Congenital Diaphragmatic Hernias

Overview

Definition

• Abnormal connection between the abdominal and chest cavities through a diaphragmatic defect 
• Arises due to the pleuroperitoneal folds failing to fuse during embryonic development

Epidemiology

• Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: 1 in 10,000 live births
• No association with gender Gender Gender Dysphoria or ethnicity
• Most commonly sporadic Sporadic Selective IgA Deficiency with rare familial incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency
• Associated anomalies occur in about 30% of congenital diaphragmatic hernia Congenital Diaphragmatic Hernia Pediatric Chest Abnormalities (CDH) cases and include: 
  • Lesions of the central nervous system Central nervous system The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges. Nervous System: Anatomy, Structure, and Classification (CNS) and cardiovascular systems 
  • Omphalocele Omphalocele Omphalocele is a congenital anterior abdominal wall defect in which the intestines are covered by peritoneum and amniotic membranes. The condition results from the failure of the midgut to return to the abdominal cavity by 10 weeks’ gestation. Omphalocele
  • Esophageal atresia Atresia Hypoplastic Left Heart Syndrome (HLHS)
• Associated chromosomal syndromes include: 
  • Trisomies 13, 18, and 21 
  • Turner syndrome Turner syndrome Turner syndrome is a genetic condition affecting women, in which 1 X chromosome is partly or completely missing. The classic result is the karyotype 45,XO with a female phenotype. Turner syndrome is associated with decreased sex hormone levels and is the most common cause of primary amenorrhea. Turner Syndrome
• The majority of CDH are Bochdalek hernias (up to 90%). 
• Morgagni hernias account for only 2%–6% of cases.

Embryology

Multiple embryological mechanisms have been proposed:

• Failure of diaphragmatic structure fusion
  • The diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy is composed of 4 embryological structures:
    • 2 pleuroperitoneal membranes
    • Septum transversum
    • Muscular ingrowth from the body wall
  • Failure of these structures to fuse during the 4th to 10th weeks of gestation leaves residual openings that can become hernias.
• Premature Premature Childbirth before 37 weeks of pregnancy (259 days from the first day of the mother’s last menstrual period, or 245 days after fertilization). Necrotizing Enterocolitis involution and malrotation Malrotation Pediatric Gastrointestinal Abnormalities of the midgut Midgut Development of the Abdominal Organs
  • 6th week of gestation: The midgut Midgut Development of the Abdominal Organs grows rapidly, extending outside the embryo Embryo The entity of a developing mammal, generally from the cleavage of a zygote to the end of embryonic differentiation of basic structures. For the human embryo, this represents the first two months of intrauterine development preceding the stages of the fetus. Fertilization and First Week.
  • 9th week of gestation: Midgut Midgut Development of the Abdominal Organs twists and re-enters the embryo Embryo The entity of a developing mammal, generally from the cleavage of a zygote to the end of embryonic differentiation of basic structures. For the human embryo, this represents the first two months of intrauterine development preceding the stages of the fetus. Fertilization and First Week’s abdomen.
  • Premature Premature Childbirth before 37 weeks of pregnancy (259 days from the first day of the mother’s last menstrual period, or 245 days after fertilization). Necrotizing Enterocolitis re-entry or incorrect rotation Rotation Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. X-rays of the bowel → higher pressure in the abdominal cavity than the chest cavity → failure of the correct formation of the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy 
• Pulmonary hypoplasia Hypoplasia Hypoplastic Left Heart Syndrome (HLHS)
  • Failure of the lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy to develop appropriately → decreased pressure in the chest cavity
  • Causes a pressure differential that pushes on the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy
  • The diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy does not fuse appropriately.

Classification

• Bochdalek hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias: 
  • Constitutes 90% of congenital Congenital Chorioretinitis diaphragmatic hernias
  • Defect in the posterolateral portion of the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy
  • More commonly left-sided with some occurring bilaterally
• Morgagni hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias: 
  • Retrosternal resulting from failure of sternal and crural portions to meet
  • More commonly right-sided 
  • The majority of Morgagni hernias are asymptomatic and discovered incidentally on imaging.
• Hiatal hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias: through the esophageal hiatus Esophageal hiatus Diaphragm: Anatomy
• Paraesophageal hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias: area adjacent to esophageal hiatus Esophageal hiatus Diaphragm: Anatomy

Pathophysiology

Pathological effects of CDH are due to lung hypoplasia Hypoplasia Hypoplastic Left Heart Syndrome (HLHS):

