Peripheral Neuropathies Flashcards
What is peripheral neuropathies?
Nerve pathologies outside the CNS of peripheral nerve
What are the causes of peripheral neuropathies
Demyelination is often secondary to an infectious, an ischemic, a metabolic, or a hereditary disorder or to a toxin (eg, alcohol, ethambutol).
Primary causes are sually autoimmune(GBS)
|What are the mechanism by which peripheral neuropathy can be caused>
demylination
axon damage
nerve compression
vacular compromise-infarction
What are the differennt type of peripheral neuropathies?
Mononeuropathies : Affect single nerve
mononueritis multiplex: affects several individual nerves
Polyneuropathy - diffuse nerve involvemnet - often symmetrical pathologies
Name 4 types of mononeuropathies?
Carpal Tunnel syndrome
Radial Nerve palse
Ulnar nerve pasly
Sciatica
What is carpal tunnel syndrome?
Carpal tunnel syndrome is caused by nerve compression of the medial nerve passing originating from C6-T1
What are the RF/CAUSES of carpal tunnel sydrome
Female>Males
>30
Obesity
Hypothyroidism, Acromegaly, preganancy, RA
How would carpal tunnel sydrome present?
Gradual onset and intermittent
Numbness and parathesia of hand
Weakened grip
Aching forearm and hand
Night time worsening (relieved by hand hanging overside bed); wake and shake
How to diagnose carpal tunnel syndrome?
Phalen test: flex wrist>1min = pain and aprathesia
Tinel test - Tapping of wrist causes tingling
Treating carpal tunnel syndrome
Wrist splint to wear at night
Steroid injection if painful
Last resort - Surgical decompression
What is radial nerve palsy?
Typically caused by injury to the radial nerve (originating from C5-T1) classically presenting wrist drop.
Radial nerve innervates extension arm muscles
tx- analgesia+ wrist splint
What is ulnar nerve palsy
Typically caused by injury to the ulnar nerve (originating from C8-T1) classically presenting with claw hand.
TX - Wrist splint and simple analgesia
What is sciatica
L5/S1 lesion due to:
Spinal disc hernation / prolapse
non-spinal: Piriformis syndrome (piriformis msucle compress spinal tracts), tumour
How would sciatica present?
Pain from buttock down lateral leg to toes
Absent Ankle jerke
Diagnosing sciatica?
Clinical examination: cant raise a straight leg without pain
MRI Spinal cord to confirm
Sciatica tx
Analgesia
Physiotherapy
Neurosurgery
What are the causes of mononeurities multiplex?
Think vasculities and
Wards PLC
Wegners
Amyloidosis
RA
DMT2
Sarcoidosis
polyarteritis boidisa
Leprosy
Carcinomas
What are the causes of polyneuropathies
Diabetic neuropathy - Mostly sensory neuropathy
Guillian barr syndrome - Motor neuropathy
Other: vasculities, malignancy , b12 def, RA
‘Glove and stocking disrubution (numbness, weakness, or pain in the hands and feet)
What is charcot mary tooth
Inherited sensory and motor PNS poly neuropathy.
Autosomal dominant inheritance pattern PUP22 gene ~ Chr7
Diagnosed via nerve biopsy
How does charcot mary tooth present
Foot drop
Stork legs ( calves are skinny)
Hammer toes (Toes always curled up)
Feet : flat/high arched
What is foot drop
Front of the patients foot drags on the ground as they walk, most commonly caused by peroneal nerve compression
What causes foot drop?
Causes:
→ Nerve injury - e.g knee injury can cause compression of the peroneal nerve, can also be injured during hip or knee replacement surgery
→ Muscle or nerve disorders that cause progressive muscle weakness - e.g Charcot-Marie-Tooth disease
→ Brain and spinal cord disorders - Stroke/MS/ALS
→ tumour/cyst/bone lesions pressing on peroneal nerve
Signs of foot drop
Difficulty lifting the front part of the foot, foot drag on the floor when pt walks
→ steppage gait - pt raises thigh more than usual when walking as though climbing stairs
→ numbness of the top of foot and toes can occur
→ can affect one or both feet
Foot Drop DX and TX
Investigations and diagnosis
→ Imaging - X-rays/ultrasound/CT/MRI
→ nerve conduction studies
TX -Treatment
→ Braces or splints
→ physical therapy
→ nerve stimulation
→ Surgery
