What are the key clinical pearls for the diagnosis and management of congenital and acquired diaphragmatic hernia?

Diaphragmatic Hernia: Key Clinical Pearls

Classification and Epidemiology

Diaphragmatic hernias are fundamentally divided into congenital (CDH) and acquired (ADH) types, with distinct anatomical patterns and clinical presentations that directly impact diagnostic and therapeutic approaches. 1

Congenital Diaphragmatic Hernia

• Bochdalek hernia accounts for 95% of all CDH cases and occurs predominantly on the posterior left side (85%) versus right side (15%) 1
• Adult CDH has an incidence of only 0.17%, typically presenting around age 40 years 1
• Right-sided CDH is particularly treacherous because the liver can mimic pleural effusion or pulmonary consolidation on imaging, leading to missed diagnoses 2
• CDH occurs in 1 in 2000-3000 newborns and is associated with variable degrees of pulmonary hypoplasia and persistent pulmonary hypertension 3

Acquired Diaphragmatic Hernia

• Traumatic diaphragmatic hernias are the most common ADH, affecting 1-5% of motor vehicle crash victims and 10-15% of penetrating lower chest injuries 1, 2
• Penetrating trauma accounts for approximately 65% of all traumatic diaphragmatic hernias but produces smaller defects than blunt trauma 2
• Overall diaphragmatic rupture occurs in 2.1% of blunt trauma and 3.5% of penetrating trauma cases 2

Hiatal Hernia Classification

• Type I (sliding): Most common (90%); gastroesophageal junction migrates above the diaphragm 1, 4
• Type II (paraesophageal): 10% of cases; gastric fundus herniates while gastroesophageal junction remains normal 1, 4
• Type III: Combined Type I and II with displaced gastroesophageal junction 1, 4
• Type IV: Large hernia accommodating stomach, colon, and spleen 1, 4

Critical Diagnostic Pitfalls

The diagnosis is frequently missed in acute settings because diaphragmatic hernia is rare, presents with nonspecific findings, and clinicians simply don't think of it. 1

Imaging Strategy

• CT of chest and abdomen is the diagnostic gold standard for evaluating complicated diaphragmatic hernia 2
• Chest radiograph or gastrointestinal contrast studies can confirm the diagnosis but are less sensitive 5
• Physical examination findings are unreliable: only 8 of 13 patients in one series had absent breath sounds or bowel sounds in the chest 5

Mandatory Cardiac Assessment

• Routine echocardiography is required in every CDH case to assess pulmonary hypertension severity and associated congenital heart disease 2
• Pulmonary hypertension coexists with CDH in approximately 63% of patients 2
• Mortality rises to 45% when pulmonary hypertension is present, making this assessment critical for prognostication 2

Life-Threatening Complications Requiring Immediate Recognition

Complicated diaphragmatic hernia can cause incarceration, perforation, or strangulation of herniated organs, respiratory failure from lung compression, or cardiac tamponade from heart compression. 1, 2

• Pulmonary hypoplasia and immaturity are the definitive limitations leading to high mortality rates in neonatal CDH 6
• Associated pulmonary hypertension and right-to-left shunt are common but rarely the primary cause of death 6

Neonatal CDH Management Algorithm

Immediate Resuscitation (Class I Recommendations)

• Immediate endotracheal intubation is mandated to keep peak inspiratory pressures low and avoid large tidal volumes 2
• Minimize peak inspiratory pressure and avoid large tidal volumes as the primary ventilation strategy 2

Escalation for Refractory Cases

• High-frequency oscillatory ventilation is reasonable when lung compliance is poor, tidal volumes are low, and gas exchange is inadequate (Class IIa) 2
• Inhaled nitric oxide may improve oxygenation in severe pulmonary hypertension but should be used cautiously if left ventricular dysfunction is suspected (Class IIa) 2
• ECMO is recommended for patients with severe pulmonary hypertension unresponsive to medical therapy (Class I) 2, 6

Surgical Decision Algorithm

All complicated diaphragmatic hernias require surgical repair; the approach depends entirely on hemodynamic stability. 2

For Hemodynamically Stable Patients

• Laparoscopic repair is preferred because it provides early detection of small diaphragmatic injuries and is associated with fewer postoperative complications 2
• Thoracoscopic approach is feasible for delayed CDH repair and appears easier than laparoscopy in selected cases 7, 8
• Primary diaphragm repair can be achieved in 92% of cases 5

For Unstable Patients or Specific Indications

• Open repair is indicated when:
  • Patient is hemodynamically unstable 2
  • Exploratory laparotomy is required 2
  • Laparoscopic expertise or equipment is lacking 2
  • Damage-control surgery is necessary 2

Mesh Reinforcement Strategy

• Biological and bio-absorbable meshes are preferred for reinforcement because they reduce recurrence rates 2
• Wide defects requiring patches may necessitate conversion to open repair 7

Critical Postoperative Complication

Severe gastric atony develops in 58% of survivors and is a major cause of morbidity, with 33% requiring further operative therapy. 5

• This complication makes transabdominal repair with simultaneous pyloroplasty and/or feeding jejunostomy the preferred operative approach in older children and adults 5
• Unlike newborns, CDH in older children and adults frequently occurs on the right side, rarely presents with severe respiratory distress, and is occasionally asymptomatic 5

Timing of Repair

Management strategy has shifted from immediate repair to delayed repair and stabilization, recognizing that CDH is more a physiological disease than a surgical disease 6

• Delayed repair allows for stabilization of pulmonary hypertension and optimization of respiratory status 6
• CDH survival approaches 90% at advanced centers using this delayed approach 6