Peripheral Neuropathy

By: Amr Mohammed Abdullah11110053

Internal Medicine: Neurology

Definition

• It is an inflammation or degeneration of the peripheral nerves with motor, sensoryand autonomic manifestations.

Pathological classification

• a. Demyelinating neuropathy:• Rapid onset, CSF is affected because of root damage, there is degeneration of

the myelin sheath due to immunological or infectious insult. • e.g. Guillian - Barré $ Myelinopathy.

• b. Axonal neuropathy:• Characterized by degeneration of the distal ends of long axons.• It starts with distal sensory manifestations & spread proximally.• It usually occur in diabetic neuropathy, and toxic neuropathy.

• c. Wallerian degeneration after nerve injury.

Terms of neuropathy

• Mononeuropathy: • affection of a single nerve trunk.• e.g. ulnar or median nerve.

• Mononeuropathy multiplex: (multi focal neuropathy or multiple mononeuropathy):• affection of more than one nerve trunk usually in one limb. • e.g. ulnar nerve + median nerve.

• Polyneuropathy: • diffuse symmetrical affection of peripheral nerves of all limbs.

causes

• Causes of mononeuropathy:• Trauma, DM, entrapment neuropathy (e.g. carpal tunnel

$).

• Causes of mononeuritis multiplex:• DM, Polyarteritis nodosa, sarcoidosis, leprosy,

amyloidosis.

Mononeuropathy

• Mononeuropathy: only affects a single nerve.• Causes:• Trauma• Infection H. Z. – leprosy• Vascular polyarteritis nodosa.• Compression Intrapment neuropathy• DM.

Mononeuropathy (Carpal tunnel $)

Polyneuropathy

INH: isonicotinylhydrazide (Isoniazid)

SCD: Specific Carbohydrate Diet

Clinical picture of polyneuropathy• Motor:

• LMNL• Bilateral symmetrical• LL > UL• Distal > proximal, & extensor > flexor• Foot & wrist drop• Lost ankle jerk, but knee jerk is preserved.• Cranial nerve affection• Gait, high steppage due to foot drop

• Sensory:• Superficial sensory loss:

• Glove stock (paresthesia) then hypothesia.• Deep sensory loss (sensory ataxia)

• Vibration normal at ASIS & decreased on malleoli.

• Autonomic:• coldness, cyanosis, loss of hair, orthostatic hypotension, impotence, nocturnal diarrhea,

constipation.

Specific types of polyneuropathy(Peroneal muscle atrophy (Charcot - Marie tooth disease))• This neuropathy is mainly motor also there is glove and stocking

hypothesia.• It is a heredofamilial autosomal dominant in 1st & 2nd decade, the wasting

starts in L.L in peronii then anterior tibial group then ascends to involve the muscles of lower 1/3 of thigh (inverted champagne bottle appearance).• It is Characterized by:

• marked wasting• minimal weakness• foot deformity e.g pes cavus and hammer toes.

• Treatment:• Bracing of the ankle for foot drop, genetic counselling.

Specific types of polyneuropathy(diabetic neuropathy)

Specific types of polyneuropathy(diabetic neuropathy)• C/P: mainly sensory

Specific types of polyneuropathy(diabetic neuropathy)Treatment• Control blood sugar.• Vit. B. complex, capillary modulators e.g Ca dobesilate (Doxium).• Carbamazepine (tegretol) 200-600mg/D for epilepsy, or Gabapentin (Neurontin) 400 mg/8 hrs for severe parathesia or neuropathic pain.

Specific types of polyneuropathy(Refsum disease)• It is a lipid storage disease presented at first and second

decades characterized by hypertrophic neuropathy.• It is presented by night blindness, cerebella ataxia and

retinitispigmentosa.

Acute infective polyneuropathy (Guilain Barre $)• It is an inflammation of the peripheral nerve & roots

with demyelination due to immune or viral insult. (1-4 wks after viral infection).• It is mainly motor (Acute paralytic neuropathy).• Cranial nerves are usually affected specially bilateral facial nerves.

Acute infective polyneuropathy (Guilain Barre $)• C/P:

Acute infective polyneuropathy (Guilain Barre $)• Investigations:• CSF examination showing cytoalbuminous dissociation

due to root affection (excess protein with either normal cell count or a moderate increase in cells).• Impaired nerve conduction velocity.

• S. Lead urinary porphyrin (to exclude porphyria).

Acute infective polyneuropathy (Guilain Barre $)• Treatment:

• Prognosis

Diphtheritic neuropathy

Leprotic neuropathy

Cranial polyneuropathy

• This means multiple cranial nerve Lesions. • This occurs with malignant infiltration e.g Lymphomas,

also it may occur with Sarcoidosis.

Exercise

? diabetic neuropathy Guilain Barre $S/M Mainly sensory Mainly motorAM Positive autonomic manifestations Positive autonomic

manifestationsCN Cranial nerves are 3,4,6 Cranial nerves are

3,7,10D/P D>P Bilateral, P>DCoarse Progressive acuteTTT • Control blood sugar.

• Vit. B. complex.• Carbamazepine or Gabapentin for

paresthesia.

• IV Immunoglobulins• Steroids (20mg

prednisolone TDS)• Plasmapheresis

References

• Churchill’s Pocketbook of Differential Diagnosis.4th.• Current Essentials Of Medicine• Davidson's Essentials of Medicine• Oxford Handbook of Clinical Medicine 9th Ed

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