A Novel Complication of Bariatric Surgery

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The incidence of obesity in the US is increasing. This has been associated with an increasing incidence and prevalence of diabetes, hypertension, and obstructive sleep apnea. Diet alone has generally been ineffective in attaining significant weight loss. Bariatric surgery is associated with significant weight loss and improvement in diabetes, hypertension, and obstructive sleep apnea. In this article we describe an unusual complication of bariatric surgery.

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Approximately two-thirds of the population of the US is overweight. About half of these are considered as obese.1 Being overweight is defined as having a body mass index (BMI) ≥25. Obesity is defined as a BMI ≥30.1,2 Five percent of the US population is morbidly obese: 23 million people in the US have a BMI of 35 or higher, and 8 million have a BMI of 40 or higher.1–4 The prevalence of obesity is also growing, with an associated increase in the prevalence of type 2 diabetes, hyperlipidemia, hypertension, obstructive sleep apnea, and coronary artery disease.1,5,6

Diet therapy alone has generally been unsuccessful in the treatment of obesity.1,7–9 Bariatric surgery can lead to effective weight loss in morbidly obese patients.1 However, like any other invasive procedure, bariatric surgery can lead to complications (see Table 1). In this article we describe an unusual complication involving the cardiovascular system in a patient who underwent bariatric surgery.

Case Study

A 48-year-old female underwent gastric bypass surgery in May 2003 for morbid obesity. She lost nearly 200lb in weight. Revision of surgery with wound hernia repair was performed in July 2004. Approximately two months later the patient developed left upper quadrant (LUQ) discomfort. This improved somewhat after the patient was started on lansoprazole. The patient, however, continued to develop a progressive feeling of fatigue and could not lie on her left side secondary to LUQ and left lower rib cage discomfort. On the day of admission the patient felt sudden onset of pressure-like discomfort behind the sternum. This was associated with diaphoresis. Her medical history was significant for her gastric bypass surgery and diabetes that resolved after the bypass surgery.

On presentation her temperature was 36.6ºC, her pulse was 90bpm, and her blood pressure was 102/62mmHg. There was no evidence of pulses paradox and the jugular venous pulse was barely visible just above the clavicle. Her white cell count (WBC) was 11,900 on admission. Electrocardiogram (ECG) showed low voltages with diffuse 0.5mm ST segment elevation with upward concavity.

A computed tomography (CT) scan in the emergency department demonstrated a 6.4x11.7cm hypodense fluid collection with irregular enhancing walls and septations in the left subdiaphragmatic space anteriorly. This produced a mass effect upon the liver. Delayed imaging demonstrated that there was no filling of this lesion with contrast. A moderate pericardial effusion was noted (see Figures 1 and 2).

The echocardiogram revealed a circumferential pericardial effusion (0.9cm posteriorly and 0.7cm anteriorly). There was no echocardiographic evidence of pericardial tamponade (e.g. no significant right ventricular diastolic collapse or variation in mitral valve inflow velocity was observed). The inferior vena cava was, however, dilated.

The patient’s condition rapidly deteriorated and she became hypotensive (systolic blood pressure of 70mmHg), tachycardic (pulse >120), and acidotic. Her WBC rose to 22,000. Pericardiocentesis was performed at this point. Thick yellow pus was obtained when the peri-cardiocentesis needle was 2–3cm under the skin just lateral to the xiphoid process. A guidewire was advanced into this space. The guidewire could not be advanced above the diaphragm and curled up under the diaphragm, suggesting that this cavity was a sub-diaphragmatic abscess. An 8F pigtail catheter was advanced into this space, and 700cc of pus was drained (see Figure 3). The patient’s clinical condition and hemodynamics improved dramatically. An echocardiogram demonstrated almost complete resolution of the pericardial effusion. A follow-up CT scan demonstrated nearly complete resolution of the sub-diaphragmatic fluid collection as well as the pericardial effusion.

Gram-positive cocci were demonstrated on Gram staining. The patient was treated with intravenous vancomycin and cefepime. Culture reports showed the responsible organism to be Streptococcus viridans. The patient’s WBC improved to 8,000 on day four. She was asymptomatic, and was discharged home on day five. Six months later she is doing well and is asymptomatic.


Bariatric surgery can result in a mean excess weight loss of 61.2% (58.1–64.4%).1 A prospective controlled study demonstrated that after two years weight increased by 0.1% in conventionally treated obese patients, but decreased by 23.4% in surgically treated patients (p<0.001). After 10 years, weight increased by 1.6% in conventionally treated patients, but decreased by 16% in surgically treated patients (p<0.001).7 Surgically treated patients had a lower energy intake and were physically more active. Resolution of diabetes and hypertension was higher in surgically treated patients. Surgery also lowered the incidence of diabetes.7

Bariatric surgery has been reported to result in complete resolution or improvement of diabetes in 86% of patients. Hypertension resolved or improved in 78.5% of the patients, while obstructive sleep apnea improved or resolved in 83.6% of patients.1 Bariatric surgery is generally very effective in achieving significant weight loss in morbidly obese patients and results in a significant decrease in the incidence of diseases such as diabetes, hypertension, and obstructive sleep apnea. The operative mortality (≤30 days) has been reported to be in the range of 0.1–1.1%.1

Our case demonstrates a rare complication of bariatric surgery presenting as purulent pericardial effusion with the patient in toxic shock. The sub-diaphragmatic abscess most likely ruptured into the pericardial cavity on the day of presentation.

We recommend that an echocardiogram or other imaging studies be performed in any patient with abscess in or near the thoracic cavity to exclude the involvement of the pericardium. Quick drainage of the abscess results in a dramatic improvement of the clinical condition. We also recommend that when such cavities are drained, a repeat echocardiogram should be performed before attempts are made to drain the pericardial fluid. In case of a communication between the two spaces, a pericardial effusion may completely resolve with the drainage of the primary abscess. Attempts to perform pericardiocentesis when the pericardial fluid may have resolved can lead to disastrous consequences.


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