Bochdalek Hernia Causing Sigmoid Colon Strangulation in an Elderly Patient

Abstract

Diaphragmatic hernia with bowel strangulation is a fatal condition requiring a prompt diagnosis. Bochdalek hernia is a common type of diaphragmatic hernia that rarely but occasionally occurs in adults. We herein report a case of Bochdalek hernia causing sigmoid colon strangulation in an elderly patient whose condition was initially misdiagnosed as empyema. The early diagnosis of strangulated bowel stemming from diaphragmatic hernia can be challenging because of its rarity and the nonspecificity of its symptoms. However, tracing the mesenteric arteries on computed tomography can enable a quick diagnosis.

Introduction

Diaphragmatic hernia is a congenital condition in which abdominal organs prolapse into the thorax cavity through a hole in the diaphragm (1). Diaphragmatic hernia is classified variously in terms of its embryology, etiology, pathologic anatomy, defect site in the diaphragm, presence of a sac, and hernia contents. However, it is sometimes difficult or impossible to classify the condition in strictly clinical terms.

From a practical standpoint, diaphragmatic hernia may be divided into traumatic and nontraumatic types. Nontraumatic diaphragmatic hernia may be further subclassified into a congenital or acquired subtype (2). Adult-onset, nontraumatic diaphragmatic hernia (i.e., diaphragmatic hernia without a history of trauma or surgery) is rare and accounts for 0.17-6% of all cases of diaphragmatic hernia but can lead to serious complications, such as bowel obstruction (3,4). Risk factors for diaphragmatic hernia in adults include pregnancy, trauma, obesity, chronic constipation, chronic cough, a low body mass index, and sarcopenia (5-7).

Bochdalek hernia is the most common form of diaphragmatic hernia. The foramen of Bochdalek is a defect in the posterior costal part of the diaphragm and occurs on the left side in 80% of cases (1). Most cases of Bochdalek hernia in adults are asymptomatic and are found incidentally (8). Furthermore, even when adult-onset Bochdalek hernia is symptomatic, its diagnosis can be challenging or delayed because the symptoms of bowel incarceration or strangulation are nonspecific (9). These symptoms may be gastrointestinal (nausea, vomiting, abdominal pain, and rarely, hematochezia) or respiratory (cough, expectoration, dyspnea, and pleural effusion) (10,11). Among respiratory symptoms, unilateral pleural effusion in particular can potentially mislead clinicians, prompting them to suspect a pulmonary infection.

We herein report a case of Bochdalek hernia of the sigmoid colon in an elderly patient causing fatal sigmoid colon strangulation that was initially misdiagnosed and treated as an empyema.

Case Report

An 83-year-old man presented to the emergency department with a 1-day history of abdominal pain, anorexia, and bloody stool. His medical history was significant for Parkinson's disease with chronic constipation and posterolateral fusion for a spinal compression fracture. He had immobility and was almost completely bedridden. He had no history of recent trauma or thoracoabdominal surgery.

A physical examination revealed a body temperature 37.5°C (99.5°F), blood pressure 112/81 mmHg, pulse rate 82/min, and respiration rate 20/min. Oxygen saturation showed a mild decrease to 93% on ambient air. His body mass index was 17. A lung examination revealed decreased breath sounds over the left lung. An abdominal examination revealed diffuse tenderness, especially in the left upper abdomen. A rectal examination revealed reddish-brown stool. Laboratory tests found an elevated white blood cell count at 10.8 (normal 3.3-8.6) ×10⁹/L, normal hemoglobin levels at 13.8 (normal range: 13.0-16.6) g/dL, and elevated C-reactive protein levels at 3.65 (normal range: 0.00-0.14) mg/dL. A venous blood gas test demonstrated mild metabolic acidosis with a pH of 7.31 and an elevated serum lactate level of 5.1 (normal range: 0.26-1.39) mmol/L.

Chest X-ray demonstrated consolidation in the left lower lung and left pleural effusion with lung compression (Fig. 1A). Chest and abdominal contrast-enhanced computed tomography (CT) revealed left pleural effusion and atelectasis (Fig. 1B, C). The Hounsfield unit (HU) density of the left pleural effusion was 20. There was no ascites or obvious cause of hematochezia in the abdomen. Left pleural puncture produced bloody and cloudy pleural fluid, which a biochemical analysis found to contain elevated polymorphonuclear leukocytes at 5,813/μL, a pleural total protein-to-serum total protein ratio of 1.2, and pleural lactate dehydrogenase (LDH) and serum LDH at 1.6, indicating exudative pleural effusion. Based on these findings, parapneumonic effusion or empyema was initially diagnosed.

Figure 1.

(A) Chest X-ray showing consolidation in the left lower lung field and left pleural effusion with lung compression. (B, C) Contrast-enhanced computed tomography demonstrating left pleural effusion and atelectasis.

The patient was admitted for chest tube placement (Fig. 2) and intravenous broad-spectrum antimicrobial administration. However, his condition and symptoms deteriorated, requiring a radiological consultation. CT findings on admission (Fig. 3) demonstrated that the sigmoid arteries, which are branches of the inferior mesenteric artery (IMA), ascended and passed into the left thoracic cavity through the posterior left diaphragm before spreading radially into the left thoracic cavity. The presence of gases from the herniated sigmoid colon in the left thoracic cavity was consistent with Bochdalek hernia, and strangulated sigmoid caused by Bochdalek hernia was finally diagnosed.