• Lack of space and increased pressure inhibit lung maturation.
• Decreased bronchial and arterial pulmonary branching
  • Reduced surface area for gas exchange Gas exchange Human cells are primarily reliant on aerobic metabolism. The respiratory system is involved in pulmonary ventilation and external respiration, while the circulatory system is responsible for transport and internal respiration. Pulmonary ventilation (breathing) represents movement of air into and out of the lungs. External respiration, or gas exchange, is represented by the O2 and CO2 exchange between the lungs and the blood. Gas Exchange
  • Arterial smooth muscle hyperplasia Hyperplasia An increase in the number of cells in a tissue or organ without tumor formation. It differs from hypertrophy, which is an increase in bulk without an increase in the number of cells. Cellular Adaptation leading to pulmonary hypertension Pulmonary Hypertension Pulmonary hypertension (PH) or pulmonary arterial hypertension (PAH) is characterized by elevated pulmonary arterial pressure, which can lead to chronic progressive right heart failure. Pulmonary hypertension is grouped into 5 categories based on etiology, which include primary PAH, and PH due to cardiac disease, lung or hypoxic disease, chronic thromboembolic disease, and multifactorial or unclear etiologies. Pulmonary Hypertension

Clinical Presentation and Diagnosis

Prenatal diagnosis

• Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship may be diagnosed on routine screening Screening Preoperative Care prenatal ultrasound at 16–24 weeks’ gestation.
• Prenatal diagnosis allows for:
  • Family counseling
  • Possible fetal interventions
  • Postnatal planning including referral to a specialized center
• Prenatal ultrasound findings include: 
  • Lung-to-head ratio index (a number below one signifies severe CDH)
  • Gastric bubble or liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy in the thorax
  • Polyhydramnios Polyhydramnios Polyhydramnios is a pathological excess of amniotic fluid. Common causes of polyhydramnios include fetal anomalies, gestational diabetes, multiple gestations, and congenital infections. Patients are often asymptomatic but may present with dyspnea, extremity swelling, or abdominal distention. Polyhydramnios
  • Chest mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast with or without mediastinal shift

Early postnatal presentation

• Respiratory distress is the most common presenting sign.
  • Tachypnea Tachypnea Increased respiratory rate. Pulmonary Examination, grunting Grunting Physical Examination of the Newborn, cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination 
  • Can develop immediately or up to 2 days after birth
• Characteristic exam findings include:
  • General: craniofacial syndromic findings often noted before signs of CDH
  • Chest: 
    • Increased diameter (barrel chest)  and asymmetry Asymmetry Examination of the Upper Limbs
    • Decreased breath sounds ± bowel sounds ± displaced maximal cardiac impulse
  • Abdomen: scaphoid deformity Deformity Examination of the Upper Limbs
• Imaging:
  • To be performed to confirm CDH immediately postnatally
  • Chest X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests shows tip of the nasogastric tube Nasogastric tube Malnutrition in children in resource-limited countries in the chest.
  • Chest computed tomography Chest Computed Tomography Hemothorax (CT) scan may be used for further delineation of the defect.

Delayed presentation

• May present after the neonatal period
• Vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia with mild respiratory symptoms
• Sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock and shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock may occur due to incarceration Incarceration Inguinal Canal: Anatomy and Hernias of the bowel through the defect.
• May be a rare cause of sudden death in infants and toddlers

Management

Prenatal management

• Close monitoring
  • Monthly ultrasounds to assess fetal well-being and amniotic fluid Amniotic fluid A clear, yellowish liquid that envelopes the fetus inside the sac of amnion. In the first trimester, it is likely a transudate of maternal or fetal plasma. In the second trimester, amniotic fluid derives primarily from fetal lung and kidney. Cells or substances in this fluid can be removed for prenatal diagnostic tests (amniocentesis). Placenta, Umbilical Cord, and Amniotic Cavity levels
  • Weekly biophysical profiles in the 3rd trimester
• Amniotic fluid Amniotic fluid A clear, yellowish liquid that envelopes the fetus inside the sac of amnion. In the first trimester, it is likely a transudate of maternal or fetal plasma. In the second trimester, amniotic fluid derives primarily from fetal lung and kidney. Cells or substances in this fluid can be removed for prenatal diagnostic tests (amniocentesis). Placenta, Umbilical Cord, and Amniotic Cavity reduction
  • Reduced fetal ability to swallow amniotic fluid Amniotic fluid A clear, yellowish liquid that envelopes the fetus inside the sac of amnion. In the first trimester, it is likely a transudate of maternal or fetal plasma. In the second trimester, amniotic fluid derives primarily from fetal lung and kidney. Cells or substances in this fluid can be removed for prenatal diagnostic tests (amniocentesis). Placenta, Umbilical Cord, and Amniotic Cavity may lead to polyhydramnios Polyhydramnios Polyhydramnios is a pathological excess of amniotic fluid. Common causes of polyhydramnios include fetal anomalies, gestational diabetes, multiple gestations, and congenital infections. Patients are often asymptomatic but may present with dyspnea, extremity swelling, or abdominal distention. Polyhydramnios.
  • Amnioreduction Amnioreduction Polyhydramnios may be indicated.
• Fetal surgeries
  • Reserved for fetuses with a CDH with poor prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas
  • High rate of failure
  • 2 options:
    • Patch Patch Nonpalpable lesion > 1 cm in diameter Generalized and Localized Rashes closure of the diaphragmatic defect in utero
    • Fetal endoscopic tracheal occlusion (FETO)

