The kidneys may be pale except where blood stained and œdematous infiltration of the surrounding tissue may be marked. Serous effusion into the peritoneum is not rare.
The eyelids are often implicated, infiltrated thickened, and rigid, and the conjunctiva, bulbar and palpebral, the seat of extensive petechiæ.
Barreau mentions extravasations on the divisions of the lumbosacral plexus causing sudden paraplegia.
Petechiæ and hæmorrhages mark endocardium, pericardium and cardiac muscle, otherwise the muscle is pale. The blood is sometimes in firm clot, at others diffluent or nearly incoagulable.
Symptoms. If hyperthermia is not already present as a feature of the pre-existing malady it usually shows itself early, at first slight, it may be (101° F.), and afterward rising in some cases to 104° to 106° F., or even higher. The general symptoms are usually those of the pre-existing disease (strangles, contagious pneumonia, influenza, nasal catarrh, pharyngitis, bronchitis, etc.), pursuing, it may be, a persistent course, or attended by special toxæmic symptoms of prostration and other signs of depression of vital functions. In some cases the hyperthermia is either absent at this stage or overlooked. On the prostration supervene the petechiæ on the visible mucosæ, and often also the swellings of the skin and subcutis. One of these may be seen before the other and it is difficult to decide whether the petechiæ always appear first as has been claimed. Cadeac claims that when œdema is first seen it has been preceded by petechiæ in that tissue (skin).
The petechiæ are usually first noticed on the nasal mucosa as fine red points, pin’s heads, or up to half an inch in diameter, or a number of these have coalesced to form extensive patches, and by and by to cover the entire wall. At first the mucosa is spotted with purple, without any marked elevation of the surface, but as the lesions extend it becomes swollen and raised at the points of extravasation and immediately around them and oozes a serous, sometimes a pinkish or yellow fluid. Even in the smallest petechiæ the color is persistent and does not disappear on pressure like the blush of the adjacent mucosa.
Usually cutaneous swellings coincide with the petechiæ, or appear within two days thereafter. The first manifestation is in the form of rounded abruptly elevated nodules, about 1½ inch to 3 inches in diameter, strongly resembling the eruption of urticaria. These show a certain predilection for the more dependent parts of the body,—limbs, abdomen, sheath, mammæ, sternal or pectoral region, nose, lips, face, etc.,—but they may develop on any part or on the whole surface. Neither tenderness nor heat is usually excessive. The swellings tend to run together so as to form extended elevations enveloping the entire limb up to a given point, forming a great pad under the chest and abdomen, or distending the whole face or head so that it seems more like that of a hippopotamus than of a horse. In such cases the lips and nostrils become so thick and rigid that prehension is impossible, and breathing if it can be accomplished at all is accompanied with a marked snuffling. The swollen eyelids are closed, and the general turgid surface of the face is hard and resistant and no longer pits on pressure.
Under the chest and abdomen the swellings show as a continuous pad or cushion, on one side mainly or extending across continuously on both sides, and from the breast to between the thighs. It usually pits on pressure, and may shed the hair and become rough and scabby or ooze a serous fluid from the surface.
On the limbs the swelling usually shows first on the fetlock or pastern and gradually extends upward until it reaches the body.
As the disease advances chaps, cracks and fissures tend to form on the swellings, showing about the head, on the lips or on the nose and maxilla where the noseband of the halter crosses; on the lower part of the body where the circingle crosses, or where the part is pressed upon in lying down, and in the limbs in the flexure of the joints—behind the pastern, or knee or in front of the hock. In many cases the skin and connective tissue sloughs, and drops off exposing the muscles, the tendons or the ligaments of the joints. In other cases the tendons are involved in the degenerative process or necrosis and become detached from their lower insertions so that the toe may be turned up or the fetlock pad may come to the ground. The matrix of the hoof wall (coronary band) may separate from the horn, leaving a gaping opening which exudes liquid freely, and if the animal survives, the entire hoof may be shed.