Postnephrectomy diaphragmatic hernia presenting as progressive dyspnoea

Abstract

The diagnosis of diaphragmatic hernia (DH) in adults is rare and may be due to missed congenital DH or acquired DH from trauma or as a postoperative complication of certain thoracic and abdominal surgeries. We present a case of a patient with well-controlled chronic obstructive pulmonary disease who presented to the hospital with progressive dyspnoea, 6 months after laparoscopic nephrectomy. The patient was initially misdiagnosed and treated for empyema after plain radiographic images were reported as consolidation with gas locules. Multislice CT imaging undertaken before diagnostic thoracocentesis confirmed the presence of a right-sided DH, which was subsequently surgically repaired in the outpatient setting, given her haemodynamic stability. As patients with DH usually present in the emergency setting, requiring urgent inpatient surgical repair, there are currently no guidelines on the method and urgency of management of asymptomatic or mildly symptomatic, stable patients. Furthermore, while plain radiography is the usual first-line imaging modality used, misdiagnosis of DH as pleural effusion or empyema can lead to unnecessary and potentially harmful procedures such as diagnostic thoracocentesis. These risks can potentially be minimised with early utilisation of multislice CT imaging in patients with high clinical suspicion.

Background

Iatrogenic diaphragmatic hernias (DHs) in adults following surgery are rare and likely underdiagnosed.¹ Unless patients present with fulminant symptoms such as bowel obstruction or marked respiratory distress, they may simply be left undiagnosed for years or misdiagnosed as pneumonia or other respiratory conditions.² When these patients do eventually present to the hospital, plain chest radiographic appearances may resemble consolidation or complicated pleural effusion.³ Diagnostic thoracentesis, based on the finding of a ‘possible pleural effusion’ on chest radiograph alone, might lead to serious complications. A high degree of clinical suspicion and scrutiny of the surgical history and operative note is necessary to identify patients at risk, with further cross-sectional imaging recommended prior to diagnostic thoracocentesis. Furthermore, there is no consensus on the urgency for surgical repair of these hernias following identification in patients with mild or absent symptoms.⁴

Case presentation

A 73-year-old woman with a normally unlimited exercise tolerance presented with an 8-week history of progressive, exertional dyspnoea, 6 months after undergoing a right laparoscopic nephrectomy for a non-functioning, chronically obstructed right kidney. She denied having any fever, cough or chest pain and had no problems of abdominal pain or other gastrointestinal (GI) symptoms. Her medical history included well-controlled chronic obstructive pulmonary disease, invasive ductal carcinoma of the breast (treated with a right mastectomy and axillary node clearance) and a right-sided nephrectomy. At the time of writing, she is a current smoker, with a 5–10 pack-year smoking history.

A year prior, she presented with several months’ history of upper abdominal pain, weight loss and loss of appetite. Following the investigation, first under the general surgeons and subsequently the urologists, she was found to have a chronically obstructed right kidney with associated perinephric abscess. She was initially treated with antibiotics and urinary diversion in the form of a percutaneous nephrostomy, which was followed by elective right laparoscopic nephrectomy in light of poor renal function, 6 months prior to presenting. The operation was complicated by an intraoperative pneumothorax secondary to a small hole in the pleura, which was closed with a V-lock suture. The patient was observed in the hospital for a few days with serial chest radiographs to ensure there was no postoperative pneumothorax. Following discharge, she was reviewed in the urology clinic 6 weeks later without any complications and was subsequently discharged from the clinic.

On examination, all observations were unremarkable, with a respiratory rate of 17, oxygen saturation of 95% on room air and she was afebrile. There was markedly reduced air entry over the right mid zones and lower zones, though there were no crepitations or wheeze. The right lung base was dull to percussion. Abdominal examination was unremarkable with a soft, non-distended and non-tender abdomen, with normal bowel sounds.

Investigations

All blood tests including inflammatory markers were unremarkable. The chest radiograph was reported as showing dense opacification in the right mid/lower zone with consolidation containing locules of gas, features that appear to be the result of right basal pneumonia with possible empyema (figure 1).

Figure 1.

Chest radiograph on admission reported as right middle/lower zone consolidation containing locules of gas, suggestive of right basal pneumonia with possible empyema.

Subsequently, this woman was admitted under the respiratory team and initiated on antibiotics for a presumed community-acquired pneumonia with a likely parapneumonic effusion or empyema. A diagnostic thoracocentesis under ultrasound guidance was requested as well as a contrast-enhanced CT thorax and abdomen.

Fortuitously, the CT scan was undertaken prior to thoracocentesis and showed a large right-sided DH, with the right colon, the entirety of the small bowel and its associated mesentery lying within the chest, having herniated through the right renal bed (figure 2). There was no evidence of bowel obstruction. Moreover, a suspicious focal pulmonary nodule was noted within the superior lingular segment of the left upper lobe of the lung. This was an incidental finding. The diagnostic thoracocentesis was promptly cancelled.

Figure 2.

Multislice CT thorax and abdomen with contrast demonstrating right-sided diaphragmatic hernia with herniation of small and large bowel.

