neurologic disorders
Polyneuropathy
Introduction
A polyneuropathy is a diffuse Overview of Peripheral Nervous System Disorders that is not confined to the distribution of a single nerve or a single limb and typically is relatively symmetrical bilaterally. Electrodiagnostic tests should always be done to classify the nerve structures involved, distribution, and severity of the disorder and thus help identify the cause. Treatment is directed toward correcting the cause. Some polyneuropathies affect primarily motor fibers. They include Immune-mediated disorders (eg, Guillain-Barré Syndrome (GBS) , multifocal motor neuropathy with conduction block) Lead toxicity Dapsoneuse Tick Bites None Porphyria Spinal muscular atrophy (a motor neuron disorder that mimics motor polyneuropathy) Others affect primarily sensory fibers. They include Dorsal root ganglionitis of cancer Leprosy None Human Immunodeficiency Virus (HIV) Infection None Diabetes Mellitus (DM) None Chronicpyridoxineintoxication Some disorders can also affect cranial nerves. They include Guillain-Barré syndrome Lyme Disease None Diabetes Diphtheria None Certain drugs and toxins can affect sensory or motor fibers or both (see table Toxic Causes of Polyneuropathies ). 