What is Bochdalek Hernia?
A Bochdalek hernia is a birth defect that happens when there’s a hole in the back side of the diaphragm, the muscle that helps you breathe. This hole can allow parts of the belly to move into the chest, which can squish the developing lungs and sometimes cause them to not fully develop. Most of the time, symptoms like trouble breathing show up in kids. Adults are rarely diagnosed with symptoms, but some might be discovered to have Bochdalek hernia during check-ups for other reasons. We’re not sure exactly why it happens, but it seems to involve a mix of environment and genes. Usually, doctors fix this problem with surgery. It’s important to know that Bochdalek hernia and a similar condition called congenital diaphragmatic hernia (CDH) often come with other long-term health issues, which require monitoring and frequent check-ups with a variety of healthcare professionals.
What Causes Bochdalek Hernia?
A Bochdalek hernia, a type of birth defect in the diaphragm, is thought to result from a mix of environmental factors and your genes. Experts believe that about 30% of these hernias are due to genetic causes, such as variations or changes in chromosomes, or in the number or order of DNA sequences. These changes often involve multiple transcription factors and the retinoic acid pathway. Transcription factors are proteins that help turn certain genes on or off, and the retinoic acid pathway is involved in how cells develop. Different genes can have different effects and change how visible or severe the defect is.
It makes sense that if there’s a development issue in one part of the body, there could be others elsewhere too. This is also true for Bochdalek hernias. Some individuals with this hernia are also found to have related health issues, like lung or heart defects.
Risk Factors and Frequency for Bochdalek Hernia
Congenital diaphragmatic hernia (CDH) is a birth defect affecting the diaphragm. It can occur in around 1 in every 2000 to 3000 births. The majority of these are a specific type known as Bochdalek hernias. A study in Utah found that CDH happened in 1 out of every 3156 births. It’s more common in boys than in girls, with a ratio of 1.72 boys for every girl. Most of these cases (64%) are isolated incidents, while some cases (23%) occur more than once, and a few (13%) are part of a syndrome.
Bochdalek hernias in adults are usually discovered by accident because symptoms are rare. Estimates suggest that asymptomatic Bochdalek hernias occur in between 0.17% and 6% of adults. However, some people believe that these hernias might have been acquired during adulthood.
- CDH is a birth defect that affects the diaphragm and occurs in about 1 out of every 2000 to 3000 births.
- Most of the CDH cases (70 to 75%) are Bochdalek hernias, a specific type of hernia.
- In a Utah study, CDH was seen in 1 out of every 3156 births.
- CDH is more common in boys than girls, with a ratio of 1.72:1.
- Most cases (64%) are single occurrences, 23% happen more than once, and 13% are part of a syndrome.
- Bochdalek hernias in adults are typically found by accident and are estimated to occur in 0.17% to 6% of adults.
- Some believe these adult hernias might have developed during adulthood.
Signs and Symptoms of Bochdalek Hernia
Bochdalek hernias, a type of diaphragm hernia, can show different symptoms in children and adults. In kids, these hernias often show up as breathing problems, which can be traced back to underdeveloped lungs due to the hernia’s compression during pregnancy. On the other hand, these hernias in adults are usually not noticeable and are often discovered during routine medical check-ups. When symptoms do appear in adults, they’re often vague or nonspecific and related to the digestive system. A physical check-up might reveal bowel sounds when the doctor listens to the chest. In severe cases, the abdomen may appear hollow because part of the intestines has moved up into the chest cavity.
Testing for Bochdalek Hernia
Various imaging techniques are used to diagnose a type of hernia called a Bochdalek hernia. These techniques include ultrasound, chest x-rays, and a special type of CT scan that provides pictures from various angles. More recently, MRI scans are also used in the evaluation of these conditions. Interestingly, MRI scans of the chest area before birth have become the most common way to check for a type of hernia called a congenital diaphragmatic hernia.
Before a baby is born, ultrasound can show signs that suggest the baby may have a congenital diaphragmatic hernia, such as the stomach appearing within the chest area or a shift of the chest contents away from the herniated (protruding) organs.
After the baby is born, ultrasound can show the whole diaphragm, the thin muscle that helps us breathe, and check for any breaks. It can also provide information about the organs that have protruded or ‘herniated’.
Chest X-rays can diagnose Bochdalek hernias by looking for gas-filled bowel loops or a soft tissue mass above the diaphragm. However, chest X-rays are not very sensitive, meaning they can miss a hernia or mistake a hernia for another condition within the chest. Therefore, CT scans that provide images from different perspectives have become the industry standard for diagnosis. This type of CT scan is more sensitive, meaning it is more likely to correctly identify a hernia, and it can also detect associated birth defects. CT scans can more accurately check for defects in the diaphragm, and they have been found to be 78% sensitive for hernias on the left side and 50% sensitive for those on the right side.
Treatment Options for Bochdalek Hernia
A Bochdalek hernia, a condition where there’s a hole in the diaphragm, is treated with surgery. This can be done by either open surgery or by using laparoscopic techniques, which involve smaller incisions and a special camera to close the hole.
