Hypertrophic osteopathy is a bone disease secondary to cancer in the lungs.
Presentation
It is characterized by new bone formation on the outside of the
diaphyses of long bones of the limbs, without destruction of cortical bone. Symptoms include stiffness and warm, firm swelling of the legs, and signs of lung disease such as coughing and difficulty breathing. Hypertrophic osteopathy in humans differs from a similar condition in dogs, in that in humans it is usually caused by lung tumors or infections such as ''
Mycobacterium fortuitum'' or ''
Corynebacterium
''Corynebacterium'' () is a genus of Gram-positive bacteria and most are aerobe, aerobic. They are bacillus (shape), bacilli (rod-shaped), and in some phases of life they are, more specifically, club (weapon), club-shaped, which inspired the gen ...
''. The most common cause in dogs is primary or metastatic pulmonary neoplasia.
Other potential causes in dogs include
heartworm disease, heart disease, and pulmonary
abscess
An abscess is a collection of pus that has built up within the tissue of the body. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pressed. The area of redness often extends b ...
es. It has also been associated with nonpulmonary diseases such as renal tumors and
rhabdomyosarcoma of the bladder. At least once it has been caused by congenital
megaesophagus in a six-year-old dog. Hypertrophic osteopathy is rare in cats.
Causes
One theory is that hypertrophic osteopathy is caused by increased blood flow to the ends of the legs, overgrowth of
connective tissue
Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ...
, and then new bone formation surrounding the bones.
This is secondary to nerve stimulation by the lung disease. The condition may reverse if the lung mass is removed or if the
vagus nerve
The vagus nerve, also known as the tenth cranial nerve, cranial nerve X, or simply CN X, is a cranial nerve that interfaces with the parasympathetic control of the heart, lungs, and digestive tract. It comprises two nerves—the left and right ...
is cut on the affected side.
See also
*
Hypertrophic pulmonary osteoarthropathy
Hypertrophic osteoarthropathy is a medical condition combining clubbing and periostitis of the small hand joints, especially the distal interphalangeal joints and the metacarpophalangeal joints. Distal expansion of the long bones as well as painf ...
References
Dog diseases
{{Veterinary-med-stub