CATARRH OF THE LACHRYMAL SAC. DACRYOCYSTITIS.
Connected above through the canaliculi with the conjunctiva, and below through the lachrymal duct with the nasal chamber this cavity is liable to be more or less implicated in all cases of nasal catarrh and conjunctivitis, (strangles, canine distemper, influenza). If the lachrymal duct is obstructed so that the tears accumulate in the sac, the tendency to catarrh is further enhanced by the distension and weakening of its walls, and by the propagation of bacteria which have entered with the tears, and find in them a favorable and abundant culture medium; the diameter of the sac in the horse being about ⅔rds. of an inch. The presence of foreign bodies is another cause.
Lesions. Symptoms. Swelling at the inner canthus, which raises the carnucle above the normal level, and the escape of tears over the lower lid are the most prominent symptoms. If the swelling is pressed it subsides, the contents, clear or purulent, escaping through the lachrymal duct, to the nose, or through the puncta and accumulating in the inner canthus or flowing over the cheek. The hair beneath the inner canthus is matted together, or drops off leaving bare patches. Wolff found in one case, a distension of the sac to over two inches in breadth, and 1⅔ inches long. To the swelling there is soon added conjunctival inflammation, closure of the puncta by swelling and the escape of all tears over the face. Suppuration supervenes in the sac, and in the larger animals the pent up pus often makes its way outward, causing destructive ulceration of the walls of the canaliculi and puncta, or of the walls of the sac, the skin, or even the subjacent bone. In this way fistula results. Caries of the bone and penetration of the molar alveoli may ensue. (Girard, Leblanc).
Treatment. The first object must be to secure a free drainage into the nose. The evacuation of the sac by compression having been accomplished, an astringent solution may be injected through the nasal opening of the lachrymal duct. If the canal is pervious the sac will be re-filled and will swell out as before. The injection may be 0.5 per cent. sulphate of zinc, 1 per cent. acetate of lead, 0.3 per cent. nitrate of silver, 1 per cent. tannic acid, 2 per cent. boric acid, or 0.02 per cent. corrosive sublimate. Cocaine may be added in the proportion of 5 per cent. The injection may be repeated thrice a day at first, then twice, and finally once as the catarrh subsides.
If the injection fails to reach the sac, thoroughly sterilized, flexible probes may be used, increasing the size as they can be passed without too great pressure.
Or the puncta and canaliculi may be injected as in the human subject, the conjunctiva having been first anæsthetized by cocaine, or general ether or chloroform anæsthesia having been induced. The slitting of the puncta and canaliculi may be resorted to, as spoken of under atresia.
The frequent passage of a sound is usually resorted to, and a stilet may even be worn, but there is always danger of resulting thickening and narrowing of the duct, and, if healing can be secured without this measure, it is to be preferred.
STENOSIS OF THE LACHRYMO-NASAL DUCT.
Obliteration of the lachrymal duct may occur from stricture of the canal, the result of wounds or other irritants: from pressure by the inflamed mucosa in nasal catarrh or strangles: from polypus or osseous tumor in the nose: from actinomycosis or other disease of the bones.
The one manifest symptom is the escape of the tears on to the face. To complete the diagnosis, injection of one punctum will cause distension of the lachrymal sac.