Definition. Nature. Result of other morbid processes. Leucocytes
polynuclear. Lymphatic leukæmia. Spleno-myelogenous leukæmia.
Leucocytes in each. Loss of amœboid movement. Charcot’s crystals.
Hæmatoblasts. Cell increase in bone marrow. Myelocytes. Enlarged
spleen and lymph glands. Hæmorrhages. Lymphoid growths. Susceptible
genera. Causes obscure. Symptoms, pallor, listlessness, weakness,
apnœa, sweating, thirst, emaciation, weak circulation, anæmic murmur,
enlarged spleen, bleedings, diarrhœa, dropsy, excess of white
globules, reduction of red globules, buffy coat, beaten fibrine is
granular, china-white mucosæ, hurried breathing, stertor, deranged
digestion, marasmus. Duration. Not inoculable. Treatment, not hopeful,
as for anæmia, good hygiene, tonics, stimulants, antiseptics.
_Definition._ An excessive and persistent increase of the white blood
globules, and associated with enlargement of the spleen, lymph glands or
bone marrow.
_Nature._ This must be distinguished from the leucocytosis which occurs
during digestion, or that which attends on tuberculosis, glanders,
pneumonia, and other extensive inflammations and profuse suppuration.
These forms are transient and the cells are of the polynuclear variety.
The cells of leukæmia are various in character, but bear some relation
to the particular organ which is the seat of hypertrophy or morbid
process.
“In =lymphatic leukæmia= the increase in the number of leucocytes is due
to the mononuclear lymphocytes, especially of the small form. As many as
ninety-five per cent. of the colorless cells may be of this form. In
=Spleno-Myelogenous leukæmia= the eosinophile cells may be especially
increased in number, and there are also large leucocytes coming
apparently from the marrow of the bones, and called myelocytes. These
most nearly resemble the larger lymphocytes of normal blood, but they
are usually larger. They have a single large nucleus which stains feebly
and their bodies may show neutrophile granules. Larger and smaller
nucleated red blood cells may be found in spleno-myelogenous leukæmia.
The leucocytes are frequently in a condition of fatty degeneration, and
there may be a decrease in the number of red blood cells.” (Delafield
and Prudden). In splenic leucocythæmia blood plates may be absent and in
lymphatic leucocythæmia they may be in excess.
Cafavy claims that many of the leucocytes have lost their active amœboid
movements.
Bright white crystals in the form of elongated octahedra are found not
only in the blood but in the diseased glands, spleen or marrow
(Charcot’s crystals). Clusters of discoid hæmatoblasts (blood plates)
are present in the blood in variable numbers (Schultze’s granule
masses).
The bone marrow is marked by an accumulation of spheroidal cells, which
tend to pass into a condition of fatty degeneration. Most of them are
colorless, larger than the lymphocytes of normal blood and have one
large often vesicular nucleus, staining less highly than the lymphocyte
nuclei, and with neutrophile granules in the protoplasm (=myelocytes=).
There are besides, nucleated red blood cells, spheroidal cells,
containing red blood cells, and Charcot’s crystals. The marrow may be
uniformly red, mottled gray and red, gray, grayish yellow, or puriform
(Delafield and Prudden). This may affect one or many bones. The affected
spleen is usually much enlarged, at first uniformly, later unevenly,
firm or softened, and with thickened white capsule. The cut surface is
smooth, brownish red, or yellow, with white lines (thickened trabeculæ)
and indistinct Malpighian corpuscles. It contains glutin, glycocoll,
hypoxanthin, zanthin, leucin, tyrosin, and lactic, acetic, or formic
acids.
The affected lymph glands are somewhat enlarged, red or gray,
exceptionally, softened or caseated and otherwise contain an excess of
leucocytes.
Slight hæmorrhages may appear in any of these structures. Lymphoid
growths may appear in a number of other organs as the liver, heart,
lungs, kidneys, bowels, tonsils, the different blood glands, the serosæ
and the retina.
_Genera affected._ It has been seen mainly in dogs, but also in horse,
ox, pig, cat and mouse. Nocard has collected the following cases: horse
9, cattle 6, pig 5, dog 22, cat 1.
Leisering found a horse’s spleen weighing 28 kilogrammes. Johne found a
pig’s spleen of 2.4 kilogrammes.
_Causes._ The primary causes of leukæmia are unknown. As in anæmia all
unhygienic conditions are invoked as causes. That it is not due to
simple hypertrophy or irritation of the leukogenic centers is plain, as
it does not follow on ordinary diseases and injuries of these parts, but
what is the precise nature of the morbid cause has so far eluded us.
_Symptoms._ Pallor of the visible mucous membranes, listlessness, lack
of energy and endurance, breathlessness and perspiration on the
slightest exertion, ardent thirst, rapidly advancing emaciation,
unsteady gait, stiffness or lameness, lies most of the time, walks with
pendent head, and jaws open, small, weak pulse, anæmic murmur in the
heart, enlarged lymph glands, or spleen felt beneath the left lumbar
transverse processes in the ox, or in the left hypochondrium in the
horse. Bleeding from the nose or elsewhere, slight hæmorrhage into the
conjunctiva, irritable conditions of the bowels, diarrhœa and dropsies
are suggestive. The blood when obtained in epistaxis or drawn by a
needle prick may be pale rose, brownish or grayish brown instead of red,
and under the microscope shows the enormous excess of leucocytes—the
ratio to the red being sometimes 1: 2, or even more, in the human
subject. In the domestic animals the following ratios have been made by
actual count: 1: 85 (Leblanc and Nocard), 1: 50, 1: 45 (Mauri), 1: 20
(Nocard), 1: 15 (Siedamgrotzky), 1: 12 (Forestier and Laforque). The
normal average for the domestic animal according to Nocard is 1: 900.
This great relative excess of white globules serves to distinguish this
malady from anæmia, and its persistency is a means of diagnosis from
transient leucocytosis.
The red globules are always reduced in number in the horse and dog to
5,082,000, and even 2,050,000 per cubic millimetre, while the normal is
7,500,000 (Nocard).
In clotting, the blood forms an extensive buffy coat, and in solipedes
which normally show this, the blood set in a test tube forms three
strata, the upper slightly yellow, semi-transparent and formed of
fibrine; a median of a dull, opaque white color and formed mainly of
leucocytes and blood plates, and a lower of a violet red and formed
mainly of red globules.
The amount of fibrine is variable. It becomes granular when beaten.
Albumen is variable but usually reduced.
The visible mucous membranes are bloodless and of a clear porcelain
white. The walk becomes weaker, fore feet wide apart and the hind limbs
partly flexed, head and neck extended, and breathing labored. The
breathing may be with constant stertor, the bowels torpid and
tympanitic, or loose and fœtid, dropsies and hæmorrhages ensue, and the
patient dies in complete marasmus.
_Duration._ The disease may prove fatal in less than a month, or it may
last for three, six, or eight months. It is mostly fatal.
_Not inoculable._ Many attempts have been made to transmit it by
inoculation, but in no case with success.
_Treatment_ is not successful. All hygienic measures should be adopted,
as for anæmia; open air and sunshine, with protection against chills;
the treatment of all complications; iron, bitters, phosphorus, arsenic
in particular, electricity to the spleen, massage; oxygen inhalation;
and locally, iodide of potassium or mercury, generally and locally.