Peripheral polyneuropathy Flashcards Preview

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Flashcards in Peripheral polyneuropathy Deck (24):
1

Sensory findings in peripheral polyneuropathy

Bilateral, symmetrical
Glove and stocking distribution: length dependent
Reduced tendon reflexes (loss of ankle jerks in DM)
Signs of trauma or joint deformity (Charcot's joints)
Loss of proprioception - positive Romberg's test

2

Motor findings in peripheral polyneuropathy

Bilateral, symmetrical
LMN weakness: wasting, fasciculations, reduced tone, hyporeflexia

3

Completion of neurone exam in peripheral neuropathy

Review drug chart
Dipstick for glucose
Gait + Romberg test
Cranial nerve exam

4

Causes of peripheral polyneuropathy

Mainly sensory:
DM
EtOH
B12 deficiency
CRF (uraemia) and Ca (paraneoplastic)
Vasculitis
Drugs e.g. isoniazid, vincristine
Mainly motor:
HMSN/CMT
Paraneoplastic (Ca lung, RCC)
Lead poisoning
Acute - GBS and botulinum

5

Specific history for peripheral polyneuropathy

Time course
Precise symptoms: ataxia - B12, painful dysesthesia - EtOH, DM
Associated events: D+V - GBS, weight loss - cancer, arthralgia, CTD.
Travel, EtOH, drugs.

6

Investigations for peripheral polyneuropathy

Dipstick: glucose
Bloods: DM (glucose, HbA1C), EtOH (FBC ± film, LFTs, GGT), CRF (U+E), B12, folate, vasculitis (ESR, ANA, ANCA), thyroid disease (TFTs).
Imaging: CXR for paraneoplastic.
Nerve conduction studies
Electromyography
Genetic (PMP22 gene in CMT)
Nerve biopsy

7

Nerve conduction studies interpretation

Demyelination - reduced conduction speed, axonal degeneration - reduced conduction amplitude

8

General management of peripheral polyneuropathy

MDT
Foot care and careful shoe choice
Splinting joints can prevent contractures

9

Specific medical management for peripheral polyneuropathy

Optimise glycemic control (DCCT, UKPDS trials)
Replace nutritional deficiencies
Avoid EtOH or other precipitants
Vasculitis: steroids/immunosuppressants
Neuropathic pain: amitriptyline, gabapentin
GBS: IVIg

10

Signs on inspection for diabetic neuropathy

Finger-pricks from BM monitoring
Peripheral vascular disease
Charcot joints
Bilateral loss of ankle jerks (sensory neuropathy)
Mononeuritis multiplex - foot drop
Distal sensory loss in stocking distribution

11

Completing diabetic neuropathy exam

Examine the fundi
Examine the upper limbs and cranial nerves: sensory neuropathy, mono neuritis multiplex (CN3, CN6, ulnar nerve).
Urine dip: glucose, proteinuria.

12

Specific history for diabetic neuropathy

Pain, especially at night
Glycaemic control
Complications of insulin
Other micro- and macro-vascular complications

13

Pathophysiology of diabetic neuropathy

Metabolic: glycosylation, ROS, sorbitol accumulation
Ischaemia: loss of vasa nervorum

14

Investigations for diabetic neuropathy

Urine: glucose, ACR
Blood: glucose, HbA1c, U+E

15

Management of diabetic neuropathy

MDT
Good glycemic control
Amitriptyline, gabapentin
Capsaicin cream

16

Describe femoral neuropathy

AKA diabetic amyotrophy AKA proximal diabetic neuropathy.
Painful asymmetric weakness and wasting of quadriceps with loss of knee jerks.
Diagnose by nerve conduction studies and electromyography.

17

Features of autonomic neuropathy

Postural hypotension - treat with fludrocortisone
Gastroparesis - early satiety, GORD, bloating
Diarrhoea - treat with codeine phosphate
Urinary retention
Erectile dysfunction

18

Synonyms to Charcot-Marie-Tooth syndrome

Hereditary Motor and Sensory Neuropathy (HMSN), peroneal muscle atrophy

19

Charcot-Marie-Tooth syndrome findings on examination

Inspection:
Pes cavus
Symmetrical distal muscle wasting - claw hand, champagne bottle leg
Thickened nerves: especially common peroneal around fibula
Motor:
High-stepping gait (foot drop)
Weak foot and toe dorsiflexion
Absent ankle jerks
Sensory:
Variable loss of sensation in a stocking distribution

20

Specific history in Charcot-Marie-Tooth syndrome

Family Hx

21

Pathophysiology of commonest types of CMT

CMT1 (=HMSN1) is the commonest form
Demyelinating
AD mutation in peripheral myelin protein 22 gene (PMP22)
CMT2 (=HMSN2) is the second most common.
Axonal degeneration, also autosomal dominant.

22

Investigations for CMT

Nerve conduction studies
Genetic testing

23

Differentiating between CMT1 and CMT2 with nerve conduction studies

CMT1 is demyelinating - nerve conduction studies will show reduced velocity
CMT2 is axonal degeneration - nerve conduction studies will show reduced amplitude

24

Management of CMT

MDT
Foot care and careful shoe selection
Orthoses e.g. ankle braces