Nutritional Secondary Hyperparathyroidism in the Horse

32 Nutritional Secondary Hyperparathyroidism in the Horse
right mandibular ramus appeared like pumice stone. There can be
little doubt that the lesions of the skull bones were those of osteitis
ilbrosa cystica. RYCHNER did not commit himself to a diagnosis. The
disease exhibited, he stated, some similarities to osteomalacia and some
to osteoporosis.
HAUBNER (1854) gave a most detailed account of the condition in
an 8-year-old riding horse, which had been developing the symptoms
for 2 years. His description of the necropsy emphasized the generalized
nature of the skeletal changes: “All bones, without exception, show
signs of the disease. The lesions are most pronounced in the flat
(Fig. 17) and so-called mixed bones and are less striking in the long
bones.” The following is quoted from his histologic description :
“The microscopic examination of thin slices of different bones always
reveals one change in the bone. This change is that the Haversian canals of the
compact bone are considerably larger than normal. On longitudinal section it is
observed that the widcning of these canals is not uniform; in some areas the canals
arc two or three times as wide as in others.”
In the same communication HAUBNER described the disease in a
pig. His histologic observations are remarkable :
“With the help of my colleague PISCIIEL it was proved that an osteoporosis
was present here also. It was concluded, however, that the osteoporosis was of a
peculiar nature, hitherto never described in textbooks on pathologic anatomy. It
differed as I have already pointed out, from the medullary porosis, which it otherwise
resembled very closely, mainly in the respect that a firm fibrous cellular
tissue occupied the bone space and, which I like to add, contributed to the enlargement
of the bones, although it may not have been the only cause of this enlargement.”
This is a clear-cut description of generalized osteitis fibrosa. It
was given in 1854, 4 years before VIRCHOW’S Cellzdar Pathology
appeared, 19 years before KOLLIKER published his classical treatise on
resorption of bone, and it anticipated VON RECKLINGHAUSEN’S description
of generalized osteitis f-ibrosa in man by 37 years.
In agreement with HAUBNER, DOR (1902) showed that the osteopathy
in maladie dzt son is generalized; he applied the term “rarefying
osteitis”. He believed that the horse disease was comparable to
PAGET’S (1877) osteitis deformans but noted a difference between the
two conditions. In PAGET’S disease the cranial bones are more commonly
involved than the jaws, which DOR, like earlier and later investigators,
found to be most severely affected in the horse.
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