Diseases characterized by injury or dysfunction involving multiple peripheral nerves and nerve roots. The process may primarily affect myelin or nerve axons. Two of the more common demyelinating forms are acute inflammatory polyradiculopathy (guillain-barre syndrome) and polyradiculoneuropathy, chronic inflammatory demyelinating. Polyradiculoneuritis refers to inflammation of multiple peripheral nerves and spinal nerve roots. The disease is Monarch Disease Ontology id MONDO_0006915 (polyradiculoneuropathy).