Definition. Bloodlessness; Deficiency of blood; Lack of red blood globules. The last named is the condition to which the term is habitually applied.
Causes. Anæmia is not so much a disease, as a result of a great many debilitating and exhausting conditions. Hæmorrhage the most direct cause of anæmia determines at first an actual lack of blood (oligæmia) and of blood pressure, which may be sufficient to cause fainting and death. In case of survival the amount of blood is rapidly made up by absorption from all available sources of liquid in the economy, but the blood so restored is essentially hydroæmic having an excess of water and a lack of globules and dissolved solids. If however the loss has been moderate the quality may be restored in a few days. Buntzen found that after moderate bleeding the volume is restored in a few hours; after a profuse hæmorrhage in 24 to 48 hours. After bleeding to 1.1 to 4.4 per cent. of the body weight the increase of the red globules may be noticed after 24 hours, and is completed in 7 to 34 days. It is noteworthy that during this repair the bone marrow becomes much redder and more cellular, and that new red cells found in the blood are nucleated (Neumann) and contain less hæmoglobin (Ott). The absence of hæmoglobin is nearly in proportion to the amount of the hæmorrhage (Bizzozero, Salvioli). If the hæmorrhage is slow and continuous this repair is counterbalanced and the anæmia is much more persistent.
Profuse secretion as of milk (cows, goats, ewes, bitches, on poor feeding), of liquid fæces, urine, or pus often determine a marked and even dangerous anæmia.
The rapid growth of multiple tumors as of melanosis in gray horses has been noticed to cause profound anæmia (Bouley).
Perhaps no cause is more potent than the attacks of parasites and especially such as live by sucking the blood. The numerous strongyli of the lungs, stomach, and intestine, the tricocephalus, and allied round worms, the trematodes of the liver, and the cytodites of birds furnish striking examples of the bloodless and debilitated condition which they may produce. In man ankylostomata causes anæmia in Egypt, Italy (St. Gothard) and elsewhere, and bothriocephala in different countries.
Chronic exhausting diseases especially those which affect the digestive organs and mesenteric glands are prolific causes. So with Bright’s disease.
Connected with these are defects in diet or hygiene. Starvation, unsuitable, innutritions, or indigestible food, too laxative food, damp, dark, draughty or unventilated stables, and irregularity in feeding, watering and work are all potent factors in inducing anæmia.
Diseases of the masticatory apparatus (broken jaw, diseased teeth,) preventing the preparation of food, and pharyngeal troubles interfering with deglutition are other causes. Finally overwork is not to be forgotten.
Toxic anæmia may occur from the ingestion of lead, mercury, or arsenic.
Symptoms. These may be little marked at the outset in slowly developing cases. Extra pallor of the mucous membranes, fatigue and even breathlessness on slight exertion, a small, weak, pulse, with a tendency to become rapid, with violent heart beats, when excited.