Introduction:
Let us break down the definition of this condition. A hernia happens when an organ bulges through an opening or weak spot when originally it should be confined to its anatomic space or boundary. The diaphragm is a dome-shaped muscle that serves as a partition between the chest and abdominal cavities. It separates the heart and lungs in the chest from the abdominal organs, namely the stomach, intestines, liver, and spleen. Hence anterior diaphragmatic hernia essentially means there exists a defect positioned anteriorly in the diaphragm through which one or more of the abdominal organs push into the chest. They can occur on the right or left side of the sternum. About 80-90% of Morgagni hernias occur on the right side.
How Common Is Anterior Diaphragmatic Hernia?
Of the four types of diaphragmatic hernias, namely hiatal hernia, paraesophageal hernia, Bochdalek hernia, and Morgagni hernia, the latter is the rarest, accounting for only 2–3% of diaphragmatic hernia cases. It was first described in 1769 by Morgagni and observed in the anterior diaphragm behind the sternum. It occurs in children and adults.
What Causes an Anterior Diaphragmatic Hernia?
A Morgagni hernia is caused by a congenital abnormality. Diaphragm development is complete by the ninth week of pregnancy. Failure of fusion of the costochondral arches' pars tendinalis and pars sternalis on the right side leads to a diaphragm defect through which abdominal viscera protrude into the thoracic cavity.
An anterior diaphragmatic hernia can also develop as a result of physical trauma such as car accidents, falls, and so on, or penetrating injuries such as stab or gunshot wounds. Another possibility is that the diaphragm was accidentally damaged during abdominal or thoracic surgery. It can occur alone or in conjunction with other chromosomal abnormalities like Edward's syndrome, trisomy 13, Pallister-Killian syndrome, Down's syndrome, and so on, as well as congenital deformities including spina bifida, heart problems, skeletal defects, and so on.
What Are the Signs and Symptoms of Anterior Diaphragmatic Hernia?
About 50% of the individuals with this condition remain asymptomatic; such individuals are diagnosed during tests for an unrelated condition. When symptomatic, they present with problems relating to the respiratory and gastrointestinal systems.
Common symptoms in children include:
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Tachypnoea - increased breath rate.
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Recurrent pulmonary infections.
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Unsatisfactory feeding.
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Coughing and sometimes choking on feeding.
Symptoms in adults may be precipitated by conditions involving increased intra-abdominal pressure like obesity, pregnancy, chronic cough, constipation, etc. Adults may experience the following:
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Chest pain that is relieved on standing.
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Difficulty in breathing.
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Flatulence.
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Indigestion.
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Abdominal pain and vomiting.
How Is a Diagnosis for Anterior Diaphragmatic Hernia Made?
The clinical examination may reveal bowel sounds in the chest, reduced or absent breath sounds on one side of the chest on auscultation, cyanosis (bluish skin discoloration), and other symptoms. Among the investigations carried out are:
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X-ray: Anteroposterior and lateral views of the chest are assessed using an X-ray. Bowel herniation manifests as a radiolucent shadow surrounding the heart region, and in such circumstances, an x-ray is generally adequate to confirm the diagnosis. When solid organs or the omentum herniate, a rounded radiopacity appears at the right cardio-phrenic angle. Further investigations, such as a CT scan, are required in some cases to provide a final diagnosis.
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Ultrasound Scan: When the herniated organ is filled with fluid rather than air, an ultrasound scan is extremely effective. A discontinuity in the linear diaphragmatic echos on sonogram may indicate abdominal contents in the chest. Hypoechoic tissue is herniated fluid-filled intestinal tissue. In comparison to the liver, a herniated omentum may be hypoechoic, isoechoic, or hyperechoic.
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CT Scan: This guarantees that the defect is correctly diagnosed. If the omentum is herniated, it looks as a dense retrosternal mass of fat.
A prenatal diagnosis of Morgagni hernia is also possible with ultrasonography. The diaphragm appears as an echo-less space in between the chest and abdominal cavity on an ultrasound scan; parts of the bowel or liver in the chest can be appreciated in the presence of a defect.
Some of the conditions that bear a close resemblance radiographically to anterior abdominal hernia include a pericardial cyst, loculated pneumothorax, or hiatal hernia when the bowel is herniated. In the case of herniation of solid organs, differential diagnoses include pneumonia, atelectasis, bronchial carcinoma, intrathoracic lipoma, etc.
Most hernias of Morgagni are diagnosed late, well into adulthood, since individuals either remain asymptomatic or present with vague symptoms.
What Are the Possible Complications of Anterior Diaphragmatic Hernia?
Morgagni hernia is not a medical emergency, but immediate surgical intervention is required in cases of strangulation. Blood supply to the herniated organ ceases in case of strangulation, which may be life-threatening. A strangulated hernia is characterized by rebound tenderness, repeated vomiting, and blood in the rectus. Immediate repair of the hernia defect is important.
Incarceration may be another complication of a long-standing hernia where the herniated organ fails to return to its original position, meaning it is no longer reducible.
Necrosis of the herniated organ can occur. Bowel obstruction is another complication that can result from an unrepaired hernia.
What Are the Treatment Options for Anterior Diaphragmatic Hernia?
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Surgery is the choice of treatment. However, it is advised, even in asymptomatic patients, to avoid complications like incarceration or strangulation.
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Conventional surgery may be performed to reduce the hernia. Two different approaches; an incision may be taken on the abdomen, or the hernia may be approached from the thoracic cavity.
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The thoracic approach provides the advantages of a better vision of right-sided defects and a safer reduction of abdominal viscera. However, since there’s no visibility of the left side, a bilateral defect might be missed.
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The abdominal approach utilizes an open laparotomy incision on the upper abdominal region. If the defect is large, a patch may be placed and sutured to close the incision.
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The hernia may be repaired laparoscopically. This is minimally invasive and is associated with faster healing and an earlier return to normal activities.
What Is the Disease Outcome of Anterior Diaphragmatic Hernia?
The prognosis for anterior diaphragmatic hernia is good, with low recurrence rates. Symptoms are relieved after surgery. Low birth weight or prematurity, as well as the presence of additional chromosomal abnormalities, are risk factors for mortality in defects discovered during infancy. The disease's overall prognosis is favorable, with full recovery following hernia repair.
Conclusion
Anterior diaphragmatic hernia, or Morgagni’s hernia, is a rare, congenital defect in the diaphragm. It might not manifest symptoms until adulthood; however, some individuals might experience respiratory and gastrointestinal symptoms. With timely medical help, one can easily avoid complications. Chest radiographs and sometimes CT scans or ultrasound scans are required for diagnosis. Awareness of this condition can help avail treatment at the right time.
