Part 103

Breeding horses, male and female, have often acute attacks and die early. The drain on the system and confinement seem to act injuriously.

Nature. Until we know the essential cause or causes of osteoporosis, we must be in doubt as to its pathology. We are even debarred from pronouncing authoritatively upon the essential identity or difference of the various forms of softening, or rarefaction of bone. In obedience to the clinical manifestations and structural changes, rachitis, fragilitas ossium and osteoporosis have been separately described, but we cannot positively say that they are not all due to one essential cause, manifesting itself differently according to the activity of trophic processes in the bones of the victim. In the growing foal the active developmental processes in the epiphyseal ligament and periosteum may determine that the symptoms shall be pre-eminently those of rickets, yet we often see these complicated by the facial and other lesions of osteoporosis. Both may be the result of one etiological factor, or there may be a complex disease resulting from the presence of two. Again in the pregnant cow in which the relaxation of the ischio-pubic symphysis and pelvic ligaments means a profound change in the bone nutrition at this point, the presence of the hypothetic microbe, or other essential factor, may determine a decalcifying and fragility of the pelvic bones generally. Again in the mature male and non-breeding female, in the absence of the disturbing conditions of nutrition just named, the vascular elements in the Haversian canals and cancelli may determine the simple rarefaction and expansion of the bone which characterizes osteoporosis. When present in the bone in any of these conditions, acids doubtless fulfill an important rôle in the decalcifying and softening process, but behind these it may be surmised that there is an unknown cause or causes, which it is for the bacteriologist, chemist or botanist to discover.

Symptoms. These are largely the same as in brain disease. There may be first a period of illness, with poor appetite, lack of spirit and energy, early perspiration and fatigue, or if at large, leaving the herd, soon followed by some stiffness of gait and lameness, which may be intermittent, disappearing under exertion, or shifting from one joint or limb to another after the manner of rheumatism. Sometimes it shows in stiffness of the neck, so that the patient finds difficulty in lowering the head to graze; in others the back and loins are stiff and arched so that the animal has difficulty in rising and turns slowly and painfully; in still other cases the dorsal and lumbar vertebræ are depressed so that the back is hollow. Even before the manifestation of lameness, the affected limb may stand forward at the fetlock or knee, the gait is clumsy and awkward, and the patient may suddenly stumble and fall, showing little or no power of prompt recovery of balance. A horse, and especially a young horse, with this habit of stumbling is always to be suspected. The long bones of the limbs tend to enlarge or thicken, and this is likely to be more uniform than in rachitis, and not to be confined so much to the epiphysis. The implication of the stifle, hock or other joint, with marked synovial distention, and mobility or dislocation of the patella, is common and may be the earliest manifestation of illness. The bones of the face usually show early changes. The superior maxillary and nasal bones, beneath the zygomatic spine and infra-orbital foramen and along the line of the molar alveoli become especially bulging and rounded, the other facial and cranial bones suffering to a lesser degree. In the lower jaw, also, the disease predominates along the region of the molar alveoli, and the loosening of the molars permits them to deviate inward so that the grinding surfaces come perceptibly nearer to the median line, and the outer half of the tooth is rapidly worn while the inner edge projects as a sharp cutting ridge (chisel teeth).

For the same reason, the softening branches of the lower jaw deviate inward, tending to still further destroy the due approximation of the upper with the lower molars, and to diminish the breadth of the intermaxillary space. The great thickening of the rami of the maxilla tends still further to reduce the intermaxillary furrow.

Fractures and detachment of tendons and ligaments are common results of the rarefaction, a portion of the bone often remaining adherent to the tendon.

Cary gives the following statistics of fifteen cases: lame in the fore limbs 11 (mostly shoulder), in hind limbs 11 (mostly hip and stifle), stiff in loins 8, unable to rise without aid 3, had indented ribs 4, had shifting lameness 8, had chronic indigestion 6; mares 5; geldings 8; mules 2; ages were—one 3 years, five 6 years, three 7 years, one 8 years, two 9 years and three 10 years.

When the bones are enlarged their softness and friability may be shown by pricking with a needle, which will often freely penetrate the rarefied bony tissue. It should be first rendered antiseptic by dipping in strong carbolic acid.

From the first the general health fails, there is difficulty in mastication, digestion is more or less impaired, nutrition is imperfect and muscular flabbiness, weakness and wasting advance more or less rapidly. In advanced cases emaciation is often a marked feature.

Examination of the urine gives valuable indications, though the results obtained have been supposed to be contradictory. While rarefaction of the bone is advancing rapidly the urine is charged with an excess of phosphates in ratio with the activity of the morbid process. When on the other hand the disease has come to a standstill and the process of repair in the rarefied bones has begun, the absence of phosphates is no less characteristic. A patient therefore may show greatly enlarged and softened bones with persistent lameness, and yet the urine may show little or no phosphate. The phosphaturia may, therefore, be made the basis of a reasonable prognosis. Excess of phosphates indicates an active pathological process, with an uncertain outcome, while the absence of phosphates indicates an arrest of rarefaction and holds out good hope of recovery.

