Changes

*Also called '''hypertrophic pulmonary osteopathy'''

Also known as: '''''Hypertrophic Pulmonary Osteopathy — HO — Marie's Disease'''''

*In '''all species'''

 

*Associated with chronic lesions (intrathoracic neoplasm or space-occupying lesion) usually in the thorax

**[[Respiratory Bacterial Infections - Pathology#Tuberculosis|Tuberculosis]]

This is a '''rare condition''' that occurs in '''all species'''.

**[[Pulmonary Neoplasia|Pulmonary neoplasia]]

 

**[[Pleuritis|Granulomatous pleuritis]]

It is a '''diffuse, periosteal proliferative condition''' of long bones secondary to '''neoplastic or infectious masses''' in the thoracic or abdominal cavity, including [[Respiratory Bacterial Infections - Pathology#Tuberculosis|tuberculosis]], [[Pulmonary Neoplasia|pulmonary neoplasia]], [[Pleuritis|granulomatous pleuritis]] and granulomatous lymphadenitis of the mediastinal lymph nodes.

**Granulomatous lymphadenitis of mediastinal nodes

 

*Grossly:

The exact pathogenic mechanism is unknown, but several theories have been proposed:

**Periosteal proliferation of bone on '''diaphyses''' of distal limbs

**Progressive and bilateral

:'''Neuronal theory''': the vagus nerve is stimulated by neural reflexes produced by thoracic tumours, and it then stimulates fibres in the distal limbs. This leads to and '''increased blood flow''' and the periosteal reaction. Regression of the bony lesions after a vagotomy has been demonstrated.

*Histologically:

 

**Hyperaemia of periosteum

**Deposition of new bone

Animals will show '''lameness, long bone pain''', and may have swelling in one or usually several limbs.

**Width of cortex may double in a few weeks

 

*Postulated to be due to stimulation of vagus by intrathoracic lesion -> increasing blood floow to extremities -> thickening of periosteum

 

'''Radiography''' is the method of choice for diagnosing the condition, as it usually reveals the primary mass and the peripheral bone reactions.

 

The peripheral reaction appears as a periosteal reaction with '''new trabecular bone''' perpendicular to and continuous with the cortical surface. New bone may also form in the '''soft tissues''' away from the cortex.

 

Histologically, there is hyperaemia of the periosteum, deposition of new bone and the width of the cortex may double in a few weeks.

 

'''Removal of the thoracic or abdominal mass''' will lead to a regression of the bony changes.

 

The prognosis is '''variable''' depending on the primary mass, but may be poor if the mass is neoplastic and aggressive.

 

 

 

 

Morgan, J. (1999) '''Radiology of veterinary orthopaedics''' ''Wiley-Blackwell''

 

[[Category:To Do - Helen]]

[[Category:To Do - Review]]

[[Category:Bones - Hyperplastic Pathology]]

[[Category:Bones - Hyperplastic Pathology]]