[Neurologic concomitant diseases in Crohn disease]

Disturbances of the central and peripheral nervous system in Crohn's disease can be directly or indirectly caused by the disease itself or by the treatment. The first mentioned disturbances are very seldom. Cerebral arterial and venous thromboses can be attributed to hypercoagulation. Malabsorption of vitamin B 12 or folic acid can lead to a subacute combined degeneration of the spinal cord, sometimes in combination with a polyneuropathy and an encephalopathy. Spinal abscesses very seldom occur. An opticusneuropathy can be caused either by vasculitis or by a lack of vitamin A and/or vitamin B. Polyneuropathies in Crohn's disease which are not induced by drugs are manifested as mononeuritis multiplex or as symmetrical sensory neuropathy. An autoimmune process is being discussed as the probable cause of there diseases. In some cases large doses and prolonged administration of metronidazole can lead to cerebral dysfunctions with state of confusion, alterations of consciousness, cerebral convulsions and cerebellar syndrome. Most of these symptoms disappear rapidly after this drug is not longer administered. In long-term administration of metronidazole 10-50% of the patients develop a sensory polyneuropathy with a total dosis of at least 22.5 g, but mostly above 60 g. After the use of metronidazole is stopped, it takes a substantial period of time until there is a full recovery from the symptoms.