Perinatal management

• Choice of timing and location of birth
  • As close to term as possible (> 39 weeks preferred)
  • In a medical center capable of extracorporeal membrane oxygenation (ECMO)
• Post-natal resuscitation Resuscitation The restoration to life or consciousness of one apparently dead. . Neonatal Respiratory Distress Syndrome:
  • Aggressive respiratory support with endotracheal intubation Intubation Peritonsillar Abscess
  • Avoidance of prolonged mask ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing due to increase in intestinal air with further respiratory compromise
  • High-frequency oscillatory ventilation High-Frequency Oscillatory Ventilation Neonatal Respiratory Distress Syndrome (HFOV), a low-pressure ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing mode, may be indicated to prevent lung injury.
  • ECMO may be used in children who fail to respond to conventional ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing and/or HFOV.
• Surgery:
  • Bochdalek hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias: surgical repair recommended 48 hours after stabilization
  • Asymptomatic Morgagni hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias: laparoscopic repair recommended due to risk of future strangulation Strangulation Inguinal Canal: Anatomy and Hernias
  • Paraesophageal hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias: Prompt repair is recommended.

Prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas

• Indicators of poor prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas include:
  • Associated major anomalies 
  • Presentation in 1st 24 hours of life
  • Severe lung hypoplasia Hypoplasia Hypoplastic Left Heart Syndrome (HLHS) 
  • Herniation Herniation Omphalocele to contralateral thorax
  • Need for ECMO
• Long-term morbidity Morbidity The proportion of patients with a particular disease during a given year per given unit of population. Measures of Health Status includes: 
  • Obstructive and/or restrictive pulmonary defects
  • Gastroesophageal reflux disease Gastroesophageal Reflux Disease Gastroesophageal reflux disease (GERD) occurs when the stomach acid frequently flows back into the esophagus. This backwash (acid reflux) can irritate the lining of the esophagus, causing symptoms such as retrosternal burning pain (heartburn). Gastroesophageal Reflux Disease (GERD) 
  • Delayed growth in the 1st 2 years of life
  • Neurocognitive deficits (especially in those receiving ECMO)

Differential Diagnosis

• Congenital Congenital Chorioretinitis pulmonary airway Airway ABCDE Assessment malformations ( CPAM CPAM Previously known as congenital cystic adenomatoid malformation (ccam): rare hamartomatous cystic and adenomatous lesions in the lung can occur in either side of the lung (unilobar or multilobar). If large enough, these lesions can lead to pulmonary hypoplasia and hydrops. Affected children can be asymptomatic at birth or can present with infections. Other risks include spontaneous pneumothorax and, rarely, malignancy. Management may involve resection before 1 year of age or close observation, depending on the size and other risk factors. Pulmonary Hypoplasia): rare congenital Congenital Chorioretinitis airway Airway ABCDE Assessment malformations, often cystic Cystic Fibrocystic Change in nature. These intrapulmonary structures prevent normal lung tissue expansion predisposing it to infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease and malignancy Malignancy Hemothorax. Like CDH, they can present with tachypnea Tachypnea Increased respiratory rate. Pulmonary Examination in a neonate Neonate An infant during the first 28 days after birth. Physical Examination of the Newborn.
• Eventration of the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy: failure of the muscle tissue to cover the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy during fetal development. This leaves only a thin fibrous Fibrous Fibrocystic Change layer which can then become elevated, protruding into the chest cavity. Eventration of the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy can present like CDH but without true communication Communication The exchange or transmission of ideas, attitudes, or beliefs between individuals or groups. Decision-making Capacity and Legal Competence between the abdominal and chest cavity.
• Oligohydramnios Oligohydramnios Oligohydramnios refers to amniotic fluid volume less than expected for the current gestational age. Oligohydramnios is diagnosed by ultrasound and defined as an amniotic fluid index (AFI) of ‰¤ 5 cm or a single deep pocket (SDP) of < 2 cm in the 2nd or 3rd trimester. Oligohydramnios: insufficient amniotic fluid Amniotic fluid A clear, yellowish liquid that envelopes the fetus inside the sac of amnion. In the first trimester, it is likely a transudate of maternal or fetal plasma. In the second trimester, amniotic fluid derives primarily from fetal lung and kidney. Cells or substances in this fluid can be removed for prenatal diagnostic tests (amniocentesis). Placenta, Umbilical Cord, and Amniotic Cavity due to low production (renal dysfunction) or chronic loss during pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care, leading to hypoplastic lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy. These patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with tachypnea Tachypnea Increased respiratory rate. Pulmonary Examination and cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination, as in CDH, but have no detectable masses in their chest cavity.