Description

This section is from the book "A Manual Of Pathology", by Guthrie McConnell. Also available from Amazon: A Manual Of Pathology.

In it the protoplasm of the cells contains an increased amount of protein substances. It accompanies very slight disturbances of nutrition, such as occur in inflammation, is found in all infectious diseases and intoxications, possibly as a result of increased bodily temperature, most likely as a result of disturbances of metabolism.

Cloudy Swelling of the Kidney Epithelium. X800 (Ziegler).

Fig. 164. - Cloudy Swelling of the Kidney Epithelium. X800 (Ziegler).

a, Normal epithelium; b, beginning cloudy swelling; c, marked degeneration; d, desquamated degenerated epithelium.

Although all the cells of the body, both glandular and stroma, may undergo this change, they are not equally affected, the glandular ones being more liable to injury. The secreting cells have as their function the removal of certain substances from the body. If the blood contains injurious materials, these cells naturally will be the first affected, as they are the more intimately concerned.

This degeneration may follow extensive superficial burns, probably as a result of the action of the poisonous substances absorbed.

Microscopically the individual cells will be swollen and larger, more granular, and more opaque than normal on account of the presence of minute granules; the nucleus, consequently, may be obscured. These latter are insoluble in alcohol and ether, but are dissolved by alkalies and weak acetic acid.

The function of the cell is more or less disturbed, but complete recovery frequently occurs. If, however, the cause persists, fatty metamorphosis results.

Fatty infiltration is the deposit of fat within the cell or intercellular tissues. In all parts of the body, except the liver, the connective tissue is affected. In this organ the secreting or parenchymatous cells are involved. May be general or local. It may occur in cells that normally contain no fat, or else appear in excess in cells that do contain it.

The fat contained within the cells is made up of neutral palmitin, olein, and stearin.

Fatty infiltration may be hereditary, as obesity in successive generations; may result from excessive nutrition, particularly if combined with lack of exercise.

The use of alcohol, especially in the form of malt liquors. The alcohol, being easily oxidized, probably takes the place of the fats which remain unused.

Anemia, on account of the insufficient oxygenation of the tissues.

In certain cachectic conditions, as in phthisis; where the liver is frequently filled with fat.

The most common seats are the subcutaneous and subserous tissues, the omentum and the mesentery, in the liver, heart, kidney, and between the muscle-fibers.

Certain other regions, such as the subcutaneous tissue of the penis, nose, ear, lips, and eyelids, are never involved.

An organ the seat of fatty infiltration is larger, paler, mottled, streaked or diffusely yellow, softer, more friable, and greasy on section.

Fatty Infiltration of the Liver (McFarland). a, Periportal connective tissue; b, fat drops in liver cells.

Fig. 6. - Fatty Infiltration of the Liver (McFarland). a, Periportal connective tissue; b, fat drops in liver cells.

Under the microscope the fat may be found either inside or outside of the cells. If outside, it is most marked along the fibrous bands.

Inside the cell, particularly the glandular variety, the fat occurs in droplets which tend to enlarge and coalesce. The nucleus is displaced, giving the "signet-ring" appearance, or obscured; is seldom destroyed. The cell wall remains intact.

The tests for fat are sudan III, which stains it scarlet, or a I per cent, solution of osmic acid, which stains black. It is soluble in alcohol, ether, and xylol; insoluble in water, acids, and alkalies.

Adipocere refers to the transformation of the fats into a waxlike substance most common in bodies that have been buried in damp earth.

Fatty metamorphosis is a conversion of the cell protoplasm into fat.

Generally speaking, the causes of cloudy swelling will bring about fatty degeneration if they are severe enough or act for a sufficiently long time. It occurs in senility, particularly when associated with marked arteriosclerosis and atheroma; in anemia, either as a result of hemorrhage or in diseases such as leukemia and pernicious anemia. The condition is probably more widespread in the latter than in any other disease. Occurs also in long-continued and high fever.

The most important substances causing the metamorphosis are the poisons, as the metallic salts, chloroform, coal-tar products, etc., and those formed by micro-organismal activity, as in yellow fever.

The fat present in the cells,is either (I) formed by actual disintegration of the protoplasm of the cells, or (2) is taken up by the cells from the blood and remains unaltered, owing to defects in the vital power of the cell to assimilate it.

This condition may result from -

1. Insufficiency of the supply of nutriment.

(a) The blood-supply may be actually diminished.

(b) There may be increased work without a corresponding increase in the blood-supply.

(c) Actual deficiencies in the blood may impair its nutritive value, as diminution in the hemoglobin or of the corpuscles.

2. The failure of the cell to make use of the material placed at its disposal is probably the more important cause.

(a) The result of bacterial toxins.

(b) The influence of inorganic poisons.

(c) A senile change dependent upon the exhaustion of the inherited vital capacities of the cells.

Organs undergoing this change are generally smaller and paler, yellowish, soft and flabby, and easily friable; they may undergo caseation.

The liver in yellow fever is a typical example.

Microscopically the cell protoplasm contains a large number of minute droplets that rarely coalesce. The nucleus is soon involved and ultimately is destroyed. The entire cell may break down into a fatty granular mass, sometimes called a "compound granule cell." Granules may be so small that their character cannot be recognized except by special staining.

Hyaline Degeneration of an Ovarian Capillary. Oc. 2; ob. 9 (McFarland).

Fig. 7. - Hyaline Degeneration of an Ovarian Capillary. Oc. 2; ob. 9 (McFarland).

To distinguish between fatty metamorphosis and fatty infiltration is frequently not only difficult, but impossible, especially so in the liver. The droplets may coalesce in metamorphosis and remain separate in infiltration.

Crystals of margarin and the notched rhombic plates of cholesterin are frequently found in the fatty areas.