In other organs-for instance, the brain, the pia mater, and the choroid-the parasites occur almost exclusively in the vessels. Kelsch and Kiener found, in 40 autopsies, 9 times intense, 17 times mild, melanemia of the vessels of the brain, while the remaining cases showed no or very little pigmentation of this organ. Kelsch and Kiener attribute the rich pigmentation of the brain and pia vessels to the rapid transition of caliber between arteries and capillaries, similar to that which is seen in the pulmonary alveoli, etc.
As stated previously, the capillaries of the pulmonary alveoli, of the intestinal villi, and of the glomeruli are frequently found filled with parasites.
It has been determined by Kelsch and Kiener that in the lymph glands also the pigment is confined to the blood vessels. An exception to this are the lymph glands at the hilum of the liver. Here the pigment is accumulated in such enormous amounts, even in the tissue itself (especially in the cortical lymph follicles), as to be visible to the naked eye. Kelsch rationally assumes that the pigment reaches these glands from the liver by way of the lymph spaces of Glisson's capsule.
In addition to the black pigment peculiar to malaria , we usually find in the organs considerable amounts of an ocher colored pigment (hemosiderin). This differs from the first in that it occurs not only in the capillaries, but also, and preferably, in the parenchymatous cells of the liver, the pancreas, the kidneys, and the thyroid gland, as well as in the connective tissue. As is well known, this ocher colored pigment is encountered in numerous processes associated with the breaking up of blood corpuscles-for instance, cirrhosis of the liver, hemoglobinuria, intoxications, stases, etc. It gives the Berlin blue reaction, and this accounts for the fact, demonstrated by Stieda, that sections of organs of malarial cadavers take on a more or less intense diffuse blue color when treated with ferrocyanid of potassium and hydrochloric acid.
The blood postmortem readily shows pigment to the microscope. When the autopsy takes place within a few hours after death, the parasites are found unchanged, but the longer the interval, the more unrecognizable they become. Eventually nothing but the pigment in the leukocytes may be evident. The most satisfactory results are obtained with blood taken from the capillaries of the brain, liver, spleen, or bone marrow, where both segmentation forms and crescents are found in the largest numbers. (In regard to the other properties of the blood see page 228.)
The spleen is always found enlarged, though to varying degree. Laveran reported, from 12 autopsies of acute pernicious fevers, the average weight as 686 gm. (minimum, 400 gm.; maximum, 850 gm.); Kelsch and Kiener likewise, from 12 cases-an average of 543 gm. (minimum, 300 gm.; maximum, 950 gm.). Since, according to Bollinger, the average weight of the spleen of a healthy adult is 161 gm. in males, 148 gm. in females, the constancy of the enlargement is evident.
The consistence, when no other complication interferes, is decreased, and often to such a degree that, on removal of the organ, it runs to a pap.
The dark brown, chocolate like color, varying to deep black, is sometimes diffuse, again in spots. The cut section is dark grayish brown; the non pigmented Malpighian bodies stand out evidently. The capsule is thin, easily torn, and sometimes shows a perisplenitic exudate.
Microscopically, we find the venous sinuses dilated, sometimes markedly, when they may give rise to hemorrhages. The pulp is covered with red blood corpuscles, the majority of which are infected. Pigment may be found free, though it is usually inclosed in macrophages.
The macrophages are generally very numerous. Their nuclei stain well, or occasionally not at all, when we may consider the cells degenerated or dead. They often contain, in addition to the parasites and granules of melanin, remains of red blood corpuscles and ocher colored pigment; sometimes, too, leukocytes, or even other macrophages. In contrast to the markedly pigmented pulp, the non pigmented Malpighian bodies are striking. In some cases the spleen is relatively poor in parasites and pigment (Thin). Capillary thrombosis and scattered necrotic foci may be found.
The liver is usually enlarged. Its color varies from a steel gray olive or chocolate color to black. Its weight is greater than the normal average.
Microscopically, we find the capillaries of the portal and hepatic veins, as well as the branches of the hepatic artery, filled with parasites. In the branches of the portal vein we see splenic macrophages, which are sometimes so large that they obstruct the lumina of the capillaries. They are almost never seen in the hepatic veins. The liver cells are swollen, often contain hemosiderin, sometimes melanin, and, according to Bignami, remains of erythrocytes.
The endothelium of the capillaries is frequently swollen; the lumina thereby narrowed, and sometimes occluded. These endothelial cells, as well as the swollen Kupffer's cells, not rarely contain malarial pigment.
Barker observed in one case isolated areas of necrosis of the liver tissue, probably due to capillary thromboses (by different kinds of leukocytes).
Collections of small cells are not infrequently found in the periportal tissue. These may constitute the point of origin of the subsequent cirrhosis.
In many cases there is a certain amount of hyperemia. To this is attributable the enlargement of the liver, and to it and the infiltration with pigment the increase in weight of the organ.
According to Kelsch and Kiener, the gall bladder is usually found filled with dark colored bile. There is frequently, too, a large amount of bile in the small intestine. Griesinger observed Several times diphtheric processes in the gall bladder, apparently the result of secondary infection.