What caused an elevated diaphragm in this woman with cough and dyspnea?

A 52-year-old woman presented to her primary care physician complaining of a nonproductive cough and dyspnea on exertion. These symptoms had a subacute onset over 4 weeks before her initial visit. She denied fever, sputum production, hemoptysis, chest pain, palpitations, abdominal pain, nausea, vomiting, and diarrhea. She did not have any known sick contacts.

Her past medical history was significant for obesity, hypertension, and recurrent bronchitis. Her surgical history was notable only for bilateral knee arthroscopies. Colonoscopy performed several months earlier was limited because of a redundant colon.

Her medications included lisinopril, 10 mg daily; a daily multivitamin; and a calcium supple- ment. She reported allergies to codeine and penicillin, both of which caused hives. Her family history was notable for breast cancer, lung cancer, and type 2 diabetes mellitus. She was a lifetime nonsmoker and reported rare alcohol consumption. She worked as a teacher and denied any occupational exposures. She was single and lived alone.

Physical examination revealed an afebrile, obese woman with normal heart rate, blood pressure, and respiratory rate. She was in no acute distress. Examination of the chest was notable for decreased breath sounds at the left lung base. She was referred for outpatient posteroanterior and lateral chest radiographs, which are shown below (Figure 1). 

Making the diagnosis

The patient's posteroanterior and lateral chest radiographs showed apparent marked elevation of the left hemidiaphragm with associated shift of the mediastinal structures to the right. Prominent bowel loops are identified in the area of apparent diaphragm elevation. The lungs were remarkable for a focal wedge-shaped opacity in the left perihilar region. There were no pleural effusions. Cardiac size was difficult to assess because of marked displacement and partial obscuration by the apparent diaphragmatic elevation.

The most striking radiographic finding was the apparent elevation of the left hemidiaphragm. In general, unilateral diaphragmatic elevation may occur secondary to conditions of the lung, intra-abdominal processes, disorders of or trauma to the nerves that control the diaphragm, or directly as a result of a diaphragmatic abnormality. For example, the diaphragm may be pulled upward by a primary pulmonary process causing loss of volume or decreased compliance, such as a lobectomy or pulmonary fibrosis. However, the diaphragm may be displaced superiorly by abdominal organ enlargement (such as splenomegaly or a distended stomach) or by intra-abdominal infectious or inflammatory processes (such as subphrenic or splenic abscess).

Paralysis of the diaphragm may result from a variety of conditions, most commonly, invasion of the phrenic nerve by lung cancer. Other causes of diaphragmatic paralysis include phrenic nerve injury, neuritis, CNS or spinal abnormalities, neural compression, and various neurological conditions. Focal eventration of the diaphragm, a muscular defect that causes weakness, also may cause unilateral elevation. Other conditions may mimic the appearance of an elevated hemidiaphragm, including a subpulmonic effusion or a diaphragmatic hernia.

Our patient had no definitive clinical or radiographic findings to elicit a clue to the cause of apparent diaphragmatic elevation, and a fluoroscopic study was initially recommended to assess for possible diaphragmatic paralysis. However, careful review of her radiological history revealed that previous CT colonography had demonstrated a left-sided diaphragmatic hernia, with displacement of omentum and 2 loops of colon into the thoracic cavity. Thus, the apparent elevation of the left hemidiaphragm on the radiograph was the result of a diaphragmatic hernia rather than a true diaphragmatic elevation.

The second major radiographic finding was the left perihilar opacity, which could have been caused by focal lung compression by the hernia and/or an infectious process, such as a postobstructive pneumonia. The patient was given a presumptive clinical diagnosis of community-acquired pneumonia and was treated with azithromycin. However, her symptoms did not improve and, on returning to her doctor, she was given levofloxacin, prednisone, and an albuterol inhaler for resistant pneumonia and concomitant exacerbation of presumed reactive airway disease.

