

Referred Pain from Internal Organs

Referred Pain Patterns

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!

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

Reye’s Syndrome

• Initial 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

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

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

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.

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

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

Spinal Tracts – know where they cross!