Veterinary medicine, pathology. Feline infectious peritonitis

Expert Solution Preview

Introduction:
Feline infectious peritonitis (FIP) is a viral disease that primarily affects young cats. It is caused by a coronavirus known as feline coronavirus (FCoV) and is characterized by a wide range of clinical signs and outcomes. In this given case, a 6-month-old male kitten presented with nasal and ocular discharge, apathy, weight loss, variable body temperature, and coordination disorders. Despite normal hematology results and negative tests for chlamydia and toxoplasma, euthanasia was performed due to the severity of the symptoms. The other kittens in the litter recovered after treatment. In this assignment, we will explore the theoretical and practical aspects of FIP, including macroscopic and microscopic changes in the body and the pathological processes that occur during the illness.

Theoretical part:
FIP is known to cause significant macroscopic and microscopic changes in the affected feline body. The clinical signs observed in this case, including nasal and ocular discharge, apathy, weight loss, variable body temperature, and coordination disorders, are commonly associated with FIP. These signs are indicative of a systemic inflammatory response resulting from viral replication and immune-mediated damage.

On a macroscopic level, FIP can result in various lesions and abnormalities in different organs. These can include effusion or accumulation of fluid in body cavities, particularly the abdominal cavity, which is known as “wet” form FIP. Other forms of FIP, such as the “dry” form, may present with granulomatous lesions in various organs such as the liver, kidney, spleen, and brain. These macroscopic changes are often associated with the infiltration of inflammatory cells and the formation of characteristic pyogranulomas.

Microscopically, FIP is characterized by the presence of pyogranulomatous infiltrates in affected tissues. These infiltrates consist of a mixture of neutrophils, macrophages, and lymphocytes. The infiltrates are often seen around blood vessels, and they can invade and destroy the surrounding tissue architecture. In the case of FIP affecting the brain, histological examination would reveal the presence of inflammatory cells within the brain parenchyma, particularly around blood vessels and in perivascular spaces. These infiltrates may cause damage to the neurons and glial cells, leading to the clinical signs observed, such as coordination disorders.

Practical part:
The provided practical part of the assignment requires a detailed analysis and description of the histological images of the brain of the affected kitten. The focus should be on identifying and marking the inflammatory cells and describing any tissue lesions observed. Arrows should be utilized to indicate the locations where inflammatory cells are evident.

Conclusion:
Based on the available information in the literature and the histological examination of the brain images, it can be concluded that FIP causes significant pathological processes in the affected body. These include the infiltration of inflammatory cells, particularly neutrophils, macrophages, and lymphocytes, leading to the formation of pyogranulomatous lesions. The presence of these lesions and the associated damage to the tissue architecture result in the clinical signs observed in affected cats. By comparing the microscopic changes observed in the practical part with the available literature, similarities in the presence of inflammatory cell infiltrates and tissue damage can be identified, further supporting the diagnosis of FIP in this case.