Nonetheless, her dyspnea and cough continued to worsen, accompanied by new production of green sputum and intermittent fevers. She still denied hemoptysis, chest pain, palpitations, nausea, vomiting, abdominal pain, melena, and bright red blood from the rectum.

Because of the patient's worsening clinical course, she was referred for additional imaging with CT. A chest CT scan demonstrated the herniated abdominal contents in the left side of the chest, with adjacent atelectasis and necrotizing pneumonia in the left lung (Figure 2). Additional CT findings included a left upper lobe abscess and a loculated left-sided pleural effusion, which represented an empyema. She was admitted to the hospital for further workup and management.

On admission, the patient's vital signs showed a temperature of 38.4°C (101.1°F), pulse of 118 beats per minute, blood pressure of 154/93 mm Hg, respiration rate of 15 breaths per minute, and an oxygen saturation of 95% on room air. Physical examination demonstrated diminished breath sounds in the left lower lung field along with new left-sided scattered crackles and tachycardia, but findings were otherwise normal and unchanged from the patient's previous examination.

Laboratory testing was notable for a red blood cell count of 3640/µL; hematocrit of 29.7%; mean corpuscular volume of 82 fL; and white blood cell (WBC) count of 12,500/µL, with 74% neutrophils, 4% bands, and 18% lymphocytes. Chemistries were remarkable for normal levels of blood urea nitrogen (9 mg/dL) and creatinine (0.6 mg/dL).

Blood was drawn for cultures, and the patient was given vancomycin, levofloxacin, and clindamycin for broad coverage. She underwent CT-guided abscess drainage, which produced approximately 70 mL of purulent material that grew Streptococcus milleri in culture. Her antibiotic regimen was simplified to ceftriaxone, 2 g intravenously every 24 hours. She responded favorably to the drainage procedure and antibiotics, with declining fever and WBC count. All blood cultures were negative.

Her anemia was attributed to chronic inflammation. After her hematocrit level dropped to 23%, she was given a transfusion of 2 units of packed red blood cells. After transfusion, her hematocrit level remained stable.

A postprocedural CT scan of the chest demonstrated minimal abscess fluid, a virtually unchanged empyema, and the herniated abdominal contents. The hernia consisted of 2 loops of large bowel, including the splenic flexure and part of the descending colon, and omental fat, as well as the upper pole of the left kidney, a new finding suggesting either an enlarging hernia or shifting hernial contents. The CT scan also showed a posterior defect in the diaphragm of less than 10 cm, and a diaphragmatic hernia of the Bochdalek type was diagnosed. Urgent herniorrhaphy was deferred given the acute, purulent pleural infection and the possible need for a prosthetic repair.

Discussion

The Bochdalek hernia is most commonly encountered as a congeni- tal anomaly of the posterolateral diaphragm in children. As Wells¹ described in 1954, congenital Bochdalek hernias usually result from the failure of the pleuroperitoneal canals to close during the first trimester of gestation, before the twisting fetal intestines return from the yolk sac to the abdominal cavity.

Because this embryological defect in the pleuroperitoneal membrane allows for persistent communication between the pleural and peritoneal cavities, these congenital hernias typically present without a hernial sac. However, a small fraction of congenital Bochdalek hernias occur later in gestation because of poor muscular development around the foramen of Bochdalek; these hernias do possess a sac. Bochdalek hernias may occur on either or (rarely) both sides of the diaphragm, but they have a left-sided predominance, which is attributed to the greater size of the left pleuroperitoneal canal early in development,¹ as well as a presumed protective effect of the liver on the right, preventing herniation.²

There are other types of congenital diaphragmatic hernias.¹ The rarer congenital Morgagni hernia results from defects in the developing diaphragm anteromedially behind the sternum. Esophageal hiatus hernias, most frequently seen in association with gastroesophageal reflux in adults, may occur as a congenital anomaly of the diaphragm.

