Neuropathy, Myopathy, and NMD Flashcards
What is a Mononeuropathy?
A single, major nerve is involved with sensory or motor deficits related to its anatomical distribution
Wha are the 2 most common causes of mononeuropathies?
Trauma or Compression
Common cause of Ulnar Mononeuropathy?
Leaning or falling on the elbow
Common cause of Peroneal Mononeuropathy?
Injury to the lateral knee
Carpal Tunnel Syndrome
Describe the pathophysiology
If there is inflammation or swelling of the flexor tendons in the carpal tunnel, they can compress the median nerve and cause pain
May also be caused by fluid retention in pregnancy
Carpal Tunnel Syndrome
Clinical Symptoms
Tingling numbness of hand (thumb, index, middle, 1/2 ring finger)
Thenar weakness and atrophy in very severe cases
Carpal Tunnel Syndrome
Treatment
Local rest
Anti-inflammatories
Splinting
Surgical decompression of the nerve
Describe Wallerian degeneration of nerves
Occurs at sites of severe nerve injury
Injury involves myelin and axons distal to the point of injury
Do nerves regenerate?
CNS neurons are not good at regenerating, but PNS neurons may regenerate. Likelihood of regrowth is based on distance needed to travel and the degree of injury sustained
What is a polyneuropathy?
Disorder of multiple, major and small nerves
Characterized by an early sensory loss in distal limbs
Polyneuropathy
Clinical Symptoms
Spontaneous tingling
Pins and needles = Paresthesia
Unpleasant stimulation from non-painful stimuli = Dysesthesia
Distal limb weakness and atrophy
Early loss or decrease of muscle stretch reflexes
What are two general big causes of Polyneuropathy?
Axonal degeneration (more common)
Demyelination
How are axonal degeneration and demyelination discriminated on nerve conduction studies?
Axonal degeneration – amplitude of waves are reduced
Demyelination – slowing of the nerve conduction
What is EMG testing?
Needle electromyography
Electrical activity of muscles within individual motor units is assessed for denervation, reinnervation, or muscle disease
When are nerve biopsies performed?
Rarely. Only for significant neuropathy and typically only done for sensory nerves.
The patient is left with numbness after the biopsy
Polyneuropathy
Treatment
Address underlying causes (diabetes, alcohol)
Orthotic devices – improve ambulation
Physical therapy
Meds to improve paresthesia or dysesthesia
Guillan Barre Syndrome
Clinical Symptoms
Ascending, areflexic paralysis
Acute polyneuropathy and weakness progressing quickly and at its worst by 4 wks
Guillan Barre Syndrome
What often precedes this syndrome? Describe the pathology.
Acute viral respiratory infection precedes the syndrome 50% of the time.
Misdirection of immune system to attack normal peripheral nerve myelin
Get inflammation and demyelination of the peripheral nerves or roots
Guillan Barre Syndrome
Diagnosis
Evidence of demyelination seen on EMG (slowing of conduction)
Elevated protein in CSF, few if any WBCs
Guillan Barre Syndrome
Prognosis and Treatment
Good prognosis with medical treatment
Plasmapheresis or IVIG may shorten illness and hasten recovery
List some potential causes of Chronic Acquired Polyneuropathies
Diabetes Hypothyroid Uremia Cancer Myeloma Rheumatoid arthritis Lupus Nutritional defects (Vit B) Infection (leprosy) Toxins (alcohol, lead)
Hereditary Neuropathies
Clinical Symptoms
Onset usually in childhood
Distal sensorimotor deficits
Little/no paresthesia or dysthesia
May affect skeletal development (scoliosis, hammertoes, pes cavus)
What is a myopathy?
Primary disease of muscle
What is the first sign of myopathy?
PROXIMAL limb weakness and atrophy (shoulder and hip)
