An umbilical hernia is an opening in the abdominal wall at the site of the umbilicus (belly button). The umbilical cord attaches between the mother and her unborn kittens, passing from the placenta attached to the wall of the queen's (mother cat) uterus through a hole in the unborn kitten's abdomen known as the 'umbilical ring'. Once the kitten is born, the umbilical ring should close within a few days, however, in some kittens, this doesn't happen which can result in abdominal contents such as visceral fat and sometimes part of the small intestine protruding (or herniating) through it.
The cat's skin covers the hole, so while the abdominal contents may push through it, it is covered by the skin. Umbilical hernias can range in size from 5mm (1/5 inch) to 18mm (3/4 inch). Obviously the larger the opening the greater the risk of the abdominal contents falling through.
Umbilical hernias may be reducible (or simple), in which the contents can be pushed back through the abdominal wall, or non-reducible (or complicated), where they have become either adhered to the skin or are obstructed from returning back through the wall.
Some umbilical hernias close spontaneously after a few months, others will not close which will require surgery. Cats with inherited umbilical hernias have a higher incidence of other congenital disorders such as cleft palate and cardiomyopathy.
There are several types of hernia which can occur in cats, an umbilical hernia is the most common.
Complications associated with hernias:
Obstruction: An intestinal loop can fall through the hole becoming trapped and may either cause an intestinal blockage due to food being unable to pass through the narrowed section of intestine. This is known as an 'incarcerated or obstructed hernia'.
Strangulation: If the neck of the hernia (located at the hernia opening) is sufficiently narrow, the intestinal loop can become compressed, or the intestines can also become twisted within the hernia, both of which can cut off the blood supply to the intestines resulting in death of the tissue. Once this happens, toxins are released into the bloodstream which causes septicaemia, organ dysfunction and death. This is known as a 'strangulated hernia'.
Both obstruction and strangulation are life threatening and require IMMEDIATE veterinary attention.
What causes an umbilical hernia?
In most cases, umbilical hernias are inherited. Normally the hole heals over shortly after birth, but in some cats, this doesn't happen, or it doesn't close completely.
Some hernias may be acquired. Other times umbilical hernias can be due to human intervention such as pulling on the umbilical cord during delivery of a kitten or improper handling of newborn (usually foster) kittens or cutting the umbilical cord too close to the kitten's body.
What are the symptoms of an umbilical hernia?
The most obvious symptom of an umbilical hernia is swelling and a visible lump at the site of the umbilicus (belly button). Depending on the cause, the swelling may be present at birth or it develops over a period of time.
Most umbilical hernias are soft, round masses located at the umbilical scar (belly button). If the abdominal contents are protruding through, it will feel firm. Reducible hernias usually flatten out when the kitten is placed on his back as the abdominal contents return to the abdomen. They should not feel warm or cause your cat pain.
A complicated (non-reducible) hernia will feel firm, warm, and will be painful.
Symptoms of intestinal obstruction include vomiting, abdominal pain, lethargy, depression and loss of appetite.
Symptoms of a strangulated hernia include fever, nausea, vomiting, loss of appetite, pain, inflamed skin around the hernia.
How is an umbilical hernia diagnosed?
Your veterinarian will perform a complete physical examination of your cat and obtain a medical history from you. Most hernias can be diagnosed during the examination. The size of the hernia will be determined. If it is smaller or larger than the intestinal loop immediate attention generally isn't necessary as the risk of obstruction or strangulation is low, however, if the hole is the size of the intestinal hoop, immediate attention to fix the hernia will be required to prevent complications due to intestinal incarceration.
An ultrasound may be performed to determine what structures are contained within the hernia and their size.
How is an umbilical hernia treated?
If the hernia hasn't resolved by six months of age and is large enough to pose a risk of intestinal herniation and incarceration, surgery will be recommended to correct it. This is known as herniorrhaphy and is usually performed at the same time as your cat's spay/neuter surgery (if they haven't already been done).
Your cat will be given a general anaesthetic, an incision will be made and the herniated tissues will be replaced back into the abdomen. The abnormal opening will then be sutured shut.
Keep your cat indoors while he recovers from surgery. Your veterinarian may send your cat home with pain medication for the first few days, administer as prescribed. Never give your cat pain medication for humans unless your veterinarian has told you to do so.
Your veterinarian may place your cat in an Elizabethan collar to stop him pulling at the stitches.
Check your cat's incision for signs of infection such as redness, swelling and oozing.
A follow-up appointment with your veterinarian will be required in 7-10 days to have the stitches removed.
The outcome is very good for simple hernias but is more guarded for complicated ones.
Preventing umbilical hernias:
- Cats who have a hernia should not be used to breed with as the condition is inherited.
- If you are helping a queen deliver kittens, be very careful to avoid pulling on the umbilical cord either during delivery or immediately afterwards.
- The cord should be cut 1 inch (2.5cm) from the kitten's body.
- Do NOT pull the dried umbilical stump off, let it fall off naturally.
- If you are bottle feeding kittens who require help toileting, only rub the genital area and not the belly.