What Are the Symptoms of FIP
Feline Infectious Peritonitis (FIP) is a complex, often devastating disease caused by certain strains of the feline coronavirus. Its presentation varies greatly depending on the form—wet (effusive) or dry (non-effusive)—and multiple clinical signs can be observed. Recognizing these symptoms early is crucial for diagnosis and management, although definitive diagnosis often requires laboratory testing.
General Malaise and Behavioral Changes
One of the earliest indicators of FIP is a noticeable decline in a cat’s overall health. Affected cats often appear lethargic, with reduced activity and curiosity. They may hide more frequently or display decreased interaction with humans and other animals. Such behavioral alterations can be subtle but are significant markers of underlying illness. Appetite loss is common, leading to weight loss over time.
Fever and Persistent Elevated Temperatures
Most FIP-infected cats present with persistent or intermittent fever that resists standard antibiotic treatment. The fever may be low-grade initially but often escalates as the disease progresses. This febrile response reflects ongoing inflammation within different organ systems. Temperature measurements, combined with other signs, can raise suspicion of FIP but are not diagnostic alone.
Abdominal Swelling and Effusions
In the wet form of FIP, rapid accumulation of fluid within the abdominal cavity (ascites) is prominent. The abdomen appears swollen, sometimes distended, and feels tense upon palpation. The accumulation of clear or slightly cloudy fluid results from vasculitis and increased vascular permeability. In many cases, effusions may also develop around the lungs or heart, leading to respiratory issues.
Respiratory Distress and Coughing
Cats with the wet form may exhibit difficulty breathing, rapid breathing, or a persistent cough due to fluid buildup in the thoracic cavity. Respiratory distress can be severe and rapidly progressive, often requiring urgent veterinary intervention. Coughing and breathing abnormalities are more characteristic of the wet form but can sometimes occur in the dry form as well, especially if granulomatous inflammation affects the lungs.
Neurological Signs
The dry form of FIP often involves the central nervous system, leading to neurological disturbances. These symptoms may include ataxia, seizures, tremors, or paralysis. Behavioral changes such as disorientation, aggression, or blindness can also occur when the brain or spinal cord are affected. The onset of neurological symptoms can be sudden or gradual, complicating early diagnosis.
Ocular Manifestations
Some cats develop ocular abnormalities, which may be the first visible signs of the disease. These include uveitis (inflammation of the uveal tract), retinal hemorrhages, or cloudiness of the cornea. Redness, squinting, and tearing are common, and ocular symptoms often coexist with systemic illness, providing clues to the diagnosis.
Gastrointestinal Symptoms
Digestive disturbances such as vomiting, diarrhea, or constipation may be observed, particularly in the dry form of FIP. These signs are often associated with granulomatous lesions affecting internal organs like the intestines or liver. Such symptoms are non-specific, making FIP diagnosis challenging without further testing.
Lymph Node Enlargement
Enlarged lymph nodes are frequently detected during physical examinations. Nodes may become swollen and tender, especially in cases with granulomatous inflammation. This physical finding, coupled with other systemic signs, suggests disseminated infection.
Skin and Subcutaneous Changes
Though less common, some cats develop skin lesions, nodules, or subcutaneous swellings. These may appear as firm lumps under the skin, sometimes ulcerated or inflamed. These signs are more characteristic of localized or extrapulmonary granulomatous foci.
Behavioral and Systemic Variations
Due to the multi-organ involvement, the disease’s presentation can be highly variable. Some cats may display only mild signs over extended periods, while others deteriorate rapidly with multi-organ failure. The combination of symptoms often confuses owners and veterinarians, underscoring the importance of ongoing clinical assessments.
Exclusivity of Symptoms and Disease Progression
Given the variability, some cats exhibit a combination of respiratory, neurological, and systemic signs simultaneously. Others show isolated symptoms, making clinical suspicion based solely on presentation difficult. Laboratory tests, including blood work, effusion analysis, and histopathology, are essential for certainty.
References
1. Pedersen, N. C. (2014). An update on feline infectious peritonitis: diagnostics and vaccination. Journal of Feline Medicine and Surgery, 16(7), 555–558.
2. Addie, D. D., et al. (2009). Feline infectious peritonitis. The Veterinary Journal, 181(3), 117–123.
3. Gunther, H. (2004). Feline infectious peritonitis: An overview. Compendium on Continuing Education for the Practicing Veterinarian, 26(4), 307–318.
4. Lipscomb, D., et al. (2018). Diagnostic approaches for feline infectious peritonitis. Veterinary Clinics of North America: Small Animal Practice, 48(5), 791–805.
