Chronic Ataxic neuropathy
Sinnreich M et al. Chronic immune sensory polyradiculopathy: A treatable sensory ataxia. Neurology 2004 Nov 9; 63:1662-9.
What is chronic Ataxic Neuropathy?:
Another Treatable Sensory Variant of CIDP?
Shin J. Oh, MD, FAAN reviewing Sinnreich M et al. Neurology 2004 Nov 9
These findings identify a new entity, chronic sensory demyelinating neuropathy, that appears to respond well to immunotherapy.
Chronic ataxic neuropathy (CAN) is most commonly due to sensory ganglionopathy, which can be identified by the classic sensory neuronopathy pattern in nerve conduction study (NCS): a marked sensory nerve conduction abnormality in the presence of normal motor nerve conduction. However, treatment of sensory ganglionopathy has been disappointing, so CAN is therefore considered untreatable.
Sinnreich and colleagues report data from 15 patients who clinically had CAN and what they term chronic immune sensory polyradiculopathy (CISP), which responded favorably to immunotherapy. All the patients had gait ataxia, paresthesias, and large-fiber sensory loss. All but 1 had reduced muscle stretch reflexes, and 9 had frequent falls. Motor and sensory nerve conduction findings were normal, including those in the sural nerve. Thus the electrodignostic NCV is NORMAL. This is so beacuse when the Ganglion are affected the peripher NCV cannot record this dysfunction.
COMMENT Few causes of chronic sensory neuropathy are treatable. One of them is chronic sensory demyelinating neuropathy, a sensory variant of CIDP (chronic inflammatory demyelinating polyneuropathy) that responds to immunotherapy and is recognized by the demyelinating index of NCSs and by a high CSF protein level. As these results show, chronic immune sensory polyradiculopathy, another sensory variant of CIDP, can be identified by a high CSF protein level, SSEP abnormalities, and thickened nerve roots on MRI. It is important to recognize these entities because of their apparent remarkable response to immunotherapies.