An Introduction to Polyneuropathy
Polyneuropathy is a disorder in which multiple peripheral nerves are affected simultaneously, writes Dr Khalid Jameel Akhtar ( Big Brother)
Polyneuropathy is a common neurological condition encountered in clinical practice, especially in Pakistan, where diabetes, nutritional deficiencies, and injection-related nerve injuries are prevalent.
Definition of Polyneuropathy
Polyneuropathy is a disorder in which multiple peripheral nerves are affected simultaneously. It usually presents in a symmetrical pattern and predominantly involves the distal parts of the limbs, such as the hands and feet. The condition may affect motor, sensory, and sometimes autonomic nerve functions.
Classification of Polyneuropathy
Polyneuropathy can be classified on different bases:
1. According to Cause
- Diabetic neuropathy
- Nutritional neuropathy (e.g., Vitamin B12 deficiency)
- Toxic neuropathy (drugs, chemicals)
- Hereditary neuropathy (e.g., Charcot–Marie–Tooth disease)
- Infective and inflammatory neuropathies
2. According to Nerve Involvement
- Motor neuropathy
- Sensory neuropathy
- Sensorimotor neuropathy
3. According to the distribution
- Polyneuropathy (multiple nerves involved)
- Mononeuritis (single nerve involved)
Causes of Polyneuropathy
The most common causes include:
- Poorly controlled diabetes mellitus
- Vitamin deficiencies, especially Vitamin B12
- Chronic alcoholism
- Certain medications and toxins
- Hereditary conditions
- Iatrogenic causes such as improper intramuscular injections
Clinical Features of Polyneuropathy
Muscle Weakness
In polyneuropathy, muscle weakness typically starts in the distal parts of the limbs:
- In the upper limbs, weakness is more prominent in the hands and fingers
- In the lower limbs, weakness is more evident in the feet and ankles
Functional Complaints by Patients
Patients commonly complain of:
- Difficulty holding objects firmly
- Inability to button shirts
- Difficulty holding a pen and writing
- Trouble using a knife or hammer
Simple Clinical Examination Tests
- Finger clicking test: The patient is asked to rapidly click fingers. Weakness of hand and finger muscles becomes obvious if the patient cannot perform this task.
- Toe and heel standing test: The patient is asked to stand on toes and then on heels. Patients with neuropathy may not be able to perform these tasks, especially as the disease progresses.
ABC of Rehabilitation in Neuropathy
Rehabilitation plays a central role in the management of polyneuropathy.
A. Diabetic Neuropathy
The cornerstone of treatment is strict control of blood glucose levels. A major complication of diabetic neuropathy is the development of a diabetic foot due to loss of sensation. Minor injuries may go unnoticed and progress to ulcers, gangrene, and eventually amputation of toes or feet if diabetes is not controlled in time.
Preventive foot care and patient education are essential components of management.
B. Nutritional Neuropathy (Vitamin B12 Deficiency)
In Vitamin B12 neuropathy, sensory symptoms are usually more prominent than vascular changes. Management includes correction and maintenance of adequate vitamin levels.
Management of Lower Limb Involvement:
Foot Drop
Many patients with polyneuropathy develop bilateral foot drop. To manage this condition:
- Ankle Foot Orthosis (AFO) is prescribed
- AFOs are usually made of polypropylene
- They help improve walking ability and prevent falls
As the disease progresses, loss of sensation leads to poor balance. In such cases, patients may require:
- Walking stick
- Walking frame
Management of Upper Limb Involvement
In upper limb neuropathy:
- Preventive or corrective splints may be used
- These splints help maintain hand position and prevent deformities
- Weak grip strength is addressed to prevent contractures
Contractures refer to the limitation of joint movement due to muscle shortening and must be prevented through early intervention.
Role of Physiotherapy
Physiotherapy is a continuous and essential part of neuropathy management:
- Strengthening exercises for weak muscles
- Stretching exercises to prevent or treat contractures
- Electrotherapy when indicated
These interventions are applied to both upper and lower limbs and require long-term follow-up, as neuropathy is often a progressive condition.
Surgical Options
If conservative management fails, surgical options may be considered:
Orthodesis
- A surgical procedure in which the ankle joint is fixed
- Helps control severe foot drop
- Usually considered when other treatments are ineffective
Many patients are reluctant to undergo surgery, but this option should remain under consideration in selected cases.
Mononeuritis (Single Nerve Injury)
Radial Nerve Injury
Improper injection near the radial groove of the upper arm can damage the radial nerve, leading to:
- Inability to extend the wrist and fingers
- Sensory loss in the radial nerve distribution
Sciatic Nerve Injury
Incorrect placement of intramuscular injections in the hip may damage the sciatic nerve, resulting in:
- Unilateral foot drop
- Loss of dorsiflexion of the foot
Management includes:
- Ankle Foot Orthosis if damage is permanent
- Physiotherapy and electrical stimulation if recovery is possible
Diagnostic Evaluation before Rehabilitation
Before starting rehabilitation, it is mandatory to perform:
Electromyography (EMG)
- Assesses how many muscles supplied by the affected nerve are functioning
Nerve Conduction Studies (NCS)
- Measure the speed and strength of nerve signal conduction
- In neuropathy, nerve conduction is reduced
These investigations guide prognosis and rehabilitation planning.
Special Neuropathy: Charcot–Marie–Tooth Disease
Charcot–Marie–Tooth disease is a hereditary neuropathy that usually affects the lower limbs and begins early in life, often between 4–5 years of age.
Clinical Characteristics
- Progressive weakness
- Thigh muscles remain relatively preserved
- Leg muscles gradually waste
- Appearance resembles an inverted champagne bottle
Rehabilitation Principles
- Similar to other neuropathies
- Early use of AFO should be avoided
- AFO should be delayed as long as possible
- Once prescribed, it should not be used continuously
- Long-term supervision by a rehabilitation consultant is essential
Conclusion
Polyneuropathy is a chronic and often progressive condition requiring a multidisciplinary approach. Early diagnosis, proper rehabilitation, patient education, and regular follow-up can significantly improve functional outcomes and quality of life for patients. Understanding practical clinical signs and rehabilitation strategies is essential for effective management in routine medical practice.
