Stages of FIP Symptom
Cats with intestinal infections with non-mutant FCoV rarely show clinical symptoms. The initial clinical manifestations of FIP cats are often non-specific and non-local, such as fever, loss of appetite, inactivity, weight loss, vomiting, diarrhea, dehydration, and mucosal paleness (anemia). As the disease progresses, these symptoms worsen, and other clinical symptoms appear. Exudative (wet) fluid exudates from the body cavity, and non-exudative (dry) organ-specific abnormalities. Approximately 75% of clinical cases are effusion. 25% is non-effusion, some cats show the characteristics of exudative and non-exudative, and some cats change from this form to another form over time.
- Once the FIP virus spreads and clinical disease occurs, FIP is actually always progressive and fatal. However, the course of the disease before death is quite variable; usually 3-6 weeks, but more than 6 months can also be seen.
- For exudative FIP, the clinical course is usually acute (several days to weeks).
- For non-exudative FIP, the clinical course is usually long-term and insidious (weeks to months).
- Affected cats whose only eyes are affected can sometimes survive for a year or more.
Effusion FIP(Wet FIP)
Key point: For exudative cat infectious peritonitis, 62% of the main parts of inflammatory exudation are in the abdominal cavity, 17% in the thoracic cavity, and 21% in the thoracic cavity and abdominal cavity.
- Abdominal effusion (peritonitis)
1.1 Exudative FIP accumulates in the abdominal cavity, causing progressive, non-painful fluid enlargement of the abdominal cavity.
1.2 Diagnose abdominal exudate by palpation and percussion fluid fluctuations. In the early stages, there is less peritoneal fluid, the intestine is slippery when palpated, and the serosal surface is also highly slippery. Pain is uncommon on palpation.
1.3 Peritoneal inflammation can extend to the gastrointestinal tract (vomiting, diarrhea), hepatobiliary system (jaundice) or pancreas (vomiting due to pancreatitis).
1.4 In uncastrated male cats, scrotal swelling may occur due to the expansion of peritoneal inflammation and the penetration of exudate into the testicular capsule.
1.5 Adhesions may accumulate in the mesentery, omentum and internal organs, forming irregular and hard masses, which can be palpable in the anterior abdomen.
1.6 Abdominal effusion can be diagnosed by radiological examination, ultrasound examination or abdominal puncture, and the results of fluid analysis are of great significance to the diagnosis of FIP.
- Pleural effusion (pleurisy)
2.1 Shortness of breath and exercise intolerance are the main clinical manifestations. This is because the accumulation of pleural fluid causes compression and restricts the expansion of the lungs.
2.2 Cats with chest effusion may prefer to sit or lie on their chest to facilitate breathing, which can increase respiratory distress during exercise. In the hospital, exercise should be restricted and stay on their side (ie, sitting and breathing).
2.3 Thoracic exudation shows cardiopulmonary murmurs on auscultation, and percussion shows fluid boundaries.
2.4 Thoracic exudation can be diagnosed by radiological examination and thoracentesis. The results of fluid analysis are of great significance to the diagnosis of FIP.
- Pericardial effusion
3.1 FIP fibrous pericarditis can occur with pericardial effusion, with or without other exudates. A survey shows that FIP is the second most common cause of cat pericardial effusion, accounting for about 14%.
3.2 FIP pericardial effusion does not often cause obvious clinical symptoms. Auscultation (heart murmur), thoracic radiology, or electrocardiogram can suspect the abnormality, and echocardiography confirms the diagnosis.
Non-Effusion FIP(Dry FIP)
Key point: Non-exudative cat infectious peritonitis is characterized by multifocal purulent granulomatous inflammation and necrotizing vasculitis in various organs, such as abdominal organs (for example, liver, spleen, kidney, pancreas and intestine), Eyes, central nervous system (CNS) and lungs.
Purulent granulomas appear as scattered or fused gray-white nodular masses of varying sizes in various organs, which are often mistaken for tumors. Exudates are often scarce or absent, and the specific organs affected and the degree of organ failure determine the degree of clinical symptoms.
