N4N18 September 2015

4 steps

Approach neuromuscular weakness

Overview

• Step 1 : Symptom defined• Step2 : Anatomical diagnosis• Step 3 : Pathological diagnosis • Step4 : Clinical diagnosis

Neu

rom

uscu

lar p

robl

emCNS

Motor

MND

Nerve

NMJ

Muscle disease

Sensory with/without motor

Nerve

Symmetricaldistal

Length dependentPinprick loss

A. AMSANC. Alcohol

H. CMT type 2

Early autonomic

A. Acute PANC.Amyloidosis

H. HSAN

Sensory ataxia

A. SCCA lungC. Sjogren

SymmetricalProximal and distal

A. AIDPC. CIDP

H. CMT type 1

Asymmetrical

Vascutitic neuropathy A. Polyarthritis nodusa

Multiple entrapmentH. HNPP

Subarachnoid infiltration

A. Tumor infiltrative

Demyelination C. MMN

Step 1 -> Step2 -> Step 3 -> Step 4

DM

Step 1: Symptom define

• Motor

Negative symptom : • Plegia = 0, Paresis >0• Hyporeflexia• Atrophy

Positive symptom: • Fasciculation• Myotonia

Subtle motor deficit test

Heel walking vs Toe walkingSciatica S1 Femoral L5

• Sensory : Anterolateral spinothalamic

Negative symptom : • Anesthesia =0 Hypoesthesia > 0

Positive sympom:• Paresthesia

- Spontaneus tingling sensation- Aberrant activity of large fiber

• Dysesthesia- unpleasant sensations when exposed to touch- Hyperexcitability of small fiber nerve terminal

• Allodynia- Painful with stimuli which do not normally provoke pain- Central sensitization

• Sensory : Dorsal corlumn

Negative symptom : • Joint position sense

- Pseudoathetosis- Positive rhomberg test

• Vibration sense- Tunning fork 128 Hz

• Autonomic

• Orthostatic hypotension• Constipation, Urinary incontinence• Early satiety • Impotence• Anhidrosis• Erythromelalgia

Step 2: Anatomical diagnosis

Note: • Preganglionic fiber myelinated• Postganglionic unmyelinated small fiber• Ach receptor of autonomic ganglion

Pure motor

• MND atrophy -> weak -> reflex

• Nervesreflex -> weak -> atrophy

• NMJ not impaired unless repetition

• Muscle weak -> atrophy -> reflex

• พ่อ Porphyria• ลูก Lead• กนิ GBS (AMAN)• ชา CMT (Charcot-Marie-Tooth type I)• ดบิ Diptheria/ Dapsone• หอม HNPP (Hereditary liability pressure palsy)• มัน MMN (Multifocal Motor neuropathy)

พอ่ลกูกินชาดิบหอมมนั

Polyneuropathy with dominant motor

Sensorywith/without motor, autonomic

• Nerves– Root

• No dissociation of sensory loss• Radicular pain• Early hyporeflexia• Early sensory ataxia

– Peripheral nerve• Each nerve function• Confluence -> polyneuropathy

– Nerve ending• Dysesthesia

Root or Nerves?

Step 3 : Pathological diagnosis

Pattern1. Symmetrical -distal

– Axonopathy

2. Symmetrical -distal and proximal – Demyelination

3. Asymetrical -distal and proximal– Axonopathy (Mononeuritis multiplex)– Demyelination (Multiple entrapment)

1 2 3

Symmetrical length dependent

Progression1

Symmetrical distal proximal Progression2

Asymetrical (Mononeuritis multiplex)Progression3

Pattern of axonopathy

• Large fiber most common: DM, Drug, Deficiency etc...

• Painful small fiber neuropathy2nd common : IFG, HIV etc…

• Small fiber with autonomic• Sensory ganglinopathy (ataxia)• Mononeuritis multiplex

• Autoimmune autonomic ganglionopathy– Ab to Achr of autonomic ganglion– GBS ,Autoimmune, Paraneoplastic

• Porphyria• Amyloidosis ( familial and primary)• HSAN

Autonomic neuropathy

• 6 Vitamin B6 toxicity• Pack Paraneoplastic anti Hu, Cisplatin• So Sjogren’s syndrome• Hit HIV, HTLV-1Idiopathic

6 Pack So HitSensory ganglinopathy

• Vasculitic neuropathy– Vasculitis– Diabeic polyradiculoplexopathy

Bruns-Garland syndrome (diabetic amyotrophy)• Subarachnoid infiltration• Multiple entrapment

– HNPP• Demyelination

– MADSAM– MMN

Asymmetrical polyneuropathy

Progression

• Acute (4 wks) to subacute (4-8 wks)– GBS, Paraneoplastic

• Chronic (>8 wks to year)– CIDP ,Paraproteinaemic

• Hereditary (definite onset – no paresthesia)– CMT, HSAN

Step 4: Clinical diagnosisClinical clues • Facial diplegia -> GBS• Pes cavus -> CMT• Shoulder fat pad -> Amyloidosis• Palpable purpura -> vasculitic neuropathy• Mee’s line -> Lead intoxication• Enlarge nerve-> Leprosy, CMT, Amyloidosis

Host status • Multiple presenatation : DM, HIV, Lymphoma• Atypical presentation : HIV, Immunosuppress• Medication associated : Cancer, HIV• Special situation : ICU, ESRD

Take home message 4 steps

Step 1 : S-A-M (Sensory, Autonomic, Motor)

Step 2 : Motor : MND, nerves, NMJ, Muscle Sensorimotor : Nerves

Step 3 : Pattern : Sym distal, Sym distal&ProxAsymetrical

Progression : Acute, Chronic, Hereditary

Step 4 : Clinical clues Host status

Reference

• ตําราประสาทวิทยาคลินิก . สมาคมประสาทวิทยาแห่งประเทศไทย 2557 หน้า 780-798

• Adams and Victor’s principle of clinical neurology 10th edition 2014