Diagnostic challenge: mare with clinical history of chronic respiratory disease. Severe interstitial pneumonia.

This research article focuses on a case study of a mare with a chronic respiratory disease, which was not responding to standard medical treatment. The mare was referred to the Veterinary Clinical Centre at Charles Sturt University to understand and diagnose the disease.

Clinical history and Physical Examination

• The mare, a 15-year-old Australian Stockhorse, showed symptoms of respiratory disease for six weeks, including coughing on exertion and increased rate and effort of respiration. She also lost weight despite receiving antimicrobials.
• On physical examination, the horse was lethargic, feverish, and showing signs of respiratory distress. It also suffered from edema and had lost weight based on its body condition score.

Medical Tests Done

• After undergoing various blood tests, it was found that the horse suffered from mild to moderate anaemia and hyperfibrinogenaemia (an excess of fibrinogen in the blood).
• An endoscopic wash of the trachea (windpipe) showed that there was an excessive amount of neutrophils, indicating infection or inflammation, and Curschmann’s spirals, stringy mucus plugs coming from the small airways of the lungs.
• A measurement of the gas in the horse’s blood indicated lower than normal oxygen levels.
• An ultrasound of the horse’s chest revealed pleural thickening (thickened tissues surrounding the lungs), and a similar observation was made from the chest x-ray, which revealed severe, diffuse multifocal interstitial pattern (a pattern indicative of diseases involving the area and support tissues around the air sacs of the lungs).

Treatment and Outcome

• Based on these findings, the horse was started on a regimen of antibiotics and anti-inflammatory drugs. However, there was no improvement in the mare’s condition over the following days.
• Due to the deteriorating health and a further decrease in oxygen levels in the horse’s blood, euthanasia was decided by the owner. A complete examination was decided to understand and diagnose what the condition was.

Postmortem Findings

• Upon examination of the lungs after death, it was found that approximately 85% of the lung area had been replaced by firm, pale nodular masses. The remaining lung tissue appeared healthy. The bronchial lymph nodes were also mildly to moderately enlarged and mild enlargement of the pituitary gland was noted.
• These significant findings could give clues to the exact abnormalities that had led to the mare’s severe respiratory distress.

This case presents a diagnostic challenge, requiring careful examination of test results, physical signs, and necropsy findings to identify the disease or diseases that the mare suffered from and to devise potential treatment options.