Page 194 - Canine Lameness

166 12 Distal Limb Region

abdomen. The pathophysiology is still unknown; however, it may be due to a neurally or growth
DISTAL LIMB REGION various other conditions have been described as causes for hypertrophic osteopathy including
factor-mediated increase in peripheral blood flow. Hypertrophic osteopathy is typically a
paraneoplastic condition, secondary to pulmonary neoplasia (Withers et al. 2015). However,

extrapulmonary causes, such as esophageal granuloma formation secondary to Spirocerca lupi,
right–left shunting, esophageal foreign bodies, and various abdominal neoplasia. The bony pro -
liferation is associated with pain during early stages of the disease, such that this together with
the thickening of the tissues, frequently causes lameness or difficulty ambulating. Other clini-
cal signs may include coughing, hyperthermia, weight loss, and depression. These signs often
precede signs associated with the primary disease. In a recent retrospective study, more than
half of the dogs with hypertrophic osteopathy displayed bilateral ocular discharge (Withers
et al. 2015).
Diagnostic investigation should include thoracic and abdominal radiographs in addition to ultra-
sound for identification of the primary cause. Radiographs of affected limbs show periosteal bone
formation in a circumferential and columnar (“palisade-like”) appearance. Initially, new bone for-
mation will be absent or minimal. Treatment requires management of the primary condition. The
osseous lesions resolve spontaneous if successful treatment of the primary disease can be
accomplished.

12.9.4 Metabolic Bone Diseases

Metabolic bone diseases are rare conditions which affect calcium, phosphorus, and vitamin D
metabolism. These can occur as a result of inappropriate nutrition, including deficiencies in cal-
cium and/or phosphorous, hypo- or hypervitaminosis A and D, and hypovitaminosis E. They may
also involve abnormal metabolism or production of these mineral and vitamins, such as primary
and secondary (renal) hyperparathyroidism, chronic renal failure, and intestinal malabsorption
conditions. These diseases tend to result in generalized bone conditions that may result in lame-
ness, such as osteopenia, osteomalacia, pathological (spontaneous) fractures, fragile (“brittle”)
bones, deformed limbs, and excessive new bone production.

12.9.5 Distal Limb Region Neoplasia

Digit neoplasia is the most common tumor encountered in the distal limb region. Digital squa-
mous cell carcinomas frequently cause bone lysis, whereas melanoma does not. Further details
about digit tumors and other neoplastic conditions affecting the region are described in Chapter 11.

References

Anis, E.A., Frank, L.A., Francisco, R., and Kania, S.A. (2016). Identification of canine papillomavirus
by PCR in Greyhound dogs. Peer J 4: e2744.
Balara, J.M., Mccarthy, R.J., Kiupel, M. et al. (2009). Clinical, histologic, and immunohistochemical
characterization of wart-like lesions on the paw pads of dogs: 24 cases (2000–2007). J Am Vet Med
Assoc 234 (12): 1555–1558.
Boemo, C.M. (1998). Injuries of the metacarpus and metatarsus. In: Canine Sports Medicine and
Surgery (eds. M.S. Bloomberg, J.F. Dee and R.A. Taylor), 150–165. Philadelphia: Saunders.