September 2018 Pulmonary Case of the Month: Lung Cysts

Lewis J. Wesselius, MD

Department of Pulmonary Medicine

Mayo Clinic Arizona

Scottsdale, AZ USA

Pulmonary Case of the Month CME Information

Completion of an evaluation form is required to receive credit and a link is provided on the last page of the activity. 

0.50 AMA PRA Category 1 Credit(s)™

Estimated time to complete this activity: 0.50 hours

Lead Author(s): Lewis J. Wesselius, MD. All Faculty, CME Planning Committee Members, and the CME Office Reviewers have disclosed that they do not have any relevant financial relationships with commercial interests that would constitute a conflict of interest concerning this CME activity.

Learning Objectives: As a result of completing this activity, participants will be better able to:

1. Interpret and identify clinical practices supported by the highest quality available evidence.
2. Establish the optimal evaluation leading to a correct diagnosis for patients with pulmonary, critical care and sleep disorders.
3. Translate the most current clinical information into the delivery of high quality care for patients.
4. Integrate new treatment options for patients with pulmonary, critical care and sleep related disorders.

Learning Format: Case-based, interactive online course, including mandatory assessment questions (number of questions varies by case). Please also read the Technical Requirements.

CME Sponsor: The University of Arizona College of Medicine-Tucson

Current Approval Period: January 1, 2017-December 31, 2018

Financial Support Received: None

History of Present Illness

A 67-year-old woman was referred for mild shortness of breath for several years, but worse since January 2018.  She has dyspnea on exertion after 1 block. An outside chest x-ray, electrocardiogram and echocardiogram are reported as normal. She was begun on prednisone at 40 mg/day and her symptoms improved. However, her symptoms worsened when the dose tapered to 5 mg/day. She gained 35 pounds while on the prednisone and tried a steroid inhaler therapy without benefit. She is still dyspneic after 1 block of exertion.

Past Medical History, Social History, Family History

• Her past medical history was only positive for gastroesophageal reflux for which she takes ranitidine and hypertension for which she takes lisinopril.
• She was a life-long nonsmoker.
• There was no occupational history, hot tub or bird exposures.
• Family history is noncontributory.

Physical Examination

• Her SpO2 was 94% on room air.
• Chest:  few crackles noted at right base.
• Cardiovascular: regular rate and rhythm without a murmur.
• Extremities: no edema or clubbing.

Which of the following should be done at this time? (Click on the correct answer to be directed to the second of eight pages)

1. Measure her SpO2 after exercise
2. Reassure the patient the patient that she has hysterical dyspnea
3. Pulmonary function testing
4. 1 and 3
5. All of the above

Cite as: Wesselius LJ. September 2018 pulmonary case of the month: lung cysts. Southwest J Pulm Crit Care. 2018;17(3):85-92. doi: https://doi.org/10.13175/swjpcc101-18 PDF 

Infected Chylothorax: A Case Report and Review

Louis Eubank¹, Luke Gabe¹, Monica Kraft¹, and Dean Billheimer²

¹Departments of Medicine and Biostatistics, College of Medicine

²Department of Biostatistics, College of Public Health

University of Arizona Health Sciences Center

Tucson, AZ USA

Abstract

Infected chylothorax is a rare complication of a rare pathology with limited literature entirely consisting of case reports, meeting abstracts, and letters to the editor. The case of a 56-year-old male with a spontaneous infected chylothorax successfully treated and discharged to home without any residual effects is described. A systematic review of the literature revealed 11 prior cases of infected chylothoraces. Their etiologies (when known), initial pleural fluid values, and treatment are described. These cases show that while infected chylothorax has a varied presentation and affects a broad range of patients, conservative management including antibiotics, pleural fluid drainage, and symptomatic relief is a safe and appropriate starting point.

