Hernias in cats (umbilical and inguinal)
There are several different types of hernia (also known as a rupture) seen in the cat and the causes vary between the different types. Some hernias can be minor, but in certain circumstances they can be very serious and often require surgical treatment.
What is a hernia?
A hernia is a swelling in which tissues that should be within the abdomen bulge out through the muscle wall. This may be through a natural opening, which is meant to be there but has become a larger opening than normal, or a gap that has developed; this can occur due to old-age or due to trauma. The swelling may appear as a lump under the skin on the abdomen (umbilical, inguinal) or beside the anus (perineal). Typically the swelling contains some fatty tissue from the omentum, a fatty membrane which lies within the abdomen, but abdominal organs could be present.
There are other hernias that occur between the muscle layers internally and so you cannot see any swelling when looking at your cat but may have noticed signs of illness (bringing up food/regurgitating for hiatal hernia) or rapid or difficulty breathing (diaphragmatic hernia).
What is an umbilical hernia?
An umbilical hernia is a soft non-painful swelling over the umbilicus (belly button). This is a hernia that is present from birth (congenital) in the majority of cases. It is at the site where the umbilical cord fed your puppy in the womb and sometimes this opening doesn’t close up following birth as it should. The hernia may be very small but can be large and associated with other defects of development within the midline (midline fusion defects). This means that other defects of the diaphragm or heart can be present in some cases. Careful physical examination and, if necessary, some diagnostic imaging checks can rule out more complicated problems.
If they are very small then no treatment may be necessary, however due to the potential for problems to be present or develop with a hernia surgery may be recommended. This decision would be based upon the assessment made by your veterinary surgeon. It is often appropriate for an umbilical hernia to be repaired at the same time as general anaesthesia for neutering to be performed.
What is an inguinal hernia?
An inguinal hernia is nonpainful swelling in the inguinal (groin) region, which can be on one side or both sides. The hernia occurs through the inguinal ring, which is a small natural opening that allows blood vessels to travel to the back leg on each side (and the testicles in the male). It is normally a slit like opening so nothing can pass through other than the vessels, however in some cats it is larger and then a hernia may develop. Inguinal hernias can be congenital (from birth) or may also be seen later in life; this is typically in entire female cats due to the influence of hormones and is seen in female cats that are overweight most often. In the male cat the hernia can extend into the scrotum and castration is recommended during the surgery to reduce the risk of recurrence.
An incisional hernia is a swelling that has occurred at the site where a previous surgery was performed. This can occur because the muscle layer of the abdominal wall has not healed back together properly; sometimes this can be due to insufficient rest after the operation but may also be due to your cat’s ability to heal. If this was done in the last 6 weeks this could be very serious and emergency veterinary assessment should be sought.
How will I know if my cat has a hernia?
You may notice a soft, doughy swelling or mass which is not painful. Depending on where the hernia is, your cat may have respiratory or gastrointestinal signs (bringing up food or having difficult passing faeces). If the hernia becomes strangulated, the hernia may become painful and the skin surrounding the hernia may be red to blue-black in colour.
How will my vet know if my cat has a hernia?
The characteristic soft and non-painful swelling in a classic location leads to the suspicion of diagnosis of a hernia. You vet can distinguish a hernia from other forms of swellings, such as an abscess or a tumour to some extent by the appearance and feel when they examine your cat. In particular, a hernia may be assessed as to whether or not it can be ‘reduced’. This means if the swelling can gently be pushed back inside the abdomen. One part of the assessment for a perineal hernia, which is besides your cat’s bottom, is a rectal examination. Further tests may be necessary to confirm the diagnosis following the assessment. These would include x-rays of the abdomen and or chest, as necessary and also possibly an ultrasound. In some circumstances a Computed Tomography (CT) scan may been chosen if it is available and additional information is considered beneficial.
How are hernias treated?
A very small hernia in the umbilical region may be left untreated, at the discretion of the responsible veterinary surgeon. It is essential that the area is regularly monitored by the cat’s owner and at the annual health check by the veterinary surgeon.
Surgical treatment of hernias is recommended due to the risk of worsening and serious complications. Surgery is performed under a general anaesthetic. The veterinary surgeon will make a skin wound overlying the area of the swelling to allow the contents to be pushed back into the abdomen. The opening is then closed; either completely if that is how the anatomy is meant to be, or almost completely, if vessels need to travel through the opening. Sometimes a larger wound along the abdomen is necessary if your vet needs to check the organs within the abdomen more thoroughly.
If a non-painful soft hernia becomes painful and firmer these are signs that you must seek urgent veterinary attention for your cat. The development of pain and firmness suggests inflammation and raises the suspicion that a serious development has occurred: if an internal organ is present within the hernia but has become twisted it may lose the blood supply and become necrotic; this means that the part of the organ dies. It is particularly serious if a portion of intestine (bowel) enters the hernia sac and becomes twisted. Bowel necrosis would lead to leakage of bowel contents into the abdomen, life threatening infection (septic peritonitis) and possibly death.
How can I prevent my cat developing a hernia?
In many cases there is nothing you can do to prevent this problem arising, however keeping your cat in healthy, fit body condition can reduce the risks as being overweight can predispose to some hernias in older age. An incisional hernia can be avoided by adhering to the instructions for post-operative rest following a surgical procedure, if your cat needs to undergo one.
What problems may occur after my cat’s hernia surgery?
There is a risk with any surgery of bleeding, wound infection and wound breakdown. With a hernia there is also the risk of recurrence. It is important to monitor for signs of bleeding, swelling of the area around the wound, recurrence of swelling beneath the wound and wound discharge. If any of these are noted please speak to your veterinary surgeon for advice.
The wound itself should be left open to the air and should be kept clean and dry, however do not bathe the wound unless specifically directed by a veterinary surgeon. Often making the wound moist can increase the risk of a wound infection. Your cat, and other pets, should be prevented from interfering with the wound. Please use a buster collar, post-op coat or T-Shirt to prevent interference and keep other pets separate when not supervising interactions.
Monitor your cat for normal behaviours such as passing urine and faeces normally and having a good appetite. Notify your vet if any concerns arise.
If your cat has a cough and seems unwell speak to your vet. It is quite common for a slight dry cough to be present for a couple of days following the anaesthetic due to the endotracheal tube causing irritation and this should not be of much concern and will self-resolve. A moist cough is suggestive of pneumonia, which can occur following any anaesthetic but is more likely if there is another predisposing factor, such as regurgitation which occurs in hiatal hernia.
It is important to keep your cat’s exercise restricted during the recovery phase, until your vet has completed a post-operative check and is happy with the healing. Your cat must be restricted to the house for 6 weeks and to a single room for 2 weeks. If your cat is inclined to jump, run or climb then use of a crate is sensible to ensure proper rest. This should have enough space for a bed, water and food area and a litter tray.