Regardless of type, larger congenital diaphragmatic defects may permit the herniated abdominal contents to compress nascent fetal lungs and compromise their development. Such hernias are typically detected by prenatal ultrasonography and tend to present acutely with life-threatening respiratory distress in the first days of life. Treatment of neonates with these hernias requires clinical stabilization to manage and prevent pulmonary complications, especially pulmonary hypertension, followed by surgical correction of the hernia.³

In contrast to the congenital diaphragmatic hernias that present in infants, adults are more likely to present with hernias of the diaphragm that are acquired secondarily. Most commonly, such hernias result from traumatic injury (blunt or penetrating) to the patient's chest or abdomen or from a postoperative complication of thoracoabdominal surgery, such as that for esophageal cancer.⁴ Other proposed causes of Bochdalek hernias acquired later in life include various activities or conditions that increase intra-abdominal pressure, such as pregnancy, labor, and delivery; exercise; sexual intercourse; sneezing; coughing; and consuming a large meal.⁵

Nevertheless, small Bochdalek (or Morgagni) hernias of congenital origin may evade early detection and persist asymptomatically for months to years until incidental diagnosis or symptomatic presentation,^2,6-8 as in our case. A large review of adults who were undergoing abdominal CT scanning identified incidental Bochdalek hernias in 0.17% of patients.⁹ Most of the hernias discovered in this adult population contained only abdominal fat or omentum, but about one quarter of these asymptomatic hernias involved solid or enteric organs, including the large intestine, stomach, liver, spleen, pancreas,and kidney.

Unlike neonates who present with respiratory distress, adults who have Bochdalek hernias are more likely to present with GI symptoms, such as abdominal pain, vomiting, and constipation, or with nonspecific chest pain.^2,7 Such complaints may be chronic and recurrent in some persons, but numerous case reports exist of adults with undetected diaphragmatic hernias who presented acutely with life-threatening GI complications, such as obstruction, strangulation, and rupture.^10-12

Adults may also present with respiratory complaints, such as chronic dyspnea and cough,^2,7 acute cough with fever,¹³ or acute cardiopulmonary compromise.^5,14,15 Recurrent respiratory infections are another clinical presentation of late-presenting diaphragmatic hernias, although this has been reported mostly among children presenting after infancy.⁷

Our patient had a history of recurring upper respiratory tract infections and was given a diagnosis of a complicated pneumonia. It is merely speculative that the patient's hernia may have contributed to her recurring respiratory infections. However, one might reasonably hypothesize that hernia-associated airway obstruction and atelectasis, suggested by her initial chest radiograph and confirmed by later imaging studies, could have caused reduced airway clearance and perhaps resulted in a postobstructive pneumonia. The presentation of an extensive ipsilateral pneumonia with abscess and multiloculated empyema, without resolution after standard regimens of adequate antibiotics, in an otherwise healthy middle-aged woman, clinically supports the presence of an anatomic abnormality.

Physical examination of patients with Bochdalek hernias may demonstrate diminished breath sounds at the lung base and, depending on the anatomy of the hernia, bowel sounds in the thorax. Most commonly, small Bochdalek hernias present radiographically as a focal bulge in the posterior left hemidiaphragm contour and are thus readily distinguishable from true diaphragmatic elevation, in which the entire diaphragm contour is elevated. However, in cases (such as in this patient) in which the hernia is large, the radiographic appearance may mimic an elevated diaphragm.

Definitive diagnosis is established by cross-sectional imaging with CT or MRI, which can clearly identify the diaphragmatic defect and involved abdominal structures as well as associated complications, such as volvulus, bowel strangulation, or pulmonary infection. Multiplanar images in the coronal and sagittal planes help characterize the precise location and extent of the herniation.

