Bilateral Bochdalek Hernia: Definition and Clinical Significance
A bilateral Bochdalek hernia is an extremely rare congenital condition where posterolateral diaphragmatic defects occur on both sides of the diaphragm, allowing abdominal organs to herniate into both thoracic cavities, which can cause severe respiratory compromise and life-threatening complications.
Anatomical Definition
Bochdalek hernia represents the most common type of congenital diaphragmatic hernia (95% of all CDH cases), resulting from incomplete fusion of the posterolateral diaphragmatic foramina during the eighth week of gestation 1, 2
The defect typically occurs unilaterally on the left posterior side of the diaphragm (85% left-sided versus 15% right-sided) 1
Bilateral Bochdalek hernias are exceptionally rare, with only 4 documented cases in the elderly population as of 2011, making this a highly unusual presentation 3
Pathophysiology and Clinical Impact
The bilateral defects allow abdominal contents (including stomach, colon, small bowel, spleen, and even liver lobes) to herniate into both thoracic cavities, severely limiting lung expansion bilaterally 4, 3
This bilateral herniation causes profound ventilatory dysfunction by compressing lung tissue on both sides, which can precipitate acute respiratory failure requiring mechanical ventilation 3
The condition may remain clinically silent for decades, with adult presentation occurring at an average age of 40 years, though cases have been documented in patients as old as 88 years 1, 3
Associated Abnormalities
Bilateral Bochdalek hernias can occur in association with other congenital malformations, including Arnold-Chiari I malformation, myelomeningocele, and other neural tube defects 5
Additional anatomical variants may include accessory hepatic lobes, intestinal malrotation, and redundant colon segments 4
Clinical Presentation Spectrum
In adults, bilateral Bochdalek hernias can progress insidiously over years, with severe thoracic cavity invasion eventually causing acute decompensation and respiratory failure 3
Symptomatic presentations include epigastric pain, abdominal tenderness, gastrointestinal dysfunction, complete mechanical bowel obstruction from incarcerated organs, and severe pulmonary disease 4, 6
Life-threatening complications include organ incarceration, perforation, strangulation, cardiac tamponade from cardiac compression, and acute respiratory failure 1, 3
Diagnostic Considerations
The diagnosis is frequently missed or delayed due to the condition's extreme rarity, nonspecific clinical findings, and lack of clinical suspicion in the acute setting 1
The bilateral nature makes this condition substantially more morbid than unilateral presentations, as compensatory lung function from the contralateral side is eliminated 3