Hypertrophic osteopathy
Encyclopedia
Hypertrophic osteopathy is a bone disease secondary to cancer in the lungs.
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
. 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
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.
, 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
is cut on the affected side.
Presentation
It is characterized by new bone formation on the outside of the diaphysesDiaphysis
The diaphysis is the main or mid section of a long bone. It is made up of cortical bone and usually contains bone marrow and adipose tissue ....
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
Mycobacterium fortuitum
Mycobacterium fortuitum is a nontuberculous mycobacterium.-Background:Mycobacterium fortuitum is a fast-growing species that can cause infections. The term "fast growing" is a reference to a growth rate of 3 or 4 days, when compared to other Mycobacteria that may take weeks to grow out on...
or Corynebacterium
Corynebacterium
Corynebacterium is a genus of Gram-positive rod-shaped bacteria. They are widely distributed in nature and are mostly innocuous. Some are useful in industrial settings such as C. glutamicum. Others can cause human disease. C...
. The most common cause in dogs is primary or metastatic pulmonary neoplasia. Other potential causes in dogs include heartworm
Heartworm
Heartworm is a parasitic roundworm that is spread from host to host through the bites of mosquitoes. The heartworm is a type of filaria, a small thread-like worm. The definitive host is the dog but it can also infect cats, wolves, coyotes, foxes and other animals, such as ferrets, sea lions and...
disease, heart disease, and pulmonary abscess
Abscess
An abscess is a collection of pus that has accumulated in a cavity formed by the tissue in which the pus resides due to an infectious process or other foreign materials...
es. It has also been associated with nonpulmonary diseases such as renal tumors and rhabdomyosarcoma
Rhabdomyosarcoma
A rhabdomyosarcoma is a type of cancer, specifically a sarcoma , in which the cancer cells are thought to arise from skeletal muscle progenitors. It can also be found attached to muscle tissue, wrapped around intestines, or in any anatomic location...
of the bladder. At least once it has been caused by congenital megaesophagus
Megaesophagus
Megaesophagus is a condition in humans, cats and dogs where peristalsis fails to occur properly and the esophagus is enlarged. Normally, when the dog's esophagus is functioning properly, it acts as a muscle and pushes the food down the esophagus into the stomach. However, when a dog has...
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 tissueConnective tissue
"Connective tissue" is a fibrous tissue. It is one of the four traditional classes of tissues . Connective Tissue is found throughout the body.In fact the whole framework of the skeleton and the different specialized connective tissues from the crown of the head to the toes determine the form of...
, 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
Vagus nerve
The vagus nerve , also called pneumogastric nerve or cranial nerve X, is the tenth of twelve paired cranial nerves...
is cut on the affected side.