Symptoms. Emphysematous anthrax develops suddenly, the incubation in experimental cases, lasting only for a few hours, and the whole course of the disease does not usually exceed ½ to 3 days. The local swelling may be the first observed symptom or there may be first febrile disturbance followed by the local swelling. The swellings show where the connective tissue is loose and abundant as on the shoulder, quarter, arm, thigh, neck, face, or trunk, and practically never where the areolar tissue is very spare and dense as on the end of the tail, or ear, or on the limb below knee or hock. They sometimes form on the palate, base of the tongue, or pharynx. The muscular system is especially liable to suffer, the looseness of the texture and the presence of lactic acid making a particularly favorable field for the propagation of the microbe. The comparative absence of muscle in the region below the metacarpus, the tail and ear is an important cause of this immunity.
The swelling is at first very small and tender, but it encreases rapidly, and in a few hours may extend to one, two, or three feet in diameter. At first smooth, rounded, pitting on pressure and destitute of crepitation on handling, it becomes softer and less sensitive and when pressed or kneaded it gives a crepitant sensation and sound, or it even appears to gurgle. When percussed the resonance is drumlike. Finally, the skin may become cold, insensible, and withered like a piece of parchment. When incised the tissues are found to be gorged with blood, and of a black or dark red color; they break down under pressure into a bloody pulp, and from the wound flows a bloody fluid which may be red in the early stages, black in the advanced, and frothy in the latest. Where the connective tissue is very loose and abundant, the bloody extravasation is surrounded by an extensive straw colored œdematous infiltration. The swelling is sometimes single, but more frequently several appear and become confluent. The lymph glands in the vicinity become greatly enlarged.
Fever is a constant condition as the swelling advances and sometimes it precedes the local engorgement. There is erection of the hair, with it may be, distinct shivering, recurring again and again. Then general stiffness, dulness, prostration, loss of appetite and rumination, accelerated breathing sometimes attended by a grunt or moan, and rapid pulse. The temperature usually reaches 104° F., and may rise to 109° F. The breathing becomes more and more labored and plaintive, colicy symptoms may set in, the prostration advances to complete adynamia, the patient can no longer stand, the temperature drops to 100° F., or 98° F., and death supervenes in from eight hours to two days from the first sign of illness.
In some cases the swelling may be invisible because it is situated deeply or it may perhaps be entirely absent, and the constitutional symptoms are the only ones observed.
Diagnosis. From malignant œdema, which it resembles in producing gas and crepitating tumors, emphysematous anthrax is distinguished by the greater length of the microbe, by its formation of spores at the pole and not in the centre of the bacillus, by the more sluggish motions of the germ, by the restriction of the germ to given infected districts instead of being generally diffused as in malignant œdema, by its not attacking man, rabbit, nor pigeon, which are subject to malignant œdema, by its deadly action on mature cattle which are usually immune from malignant œdema, and by the abundant blood extravasation on the swelling.
From anthrax it is distinguished by the motility of the bacillus, by its polar sporulation and club shape, by its rounded ends, by its absence from the blood in the earlier stages, by the presence of gas and crepitation in the swellings, and by the deadly action of the infection on Guinea pigs, but not on rabbit, man, nor pigeon. Anthrax is easily inoculable on a cutaneous sore or intravenously whereas emphysematous anthrax is not.
Lesions. The carcass is liable to be bloated with gas and a reddish, frothy liquid often escapes from mouth nose and anus. Gas is particularly abundant in the substance of the tumor, and the skin covering it may be dry and crackling. An incision made into the swelling exposes a mass of blood extravasation and lymph exudate, the blood predominating in the centre so that it may appear clotted and black, and mixed with gas bubbles, while the yellowish lymph forms the periphery of the tumor, yet streaked more or less with blood, or even pink throughout. The abundance of gas is usually in inverse ratio to the amount of œdema. The muscles beneath or surrounded by an exudate are of a dirty brown or black, and are disintegrated so as to break down readily under pressure of the finger into a blackish pulp. They are infiltrated with gas, crepitate under pressure and assume a golden yellow color on exposure to the air. The gas is comparatively inodorous immediately after death, being mainly carbon dioxide and carbide of hydrogen. Later it may show distinct and even offensive odor, from the formation of hydrogen sulphide, or lactic acid. The muscular fibres are easily teased apart, and show under the microscope masses of blood globules, leucocytes, lymph cells, free nuclei and granules, with, in some points, fatty or waxy degeneration of the fibres, or granular masses that are stained black by osmic acid. The bacillus is present in large numbers, and this with its absence immediately after death from the blood becomes characteristic. The lymph glands near the swelling are usually enlarged and gorged with blood. The lymph plexuses and vessels contain bubbles of gas.
The swellings may be subcutaneous, or submucous in the tongue or pharynx, but they occur also in the pleuræ, lungs, heart, pericardium, mediastinum, the peritoneum, the sublumbar connective tissue, and even the walls of the stomach or intestine. It is not uncommon to find a pink effusion into one of the serous membranes. The liver is usually hyperæmic, as may be also the kidneys, but the spleen is rarely enlarged. In this and in the integrity of the blood globules this affection differs from anthrax.
Treatment. This disease is so often speedily fatal, cutting off its victim in eight hours, often during the night, that no opportunity is allowed for treatment. Even in those that survive for two days, the affection must always be looked on as exceedingly grave, and as little amenable to treatment. Yet much depends upon the patient and the country. Dr. Phares in Mississippi found that it yielded readily in many cases to ½ oz. doses of tincture of chloride of iron every four hours, and a local application composed of equal parts of tincture of iodine, aqua ammonia and oil of turpentine. Galtier tells us that recoveries are frequent in Algeria, while they are rare in France. Tisserant gives the French recoveries as 2 per cent. It is probable that in districts and countries where the malady is all but ubiquitous, the surviving animals are racially immune, or they have been largely exposed and in some degree virtually immunized at an early age.
Wallraff mentions a success from applying a tight ligature around an infected limb, above the seat of the tumor and freely scarifying the latter so as to freely admit the air. For swellings elsewhere, scarifications and the free application and injection of peroxide of hydrogen or potassium permanganate (2 to 3:100) would be rational treatment. The same agent might be given by the mouth in doses of 2 or 3 ozs. at frequent intervals. Antiseptics and tonics have been freely employed, including phenol, salicylic acid, sodium salicylate, potassium iodide, quinia, alcohol, phosphorated oil, ammonia acetate, and as an eliminant soda sulphate, but with no very good result. Locally, scarification, antiseptics and caustics, have been employed.