What is Congenital Cytomegalovirus Infection?
Congenital cytomegalovirus (CCMV) is the leading cause of infections in the womb in the U.S., and the main non-genetic reason for hearing loss in children. Most of the time, this disease doesn’t show signs (in 85 to 90% of cases). When symptoms do appear, it’s usually after the mother gets infected for the first time during pregnancy. Though less frequent, symptomatic CCMV is dangerous and may cause death in 7 to 12% of newborns early in their life. It can also result in severe health problems due to damage to the brain, leading to developmental delays, hearing loss, and vision problems. It’s worth noting that even when the disease doesn’t show symptoms, it’s not harmless. In fact, 10 to 15% of those cases can result in long-term health issues. Despite these significant risks, we need to highlight that many women in their childbearing years are not properly informed about CCMV.
What Causes Congenital Cytomegalovirus Infection?
Cytomegalovirus (CMV) is the largest type of herpes virus, and humans are its main carrier. The virus can be found in body fluids such as spit, urine, breast milk, semen, and blood. When someone who’s never had the virus gets it for the first time, it’s called a primary infection. But there can also be other, non-primary infections. These happen when a previous infection comes back or when a person gets a different strain of the virus.
Hormone changes that happen during pregnancy and breastfeeding might cause the virus to reactivate. A primary infection poses the biggest risk of passing the virus to a baby during pregnancy (30 to 35%), compared to a 1.1 to 1.7% risk for non-primary infections. However, since many pregnant women have had prior contact with the virus, they mainly tend to pass on the disease due to non-primary infections.
Spending a lot of time with young children is a significant risk factor for getting the virus during pregnancy. Kids under 2 who have the virus can spread it through their urine and spit for about two years. As a woman’s pregnancy advances, there’s more virus to be found in urine and vaginal secretions, increasing the likelihood of disease transmission. The stage of the pregnancy also affects the chances of passing on the disease, with a higher risk (58 to 78%) in the third trimester compared to the first (30 to 45%). However, if a fetus gets infected later in pregnancy, they are less likely to have long-term health issues due to the virus.
Risk Factors and Frequency for Congenital Cytomegalovirus Infection
The likelihood of women of reproductive age having antibodies (a condition known as seroprevalence) tends to vary based on their social and economic status. In developed countries, the seroprevalence rate can range from 40 to 83%. However, in developing countries, almost all women in this age group are found to have these antibodies. Interestingly, in lower socioeconomic sections of developed countries, the seroprevalence rates are similar to those in developing nations.
How people acquire CMV (an infection causing illness) differs between industrialized and developing countries. In industrialized nations, CMV is usually contracted through regular contact with small children. In contrast, in the developing world, CMV transmission happens early in life because of breastfeeding and overcrowded living conditions.
- In developed countries, about 0.6 to 0.7% of babies are born with this condition, resulting in roughly 40,000 cases in the United States each year.
- However, in developing countries, the rate of congenital CMV (CCMV) infection in newborns is higher, about 1 to 5%.
- But only around 10% show symptoms as newborns, which makes the disease hard to spot.
For those babies who do show symptoms, the risk of developing long-term neurological issues is higher. About half of them (40-58%) may go on to develop permanent problems like hearing loss, eye deficits, and delays in brain development. Hearing loss is the most common problem resulting from CCMV infection, which affects 35% of symptomatic newborns and 7 to 10% of those who showed no symptoms at birth.
Signs and Symptoms of Congenital Cytomegalovirus Infection
When a mother gets infected with cytomegalovirus (CMV), she often doesn’t show any symptoms. It is hard to tell the difference between CMV and the Epstein Barr virus, because both come with a variety of symptoms. These can include fever, feeling tired, headaches, sore throat, swollen lymph nodes, enlarged liver and spleen, joint pain, and rashes.
The baby in the womb can develop various issues due to CMV. Problems can include abnormal calcium deposits in the brain, small head size, abnormal enlargement of the brain’s ventricles, changes to the blood vessels in the brain, unusual growth in the brain’s occipital horns, an overly bright bowel in the ultrasound images, abnormal slowing of fetal growth, enlarged liver, fluid build-up around the heart, and amniotic fluid in the abdominal cavity. Furthermore, inflammation of the placenta and fetal death are potential consequences. In newborns, CMV infection can cause yellowish skin and eyes (jaundice), small red or purple spots on the skin, an enlarged liver and spleen, and a smaller than normal head size. Other signs of infection can be an inflammation of the retina with or without damage to the optical nerve and cataracts. Newborns might be premature or have a low birth weight. They may also have hearing loss right after birth or later in life, which underlines the necessity for regular hearing tests in children that have been affected by CMV.
Lab tests may show elevated aspartate transferase, increased levels of conjugated bilirubin, platelet count deficiency, and unusually high protein in the cerebrospinal fluid. Pictures of the brain can display periventricular calcifications, enlarged ventricles, ventricular cysts, and lenticulostriate vasculopathy.
Testing for Congenital Cytomegalovirus Infection
Diagnosis of Congenital Cytomegalovirus (CCMV) can take place before or after birth. Before birth, it involves testing both the mother and baby, but isn’t usually done because the tests may not be accurate enough and there are limited options to treat the virus during pregnancy.
However, testing may be advisable in certain situations. This may include if the mother is displaying symptoms similar to mononucleosis, has been exposed to someone with a CMV infection, works in a healthcare or childcare setting, or if a baby’s ultrasound scan shows signs of CCMV. These signs may include larger than normal brain cavities, a bright appearing bowel, calcium deposits in the brain, or an abnormal amount of fluids in the fetus.
