Neuromuscular diseases Flashcards
anterior horn cell diseases
- proximal spinal muscular atrophies
- werdnig-hoffman disease
- wohlfart-kugelberg-welander disease - amyotrophic lateral sclerosis (ALS)
- infectious disorders
- poliomyelitis anterior acuta
- congenital and trauma
ALS
progressive degeneration of motor cells throughout the nervous system resulting in muscle wasting and weakness
- familial type: onset 40-60 years
- sporadic type: onset 65 years
MC in males; 1 in 50 000 canadians have it
Etiologies of ALS
Immune response: Ab-Ag response that kills nerve cells
- chemical imbalance: ALS patients have higher levels of glutamate near the motor neurons (toxic in high concentration to nerve cells)
- Abnormal protein synthesis: abnormal processing/accumulation of protein, resulting in cell death
Signs and Symptoms of ALS
first s/s
- 50% of cases have weakness in one arm (dropping things, dexterity loss)
- 25% of cases weakness in one foot (foot drop, falling)
- 25% of cases weakness of bulbar musculature (mm of jaw, face, deglutition)
Initial s/s -muscle cramps: especially at night, interfering with sleep -fasciculations -weakness or clumsiness in leg/hand -difficulty speaking and swallowing Pain: more prevalent in later stages -joint discomfort, cramping -muscle: cramping, spasticity (jaw mm), and fasciculations can cause pain
emotional/social: difficulties due to pain/disability
shortness of breath and choking: more as disease progresses; need for ventilator and tube to stomach as breathing and swallowing muscles stop functioning
treatments for ALS
therapy: help with pain management and fall risk
- gentle, low impact aerobic exercise: to strengthen unaffected muscle and improve cardiovascular health
ROM and stretching: prevent painful spasticity and contracture of muscles
spinal mobiltiy and stabilization: prevent spinal curvatures, better mobility and enhance well being
speech therapist: provide adaptive strategies
natural therapies: manual, acupunture, cannabis
rx: Riluzole (reduces damage to motor neurons by decreasing the release of glutamate; increases survival rate by several months)
purpose of ALS treatment
symptom relief and improved quality of life for patients
no cures, and prognosis is very poor; it progresses until you need machines to support the body. A horrifying disease where the mind slowly becomes trapped in a shell of a body
Neuropraxia
Characterized by a focal segmental demyelination at the site of injury without disruption of axon continuity and its surrounding connective tissues
Results in blockage of nerve conduction and transient weakness or paresthesia
Type A conduction blockage
- circulatory arrest
- metabolic block
- NO neuropathology
- reversible
Type B conduction blockage
Edema within the nerve
- vasa nervorum compressed
- worse with co-morbid disease (e.g. diabetes)
- intraneural pressure increased
Axonotmesis
Injury to a peripheral nerve of one of the extremities of the body and their myelin sheath are damaged in this kind of injury
-but endoneurium, perineurium, and epineurium remain intact
Neurotmesis
Complete transection of peripheral nerve
Will produce complete sensory and motor deficits to skin and muscles innervated by the injured nerve
Charcot Marie Tooth Disease
hereditary condition characterized by progressive degeneration of the muscles of the lower leg, specifically those associated with the fibula
- 1 in 2500 people diagnoses
- mutations in genes
- BOTH motor and sensory nerves are affected; gradual symptom progression
- mild-severe pain
Weakness of foot and lower leg muscles
- increased fall risk
- high steppage gait as weakness occurs
- foot deformities: high arches, hammer toes, leg atrophy
- difficulty with fine motor skills
GUillain-Barre Syndrome
Usually occurs after infection elsewhere in the body; nervous system is attacked by antibodies from infection
Acute onset of peripheral and cranial nerve dysfunction
-viral respiratory or GI infection procedes neurological symptoms by 1-3 weeks
Features of GBS
- rapidly progressive symmetric weakness
- loss of tendon reflexes
- facial diplegia (stiffness, weakness or lack of mobility in facial muscles)
- respiratory paresis
- sensory loss in hands and feet
S/s most severe within 1 week of onset but may progress for 3+ weeks
Self-limiting; death from GBS is rare
Myasthenia gravis
Acquired autoimmune disorder characterized clinically by weakness of skeletal muscles and fatiguability on exertion
Ab against ACh receptors in NMJ of skeletal muscles
Muscle weakness worsens after period of rest
Significant muscle weakness: eyelids and oculomotor; facial expression, chewing, talking, swallowing, respiratory and peripheral skeletal muscles
Lambert eaton syndrome: where in NMJ is the problem
Antibodies agaisnt presynaptic calcium channels of the NMJ
