Neuropathy and Myopathy Flashcards
Mononeuropathy
A single large, “named” nerve is affected, usually by compression or trauma
Polyneuropathy
AKA peripheral neuropathy and is a disorder of multiple large or small nerves
What is the most common presentation of polyneuropathy?
Stocking and glove sensory deficits
Paresthesia
Spontaneous tingling with a pins and needles sensation
Dysesthesia
Unpleasant sensation from a non-noxious stimulus
Carpal Tunnel Syndrome
Results from the compression of the median nerve in the wrist
What is the most common mononeuropathy?
Carpal Tunnel Syndrome
Guillain-Barre Syndrome
Affects people of all ages and occurs most often after an infection - immune system will target myelin and cause an ascending areflexic paralysis
What infection is Guillain-Barre Syndrome associated with?
Campylobacter jejuni
What is a lab finding with Guillain-Barre Syndrome?
Elevated protein found in the CSF
What is one of the most frequent causes of polyneuropathy?
Diabetes mellitus
Myopathy
Pathology of the muscle directly which can be seen with proximal weakness or fatigue alongside normal sensation and late loss of reflexes after significant atrophy
What are some possible causes of myopathy?
- Viral infection
- Statins
- Cushing’s
Polymyositis
Inflammation and weakness of multiple muscles may occur from viral infections or drug reactions
What is the most common cause of polymyositis in the US?
An autoimmune cause is most common in the USA:
– proximal weakness developing over weeks to months
– a rash around the eyes or fingers may occur
Dermatomyositis
Rash around the knuckles and periorbital areas from polymyositis
Muscular dystrophy
Hereditary myopathies of variable progression and severity
What is the inheritance of Duchenne’s Muscular Dystrophy?
X-linked
What is the mutation of Duchenne’s muscular dystrophy?
Absence of dystrophin, a critical structural protein in muscle and involves respiratory and cardiac muscles as well
What are some clinical signs of Duchenne’s muscular dystrophy?
- Calf pseudohypertrophy
- Proximal weakness since childhood
What is Gower’s maneuver?
It is seen in Duchenne’s dystrophy where young children push up their trunk to get to a standing position
Myotonic Dystrophy Type I
Autosomal dominant. Excessive trinucleotide repeats on Ch19 which produces abnormal protein kinase in muscle fibers.
Myotonia
Impaired relaxation of muscles after volitional contraction
Motor Neuron Disease
Disorders, occasionally hereditary, where degeneration of upper (UMN) or lower (LMN) motor neurons, or both, occurs with varying severity and rate of progression
Spinal Muscular Atrophy
Group of disorders that involve just the anterior horn cells - most are hereditary with LMN signs of weakness, atrophy, areflexia, fasciculations
Werdnig-Hoffmann Disease
Infantile onset of anterior horn cell degeneration that is a terminal condition due to
rapid development of diffuse weakness, with no current curative treatment
What is the most common motor neuron disease?
Amyotrophic Lateral Sclerosis
Amyotrophic Lateral Sclerosis
Progressive degeneration of UMN and LMN
What are the symptoms of ALS?
Frequently begins with regional weakness and atrophy of a limb (e.g., shoulder), which spreads and becomes bilateral; or initial weakness of swallowing or speech
What mutation is seen in familial ALS?
Defective Copper-Zinc Superoxide Dismutase
What is the only drug for ALS (not curative)?
Riluzole (glutamate antagonist) prolongs survival by months (glutamate may “overly excite” motor neurons)
