Neuropathies Flashcards by B M

What is mononeuritis multiplex? What are the causes?

Dysfunction of 2+ peripheral nerves
Most common: DM
-HIV, amyloidosis, sarcoid

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Describe the presentation of an ulnar nerve palsy

Partial claw hand

Flexion of the intrinsic muscles of the hand
Hypothenar wasting
Loss of sensation to medial 1 1/2 fingers

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What is the most common cause of an ulnar nerve palsy?

Elbow trauma eg. supracondylar fracture

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What are the ulnar nerve roots?

C7-T1

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Describe the presentation of a median nerve palsy

Carpal tunnel syndrome

Thenar muscle wasting
Parasthesia/anaesthesia of the palmar side of lateral 3 1/2 digits and palm
LLOAF muscle weakness
Tinel’s and Phalen’s test +ve

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What are the causes of median nerve palsy?

Carpal tunnel syndrome 
-Pregnancy 
-High BMI 
-Occupational factors
-Acromegaly
Trauma

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What are the median nerve roots?

C6-T1

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Describe the presentation of radial nerve palsy

Wrist drop

Weakness of the extensor muscles of the forearm and hand
Parasthesia/anaesthesia of the dorsal thumb

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What are the radial nerve roots?

C5-T1

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What are the causes of radial nerve palsy?

Trauma

Wrist fracture
Fracture of the humeral shaft

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Describe the presentation of Erb’s palsy. What are the affected nerves?

Caused by lesion of upper branch of brachial plexus (C5-6)

Internally rotated shoulder
Flexed wrist (waiter’s tip)
Often present from birth

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Describe the presentation Klumpke’s palsy. What are the affected nerves?

Caused by a lesion of the lower branch of the brachial plexus (C8-T1)
-Claw hand

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What is the name of palsy of the lateral cutaneous nerve of the thigh?

Meralgia parasthetica

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What are the nerve roots of the sciatic nerve?

L4-S3

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What are the nerve roots of the common peroneal nerve?

L4-S2

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What are the nerve roots of the tibial nerve?

L4-S3

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Describe the presentation of a tibial nerve palsy

Inability to tip-toe walk

Weakness of ankle plantarflexion and inversion, digit flexion
Parasthesia/anaesthesia of the posterolateral leg, lateral foot and sole of the foot

Describe the presentation of a common peroneal nerve palsy

Footdrop- inability to heel-walk

Weakness of ankle dorsiflexion and eversion, digit extension
Parathesia/anaesthesia of the lateral leg, dorsum of foot

What are some causes of common peroneal nerve palsy?

Fracture of fibula

- Tight plaster cast

Describe the presentation of sciatic nerve lesion

Weakness of knee flexion
Weakness of ankle and digits movements
Reduced sensation to posterolateral leg and foot

What are the nerve roots of the femoral nerve?

L2-L4

Describe the dermatomes of the lower limb

L1: groin 
L2: anterolateral thigh
L3: medial thigh to the knee 
L4: medial leg
L5: big toe/ anterior leg 
S1: small toe and heel 
S2: posterior leg 
S3: buttock

Describe the dermatomes of the upper limb

C5: upper shoulder (deltoid), lateral arm 
C6: lateral forearm, thumb 
C7: middle finger 
C8: pinky finger, medial forearm
T1: medial arm

Describe the presentation of Bell’s palsy

7th/facial nerve palsy

Sudden onset unilateral weakness of the facial muscles, non-forehead sparing
Altered taste sensation
Hyperacusis, otalgia

What are the differentials for Bell's palsy?

- Lyme disease - Ramsay Hunt syndrome - UMN: stroke - Neoplasms

Describe the diagnostic process for suspected Bell's palsy

- History suggestive - Examination: full cranial nerves, otoscopy - Consider: Lyme serology, EMG, MRI

Describe the management of Bell's palsy

Conservative: corneal protection (glasses, drops) Medical: corticosteroids within 72 hours of onset -60mg PO for 5/7 -> taper Surgical: decompression in severe cases

What is the prognosis of Bell's palsy? Name some complications

70% fully recover within several months Improved with steroids Complications: corneal abrasion, keratoconjunctivitis sicca, crocodile tears (eat -> tears), synkinesis (blink -> upturn mouth)

Describe the presentation of Ramsay Hunt syndrome

Otalgia followed by facial weakness, dysgeusia, hyperacusis (very similar to Bell's palsy) Presence of vesicles on the TM/ear canal, hard palate -May also have 8th nerve involvement

Describe the treatment of Ramsay Hunt syndrome

Valaciclovir and prednisolone

Name some causes of bilateral polyneuropathy

- DM - Inflammatory: GBS - Infectious: HIV - Toxins, medications, alcohol - Metabolic: B12 deficiency, hypothyroidism - Vascular

What investigations would you consider for polyneuropathy?

- History and exam - Bloods: FBC, CRP and ESR, U+Es, LFTs, HbA1c, TFTs, B12, HIV - Special tests: EMG, NCS

Describe the presentation of diabetic neuropathy

- Sensory neuropathy in a glove + stocking distribution - Reduced/absent deep tendon reflexes - Foot drop, muscle weakness - Joint deformity

Describe the presentation of GBS

- Acute onset symmetrical polyneuropathy - Distal sensory abnormality and progressive proximal ascending muscle weakness (LMN) - Following GI/resp infection - Peaking within 2 weeks, resolving within months

Describe the diagnostic process in suspected GBS

- History and examination suggestive - Bloods: general screen, anti-ganglioside antibodies, LFTs - NCS - LP for CSF analysis (raised protein w normal cell count) - Spirometry 6 hourly initially to determine ICU need - Consider MRI if unclear or ?spinal cord lesion

Describe the management of GBS

``` Supportive: -Analgesia -Airway -Antithrombotic -Autonomic support IVIG or plasma exchange Rehabilitation ```

What is Charcot Marie Tooth disease?

A group of hereditary peripheral neuropathies

Describe the presentastion of CMT

- Onset during puberty - Mixed motor and sensory polyneuropathy - Motor: weakness of anterior leg muscles: foot drop, champagne bottle legs, pes cavus, toe clawing. Absent ankle jerks - Sensory: stocking pattern loss

What are the investigations for CMT?

- NCS | - Genetic testing

What is the use of nerve conduction studies?

- To diagnose peripheral neuropathies | - Can differentiate between sensory and motor neuropathy