Introduction

Chylothorax, a pleural effusion caused by chyle accumulation from obstruction or disruption of the thoracic duct (please see SWJPCC’s Image of the week: chylothorax for an image of non-infected chyle fluid), is a rare condition that may arise from a diversity of etiologies broadly categorized as traumatic or non-traumatic/spontaneous (1). Traumatic causes commonly include iatrogenic injury and chest trauma, although insults as minor as sneezing, light exercise and emesis have been reported (1-3). Non-traumatic chylothorax has been linked to several immunologic and infectious etiologies (1). Regardless of the underlying mechanism, chyle has classically been considered inherently bacteriostatic (1). We present a case of spontaneous infected chylothorax and the first review of infected chylothoraces reported in the literature.

Case Report

A 56-year-old man with alcoholic cirrhosis and remote right-sided hepatic hydrothorax presented to the emergency department complaining of shortness of breath. Patient reported slowly worsening dyspnea over the last six weeks without any other symptoms that had acutely worsened on morning of presentation

Initial vital signs were temperature 38.0°C, heart rate 115, blood pressure 81/60mmHg, and respiratory rate 30 breaths/min on 4L O₂ by nasal cannula; labs significant for white blood cell count of 3100/mm³ and lactate 5.0 mmol/L (normal <2.0 mmol/L).  Physical exam demonstrated a fatigued patient with accessory muscle use on inspiration and absent breath sounds at the left lung base. Computed tomography (CT) study of the chest showed a large free-flowing left-sided pleural effusion (Figure 1A&B) as well as subacute rib fractures (Image 1C).

Figure 1. Thoracic CT on the day of presentation. Panel A: Axial view showing pleural effusion. Panel B: Sagittal view showing pleural effusion. Panel C: Coronal view showing rib fractures (white arrows).

Chart review demonstrated an emergency department visit five months previously for a fall with acute left-sided rib fractures and minimal left-sided pleural effusion.

Thoracentesis removed two liters free-flowing, brown, milky, purulent fluid; analysis significant for 58,880 total nucleated cells (32,800 RBCs), 94% neutrophils, glucose <5, LDH 573 IU/dL (serum 193 IU/dL), triglycerides 191 mg/dL, albumin 1.8 g/dL (serum albumin 2.6 g/dL, laboratory lower limit of normal 3.4 g/dL).

The patient remained hypotensive despite fluid boluses, tachypneic with increasing oxygen requirements, and a repeat lactate was 6.4 mmol/L. Norepinephrine and broad-spectrum antibiotics were started and patient was admitted to the intensive care unit.

Pleural fluid and blood cultures grew Escherichia coli resistant to fluoroquinolones. Chest x-ray showed persistent pleural effusion; a chest tube was placed which drained an additional 1.6 L over the following 24 hrs. The patient subsequently improved: serum lactate normalized within 24 hours, vasopressors were weaned within 36 hours, and supplemental oxygen was discontinued within 72 hours.

Chest tube output decreased to less than 200 ml/day within 48 hours of placement; however, repeat thoracic CT demonstrated a persistent multi-loculated left pleural effusion. Surgical evacuation and pleurodesis were considered given the lack of literature regarding intrapleural lytic therapy in infected chylothorax (a single case report described use of streptokinase in a persistent non-infected chylothorax, 1).  However, the patient’s operative risk was considered prohibitively high. He was managed conservatively with a fat-free diet to reduce chyle leak.

Eleven days after initial presentation fluid studies were significant for triglyceride 45mg/dL with negative cultures. Given that a pleural fluid triglyceride level <50mg/dL yields a less than 5% likelihood of being chylous and the clinical stability of the patient, the chylothorax was felt to be resolved (1). The patient was discharged to home twelve days after initial presentation.

The etiology of patient’s infected chylothorax was never fully elucidated. The most likely explanation is the trauma causing rib fractures also caused a traumatic chylothorax that later became infected. The thoracic duct lies alongside the vertebrae until it drains into the left brachiocephalic vein (Figure 2).

