The significance of hyperhidrosis in patients with post-traumatic syringomyelia.

Eight patients are described with post-traumatic syringomyelia. In each of the eight, excessive sweating was the first feature of the disease, although it was only the main problem with two. Usually specific enquiry must be made to elicit the history of hyperhidrosis. The special features of the sweating are: it may occur above or below the level of transection; it tends to occur in dermatomes whose sensation is later altered by the syrinx; it is of excessive quantity; it may be affected by posture; it is related to central temperature but not to visceral reflexes; in patients with a complete cord transection who are 'neurologically silent' it is the only indicator of a descending syrinx; it ceased after surgical drainage of the syrinx cavity.