IQ23. No. l6. THE NEUROLOGICAL ASPECT OF LEPROSY. 7I 



The most difficult point in the differential diagnosis is commonly sup- 

 posed to be the distinction between leprosy and syringoDiyclia. It may at 

 once be admitted that cases may be found where the neurological findings 

 are such that the differential diagnosis cannot be made, but has to be left 

 in suspenso. But such cases are not frequent. Quite apart from the fact 

 that cutaneous manifestations will in the majority of cases settle the dia- 

 gnosis, it will be found that a thorough neurological examination elicits one 

 or niore signs that decide the diagnosis conclusively. 



First and foremost it has to be kept in mind that whilst syringomyelia 

 is due to gliosis of the grey matter of the spinal cord (with secondary 

 cavity formation — "syrinx"), the neurological manifestations of leprosy are, 

 as we have seen, practically entirely due to a pepripheral polyneuritis - 

 and that a very peripheral one. This gives the key to the understanding 

 of the whole distinction, the more important points of which will now be 

 mentioned. 



As regards the cranial /icn'cs, it has to be remembered that pronounced 

 bulbar phenomena, i. e. disturbances in the functions of the last 4 cranial 

 ner\es, evidenced chiefly by dysarthria and dysphagia (particularly the for- 

 mer I, are comparatively common in syringomyelia (due to the fact that the 

 original gliosis is often continued upwards into the medulla oblongata — 

 "syringobulbia"!. I have seen a unilateral lingual paral3-sis with pronounced 

 hemiatrophy in a number of cases of syringomyeli, but only in three cases 

 of leprosy, and in these the paresis as well as the atrophy was very slight. 

 A cervical sympathetic syndrom (miosis, pseuoptosis, enophtalmusi is often 

 seen in syringomN-elia (due to a lesion of the anterior grey horn in the 

 cer\ico-dorsal region of the spinal cord). In leprosy the above is practi- 

 cally never found. When dysarthria occurs, it is as a rule but little pro- 

 nounced, and is confined to difficulty in pronouncing the labial sounds, due to 

 facial paralysis (cfr. page 26). — On the other hand, facial paralysis of the peculiar 

 character which has been described in a previous chapter, is never seen in 

 syringomyelia.' When facial paralysis occurs in this disease it is, as a rule, 

 one-sided and chiefly confined to the lower part of the face. It will be 

 remembered that the facial paralysis in leprosy is chiefly pronounced in the 

 upper part of the face, and that it is here bilateral and fairly symmetrical, 

 whilst the accompanying affection of individual muscles of the lower part 

 of the face is as a rule less symmetrical. 



As regards the motor disturbances, these may be absolutely identical 

 in the upper limbs, consisting of paresis and atrophy of the intrinsic mus- 

 cles of the hands, accompanied by a more or less pronounced hypotonic 

 paresis and atrophy of the antibrachia and arms. As regards the lower 

 limbs, however, there is a considerable difference. In the syringomyelia the 

 feet are rarely (if ever) the seat of the same atrophy as the hands. In this 

 disease the lower limbs, when affected, as a rule show characteristic signs 

 of a central lesion ("spastic paresis") with typical reflex changes, chief 