Figure 2.

Chest X-ray after insertion of a chest tube showing discharge of the left pleural effusion and remaining opacity in the left lower lung field.

Figure 3.

(A) Contrast-enhanced CT of the arterial phase demonstrating the sigmoid artery (yellow arrows) branching from the inferior mesenteric artery (IMA) (yellow circle) and passing upward through a defect consistent with the foramen of Bochdalek before spreading radially into the thoracic cavity. Gases from the herniated sigmoid colon can also be seen in the thoracic cavity (yellow asterisks). The superior rectal artery, a branch of the IMA, can be seen descending caudally (white arrows). (B) Volume rendering image reconstruction CT demonstrating the IMA branches in blue. The IMA originates in the aorta (yellow circle) and branches off into the sigmoid arteries (yellow arrows) and superior rectal arteries (white arrows). The sigmoid arteries subsequently spread radially (pink circle) just after passing upward through the level of the diaphragm, indicating sigmoid colon strangulation in the thoracic cavity.

Although surgery was recommended, the patient declined this option and elected for conservative treatment and palliative care. After discussion with the patient, only palliative care and antimicrobial therapy were continued. The strangulated sigmoid colon became perforated, and the patient died on hospital day 22. No autopsy was performed.

Discussion

Strangulated bowel obstruction occurs as a complication in 18% of cases of diaphragmatic hernia (10). Because the mortality rate associated with strangulated diaphragmatic hernia is as high as 30% (12,13), a prompt diagnosis and intervention are crucial. However, 38% of cases are incorrectly diagnosed, partially owing to a lack of awareness about this condition (14). The present case was initially misdiagnosed as a pulmonary or chest cavity infection based on the presence of left pleural effusion; the fluid was actually induced by bowel strangulation related to Bochdalek hernia. Correctly interpreting the CT findings by tracing the branches of the mesenteric arteries was the key to the correct diagnosis.

In cases of small bowel obstruction in the abdominal cavity, the presence of ascites is a warning signal suggesting the possibility of strangulation or necrosis. However, clinicians should realize that, in cases of diaphragmatic hernia, exudative fluids can accumulate in the thoracic cavity rather than the abdominal cavity. Pleural effusion in strangulated diaphragmatic hernia usually demonstrates an exudative pattern with polymorphonuclear dominance, as in the present case (15), which can mislead clinicians into suspecting a pulmonary infection. Lung compression in diaphragmatic hernia caused by herniated organs can induce respiratory symptoms, including dyspnea, chest pain, and cough (16), and respiratory symptoms may be preceded by gastrointestinal symptoms in 17% of Bochdalek hernia cases (10). Recognizing the combination of abdominal symptoms and unilateral chest radiographic abnormalities is key to diagnosing this condition. The present patient had only a mild decrease in oxygen saturation as a respiratory symptom.

CT is the gold standard for the radiographic diagnosis of diaphragmatic hernias. However, in the present case, recognition of the strangulated diaphragmatic hernia was delayed because the strangulation reduced the contrast enhancement effect of the intestinal wall and made it difficult to recognize the prolapsed intestine in the thoracic cavity. Furthermore, the filling of the prolapsed intestine with sequestered fluid created a “gas-less” appearance, which hampered recognition of the herniated intestine. In the present case, tracing the branches of the inferior mesenteric arteries was useful for visualizing the course of the intestinal tract and making the correct diagnosis. An accurate understanding of the configuration of the mesenteric arteries on CT is important to achieve during the preoperative evaluation, as it can help identify intestinal herniation, although our patient declined the operation.

Sigmoid colon involvement in Bochdalek hernia is extremely rare. A study of 109 cases of adult Bochdalek hernia reported stomach, small bowel, and colon involvement in 39%, 28%, and 33% of Bochdalek hernia cases, respectively, with almost all cases involving the colon being hernias of the transverse colon (10). To our knowledge, only one case report of Bochdalek hernia of the sigmoid colon exists (17). In the present case, it was hypothesized that the chronic constipation caused by Parkinson's disease and the patient's long sigmoid colon were predisposing factors for hernia of the sigmoid colon. Chronic constipation can increase abdominal pressure, with a stool mass in the sigmoid colon serving as the lead point. Furthermore, the sigmoid colon is known to lengthen with age (18); a long sigmoid colon tends to easily elevate and become a risk factor for sigmoid colon volvulus (19,20).

Conclusion

Bowel strangulation in diaphragmatic hernia can be fatal, but a prompt diagnosis may be challenging because of the rarity of the condition and the nonspecificity of the symptoms. Strangulated Bochdalek hernia should be included in the differential diagnosis of patients with both gastrointestinal and respiratory symptoms or left-sided pleural effusion. Pleural effusion in strangulated Bochdalek hernia is usually left-sided and demonstrates an exudative pattern with polymorphonuclear dominance, which can mimic empyema. CT is the gold standard for a radiological diagnosis, and tracing the branches of the mesenteric arteries can be useful for correctly identifying organs that have prolapsed into the left thoracic cavity.

Consent to publish the details of the case was obtained from the patient.

The authors state that they have no Conflict of Interest (COI).