Oxalate of Lime, and its relations to certain forms of Neuralgia.
By H. A. Johnson, M. D.—We are indebted for what we know of
this deposit mostly to Dr. Golding Bird. From his observations he
was led to the conclusion that oxalate of lime occurs in more than
one-third of the cases in connection with an excess of uric acid or
urate of ammonia, that in all cases there is an excess of urea, and that
it is frequently accompanied by an excess of the phosphates; he also
thinks it probable, that the uric and oxalic diatheses are both produced
by the same morbid influences.
Uric acid, as existing in normal urine, is, without doubt, derived
from the nitrogenized tissues of the body, but when found in excess, it
may usually be traced either to ingesta, which the juices of the stomach
have not power to dissolve, or to a too rapid destruction of tissues
under the influence of heat, &c., as in fevers and inflammations; can
oxalic acid be traced to a similar source ?
Dr. G. Bird has presented a very ingenious theory for the produc-
tion of this acid from urea and uric acid, but there is generally an
excess of one or both of these ingredients accompanying the oxalic
deposits. Should we expect this to be the case, if the abnormal product
was the result of a transformation of the urea and uric acid ? It seems
to me not. My own observations have been limited, but I have thought,
from a careful study of quite a number of cases, that, while a temporary
functional disease of the digestive organs or the introduction into the
digestive tube of a large amount of food, difficult of perfect solution in
the juices of the stomach, will generally give rise to uric acid deposits
in the urine, chronic disease of the alimentary canal, whether functional
or organic, will more generally be found to exist with the oxalic dia-
thesis.
In quite a large number of instances in which I have observed the
oxalate of lime in the urine, the patients have not only been affected
with dyspepsia, but have also been subject to severe attacks of neuralgia.
In the first few instances, the neuralgic pains were confined to the
lower extremities, and I strongly suspected that they were produced by
mechanical irritation of the vesical mucus membrane from the crystals
of the oxalate with which the urine was loaded at the commencement of
the attack, but which, towards the termination, were replaced by an
excess of the phosphates.
I have since observed neuralgic pains in the face, superior extremities
and in the chest, co-existing with oxaluria, and, after carefully studying
a number of cases, it seems to me evident, that the neuralgia and the
urinary deposits sustain to each other an intimate relation through a
common cause, viz : the derangement of the digestive organs.
It is perhaps probable that oxalic acid, whether produced from mal-
assimilated food, as I think, or, from a metamorphosis of urea and uric
acid, may exist first in combination with ammonia, as Dr. G. Bird has
suggested. If so, it is possible, that it may, instead of being selected by
the kidneys and combining in those organs with lime, be precipitated in
the tissues. The crystals of this new salt, many of them smaller than
blood globules, and presenting sharp angles and edges, may thus, by
mechanical irritation, act directly upon the suffering structures, produ-
cing that intense and indescribable pain, for controlling which, anodynes
and narcotics have so little power.
Permit me to allude to my own personal experience. During the
last few months I have been frequently annoyed by neuralgic pains, and
always after eating freely of oranges. I had never been in the habit of
using this fruit until during my recent visit south, but while in Natchez
and New Orleans, it constituted almost my only diet. I also ate very
freely of it during my return home.
It is to my mind an interesting fact, that the first neuralgic pain that
I ever experienced, so far as my memory serves me, was while in Natchez-
Since my return I have frequently partaken of the fruit, and almost
always with the same result, pains of a neuralgic character in my face,
chest, knee, dorsum of the foot, &c. These facts induced me to institute
the following experiment.
At 8 o’clock A. M., I breakfasted on beef steak, potatoes, corn bread
and two eggs. After breakfast I walked two miles. At 11 A. M., the
urine passed, was normal in color, specific gravity 1030. After standing,
there was no deposit of any kind; on a careful microscopic examination,
I was unable to detect a single crystal of the oxalate of lime. I then
ate four large oranges; at 1 P. M., I dined on a small quantity of roast
beef, and whortleberry and green currant pie. At 7 P. M., the urine
passed was of straw color, specific gravity 1036. After standing 30
minutes, a sediment was thrown down, consisting mainly of oxalate of
lime in very large beautiful crystals. I think I never saw a specimen
of urine in which it existed in greater abundance, or in which the
crystals were larger. It also contained urate of ammonia and an excess
of urea. I placed some of it in a watch glass, and added strong nitric
acid; in a few moments it was almost a solid mass from the crystals of
nitrate of urea. The urine passed the next morning at 7 o’clock had a
specific gravity of 1030, and contained an excess of urea and uric acid
and epithelial scales. At 11 P. M., the urine was normal. I then ate
four more large oranges, and went to bed. The urine passed at 7
o’clock the next morning was loaded with the oxalates. These two
experiments, one upon the urine of food, and the other upon the urine
of blood, seem to me to indicate : 1st, that oxalic acid may be produced
from the ingesta; 2d, that oranges, and probably all fruits containing
citric acid, may give rise to the oxalic diathesis.
The manner in which the transformation is effected is uncertain, nor
is it a matter of much consequence. I venture, however, to present as
a possible explanation the following formula:
f c.	II.	o.
C.	! H.	O. ,	12	18 = 6 at. oxalic acid.
6 at. of cit. acid = 24	18	30. t = 1 12	10	10j= 2 at. lactic acid.
J	2	2 = 2 at. of water.
6
We have remaining six atoms of hydrogen, which, united with 2 at. of
nitrogen, would produce 2 at. of ammonia.
What influence have the organic acids in causing neuralgia through
the derangement which they produce in the performance of the digestive
functions ? l)o the neuralgic pains depend upon mechanical irritation,
as I think may be possible, or do they depend upon perverted nutrition
of the nervous structures, as I think more probable ? These are inter-
esting subjects of inquiry, but I have not time to pursue them further.
—North Western Med. and Surgical Journal.