If primary CMV infection is suspected, both the mother and baby need to be tested. For the mother, a test will identify if there’s a change from having no antibodies for CMV to having them. The presence of certain antibodies (IgM) can indicate a new infection, but they can also show up in your blood for several months after the infection. Thus, another test (IgG antibody avidity testing) needs to be done to confirm the timing of the infection.
The baby’s diagnosis before birth is achieved through a procedure called amniocentesis, where a small amount of amniotic fluid is tested, ideally after 21 weeks of pregnancy and 7 weeks after the mother’s infection. Also, fetal ultrasound is performed, but the findings are not specific to CMV and only seen in about 15% of infected fetuses. The presence of abnormalities in ultrasound coupled with a new infection in the mother strongly indicates that the fetus might be infected.
After birth, testing the baby involves isolating the virus from urine or saliva via culture or a DNA PCR test within the first 3 weeks of life. It’s crucial to perform these tests within this timeframe because after 3 weeks, doctors can’t determine when the infection happened – before, during, or after birth.
Overall, testing for CMV in babies is often missed because most newly born babies with the virus don’t show symptoms. Therefore, tests should be done more than an hour after breastfeeding due to the risk of test contamination from CMV positive breast milk. If a newborn is found to have CCMV, additional tests should include a complete blood count, hepatic panel, serum bilirubin, and cranial imaging (initially an ultrasound, followed by a MRI if needed).
Treatment Options for Congenital Cytomegalovirus Infection
There isn’t a clear-cut way to treat babies who contract CMV, a type of virus, while they are still in the womb. If doctors find that the fetus has the virus, one possible option is ending the pregnancy. But this is a deeply personal decision for parents and they should be fully informed and counseled before they make their choice. If the parents decide to move forward with the pregnancy, it’s crucial that they have regular ultrasound check-ups.
One preventive measure is the use of a specialized type of medicine that targets CMV, which might lower the rate of babies born with the virus. But since it’s not certain how effective this is and there are potential side effects, this isn’t generally recommended.
Once born, it is crucial for the baby to be tested within the first three weeks. They can do this through a mouth swab or a urine test. If the virus is present, the baby needs to be monitored closely. This is true for babies with symptoms as well as without, since they should receive regular hearing tests. Various pediatric experts, such as hearing, throat, eye, brain specialists, behavioral specialists, infectious disease experts, and therapists, will be needed for the baby’s care.
Babies that do show symptoms should be treated with oral valganciclovir for 6 months. This treatment can either preserve normal hearing or prevent hearing loss from getting worse. In addition, this treatment is linked with better long-term brain development results. It’s also considered safer than intravenous Ganciclovir which can have side effects like creating low white blood cell count and harm to the reproductive system. Regardless of whether or not they show symptoms, it’s essential to monitor the babies closely for any late-onset effects of the virus.
What else can Congenital Cytomegalovirus Infection be?
There are numerous infections that fall under the term TORCH, which includes toxoplasmosis, rubella, the herpes simplex virus (HSV), and syphilis. Each of these infections can lead to different signs in newborns:
- Toxoplasmosis often causes eye inflammation (chorioretinitis), unusually small eyes (microphthalmia), a build-up of fluid in the brain (hydrocephalus), scattered calcifications in the body, and a red spotted rash.
- Infants born with congenital rubella syndrome can have cataracts and heart defects present from birth.
- Herpes simplex infection usually stands out because of a rash with fluid-filled blisters.
- Syphilis in newborns is typically linked with a runny nose (rhinitis) and inflammation of the bone and cartilage (osteochondritis).
Newborns with CCMV may also show symptoms similar to those seen in other serious bacterial, viral, or fungal infections. In addition, certain hereditary metabolic disorders, like galactosemia and tyrosinemia, can mimic the signs of CCMV. For these metabolic conditions, the newborn would typically test positive on a newborn metabolic screening test. The best way to differentiate between these various conditions is by taking a detailed health history, performing a physical examination, and obtaining bacterial or fungal cultures when needed.
What to expect with Congenital Cytomegalovirus Infection
The outlook for babies with symptomatic congenital cytomegalovirus is generally not good. This condition can lead to long-term complications like loss of hearing, mental and developmental disabilities, as well as issues with vision. About 10% of newborns showing symptoms may not survive past the newborn period, and this is possibly an underestimate.
Even babies who show no symptoms at birth are not safe from long-term complications—10 to 12% of them may develop hearing loss, with a smaller percentage developing motor disabilities and vision problems.
The situation is toughest for babies of mothers who either got cytomegalovirus for the first time during pregnancy or who show symptoms like an unusually small head (microcephaly), mineral deposits in the brain (intracranial calcifications), or inflammation of the retina (chorioretinitis). These babies generally have the worst outlook.
Possible Complications When Diagnosed with Congenital Cytomegalovirus Infection
Complications are more likely to occur if you have symptoms of CMV infection. These complications can include:
- Loss of sensorineural hearing: This is the most common complication and it can affect both newborns with symptoms and those without symptoms.
- Delays in neurodevelopment: These can include motor deficits such as cerebral palsy, and cognitive deficits.
- Eye problems: These can range from chorioretinitis (a clinical finding) to optic atrophy, which could be associated with loss of vision.
- Seizures
- Death
Preventing Congenital Cytomegalovirus Infection
The biggest risk for pregnant women comes from contact with the urine or saliva of young children. To help reduce the chance of infection, it’s important for pregnant women to know more about CMV. This can be done by following certain simple steps such as washing hands thoroughly after coming into contact with items that could be infected, like dirty diapers and toys. They should also limit close contact with children under the age of six, like kissing them on the mouth or cheek, sharing a bed, and wiping away their saliva.
Pregnant women should also be advised not to share things like spoons or forks with their kids, or put a child’s pacifier in their mouth. For women working in childcare who are planning to get pregnant, it’s a good idea to let their employers know so that measures can be taken to reduce any risk as much as they can.