Peripheral neuropathy refers to damage to peripheral nerves. There are three main types: mononeuropathy affecting a single nerve, mononeuritis multiplex affecting multiple nerves asymmetrically, and polyneuropathy affecting multiple nerves concurrently and symmetrically. Polyneuropathy can be classified as axonopathy, myelinopathy, or neuronopathy depending on whether the axons, myelin sheaths, or neurons are affected. Symptoms and signs include both negative symptoms like numbness and weakness as well as positive symptoms like tingling and pain. Evaluation involves taking a history and examining for patterns of onset, progression, fluctuations, and other systemic diseases. Diagnosis involves nerve conduction studies and sometimes nerve biopsies. Treatment focuses

1. Peripheral neuropathy
Damage to peripheral nerves

2. Types
 Mononeuropathy- affects single nerve
 Compression, trauma, ischemia, inflammation
 Mononeuritis multiplex- multiple nerves
involved, asymmetrically
 DM, vasculitides, SLE, sarcoidosis, leprosy, amyloid
 Polyneuropathy- multiple nerves
involved, concurrently & symmetrically
 DM, AIDP/CIDP, toxic/metabolic, hereditary

3. Polyneuropathy- classification
 Axonopathy
 Stocking & glove type sensory loss, diminished DTR
& autonomic function in involved areas
 Toxins, DM, SACD, alcoholism, chemotherapy drugs
 Myelinopathy
 AIDP, CIDP
 Neuronopathy
 MND, Herpes zoster, Vincristine

4. Symptoms & signs
 -ve symptoms/signs-
 Sensory- numbness, tremor, gait abnormality
 Motor- weakness, heaviness, gait abnormality
 +ve symptoms/signs-
 Sensory- tingling, pain, itching, pins & needles
 Motor- cramps, tremor, fasciculations
 Absent ankle jerk

5. Evaluation
 History-
 Pattern of onset- mostly LL>UL & distal>proximal
 Progression- acute-AIDP or chronic-DM/hereditary
 Fluctuation- toxin exposure
 Other systemic diseases
 Family history
 Examination-
 Palpate nerve- thickened-leprosy
 Small-fibre- predominantly spinothalamic tract-
dysesthesias, impaired pain/temperature sensation,
autonomic dysfunction ±, Fabry’s dis./DM/amyloid
 Large-fibre- predominantly posterior column-
areflexia, ataxia, severe motor dysfunction,
minor cutaneous sensory deficit

6. Diagnosis
Nerve conduction studies
Sural nerve (at ankle) biopsy,
specially for mononeuritis multiplex

7. Treatment
 Correct underlying cause
 Control of DM
 Correction of vitamin deficiency
 Rx of leprosy
 Avoid alcohol
 Immunosuppression for AIDP/CIDP
 Surgery for carpal tunnel syndrome
 Neuropathic pain-
 Amitriptyline, Carbamazepine, Gabapentin,
Pregabalin

8. SACD
 Sub-acute combined degeneration
 Due to vitamin B12 deficiency
 Manifestation-
 Paresthesias, sensory loss- LE>UE
 Ataxia
 Loss of ankle jerk, extensor plantar
 Memory loss
 Reduced vision, central scotoma
 Sphincter disturbance
 Rx- vitamin B12 supplementation, IM