Before birth, routine check-ups to monitor for any complications are the usual approach. In cases where the herniation is severe, a procedure called Fetoscopic endoluminal tracheal occlusion (FETO) might be considered. This technique involves temporarily blocking the windpipe, which can help improve the development of the lungs according to early studies.
After birth, the focus shifts to managing any underdeveloped lung tissue. This could involve gentle ventilation, high-frequency oscillatory ventilation (a technique to deliver small, quick breaths), and extracorporeal membrane oxygenation (a machine outside the body to help with breathing).
Persistent pulmonary hypertension (PPH) can also occur due to this hernia, and is caused by mechanical pressure on the lungs during development. PPH is generally treated with inhalable nitric oxide (iNO), a gas that helps to open (dilate) blood vessels in the lungs, and sildenafil, a medication that also helps to widen blood vessels.
What else can Bochdalek Hernia be?
Babies in the womb can sometimes develop abnormalities in the diaphragm (the muscle that separates the chest and abdomen). The most common of these is called Bochdalek hernia. But there are other rare conditions that could also occur:
- Congenital diaphragmatic eventration: This is when the muscular part of the diaphragm doesn’t develop properly, causing a section of it to become thin.
- Diaphragmatic paralysis: This is when the diaphragm muscle stops working.
- Extralobar pulmonary sequestration: This condition is where a part of the lung develops with its own covering and separate blood supply, disconnected from the rest of the lung.
In adults, different issues can cause the diaphragm to become damaged, such as a rupture, resulting in what’s known as an acquired diaphragmatic hernia.
What to expect with Bochdalek Hernia
The overall survival rates for specific medical conditions can differ depending on the study source. Most broad-based studies suggest a mortality rate, or the number of deaths, between 42 to 68%. However, some studies that are specific to certain institutions suggest a survival rate of up to 90%.
This significant difference in survival rates is sometimes attributed to what’s called ‘hidden mortality.’ This term refers to the deaths that occur before arrival at the hospital or institution that reports these numbers.
Some research suggests that there’s an increase in patient survival rates overall. This improvement is believed to be due to advancements in critical care, which is the specialized care given to patients with life-threatening health conditions.
Possible Complications When Diagnosed with Bochdalek Hernia
For survivors of Bochdalek hernia and congenital diaphragmatic hernia, it’s common to experience symptoms related to the lungs and chronic lung disease. These can include conditions such as Pulmonary Hypertension (PPH) and inadequate lung growth, contributing to smaller and narrower lungs. This lack of normal lung growth could lead to breathing difficulties and increased dependency on oxygen, resulting in lung injuries from prolonged ventilator use or even conditions like bronchopulmonary dysplasia. Aside from these, patients may also suffer from reactive airway disease, reduced airflow, and repeated lung infections. On a brighter note, many of these patients tend to see improvements as they grow, with their lung functions nearing normal levels when they reach adulthood, although a small portion may still show some persistent issues based on lung function tests.
Aside from lung-related issues, cognitive and motor dysfunction, emotional or behavioral problems, and brain lesions like periventricular leukomalacia could also affect patients with congenital diaphragmatic hernia. Common gastrointestinal issues include GERD and failure to thrive, encountered by almost all and over half of the patients, respectively. Musculoskeletal irregularities such as chest wall deformities and scoliosis are also associated with congenital diaphragmatic hernia. Moreover, there’s a likelihood of hernia recurrence, with larger initial defects known to increase this risk. For patch repair surgeries, around 27-41% have seen hernia recurrence, while only 4-13% have observed a recurrence following primary repairs.
Common Symptoms for Survivors:
- Pulmonary Hypertension (PPH)
- Inadequate lung growth
- Requiring high levels of oxygen
- Ventilator-induced lung injuries
- Reactive airway disease
- Reduced airflow
- Recurrent lung infections
- Brain lesions such as periventricular leukomalacia
- Cognitive and motor dysfunction
- Emotional or behavioral problems
- GERD
- Failure to thrive
- Chest wall deformities
- Scoliosis
- Hernia recurrence
Preventing Bochdalek Hernia
Between 30 to 50% of individuals who are born with a diaphragmatic hernia (a hole in the muscle that separates the chest from the abdomen) can lead healthy, symptom-free lives without any limitations. Surprisingly, many adult survivors don’t show any symptoms and don’t need further treatment. Those who do show symptoms often get diagnosed at a young age, even before they are born in some cases, thanks to advancements in prenatal (before birth) screening.
It’s now possible to closely monitor these babies while they are still in the womb and ensure they are born in a specialized hospital capable of offering extra support if needed. It’s been identified that multiple health problems can occur alongside this condition, making long-term check-ups necessary as the number of survivors from diaphragmatic hernia grows.
Hence, it’s very important to teach these patients not only about the symptoms linked with diaphragmatic hernia and its repair, but also about the long-term effects it might have on their health. Discussing surgical treatments, expectations from those treatments, and potential associated chronic health conditions are crucial for patients and their families to make informed decisions about treatment and management.