Figure 2. Thoracic duct anatomy (black arrows).

A blow to the posterior left thorax sufficient to fracture multiple ribs is more than sufficient to damage the nearby thoracic duct (1-4).  Arguing against this is most patients with large traumatic chylothoraces present within 10 days of injury (1,2).

Another explanation is the patient developed bacterial empyema secondary to hepatic hydrothorax (ascites that has passed through diaphragm from the peritoneal cavity) followed by non-traumatic chylothorax. These empyemas can demonstrate an indolent course and Escherichia coli is one of the most common causative pathogens isolated (1). Arguing against this is the patient’s previous hepatic hydrothorax was right-sided.

Finally, the chylothorax may have arisen from one of the many known causative medical pathologies (2). Chylous ascites secondary to cirrhosis that migrates into the pleural space via diaphragmatic leaks defects is a known phenomenon, albeit extremely rare (2).

In follow-up two months after discharge the patient had total resolution of respiratory symptoms and no recurrence of the effusion.

Systematic Review

Methods

A MEDLINE search (PubMed) from January 1975 to January 2018 and a Google Scholar search (all years) was conducted to identify eligible studies using the following terms: “Infected Chylothorax” (all fields) OR “Infection AND Chylothorax” (all fields) OR “Chylothorax AND Empyema” (all fields) OR “Chylous Empyema” (all fields). The inclusion criteria for studies were patients with infected non-traumatic chylothorax. A triglyceride level > 110 mg/dL or the presence of chylomicrons in pleural fluid was used to confirm the diagnosis of chylothorax; pleural fluid culture speciation was used to confirm the infection. The exclusion criteria were a lack of laboratory data and duplicate data. Two reviewers (LE, LG) independently reviewed the titles, abstracts, and, when necessary, the full text regarding the inclusion/exclusion criteria. Data extraction was performed independently by two reviewers (LE, LG) using data extraction forms defined beforehand. Discrepancies were resolved by consensus discussion with a third reviewer (MK).

Results

Eight case reports, two published abstracts, and one letter to the editor met the inclusion criteria; all eleven were included in the analysis (Figure 3, 13-23). 

Figure 3. Flow diagram of the literature review.

The general characteristics, demographics, and etiology of infected chylothorax are summarized in Table 1, the initial pleural fluid values are reported in Table 2.

Table 1. Population data.

Table 2. Initial pleural fluid values.

There were 11 patients total: six males and five females; age range 5 days-78 years, mean age 40.5 years (standard deviation 28.5 years). One patient was pharmacologically immunosuppressed while others had chronic diseases known to reduce immune system function including diabetes, excessive alcohol intake, and obesity (24-26). Four (36%) were iatrogenic. Three patients (27%) were infected with Streptococcus viridans and five (45%) were infected with Streptococcus genus. In those with available data, three of ten patients (30%) required intravenous vasopressors. No patients required ventilator management for their chylothorax (two patients were already intubated, one for acute respiratory distress syndrome, the other for unstable hemodynamics secondary to large subarachnoid hemorrhage). Two patients (18%) were managed surgically – one was specifically noted to have failed conservative management (17). Of the known outcomes, eight of nine (89%) survived to discharge and all eight remained asymptomatic at follow-up. The mean follow-up duration was 13.3 months (range 6-24 months).

Discussion

Given the paucity of published experience regarding infected chylothoraces, we believe a descriptive summary is warranted. First, there is a large variation in patient characteristics, including age range, immune competence, comorbid medical conditions, and infectious organism (eight different bacterial species and one parasite).

Second, many of the reviewed cases had a more benign presentation than might be anticipated in the context of a large, infected intrathoracic fluid collection.  Seven of the patients (73%) were hemodynamically stable on presentation and the majority of these patients had very mild chief complaints.

Third, the available data suggest a surprisingly good prognosis considering a previously estimated morality of 10-25% in non-infected chylothoraces, depending on etiology (27). The one patient who did not survive to discharge died due to brain herniation. Those with documented outpatient follow-up were asymptomatic up to 16 months post-discharge. 

