682 LEWELLYS F. BAKKEK 



Encephalitis and EncephalomyelUis. Now that encephalitis lethar- 

 gica is epidemic and many atypical cases are seen, in which hyperkinetic 

 phenomena on the one hand or paretic phenomena on the other, along 

 with myoclonias, fibrillary twitchings, fascicular twitchings and the like, 

 are met with, the possibility of confusion of this disease with tetany 

 should be kept in mind. An exact neurological examination will easily 

 differentiate. Frequently, the results of a study of the cerebrospinal fluid 

 will be decisive, though not always, for the fluid is often normal in 

 encephalitis. 



Myasthenia grams. In tetany accompanied by paresis and by great 

 general weakness, myasthenia gravis may be suspected; but the peculiar 

 fatiguability, the absence of tendency to spasm, the exhaustibility of the 

 muscles by the electrical current (so-called myasthenic reaction), and the 

 absence of any increase of the electrical excitability of the motor nerves 

 are marks of myasthenia gravis, which, if absent, rule out this disease. 



3. Conditions (Other than Tetany) That May Be 



Associated with Sensory Phenomena Resembling 



Those of Tetany 



Acroparesthesias. Cases of so-called "sensory tetany" occur, in 

 which abnormal motor phenomena are almost absent, the patient complain- 

 ing chiefly of paresthesias in the extremities. Similar acroparesthesias are 

 met with under different conditions, especially at the climacterium, in the 

 functional neuroses, and in several endocrine affections other than tetany. 

 In pernicious anemia, also, it is quite common to meet with remarkable 

 acroparesthesias in the fingers and toes dependent upon degeneration in the 

 funiculi of the spinal cord. 



Unless acroparesthesias can be shown to be associated with the signs 

 of latent tetany, they should not be ascribed to tetany. 



Arthritides. Physicians in Vienna have reported that patients often 

 come to them with a diagnosis of rheumatism, or of arthritis, when the 

 true explanation of their symptoms is the existence of tetany. The con- 

 fusion doubtless depends upon the peculiar drawing pains in the extremi- 

 ties, variable in localization and in intensity, that occur in tetany. When 

 the pains are very severe and the hyperesthesia of the skin is marked, 

 tetany may be mistaken for acute infectious arthritis or for acute articular 

 rheumatism. There may be even swelling and redness -of the hands in 

 tetany. 



It must not be forgotten that true tetany may be combined with true 

 arthritis, the arthritis, just like any other infection, acting as a re- 

 leasing factor for the attack of tetany. In the differential diagnosis one 



