Earthy basis, nucleus, stratification, in cæcum or colon, multiple,
size, number up to 1000. Composition, phosphates of lime, magnesia,
and ammonia, silica, mucus, epithelium, organic matter.
Ammonio-magnesian tend to crystalline form, common phosphate of lime
to smooth forms. Concretions. Source in food. Ammonia from bacteridian
fermentation, action of colloids, varied nuclei, rapid growth.
Lesions: catarrh, dilation, obstruction, rupture, peritonitis.
Symptoms: intermittent colics with obstruction, tympany, bowel
distension, liquid and gaseous, before obstruction. Diagnosis: by hand
in rectum, hard obstruction with distension in front. Treatment:
purgative dangerous, but exceptionally successful, extraction,
oleaginous enemata, laparotomy.
=Horse.= Intestinal calculi have an earthy basis (ammonio-magnesian
phosphate, or oxalate of lime, and more or less silica) glued together
by mucus and having a central nucleus usually of some foreign body, (a
particle of sand, pebble, morsel of hair, lead, cloth, nail, coin, blood
clot, or inspissated mucus) around which the earthy salts have been
deposited layer after layer. They are usually formed in the cæcum or
double colon and may be multiple and moulded upon each other, so that
they become discoid, angular or otherwise altered from the globular
shape. The worn, flattened surface in such cases shows concentric rings
representing the layers as deposited in succession.
The _size_ of the masses may be from a pea or smaller, up to calculi of
six inches in diameter.
In _number_ there may be a single calculus or there may be an indefinite
quantity. Zundel counted 400 in a single colon, and Gurlt 1,000.
_Composition._ They are usually composed of phosphate of lime and of
magnesia, of ammonio-magnesian phosphate, with a little silica, mucus,
epithelium, and organic matters from the ingesta. Traces of sodium
chloride, and iron oxide may also be present.
The phosphates of lime, magnesia, and of ammonia and magnesia usually
constitute the main part of the calculus. Fürstenberg found specimens in
which the ammonio-magnesian phosphate amounted to 72 to 94 per cent.
The calculi containing an excess of ammonio-magnesian phosphate tend to
assume a crystalline or coralline form which causes them to be specially
irritating to the mucosa. When broken they show a radiated structure
from the centre to the circumference in addition to the concentric
rings. These are usually of a yellowish brown or a gray color and have a
specific gravity of 1694 to 1706.
Calculi in which the common phosphate of lime abounds are likely to be
smooth on the surface and on section show the concentric rings more
distinctly and the radiating lines less so. The brownish calculi of this
variety are much more compact, and harder than the crystalline or
mulberry calculi, and have a higher specific gravity—(1823).
Bluish calculi with a smooth glistening surface and lower specific
gravity—1681—, have been found of small size and in great numbers in the
colon (1000 in the colon, Gurlt).
In some calculi there is a large admixture of alimentary matters, and a
low specific gravity (1605 to 1674). These were designated as _pseudo
calculi_, by Fürstenberg.
In still other cases a calculous looking mass, when broken into, is
found to be composed of a mass of dried alimentary matter enclosed in a
thin layer of lime salts. These have a low specific gravity (1446 to
1566) and have been named _concretions_ by Fürstenberg.
_Causes._ As a large proportion of the calculus is phosphate of lime or
ammonio-magnesian phosphate, we must look for the source of these in the
food and then at the conditions which determine their precipitation.
The percentage of ash and of phosphoric acid in the common foods of
horses may be seen in the following table:
PO_{5} in the PO_{5} in the
Ash. Ash. entire food.
Per cent. Per cent. Per cent.
Wheat bran 7.3 50 3.65
Wheat grain 3.0 46.38 1.3914
Oats grain 2.50 26.5 0.6625
Barley grain 3.10 39.9 1.2276
Bean grain 3.10 31.6 0.9864
Pea grain 2.75 34.8 0.957
Tare grain 3.00 36.2 1.086
Indian corn grain 1.5
Rye grain 1.6 39.9 1.0384
The source of the magnesia may be found to a large extent in the grains
represented in the following table:
Ash. Mg. in Ash.
Per cent. Per cent.
Oat, grain 2.50 7.3
Barley, grain 3.10 8.5
Rye, grain 1.6 2.4
Wheat, grain 2.12 9.98
Wheat, bran 7.3 11.2
Bean 3.1 6.6
Pea 2.7 5.6
The amount of magnesia in each of these grains is amply sufficient to
furnish the material for the constant growth of a calculus. Wheat bran
is preëminent in the amount of its magnesia and therefore wheat bran has
been charged with predisposing to calculi. In the perisperm as a whole,
Fürstenberg found 1 per cent. of phosphate of magnesia, and in coarse
bran not less than 2.5 per cent.
The ammonia which is essential to the precipitation of the phosphate of
magnesia in the form of the compound salt (ammonio-magnesian) can be
found wherever proteids are in process of septic fermentation. The
slightest failure to peptonize every particle of such proteids, implies
septic change and the evolution of ammonia, which on coming in contact
with magnesia phosphate instantly precipitates the insoluble salt.
This fully agrees with the doctrine of the formation of urinary calculi
through the agency of bacteria, since the ammonia is essentially a
fermentation or bacterial product.
