Pyometra & Cystic Endometrial Hyperplasia
Pyometra is defined as an infection in the uterus. It is considered a serious and life threatening condition that must be treated quickly and aggressively. It’s a secondary infection that occurs as a result of hormonal changes in the female's reproductive tract. During estrus ("heat"), the white blood cells, which normally would protect the female against infection, are inhibited from entering the uterus. This allows sperm to safely enter the female's reproductive tract without being damaged or destroyed by these immune system cells.
Following estrus ("heat") in the dog, progesterone hormone levels can remain elevated up to two months and cause thickening of the lining of the uterus in preparation for pregnancy. However, if pregnancy doesn’t occur for several consecutive estrus cycles, the uterine lining continues to increase in thickness until cysts often form within the tissues (a condition called Cystic Endometrial Hyperplasia). The thickened, cystic lining secretes fluids that create the ideal environment that bacteria can grow in. Additionally, high progesterone levels inhibit the ability wall muscles of the uterus to contract and expel accumulated fluids or bacteria. The combination of all these factors can often lead to infection.
The use of progesterone-based drugs can cause changes in the uterus similar to the estrus cycle, such as estrogen or synthetic estrogen drugs will increase the effects of progesterone on the uterus. Drugs containing both estrogen and progesterone are occasionally used to treat certain conditions of the reproductive system. Any intact female receiving hormones must be carefully monitored for the increased risk of a Pyometra.
The cervix is the entrance to the uterus. It remains tightly closed except during estrus, when it relaxes to allow sperm to enter the uterus. "If the cervix is open or relaxed, bacteria that are normally found in the vagina can enter the uterus easily." If the uterus is normal, the uterine environment is adverse to bacterial survival; however, when the uterine wall is thickened or cystic, perfect conditions exist for bacterial growth. In addition, when these abnormal conditions exist, the muscles of the uterus cannot contract properly; this is either due to thickening of the uterine wall or the hormone progesterone. Unfortunately, any bacteria that enter the uterus cannot be expelled.
Pyometra can occur in any sexually intact young to middle-aged dogs; however, it is most common in older dogs. "Pyometra usually occurs two to eight weeks after the last estrus." After many years of estrus cycles without pregnancy, the uterine wall undergoes the changes that can promote this disease. Pyometra usually occurs two to eight weeks after the last estrus ("heat cycle").
The clinical signs are dependant on whether or not the cervix remains open. If it is open, pus will drain from the uterus through the vagina to the outside. This is called an “Open Pyometra”. Pus or an abnormal discharge is often seen on the skin or hair under the tail or even bedding and furniture where the dog has recently laid. Fever, lethargy, anorexia, and depression may or may not be present.
If the cervix is closed, pus that forms is not able to drain to the outside. It collects in the uterus ultimately causing the abdomen to distend. “This is a Closed Pyometra”. The bacteria release toxins that are absorbed into the bloodstream. Dogs with closed Pyometra become severely ill very rapidly. They are anorectic, listless and depressed. Vomiting or diarrhoea can also be present.
Toxins released by the bacteria affect the kidney's ability to retain fluid. Therefore there is an increase of urine production, and many dogs will drink an excess of water to compensate. Increased water consumption may occur in both open- and closed-cervix Pyometra.
Dogs that are examined early in the course of the disease may have slight vaginal discharge and show no other signs of illness. However, most dogs with Pyometra are seen later in the illness, as often there are no signs. A very ill female dog with a history of recent "heat" that is drinking an increased amount of water should be suspected of having Pyometra. This is especially true if there is a vaginal discharge or a painful, enlarged abdomen.
Dogs with Pyometra usually have a significant elevation of the white blood cells and often have an elevation of globulins (a type of protein often associated with the immune system) in the blood. The specific gravity (concentration) of the urine is generally low due to the toxic effects of the bacteria on the kidneys. These changes however, are non-specific and may be present in any dog with a major bacterial infection.
If the cervix is closed, x-rays of the abdomen will often identify the enlarged uterus. If the cervix is open, there will often be such minimal uterine enlargement that the x-ray may well be inconclusive. An ultrasound examination may be the most helpful way to identify an enlarged uterus and differentiating that from a normal pregnancy. Ultrasound changes that indicate Pyometra can include increased uterine size, thickened uterine walls, and fluid accumulation within the uterus.
The preferred treatment is to surgically remove the infected uterus and ovaries, or perform an ovariohysterectomy more commonly known as a bitch spay. Dogs diagnosed in the early stage of the disease are very good surgical candidates. The surgery is somewhat more complicated than a routine spay at this stage. Unfortunately, most dogs are diagnosed with Pyometra when they are very ill resulting in a more complicated surgical procedure and a longer period of hospitalization. Intravenous fluids are required to stabilize the dog before and after surgery. Antibiotics are usually given for two weeks after surgery, and even then your dog may not be out of the woods.
There is a medical approach to treating Pyometra, although the success rate is widely variable and not without considerable risk and potential long-term complications. Prostaglandins are a group of hormones that lower the blood level of progesterone, relax and open the cervix, and cause the uterus to contract and expel bacteria and pus. They can be used to treat this disease, but they are not always successful and have some important limitations. The chance of successful resolution without surgery or prostaglandin treatment is extremely low. If treatment is not performed quickly, the toxic effects from the bacteria will be fatal in most cases. If the cervix is closed, it is possible for the uterus to rupture, spilling the infection into the abdominal cavity. This will also be fatal. Pyometra is a serious medical condition that requires prompt treatment. The only way to avoid this condition completely is to neuter young.