Differential diagnosis

The initial working diagnosis was a right basal community-acquired pneumonia with associated parapneumonic effusion or empyema. This was mainly based on progressive dyspnoea, examination findings consistent with consolidation and the radiological findings suggesting consolidation and effusion with gas locules, attributable to gas-forming organisms seen with empyema. While this was the most likely diagnosis at the time of presentation, the absence of fever, cough or other infective signs and the more subacute time course were inconsistent with this diagnosis, in addition to the unremarkable inflammatory markers.

Treatment

Given the CT findings, antibiotic therapy was ceased and the thoracocentesis was cancelled. An urgent surgical opinion was sought and because the patient was stable with no signs of obstruction, she was discharged with outpatient upper-GI surgical follow-up for further management. She was also referred to the lung nodule multidisciplinary team (MDT) for discussion in light of the incidental nodule on the contralateral lung.

Outcome and follow-up

The outcome of the lung nodule MDT was for a surgical biopsy of the lung nodule and consideration for lung resection, though only after the DH repair. Thereafter, this woman attended an upper-GI surgical clinic and underwent an elective laparoscopic repair of the DH 5 weeks after the initial presentation, with no complications to date (figure 3). She subsequently improved remarkably from a symptomatic point of view and her shuttle walk test was 260 m with no significant desaturation at the follow-up clinic. She was seen by the cardiothoracic surgeons who arranged a CT-guided biopsy and are planning to undertake a left upper lobectomy, which she is awaiting, following discussion at the high-risk MDT.

Figure 3.

Repeat CT thorax and abdomen with contrast 1 month following laparoscopic repair of the diaphragmatic hernia.

Discussion

Adult-onset DH can either be due to missed congenital DHs or acquired. Acquired DHs are rare, with an overall incidence of <5%. They can be secondary to trauma or iatrogenic, following thoracoabdominal surgery.¹ Though iatrogenic DH is a rare postoperative complication, the surgeries most commonly implicated include liver transplant surgery, transthoracic hiatus hernia repair, oesophagogastrectomy or radiofrequency ablation of liver tumours.⁵ In a comprehensive literature review, we have found only 12 cases of DH postnephrectomy, the majority of these, unlike our case, being left-sided, possibly due to the protective physical barrier of the liver.⁶

Symptoms described include nausea and vomiting, chest pain, abdominal pain, dyspepsia, dyspnoea and occasionally, intestinal obstruction, with the onset of symptoms varying from immediately postsurgery to 6 years postsurgery.⁶ Due to the possible latent nature of the presentation, the missed diagnosis of acquired DH with resultant obstruction, ischaemia and perforation of the bowels can have life-threatening consequences.

With regards to the optimal imaging modality, it is reported in previous case reports that plain radiography is the preferred initial imaging, with the presence of visceral gas with or without hydro-aerial level visualised in the thorax being pathognomonic for DH.⁷ As with our case, this approach may result in some cases being initially misdiagnosed as complex pleural effusions or hydropneumothorax, with dangerous consequences should a diagnostic or therapeutic thoracentesis be undertaken without further investigation. Such was the case in one report in which the ultrasound misidentified an acquired DH as a thick pleural effusion at the time of thoracentesis.³

In our view, multislice CT imaging is the most effective technique for imaging patients with a high clinical suspicion of acquired DH. This is due to its accessibility, short duration and ability to identify concomitant pathologies including rib fractures, hydropneumothorax, abdominal injuries and degree of bowel compromise if any.⁷ Plain chest radiograph will not show a typical Ellis S-shaped curve that you see with pleural effusion.

Moreover, in our case, our patient was overall haemodynamically stable with an oxygen saturation of >94%, with only progressive dyspnoea as the major presenting problem despite the size of the herniation, adding to the rarity of our case. A literature review revealed only two cases of relatively asymptomatic DH, both of which were missed congenital DH.⁴ Based on previous case studies, acquired DH almost always presents with severe symptoms and haemodynamically unstable presentation, needing emergency intervention. The intervention of choice is a surgical reduction, either via a thoracic or an abdominal approach that can either be minimally invasive or open.² For stable, relatively asymptomatic patients like ours, there is no consensus on the urgency of a surgical repair. Her case was discussed with the MDT comprising radiologists, chest physicians, thoracic and upper-GI surgeons. Given the fact that she had a high Brock score incidental lung nodule on the opposite lung, which warranted prompt investigation, we opted to do her DH repair as a matter of urgency, around 5 weeks post presentation. This was to optimise lung function for further investigation of her lung nodule, with a view to ultimately undertake lung resection.

As acquired DH is a rare presentation, prognosis and recurrence rate postrepair remain unknown.

Learning points.

• Iatrogenic postoperative diaphragmatic hernias (DHs) are rare but likely underdiagnosed in patients with minimal or absent symptoms.

• Plain chest radiography should be promptly followed by multislice CT imaging scan if DH is suspected.

• Awareness of postoperative causes of dyspnoea might help with the differentials. A robust surgical history and scrutiny of operation notes are vital.

• Most patients present late, haemodynamically unstable and emergency surgical repair is usually necessary. There is no consensus on the management of stable DH.