- Kidney disease
1.1 Purulent granulomatous nephritis makes the kidney enlarged, hard and not smooth (uneven) on palpation. Purulent granulomas are distributed on the surface of the kidney or infiltrate the cortical layer of the kidney.
1.2 Severe kidney damage can cause renal failure, polyuria-polydipsia and azotemia (increased blood urea nitrogen and creatinine concentration).
1.3 Proteinuria is common when FIP kidney is damaged. In addition, a large number of immune complexes in the circulation can lead to subclinical glomerulonephritis.
- Liver disease
2.1 Purulent granulomatous hepatitis (symptoms of hepatomegaly, jaundice, and liver failure) can occur in FIP.
2.2 The most common laboratory abnormalities are bilirubinuria and hyperbilirubinemia. Serum liver enzyme activity and bile acid concentration are slightly to moderately elevated (alanine aminotransferase, alkaline phosphatase).
- Diseases of other abdominal organs
3.1 Purulent granulomatous injury can cause enlargement of organ lymph nodes, spleen or omentum.
3.2 Purulent granulomatous enterocolitis can cause diarrhea and diffuse or swollen intestinal thickening, especially in the ileocecal colon area.
3.3 Pancreatitis can sometimes be caused when the pancreas is damaged, and diabetes is rare.
- Eye diseases
4.1 FIP eye damage is usually bilateral, affecting the vascular membrane or uveitis (uveitis). Injuries sometimes cause blindness.
4.2 The manifestations of exudative anterior uveitis (iridocyclitis) may include miosis, flashing aqueous humor, corneal fibrin cell precipitation, anterior chamber empyema (cells and fibrin “lamb fat”-like precipitation), anterior chamber Hemorrhage, anterior chamber adhesion (iris adhesion), corneal edema, and corneal vascularization.
Feline infectious peritonitis anterior uveitis. Cat infectious peritonitis is often accompanied by typical perivascular purulent granulomatous inflammation. The cat’s aqueous humor is full of red blood cells and fibrin, and there are significant new blood vessels in the iris.
Chorioretinitis is caused when the posterior uvea is damaged, which is diagnosed by ophthalmoscope examination, including perivascular cuffs, exudative retinal detachment, and retinal hemorrhage.
Uveitis after infectious peritonitis in cats. White light (a) and blue light (b) in the same area showed significant vasculitis and perivascular edema.
5 Common Myelitis. Inflammatory damage is around the blood vessels, often including the meninges and ependymal layers. A report showed that 29% of cats with FIP have neurological symptoms. A retrospective survey of 286 neurological diseases found that FIP central nervous system damage accounted for 16%. Another large survey showed that FIP is the most common spinal cord disease in cats.
5.1 The location of nerve damage determines the clinical symptoms; the most common are ataxia, tremor, vestibular dysfunction, epilepsy, hindquarters paralysis, hyperesthesia, and behavioral abnormalities. The progressive and multifocal nature of these symptoms is typical of neurological FIP.
5.2 Neurological diseases sometimes include cranial nerves (for example, trigeminal nerve or facial nerve) or peripheral nerves (for example, brachial nerve or sciatic nerve).
5.3 When inflammation blocks the cerebrospinal fluid (CSF), cats with neurological FIP develop secondary hydrocephalus. A study of 24 cases of neurological FIP showed that 75% had hydrocephalus. CT and MRI scans showed dilation of the ventricles and central canal.
5.4 The diagnosis of neurological FIP depends on cerebrospinal fluid (CSF) analysis.
6 Lung disease
6.1 Purulent granulomatous pneumonia can be found during thoracic radiological examination or necropsy in cats with FIP, but most cases do not show clinical symptoms or cause only mild cough.
6.2 Radiology shows diffuse, plaque or nodular interstitial lung infiltration.
7 Diseases of the reproductive system
7.1 Purulent granulomatous orchitis can cause swelling of the scrotum.
Contrary to past speculations, FCoV does not directly cause reproduction problems, death of newborn cats, or weak children.