Small nerve fibre dysfunction in a patient with Sjögren's syndrome. Neurophysiological and morphological confirmation.

An morphological confirmation of neurophysiologically assessed small nerve fibre dysfunction in a patient with Sjögren's syndrome was sought. Conventional motor and sensory nerve conduction studies were normal, while examination of the thermal specific and thermal pain sensitivity and an autonomic nervous system evaluation showed striking abnormalities. Sural nerve electron microscopy showed almost normally large nerve fibres and abnormalities in unmyelinated nerve fibres or Schwann cells, and verified morphologically the neurophysiologically supposed small nerve fibre involvement.