DIABETES INSIPIDUS 



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depending somewhat on a number of factors which include method of 

 test, diet, and age of the individual. A fair average for an adult is 1.055. 

 In a case reported by Strubell in which the thirst was very great, the 

 specific gravity of the blood rose to 1.071. In Williams' case it was 1.052 

 on a day when 4,000 c.c. of urine was voided.. 



Ocular disturbances occur very commonly in diabetes insipidus, par- 

 ticularly in those cases where there is tumor formation, injury, or any 

 other cause which produces pressure on the optic chiasm. This brain 

 structure, lying directly in front of the hypophysis, is easily affected when 

 lesions occur in the hypophysis or neighboring brain areas. The eye 



L. E. 



R.. 



Fig. 2. Case Mrs. W. Severe diabetes insipidus. First observation. Slight 

 concentric contraction of visual fields and well marked contraction of color fields; 

 temporal side most involved. 



symptoms which have been observed by different writers are as follows: 

 relative or absolute scotoma; unilateral, bitemporal, or homonymous 

 hemianopsia or hemiachromatopsia. The latter condition is the one which 

 is most commonly seen. In brief, the changes are usually functional and 

 consist in contraction, concentric or quadrantal, of the color fields. 



The temporal side often in the upper quadrant, according to Gushing, 

 is most frequently involved. Later the visual or form fields may be in- 

 volved. In Williams' case at the first examination, there was a very slight 

 concentric contraction of the visual fields and a well marked contraction 

 of the color fields. In the color fields the temporal side was most involved 

 (see Figure No. 2). Five months later, both the visual and color fields 

 were very much contracted (see Figure No. 3). Three and one-half 

 years later the visual and color fields were approximately the same as 

 at the first examination, although in the left eye there was in the lower 



