Polyneuropathies can be classified according to cause, course, and affected nerve fibers:

1. By cause:
   • Diabetic polyneuropathy: A common consequence of diabetes mellitus due to chronically elevated blood sugar levels.
   • Toxic polyneuropathy: Triggered by alcohol, heavy metals, or chemotherapeutic agents.
   • Hereditary polyneuropathy: Genetic forms such as Charcot-Marie-Tooth disease.
2. By course:
   • Acute polyneuropathy: Sudden onset, often caused by infections or toxins.
   • Chronic polyneuropathy: Slowly progressive, often in diabetes or autoimmune diseases.
3. By affected nerve fibers:
   • Sensory polyneuropathy: Affects sensory nerves, leading to numbness or tingling.
   • Motor polyneuropathy: Damage to motor nerves with muscle weakness.
   • Autonomic polyneuropathy: Impairs the nerves that control organs, leading to digestive or heart problems.

Polyneuropathy has a variety of causes:

• Metabolic disorders:
  • Diabetes mellitus is the most common cause. Chronically high blood sugar levels damage the nerves.
• Toxic influences:
  • Long-term alcohol abuse or exposure to heavy metals (e.g., lead) damage the nerves.
• Autoimmune diseases:
  • Diseases such as Guillain-Barré syndrome or lupus erythematosus can trigger inflammation in the nerves.
• Infections:
  • HIV, Lyme disease, or hepatitis can lead to polyneuropathies.
• Vitamin deficiency:
  • A deficiency in vitamin B1, B6, or B12 impairs nerve function.
• Medications:
  • Side effects of certain medications, such as chemotherapeutic agents, can trigger polyneuropathies.

The symptoms of polyneuropathy depend on the affected nerve fibers and can include the following:

- **Sensory symptoms:**

- Tingling, numbness, or burning pain, especially in the hands and feet.

- Over- or under-sensitivity to touch.

- **Motor symptoms:**

- Muscle weakness that makes walking or climbing stairs difficult.

- Muscle cramps or twitches.

- **Autonomic symptoms:**

- Digestive problems, dizziness, or heart rhythm disturbances.

- Excessive sweating or dry skin.

The diagnosis is based on a thorough medical history, clinical examination, and supplementary tests:

1. Medical history: The doctor asks about previous illnesses (e.g., diabetes), medications, alcohol, or toxin exposure.
2. Clinical examination:
   • Checking reflexes, muscle strength, and sensory ability.
   • Tests for vibration sense and pain sensitivity.
3. Diagnostic procedures:
   • Nerve conduction velocity measurement (NCV): Determination of nerve function.
   • Electromyography (EMG): Examination of muscle activity.
   • Blood tests: Checking for diabetes, vitamin deficiencies, or autoimmune markers.

Conservative Therapy

The treatment depends on the underlying cause and symptoms:

• Treat underlying condition:
  • Optimize blood sugar levels in diabetes.
  • Avoid alcohol or toxic substances.
• Pain therapy:
  • Medications like Pregabalin, Gabapentin, or Amitriptyline relieve neuropathic pain.
• Physiotherapy:
  • Exercises to improve mobility and muscle strength.
• Vitamin supplementation:
  • Substitution of vitamin B in case of proven deficiency.

Surgical Therapy

Surgical interventions are rare but may be necessary in cases of mechanical nerve compression, such as with a tumor.

The following measures are helpful in preventing polyneuropathy:

1. Healthy lifestyle: Balanced diet and abstaining from alcohol.
2. Blood sugar control: Regular regulation of blood sugar in diabetes.
3. Avoidance of toxins: Protection against heavy metals and chemicals.
4. Regular exercise: Promotion of circulation and nerve function.
5. Early detection: Seek medical advice promptly at the first signs such as tingling or numbness.