What is your diagnosis? Pleural fluid from a neonatal Thoroughbred filly with pneumonia.

This research represents a case study of a newly born Thoroughbred filly that developed a lung condition named pleuropneumonia due to inhalation of foreign materials following a surgical procedure. This condition was possibly exacerbated by the administration of general anesthesia.

Case Overview

• This case revolves around a 3-day old filly who was admitted to the Cornell University Hospital, due to an umbilical hematoma and a mild aspiration pneumonia. Following the surgery to remove the hematoma, the filly developed progressive tachypnea (rapid breathing rate).

Diagnostic Measures

• Diagnostic imaging was performed, revealing the presence of fluid collections within the pleural space and symptoms of pneumonia.
• A cytological inspection and bacterial culture of the extracted pleural fluid revealed sterile exudates majorly comprising of neutrophils, and a lower count of macrophages and lymphocytes.
• It was noticed that the macrophages within the pleural fluid had various amounts of purple-magenta globular material in their cytoplasm. Furthermore, a lighter granular precipitate was observed in the background of the fluid smear.

Investigation and Findings

• Similar globular material was found in a macrophage in a peripheral blood smear made two days after surgery. The blood smear also had a larger quantity of a pink precipitate.
• The unnamed material and the pink precipitate persisted in the blood for a week after surgery.
• During the surgery, a protective lubricant called carboxymethylcellulose was inserted into the abdominal cavity to avert intra-abdominal adhesions. The researchers inferred that the intracytoplasmic pigment and the extracellular precipitate were actually remnants of this substance.
• The substance was likely obtained hematogenously (through the bloodstream) and was considered an incidental finding, not likely the root cause of the filly’s condition.

Probable Causes

• The researchers concluded that the inflammation of the pleura (pleuritis) observed was most likely an exacerbation of the initial aspiration pneumonia incident caused by the anesthesia applied before surgery.