Small, incidental diaphragmatic hernias in adults may be managed expectantly and monitored with symptom assessment and serial cross-sectional imaging. However, surgery is the definitive treatment for symptomatic, and especially complicated, diaphragmatic hernias in adults. In general, corrective surgery entails reduction of abdominal structures followed by repair of the defective diaphragm, either through an open abdominal or thoracic incision or by using minimally invasive techniques, such as laparoscopy¹⁶ or thoracoscopy.¹⁷Outcome in this case

The patient was discharged afebrile without leukocytosis on a regimen of intravenous ceftriaxone, which was switched to oral levofloxacin and clindamycin (500 mg and 450 mg daily, respectively) because of the development of a pruritic rash while she was taking ceftriaxone. Her skin symptoms quickly resolved, and antibiotic treatment continued for a total of 19 weeks with resolution of the empyema and without diarrhea or other complications. The patient subsequently underwent surgical correction of her diaphragmatic hernia using a polytetrafluoroethylene prosthesis through a left thoracotomy. Surgical exploration demonstrated a large hernial sac containing stomach, transverse colon, and omentum herniating through a left-sided posterolateral diaphragmatic defect, consistent with a congenital Bochdalek hernia. Her postoperative course was unremarkable, notable only for a transient, small ipsilateral pneumothorax.

References:

REFERENCES

1. Wells LJ. Development of the human diaphragm and pleural sacs. Contrib Embryol. 1954;35:109-134.2. Kirkland JA. Congenital posterolateral diaphragmatic hernia in the adult. Br J Surg. 1959; 47:16-22.3. Frenckner B, Ehren H, Granholm T, et al. Improved results in patients who have congenital diaphragmatic hernia using preoperative stabilization, extracorporeal membrane oxygenation, and delayed surgery. J Pediatr Surg. 1997;32: 1185-1189.4. Eren S, Kantarci M, Okur A. Imaging of diaphragmatic rupture after trauma. Clin Radiol. 2006;61:467-477.5. Salacin S, Alper B, Cekin N, Gulmen MK. Bochdalek hernia in adulthood: a review and an autopsy case report. J Forensic Sci. 1994;39: 1112-1116.6. Sugg WL, Roper CL, Carlsson E. Incarcerated Bochdalek hernias in the adult. Ann Surg. 1964;160:847-851.7. Osebold WR, Soper RT. Congenital posterolateral diaphragmatic hernia past infancy. Am J Surg. 1976;131:748-754.8. Mei-Zahav M, Solomon M, Trachsel D, Langer JC. Bochdalek diaphragmatic hernia: not only a neonatal disease. Arch Dis Child. 2003;88:532-535.9. Mullins ME, Stein J, Saini SS, Mueller PR. Prevalence of incidental Bochdalek's hernia in a large adult population. AJR. 2001;177:363-366.10. Hines GL, Romero C. Congenital diaphragmatic hernia in the adult. Int Surg. 1983;68: 349-351.11. Sinha M, Gibbons P, Kennedy SC, Matthews HR. Colopleural fistula due to strangulated Bochdalek hernia in an adult. Thorax. 1989;44:762-763.12. Karanikas ID, Dendrinos SS, Liakakos TD, Koufopoulos IP. Complications of congenital posterolateral diaphragmatic hernia in the adult. Report of two cases and literature review. J Cardiovasc Surg (Torino). 1994;35:555-558. 13. Perhoniemi V, Helminen J, Luosto R. Posterolateral diaphragmatic hernia in adults--acute symptoms, diagnosis and treatment. Case report. Scand J Thorac Cardiovasc Surg. 1992;26:225-227.14. Kanazawa A, Yoshioka Y, Inoi O, et al. Acute respiratory failure caused by an incarcerated right-sided adult Bochdalek hernia: report of a case. Surg Today. 2002;32:812-815.15. Dalton AM, Hodgson RS, Crossley C. Bochdalek hernia masquerading as a tension pneumothorax. Emerg Med J. 2004;21:393-394.16. Frantzides CT, Carlson MA, Pappas C, Gatsoulis N. Laparoscopic repair of a congenital diaphragmatic hernia in an adult. J Laparoendosc Adv Surg Tech A. 2000;10:287-290.17. Yamaguchi M, Kuwano H, Hashizume M, et al. Thoracoscopic treatment of Bochdalek hernia in the adult: report of a case. Ann Thorac Cardiovasc Surg. 2002;8:106-108.