Pulmonary Mineralizations in Cats
When a cat's lungs begin to calcify (a buildup of the mineral calcium in the soft tissue) or ossify (connective tissues, such as cartilage, are turned to bone or bone-like tissue) it is referred to as pulmonary mineralization.
This condition generally affects older cats and it may be generalized or localized. But if the mineralization is discrete, meaning that it is in only one place, individual mineral deposits can be identified. If mineralization is diffuse, however, it will spread out to more than one location, making it impossible to identify the individual deposits.
Pulmonary mineralization can affect both dogs and cats. If you would like to learn how this disease affects dogs, please visit this page in the PetMD health library.
Symptoms and Types
Cats with pulmonary mineralization may display no symptoms at all. However, some signs or symptoms that may be observed include:
- Shortness of breath
- High respiratory rate
- Abnormal breathing sounds
- Exercise intolerance
Calcification can be dystrophic (degenerative), which occurs secondary to tissue degeneration or inflammation, or it can be metastatic (transmissible throughout the body), which occurs secondary to metabolic disease, affecting the breakdown of food and its transformation into energy.
Calcification may also be considered a normal part of the aging process, or with particular breeds (e.g., premature calcification of the tracheal and bronchial cartilages in chondrodystrophic [dwarf] breeds). Calcification is often associated with a wound, thus most focal calcifications are functionally unimportant.
Ossification, also called heterotopic bone formation (the abnormal formation of true bone within extraskeletal soft tissues), can take different forms: calcification of a bony matrix (formative tissue), and pulmonary ossification in the form of small, multiple nodules.
Generalized pulmonary mineralizations of unknown cause are reported in cats under these descriptive terms: pulmonary alveolar microlithiasis or pumice stone lung; bronchiolar microlithiasis; idiopathic pulmonary calcification; or idiopathic pulmonary ossification.
The underlying cause for pulmonary fibrosis is usually unknown (idiopathic). However, it may be also due to:
- Metastatic calcification -- secondary to metabolic disease that induces high calcium concentration and/or bone resorption (dissolution)
- Hyperadrenocorticism (excessive cortisol secretion by the adrenal glands), which may cause dystrophic mineralization
- Alveolar and bronchial stones -- may be secondary to exudative lung disease (where fluid filters from the circulatory system into lesions or areas of inflammation), or granulomatous lung disease (a rare inherited primary immune deficiency disorder which causes inflammatory tissue growth of granulation tissue -- tissue that is formed in response to a wound)
Your veterinarian will conduct a full physical examination on the cat, including a chemical blood profile, complete blood count, and a urinalysis. Your veterinarian will conduct a lung biopsy to retrieve samples of tissue from your cat’s lungs in order to determine whether mineralization is occurring. Testing for the presence of bacteria and fungus will also be done.
Other diagnostic tools include chest X-rays and a computed tomography (CT) scan, so that your veterinarian can get a better look at the condition of the lungs and lymph nodes. These tools will also help confirm or exclude the presence of a tumor or fungal infection.