I have long observed the same in cases of obstinate and intractable spavins, splints, ringbones and other bone diseases. Phosphaturia bespeaks a faulty nutrition of the bone and explains the failure of remedial measures, while lack of phosphates in the urine, or a reduction to the normal amount is likely to become a guarantee of improvement under local treatment. The treatment however, must be first constitutional to correct the condition of malnutrition and then local to correct the osteitis.

Prevention and treatment. As in rachitis hygienic measures give the most uniformly good results. The change of stable is especially demanded from a cellar or basement stable, one with joists laid on the ground or one with an earth floor saturated with urinary and feculent products. In different cases an enzootic has been arrested, coincidently with the removal of the stock to the floor above, and in others with the removal of the filth saturated earth beneath a ground floor, and the laying of a new floor with ample space beneath for the free circulation of air. In the same line would be thorough drainage of the site and to carry off liquid manure to a well ventilated receptacle. Exposure to cold and wet is to be sedulously avoided as greatly favoring the onset of the disease, and hurrying the milder cases into a fatal activity. Free air and sunshine are all important and it is the universal experience that city cases taken early and sent to dry, sunny pastures, mostly recover, or at least undergo marked amelioration. The fact that certain cases originate during an open air life does not invalidate this position but merely shows that other pathogenic conditions may be too potent to be overcome by this hygienic one.

A liberal allowance of sound grain is essential to success, even in the case of patients sent to pasture. Those that have recovered or improved at pasture, should be retained in the country and on no account returned to the same city stables in which they contracted the disease. Even in the country a different stable should be secured if possible.

Any food that has manifestly contributed to the disease, should be withheld (bran, millet, musty or fermented food or that drawn from particular fields).

Overwork must be forbidden, and indeed any work at all during the active stage of the disease. The victim should also be withdrawn from breeding, at least until it has fully recovered the normal consistency of its bone.

In cases aggravated by cold or wet, or which show the rheumatic propensity to shift from place to place, sodium salicylate in ounce doses several times a day may appear to benefit, and as a germicide this may be tried on all cases. Salicin, salol, or phenacetin may be used as substitutes. Where the disease has been largely localized, blisters have appeared to be beneficial.

Phosphates and phosphorus have been lauded by German veterinarians, but in other hands, and when the morbid process was active they have proved useless, or even hurtful. Bone dust or phosphate of lime or soda may be freely used at any time and appears to act as a general tonic, beside supplying lime and phosphoric acid which may possibly be availed of for bone nutrition. Phosphorus and phosphorated oil in excess always softens the bone and much more so when this process is already excessive. In small doses (gr. ⅙ to ½) and after the process of rarefaction has ceased, it is valuable in hastening bone consolidation and fitting the patient to return to work.

Bitters, iron and other tonics are valuable in improving the general tone and indirectly the bone nutrition.

Cary had prompt improvement in connection with intravenous injection of barium chloride once a week for four weeks, and ½ oz. doses of sodium salicylate thrice a day. It remains to be seen whether or not this is generally applicable.

OSTEO-MALACIA IN OTHER ANIMALS.

The internal softening and rarefaction of bones in mature animals has been noted in dogs by Pillvax and Röll, in lambs by Haubner, in pigs by Haubner and Anaker, and in goats by different observers. The genuineness of these cases has been questioned by Cadiot and Leclainche, by Virchow and by others, but in the present uncertainty as to the dividing lines between rarefaction, rachitis and other diseases, they deserve notice in this connection.

In dogs the lesions are mostly in the young and are largely rachitic, yet the enormous swelling of the facial bones, and especially of the superior maxillary in the comparatively mature animal suggests osteo-malacia. As in rachitis there are usually impaired digestion, unthriftiness, slow, stiff movements and lack of life and vigor.

In goats Virchow believes the disease to be neither rachitic nor osteo-malacia, basing his opinion on the lesions in the bones: “On the maxillary bones of goats there are often found peculiar formations in which the parts that have already assumed osseous structure, have failed to fix the earthy salts. The tumor, which forms a circumscribed swelling on the upper or lower maxillary bone, is soft and easily cut with the scalpel, with at certain points only, a hard resistant material. It is a simple osteoid chondroma, though veterinarians for some reason associate it with rheumatism.” Profuse salivation is present.

In lambs it is according to Haubner an atrophy with destructive ulceration of the bones of the face, complicated by purulent infiltration of the medullary spaces. “The incisors, and later the molars, fall one by one, because of the changes in the alveoli, the gums swell, become violet, red, and ulcerate, the ulcers extending through the hard palate into the nose, and causing a highly offensive discharge from both nose and mouth.

In pigs the disease has been mainly seen in connection with insufficient or unwholesome food, and badly balanced rations, and especially with fermented swill and an exclusive maize diet. The symptoms are shown in the limbs and face, especially (“snuffles”), as noted under rachitis.

Prevention and treatment are to be sought in avoidance of the obvious causes, and in applying the same line of tonic treatment as in the larger animals.

INDEX.

Abnormal conditions of the hair, 456.

Abrasions, 455.