A system of practical medicine. By American authors. Vol. 2

by Unknown

²²⁸ Clinical Lectures on Diseases of the Liver, loc. cit.

Distoma hepaticum and Distoma lanceolatum (Liver-Flukes).

The Distoma hepaticum, entitled by Linnæus Fasciola hepatica, occurs very frequently in herbivorous animals and occasionally in the biliary passages of man.²²⁹ It is, however, less important than the Distoma lanceolatum, which, although much smaller than the former, occurs in much larger numbers.

²²⁹ Davaine, Traité des Entozoaires, Paris, 1877, p. 240 et seq.; also, Cobbold, Entozoa, p. 148.

Distoma hepaticum is a leech-like parasite from 25 to 30 mm. in length, of a brownish color, smooth to the naked eye, but thickly covered with minute spikes or spines to be seen with a low power, and provided with a cephalic (entrance to oral cavity) and an abdominal sucking disk, which are also organs of locomotion. The Distoma lanceolatum owes its name to its lancet shape; it is smaller than D. hepaticum, measuring about 8 mm. in length and half this or less in width; it is unprovided with spines, but contains two suckers at the side. Both parasites are hermaphrodite; the ova, according to Cobbold (p. 166), have "an average longitudinal diameter of ¹/180, whilst their greatest transversal measurement is about ¹/270." These ova are capable of some movement, provided as they are with a ciliated envelope.

The disease known as the rot in sheep, and a peculiar cachexia entitled by Davaine la cachexie aqueuse, are caused by the presence of distoma. The ova gain access to man through the use of unwashed cress, lettuce, and similar vegetables eaten in the raw state, and in drinking-water. Fortunately, this accident is rare. The number of reported examples collected from all sources by the indefatigable Davaine is twelve.²³⁰

²³⁰ Ibid., p. 253 et seq.

The larger distoma passes into the common and hepatic duct and gall-bladder, whilst the smaller (lanceolatum) enters the finer ramifications, and, there multiplying, several consequences may ensue. The irritation caused by their presence and development will excite a more or less severe cholangitis, or, accumulating in sufficient numbers, an actual obstruction will be induced, and jaundice and structural alterations of the liver will in turn be brought on.

The DIAGNOSIS of such a malady is, in the very nature of the case, uncertain at best, and in most cases impossible. Nevertheless, it may be made in rare instances. The existence of the rot may cast suspicion on the mutton and kitchen vegetables so situated as to suggest the possibility of contamination with the ova of distoma. Definite and conclusive information will be afforded by the presence of the ova, still more of the more or less fully-developed parasite, in the feces of a patient effected by the symptoms of catarrhal jaundice or occlusion of the biliary passages. By tapping the gall-bladder parasites may be withdrawn.

The SYMPTOMS are those common to cases of catarrh of the bile-ducts (cholangitis), catarrhal jaundice, or occlusion of the passages, as may be. As these have been detailed under their respective heads, it is not necessary to repeat the observations already made.