Neuropathies Flashcards
Hereditary Vs Acquired polyneuropathies
Cause:
- Hereditary is genetic
- Acquired is due to environmental or medical factors
Onset:
- Hereditary types typically start early in life (but can develop later)
- Acquired types can begin at any age
Progression:
- Hereditary neuropathies usually have a slower progression
- Acquired neuropathies can come on more suddenly
Acquired polyneuropathy example
Guillain-Barré syndrome
- Rare neurological autoimmune disorder in which the body’s immune system mistakenly attacks the peripheral nerves
S&S:
- Weakness or tingling in the legs
- Difficulty walking
- Loss of reflexes
- Severe cases can lead to paralysis or difficulty breathing, requiring urgent medical care.
CAUSE:
- The exact cause isn’t always known, but GBS often follows infections like respiratory or gastrointestinal viruses.
Hereditary polyneuropathy example
Charcot-Marie-Tooth
- Group of inherited neurological disorders that affect the peripheral nerves
S&S:
- Progressive weakness in the muscles of peripheral limbs
- Sensory loss in the hands and feet
- Muscle atrophy
- Deformities in feet & hands
- Reduced reflexes
CAUSE:
- Most common type is caused by mutations in genes that produce proteins involved in the structure and function of the nerve cells, leading to damage to the myelin sheath or the axon
What is a polyneuropathy?
Polyneuropathy is a condition that affects multiple peripheral nerves throughout the body
What is a mononeuropathy?
Mononeuropathy refers to damage or dysfunction of a single peripheral nerve
It is typically caused by trauma, compression, or other localised issues that specifically impact one nerve or a nerve group.
What is a myopathy?
Myopathy refers to a group of disorders that affect the muscles, leading to muscle weakness, pain, and sometimes muscle wasting.
Upper limb (shoulder) mononeuropathy examples
Long thoracic
- C5-C7
- Innervates: serratus anterior
- Function: protraction
- Visual: scapular winging
Dorsal scapular
- C5
- Innervates: levator scapulae & rhomboids
- Function: abduction
Suprascapular
- C5-C6
- Innervates: supratspinatus & infraspinatus
- Function: abduction
Axillary
- Posterior chord of brachial plexus
- Innervates: deltoid & teres minor
- Function: abduction & sensory (lateral upper arm)
Upper limb mononeuropathy examples
Median
- C6-C7
- Numbness/tingling in thumb, index, middle, and half of ring finger
- Weak grip, thenar muscle wasting
- Innervates: lateral hand & forearm muscles
- Example: carpal tunnel syndrome
Ulnar
- C8-T1
- Numbness/tingling in ring and little finger
- Weak finger abduction
- Hand muscle wasting (especially hypothenar)
- Claw hand
- Innervates: intrinsic hand muscles
- Example: cubital tunnel syndrome
Radial
- C5-T1
- Wrist drop
- Weak finger/wrist extension
- Numbness over back of hand and forearm
- Innervates: extensor muscles
- Example: Saturday night palsy
Causes of upper limb neuropathies
- Stretch
- Transecting injury
- Compression
- Entrapment
- Brachial plexus neuritis
Lower limb neuropathy examples
Peroneal (MC)
- L4-S2
- Vulnerable at fibula head
- Innervates: muscles of the anterior and lateral compartments of the lower leg and provides sensory innervation to parts of the foot
- Clinical presentation: steppage gait, foot slap, weak dorsiflexion/eversion, diminished sensation (dorsum of foot & lateral distal leg)
Tibial
- L5-S2
- Innervates: muscles (hamstrings & calf) and skin along the posterior and plantar aspects of the leg and foot.
- Clinical presentation: weakness in plantar flexion & inversion & sensory deficit in heel & plantar areas
- Example: tarsal tunnel syndrome
Femoral
- L2-L4
- Innervates: ilopsoas & iliacus
- Clinical presentation: weak hip flexion, diminished patella reflex, loss of sensation in anteriomedial thigh
Lateral femoral cutaneous
- L2-L3
- Innervates: skin on the lateral aspect of the thigh
- Clinical presentation: numbness & dysesthesias in lateral thigh
- Example: Meralgia parasthetica (entrapment)
Hereditary myopathy examples
- Muscular Dystrophies
- Characterised by progressive muscle weakness and degeneration
- Often result from mutations in genes encoding proteins essential for muscle function - Mitochondrial Myopathies
- Defects in the mitochondria which produce energy within cells - Channelopathies
- Defects in ion channels that regulate muscle contraction - Metabolic Myopathies
- Defects in enzymes involved in the breakdown or storage of glycogen, the body’s energy reserve
Acquired myopathy examples
- Inflammatory Myopathies
- Inflammation of the muscle tissue and often have an autoimmune component - Endocrine Myopathies
- Related to abnormal hormone levels affecting muscle function - Toxic Myopathies
- Exposure to toxins or drugs that damage muscle tissue
