[Chronic polyneuropathy--evaluation and diagnosis]

Chronic polyneuropathy is a common disorder with heterogenic clinical presentation and many possible etiologies. This review presents diagnostic guidelines for physicians without specialist competence in neuromuscular disorders.

The article is based on a review of articles identified in PubMed using the search terms "peripheral neuropathy", "cause" and "investigation", relevant book chapters and own clinical experience.

All patients should undergo a routine investigation for the most common causes of polyneuropathy, such as diabetes, heredity, alcohol abuse, toxic medications and agents, symptoms of Sjögren's syndrome and renal failure. The following laboratory assessments should be done if the medical history proves negative: glucose, haemoglobin, leucocytes, thrombocytes, ESR, creatinin, ALAT, GT, vitamin B12, serum electrophoresis, TSH and thyroxin. If the routine investigation proves negative, a targeted approach based on clinical type and electrophysiological findings is recommended. The most common sensory type with slowly progressing, symmetric sensory symptoms beginning in the feet can often be classified as cryptogenic without further investigation. Polyneuropathies with subacute onset, progressive weakness, asymmetric symptoms, proximal weakness, selective involvement of sensory fibres or demyelinating pathology, or other organ manifestations, have different etiologies that necessitate individually focused investigations.