Pulmonary Mineralizations in Dogs
Pulmonary mineralization occurs when there is a buildup of mineral calcium in the soft tissues of the lungs, leading to both calcification and ossification. This condition is commonly observed in older dogs and can manifest as either localized or generalized mineralization. In cases where the mineralization is localized, individual mineral deposits can be identified, whereas diffuse mineralization spreads out across multiple locations, making it challenging to pinpoint individual deposits.
Pulmonary mineralization can also affect cats.
Symptoms and Types
Dogs afflicted with pulmonary mineralization might not exhibit any noticeable symptoms. Nevertheless, certain signs or indications that may manifest include:
- Cyanosis
- Coughing
- Shortness of breath
- Elevated respiratory rate
- Abnormal breathing sounds
- Exercise intolerance
Calcification can occur in two primary forms: dystrophic (degenerative), which arises as a result of tissue degeneration or inflammation, and metastatic (spreading throughout the body), which is secondary to metabolic disorders impacting the breakdown of food into energy.
Furthermore, calcification may be a natural aspect of the aging process or prevalent in certain breeds (e.g., premature calcification of tracheal and bronchial cartilages in chondrodystrophic [dwarf] breeds). Focal calcifications are often linked with wounds, rendering most of them functionally insignificant.
Ossification, also termed heterotopic bone formation (the abnormal development of genuine bone within soft tissues outside the skeleton), can present in various forms, including calcification of a bony matrix (formative tissue) and pulmonary ossification in the form of numerous small nodules.
In dogs, generalized pulmonary mineralizations of unknown etiology are documented under descriptive labels such as pulmonary alveolar microlithiasis or pumice stone lung, bronchiolar microlithiasis, idiopathic pulmonary calcification, or idiopathic pulmonary ossification.
Causes
The primary cause of pulmonary fibrosis typically remains unknown (idiopathic). Nonetheless, it may also stem from:
- Metastatic calcification: This is secondary to metabolic disorders that lead to elevated calcium levels and/or bone resorption (dissolution).
- Hyperadrenocorticism: Excessive secretion of cortisol by the adrenal glands, which can induce dystrophic mineralization.
- Alveolar and bronchial stones: These may arise as secondary effects of exudative lung disease (where fluid seeps from the circulatory system into lesions or areas of inflammation) or granulomatous lung disease (a rare inherited primary immune deficiency disorder characterized by the inflammatory growth of granulation tissue in response to injury).
Diagnosis
Your veterinarian will perform a thorough physical examination, which includes a chemical blood profile, complete blood count, and urinalysis. A lung biopsy will be conducted to collect tissue samples from your dog’s lungs to determine if mineralization is occurring. Additionally, tests for bacterial and fungal presence will be conducted.
Further diagnostic methods include chest X-ray imaging and computed tomography (CT) scans to provide detailed insights into the lung and lymph node conditions. These tools aid in confirming or ruling out the presence of tumors or fungal infections.
Treatment
Certain medications can alleviate breathing difficulties, and antibiotics or antifungal medications may be prescribed if your veterinarian identifies a concurrent infection. If an underlying metabolic disorder is present, your veterinarian will prescribe appropriate medications for its treatment. Otherwise, providing a calm and quiet space for your dog to recuperate is all that is required.
Living and Management
As with any respiratory system disorder, this condition is serious. You and your veterinarian will need to closely monitor your dog’s progress.