Egg yolk peritonitis is the inflammatory response caused by the presence of yolk material in the peritoneum (the thin layer of tissue covering the inside of the duck's abdomen and most of the organs) from a ruptured egg or a retained egg in the oviduct. The yolk material itself may only cause a mild inflammatory response, and be reabsorbed by the peritoneum. However, since yolk material is an excellent growth medium for bacteria, it can lead to a secondary bacterial infection.
Escherichia coli is the most frequent bacteria isolated from affected birds. Other common types of bacterial organisms that have been isolated include
Klebsiella sp., Proteous sp., Staphylococcus sp., and
Streptococcus sp.,.
In cases of egg yolk peritonitis, it's important to determine the underlying cause, since it often occurs as a secondary or concurrent event to several of reproductive conditions, including:
- Salpingitis
- Oviductal impaction
- Ovarian neoplasia
- Cystic ovarian disease
- Chronic obesity
- Oviductal torsion
Symptoms of Egg Yolk Peritonitis
Clinical signs may vary widely, depending on the severity of the infection and overall health status of the duck. Commons signs of egg yolk peritonitis include:
- Lethargy
- Depression
- Reduced activity and changes in normal behavior
- Excessive nestbox sitting or broody-like behavior
- Palpable abdominal distension, indicating the presence of fluid in the abdominal lining occurs often in more severe and advanced stages.
- Reduced or loss of appetite
- Exhibiting a "penguin-like" stance
- Delayed molt
- History of egg laying which abruptly stopped or associated with shell-less eggs.
Depending on the amount of fluid present in the bird's abdomen, it may cause respiratory difficulty, due to the pressure and space occupying nature of the fluid present.
Diagnosis of Egg Yolk Peritonitis
Egg yolk peritonitis is diagnosed through a combination of history, clinical signs, physical exam, and a variety of diagnostic imaging equipment and laboratory tests. Tests that can be beneficial to help in the diagnosis of egg yolk peritonitis in chickens include:
- Palpation of the abdomen can sometimes reveal the presence of soft-shelled or firm shelled eggs in the oviduct, ectopic eggs free within the abdomen, ovarian masses, or displacement of the ventriculus.
- A blood test, called a complete blood count (CBC), measures the white blood cell count. A high white blood cell count usually signals inflammation or infection. A blood culture can help to identify the bacteria causing the infection or inflammation. Antibiotic sensitivity testing helps to identify the best antibiotic to use to treat the infection.
- Fluid recovered from an abdominocentesis (a procedure your veterinarian can perform using a needle, to remove any abdominal fluid present. They can send this to a laboratory for fluid analysis. A bacterial culture of this fluid can help identify the specific bacteria.
- Radiography and ultrasound imaging may help in revealing the presence of accumulated egg material and space-occupying lesions.
Treatment of Egg Yolk Peritonitis
Treatment of egg yolk peritonitis varies depending on the cause and severity of clinical signs in the bird. Mild cases where no secondary bacterial infection is involved may only require supportive care. In other cases, when an infection is present, usually treatment requires a combination of analgesics, anti-inflammatories, broad-spectrum antibiotics, aggressive supportive care, and other therapies aimed at reducing egg laying activity. Surgery may sometimes be needed, to remove excessive accumulations in egg material. In persistent cases where duck's develop recurring egg laying problems, more aggressive treatment methods such as salpingohysterectomy (spaying) may be indicated.