Pyometra is defined as an infection in the uterus. It is considered a serious and life threatening condition that must be treated quickly and aggressively. It’s a secondary infection that occurs as a result of hormonal changes in the female's reproductive tract. During estrus ("heat"), the white blood cells, which normally would protect the female against infection, are inhibited from entering the uterus. This allows sperm to safely enter the female's reproductive tract without being damaged or destroyed by these immune system cells.
Following estrus ("heat") in the dog, progesterone hormone levels can remain elevated up to two months and cause thickening of the lining of the uterus in preparation for pregnancy. However, if pregnancy doesn’t occur for several consecutive estrus cycles, the uterine lining continues to increase in thickness until cysts often form within the tissues (a condition called Cystic Endometrial Hyperplasia). The thickened, cystic lining secretes fluids that create the ideal environment that bacteria can grow in. Additionally, high progesterone levels inhibit the ability wall muscles of the uterus to contract and expel accumulated fluids or bacteria. The combination of all these factors can often lead to infection.
The use of progesterone-based drugs can cause changes in the uterus similar to the estrus cycle, such as estrogen or synthetic estrogen drugs will increase the effects of progesterone on the uterus. Drugs containing both estrogen and progesterone are occasionally used to treat certain conditions of the reproductive system. Any intact female receiving hormones must be carefully monitored for the increased risk of a Pyometra.
The cervix is the entrance to the uterus. It remains tightly closed except during estrus, when it relaxes to allow sperm to enter the uterus. "If the cervix is open or relaxed, bacteria that are normally found in the vagina can enter the uterus easily." If the uterus is normal, the uterine environment is adverse to bacterial survival; however, when the uterine wall is thickened or cystic, perfect conditions exist for bacterial growth. In addition, when these abnormal conditions exist, the muscles of the uterus cannot contract properly; this is either due to thickening of the uterine wall or the hormone progesterone. Unfortunately, any bacteria that enter the uterus cannot be expelled.
Pyometra can occur in any sexually intact young to middle-aged dogs; however, it is most common in older dogs. "Pyometra usually occurs two to eight weeks after the last estrus." After many years of estrus cycles without pregnancy, the uterine wall undergoes the changes that can promote this disease. Pyometra usually occurs two to eight weeks after the last estrus ("heat cycle").
The clinical signs are dependant on whether or not the cervix remains open. If it is open, pus will drain from the uterus through the vagina to the outside. This is called an “Open Pyometra”. Pus or an abnormal discharge is often seen on the skin or hair under the tail or even bedding and furniture where the dog has recently laid. Fever, lethargy, anorexia, and depression may or may not be present.
If the cervix is closed, pus that forms is not able to drain to the outside. It collects in the uterus ultimately causing the abdomen to distend. “This is a Closed Pyometra”. The bacteria release toxins that are absorbed into the bloodstream. Dogs with closed Pyometra become severely ill very rapidly. They are anorectic, listless and depressed. Vomiting or diarrhoea can also be present.
Toxins released by the bacteria affect the kidney's ability to retain fluid. Therefore there is an increase of urine production, and many dogs will drink an excess of water to compensate. Increased water consumption may occur in both open- and closed-cervix Pyometra.
Dogs that are examined early in the course of the disease may have slight vaginal discharge and show no other signs of illness. However, most dogs with Pyometra are seen later in the illness, as often there are no signs. A very ill female dog with a history of recent "heat" that is drinking an increased amount of water should be suspected of having Pyometra. This is especially true if there is a vaginal discharge or a painful, enlarged abdomen.
Dogs with Pyometra usually have a significant elevation of the white blood cells and often have an elevation of globulins (a type of protein often associated with the immune system) in the blood. The specific gravity (concentration) of the urine is generally low due to the toxic effects of the bacteria on the kidneys. These changes however, are non-specific and may be present in any dog with a major bacterial infection.
If the cervix is closed, x-rays of the abdomen will often identify the enlarged uterus. If the cervix is open, there will often be such minimal uterine enlargement that the x-ray may well be inconclusive. An ultrasound examination may be the most helpful way to identify an enlarged uterus and differentiating that from a normal pregnancy. Ultrasound changes that indicate Pyometra can include increased uterine size, thickened uterine walls, and fluid accumulation within the uterus.
The preferred treatment is to surgically remove the infected uterus and ovaries, or perform an ovariohysterectomy more commonly known as a bitch spay. Dogs diagnosed in the early stage of the disease are very good surgical candidates. The surgery is somewhat more complicated than a routine spay at this stage. Unfortunately, most dogs are diagnosed with Pyometra when they are very ill resulting in a more complicated surgical procedure and a longer period of hospitalization. Intravenous fluids are required to stabilize the dog before and after surgery. Antibiotics are usually given for two weeks after surgery, and even then your dog may not be out of the woods.
There is a medical approach to treating Pyometra, although the success rate is widely variable and not without considerable risk and potential long-term complications. Prostaglandins are a group of hormones that lower the blood level of progesterone, relax and open the cervix, and cause the uterus to contract and expel bacteria and pus. They can be used to treat this disease, but they are not always successful and have some important limitations. The chance of successful resolution without surgery or prostaglandin treatment is extremely low. If treatment is not performed quickly, the toxic effects from the bacteria will be fatal in most cases. If the cervix is closed, it is possible for the uterus to rupture, spilling the infection into the abdominal cavity. This will also be fatal. Pyometra is a serious medical condition that requires prompt treatment. The only way to avoid this condition completely is to neuter young.