- © 2007 Canadian Medical Association or its licensors
The case: A 28-year-old woman, previously healthy, came to our emergency department after 2 days of progressive left-sided chest pain. The onset had been sudden, in the midst of her doing a few abdominal crunches. She described the pain as sharp, nonradiating and pleuritic. Physical examination found her to be afebrile, with stable vital signs and no evidence of respiratory distress. Faint crackles could, however, be heard on the left side of her chest.
Two hours after her arrival, the patient developed fever and worsening chest pain. Re-examination revealed decreased air entry into the left lobes of the lung. Chest radiography showed a 7.5-cm mass arising from her left posterior mediastinum (Fig. 1). This later progressed to a large left-pleural effusion (Fig. 2); upon thoracentesis, it was found to be empyematous.
CT scans revealed a left-sided, posterior, heterogeneous, multicystic mass with punctate areas of calcification (Fig. 3). Via angiography, the blood vessels feeding it were identified as branches of the inferior phrenic and left gastric arteries; drainage was via both the systemic and portal venous systems. The patient was admitted to hospital and administered ciprofloxacin and clindamycin intravenously. A chest tube was inserted into her left pleural space. After consultation about exploration and mass excision, our thoracic surgery service recommended surgical management. Forty-eight hours before the operation, the vessels feeding the mass were embolized with angiographic guidance.
A multicystic extralobar sequestration was uncovered and resected from the left lower lobe of her lung. This mass was found to be perforated; when manipulated, it exuded pus. The patient's postoperative recovery was uneventful; she was discharged within 2 weeks of hospital admission.
Described is a case of empyema secondary to rupture of a pulmonary sequestration induced by abdominal crunch exercises. A rare congenital malformation, the incidence of these pulmonary “cysts” has been reported1 as being about 1.5–17 per thousand population — an underestimate, given that they are usually asymptomatic. A pulmonary sequestration (also called a bronchopulmonary sequestration) is a segment of lower-respiratory-tract parenchyma that is nonfunctional, with no communication with the rest of the tracheobronchial tree. Its arterial supply derives from the systemic vasculature of the developing embryo. Pulmonary sequestration may arise in the womb from traction of the lung bud by migrating abdominal organs, from caudal migration of a tracheobronchial bud along with its blood supply, or from accessory lung buds.2
Pulmonary sequestrations are classified as intralobar or extralobar, with a respective relative prevalence of 6:1 (Table 1).3 They have several clinical manifestations, which may appear at any age. They may be discovered during prenatal ultrasound; upon investigation of postnatal respiratory distress, recurrent pneumonia and bronchitis, or hemoptysis; and incidentally in radiologic findings, even when asymptomatic. Cases of empyema, hemothorax and pneumohemoperitoneum resulting from cystic rupture have also been described.2
Cyst wall degeneration and subsequent rupture has been associated with activities that cause a physiologic increase in intra-abdominal pressure.4 Hepatic cyst rupture with fatal complications has been described in conjunction with physiologic activities such as coughing episodes.3 A variety of exercises and manoeuvres have been shown to increase intra-abdominal pressures from an at-rest range of 1–6 mm Hg (Table 2);5 abdominal crunch–type exercises, for example, can increase them to 130 mm Hg.6 Because diaphragm elevation transmits these high pressures to the thorax and the intrapleural cavity, similar sequelae in the thorax are not surprising.
We hypothesize that the increase in intra-abdominal pressure with abdominal crunch exercises caused the rupture of our patient's pulmonary sequestration and her subsequent empyema. When evaluating patients with intra-abdominal or -thoracic cyst ruptures, clinicians should enquire about activities that may raise intracompartmental pressures.
Patients with ruptured cysts are best managed surgically, with perioperative antibiotic therapy. Intralobar sequestration is corrected by lobectomy rather than by segmental resection, although extralobar sequestrations can be completely removed without disturbing the remaining lobes. Despite the risks of intraoperative exsanguination from anomalous vasculature, rates of complications, illness and death are low if the resection is done before infections have become recurrent. The postoperative prognosis is uniformly good. Patients with incidentally discovered cysts that are asymptomatic should be warned away from activities that can raise intrathoracic pressure.
Competing interests: None declared.