It may also be noted that the experiments of Rainey and Ord showed that
in the presence of colloids (mucus, epithelium, pus, blood) the earthy
salts are precipitated as minute globular bodies which by further
accretions become calculi. In the absence of colloids the salts tend to
precipitate in angular crystalline forms, so that the mulberry and
coralline calculi may possibly have been precipitated in the absence of
such bodies. From the solvent quality of ammonia, however, the contents
may easily pass from a fermenting liquid containing colloids to a
non-fermenting and noncolloid mixture.
The presence of a solid body which may act as a nucleus is an essential
element, and the condition of the food or drink will often supply this.
It has been noticed that army horses in the field, feeding from the
ground and taking in sand and pebbles, are unusually liable to
intestinal calculus. Horses which lick earth in connection with acidity
of the stomach or other dyspepsia are specially subject to it. Horses
watered from shallow streams with sandy bottoms, where they take in sand
with the water, have been similarly affected. Millers’ horses, in the
days of old process milling, suffered not alone because of the abundance
of oat hairs in the feed but also on account of the grit from the
millstones. Hay and other fodders that have lain on the ground and which
contain earth and sand furnish other sources of such nuclei. Shingle
nails and other small nails, pins, needles, coins, etc., which have
mixed with the feed are common causes of trouble, and indeed any foreign
body may become the centre and starting point of a calculus.
Catarrhal affections and other lesions of the mucosa, which furnish
excess of mucus, beside pus, lymph and even blood as nuclei, are invoked
as starting points of the calculi, but however true this may be in
particular cases, irritation and catarrh appear to be much more
frequently the result than the cause of the calculus.
Attempts have been made to estimate the time taken in the formation of a
calculus by allowing a ring for each feed and successive deposit
therefrom (Fürstenberg, Colin). Thus a calculus of 14 pounds with 720
layers, it was estimated could be formed in one year at two feeds per
day. More definite evidence was found in the case of Pastore in which a
coin with the mint mark of 1847 was found as the nucleus of a calculus
the size of the fist in 1848.
_Lesions._ Formed in the most spacious parts of the colon and cæcum,
calculi usually rest there for a length of time without visible injury,
and it is only when they are moved onward and get arrested at a narrow
part of the gut (pelvic flexure, floating colon, rectum) that they cause
appreciable trouble. Yet it is claimed that by their weight they drag
upon the yielding walls of the bowel, causing dilatation and
attenuation, weakening the peristalsis and predisposing to rupture. The
compression of the vessels also tends to anæmia and atrophy. In the case
of rough crystalline calculi the mucosa is subjected to attrition,
irritation, and inflammation. The more serious and urgent trouble is
that of obstruction of the narrower portions of the colon and rectum,
which may be absolute and persistent, leading to rupture and death or a
fatal inflammation on the one hand, or may end in recovery on the other,
in connection with a displacement onward or backward of the calculus as
the result of peristalsis or anti-peristalsis.
_Symptoms._ These are intermittent colics, each reaching a climax and
followed by a sudden recovery as the calculus is displaced into a more
spacious part of the colon. A significant feature is the complete
obstruction, fæces being passed for a short time at first and then
suddenly and absolutely stopped. Coincident with this are tympany,
violent colics, straining, rolling, sitting on the haunches,
perspirations, anxious countenance, and all the symptoms of obstruction.
_Diagnosis_ is never quite certain unless the practitioner with his
oiled hand in the rectum can detect a hard stony mass obstructing the
pelvic flexure of the double colon with a tense elastic distended bowel
immediately in front of it, or a similar hard obstruction of the
terminal part of the floating colon with a similar distension in front
of it. The pelvic flexure may usually be felt below and to the right at
the entrance to the pelvis, and the floating colon above, under the
right, or more commonly the left kidney. Calculi in the more spacious
parts of the double colon or in the cæcum are inaccessible to
manipulation. The feed (bran, ground feed) will be suggestive, as will
the occupation of the proprietor (miller, baker).
_Treatment._ This is rather a hopeless undertaking. No effective solvent
of the calculus can be given, and purgatives usually increase the danger
by increasing the peristalsis and dangerously distending the bowel above
the point of obstruction. It is true that this is sometimes followed by
a temporary recovery the calculus being loosened and falling back into
the dilated portion of the bowel. Less frequently the increase in the
peristalsis forces on a moderately sized calculus to complete expulsion.
It is a desperate though sometimes successful resort. A more rational
course of treatment is the dilation of the bowel back of the obstruction
by copious mucilaginous, soapy or oleaginous enemata. Trasbot suggests
CO_{2} produced by injecting sodium bicarbonate and tartaric acid. This
may be seconded by the hypodermic injection of barium chloride or of
atropia. When the calculus is lodged in the floating colon or rectum it
may be possible to reach it with the hand and extract it at once. The
last resort, is by laparotomy for the removal of the calculus. One such
successful case is on record in which Filizet removed a calculus as
large as an infant’s head. In other cases the horses failed to survive.
Desperate as the resort may be it is not to be neglected in a case of
undoubted calculus, solidly impacted and of such a size that its passage
is impossible. A fatal result is imminent, and even if the present
attack should pass off it can only be looked on in the light of an
intermission, so that there is practically nothing to lose in case the
result should prove fatal. Anæsthesia and rigid antiseptic measures
should of course be adopted.