Mid-Chest Inflammation in Dogs

The mid-chest area in dogs is known as the mediastinum and contains the heart, the central bronchi, and the lymph nodes. This area can become inflamed for several reasons as the condition, known as mediastinitis, is a complication of several diseases and disorders. Treatment can range from simple anti-inflammatory drugs to surgery and chemotherapy, depending on the underlying cause of the swelling and the extent of the inflammation. Dogs that are displaying symptoms that indicate inflammation in the thorax should be evaluated by a veterinary professional.

The mid-chest area, or mediastinum, contains vital organs such as the heart, central bronchi, and lymph nodes, and when this area becomes inflamed, it can lead to serious complications.

Inflammation of the canines mediastinum tends to have the same symptoms regardless of the cause. Some signs that your dog may be suffering from inflammation of their mediastinum may include:

• Chest pain
• Coughing
• Difficulty breathing, particularly on the in breath
• Excessive drooling
• Loss of appetite
• Rapid heart rate
• Unusual vocalizations
• Vomiting
• Weight loss

Types

Mid-chest inflammation has a number of triggers and symptoms can either appear suddenly or may take longer to develop, depending on the underlying cause of the condition.

• Acute - When the symptoms develop quickly it is known as acute mediastinitis, and this is more likely to be due to perforation of the esophagus, certain types of bacterial infection, and from postoperative complications 
• Chronic - Symptoms of chronic mediastinitis may appear more gradually than when the condition is acute and is frequently accompanied by visible swelling and vocal changes when it is caused by neoplasia, although chronic mediastinitis can also be triggered by stubborn fungal infections 

There are several circumstances that can encourage inflammation to occur in the mediastinum, some more serious than others. Some of the causes of inflammation of the mid-chest area can include:

• Bacterial infection
• Esophageal diverticula
• Foreign substance in the pleural space
• Fungal infections
• Internal rupture
• Neoplasia 
• Parasitic infestation
• Physical damage
• Postoperative complications

The initial visit with your veterinarian is likely to start with a full physical evaluation, most likely with a focus on the chest region, also known as the thoracic area. The thoracic area may be difficult to compress, and the animal may exhibit pain when palpated. Standard blood tests such as a complete blood count and biochemical profile will help to detect if there are a larger number of leukocytes present, indicating an infection as well as identifying if there are any additional imbalances, such as anemia.

In most cases, radiography and ultrasound imaging will be employed in order to get a clearer view of the patient's thoracic cavity and the extent of the swelling and damage. This may also expose perforations in the dog’s esophagus or masses like neoplasms and cysts that are located in the mediastinum. The examiner will take samples of any masses that are found in the mid-chest region as well, and a biopsy will help determine if they are made up of cancer cells.

If your canine is showing signs of distress at the clinic, supportive treatments may be started before a definitive diagnosis is ascertained. The types of supportive treatments that are typically offered include the administration of fluid therapies by IV, and in the event that your canine is having trouble breathing, oxygen may also be recommended. In most cases, anti-inflammatory medications will also be prescribed to reduce both the swelling and the pain, although circumstances such as animals with bleeding disorders or poor liver function may not make these medications feasible. 

From there, treatments for this disorder are as varied as the sources of the ailment; blood transfusions may be required if anemia is detected in order to counteract internal bleeding and antibiotic or antifungal drugs may be needed to fight off any infections. Any growths that are located will be evaluated for removal, and if biopsies of the tissues show cancerous cells in the mass, then radiation and chemotherapy may be needed.

Prognosis for dogs that experience inflammation in the mid-chest region referred to medically as mediastinitis is largely dependent on which underlying causes are influencing the disorder. Canines that are recovering from anesthesia, as may be required for diagnosis and treatment of this condition, may have difficulties with their coordination when they first return home. They are often disoriented and confused, and isolation from other pets and from children may be advised until the sedatives have fully cleared your companion’s system. It is also crucial to ensure that your pet completes the full measure of any prescribed antibiotic medication to help prevent any relapses or new infections.