Fourth, conservative management was frequently efficacious. Eight patients (73%) were medically managed without complication and did not require extensive antibiotic duration, intrapleural lytic therapy, or surgical intervention. The decision to pursue surgical intervention is not well defined given the very limited number of cases requiring surgical management. A brief discussion of non-infected chylothoraces and their management is therefore warranted.

Non-infected chylothorax is universally described as a rare event, although its exact incidence has not been described. Chylous ascites, which sometimes shares pathogenesis with chylothorax and is one of the causes of spontaneous chylothorax, has an occurrence of one in 20,000 hospital admissions (12). Trauma accounts for approximately 50% of chylothoraces, with esophagectomy being the most common iatrogenic cause (28). Thirty percent are due to malignancy; lymphoma accounts for 70-75% of malignant cases (11). While there are no consensus guidelines on how to treat chylothoraces, many authors agree that first line treatment is conservative management with thoracentesis or chest tube drainage, fat free or medium chain triglyceride diet, and consideration of somatostatin or octreotide (1,5,11,27-29). Although somatostatin or octreotide are used at many institutions, data regarding indications & efficacy of these medications are limited and/or inconsistent – some institutions use these medications at the beginning of treatment, others only if/when initial management has failed (5,27).

Additional treatments may depend on the etiology of the chylothorax: it is suggested that earlier surgical intervention in iatrogenic traumatic chylothoraces, especially post-esophagectomy, may be beneficial (30). Conservative management is likely to fail and surgical intervention is recommended in the following situations: 1) daily drainage greater than 1000 mL chyle (adults) or greater than 100mL chyle/kg body weight (children); 2) chyle leak that persists for more than 14 days; 3) unchanged chest tube output for 7-14 days; 4) clinical deterioration (27,28).

Conservative management for infected chylothoraces appears efficacious in our small sample size with the obvious modification of treating the infection. Most antibiotics adequately penetrate the pleural space, although aminoglycosides should be avoided as they appear to be inactivated by the low pH and relative anaerobic conditions (31).

Limitations

The limitation of this systematic review was the inclusion of only case reports, abstracts, and letters to the editor and the small sample size. Unfortunately, given the rarity of infected chylothoraces, studies with sufficient sample size are unlikely to be available.

Conclusion

Infected chylothorax is a rare complication of an already rare pathology. Our case report and literature review show that it can affect any age group, can be caused by several different organisms, and has a variable presentation. Our data suggests that an initial conservative management strategy in infected chylothoraces can be a safe and effective option.

References

1. McGrath E, Blades Z, Anderson P. Chylothorax: aetiology, diagnosis and therapeutic options. Respir Med. 2010;104:1-8. [CrossRef] [PubMed]
2. García-Tirado J, Landa-Oviedo HS, Suazo-Guevara I. Spontaneous bilateral chylothorax caused by a sneeze: an unusual entitiy with good prognosis. Arch Bronconeumol. 2017 Jan;53(1):32-3. [CrossRef]
3. Torrejais JC, Rau CB, de Barros JA, Torrejais MM. Spontaneous chylothorax associated with light physical activity. J Bras Pneumol. 2006 Nov-Dec;32(6):599-602. [CrossRef] [PubMed]
4. Rodrigues AL, Romaneli MT, Ramos CD, Fraga AM, Pereira RM, Appenzeller S, Marini R, Tresoldi AT. Bilateral spontaneous chylothorax after severe vomiting in children. Rev Paul Pediatr. 2016 Dec;34(4):518-521. [PubMed]
5. Bender B, Murthy V, Chamberlain RS. The changing management of chylothorax in the modern era. Eur J Cardiothorac Surg. 2016 Jan;49(1):18-24. [CrossRef] [PubMed]
6. Verma SK, Karmakar S. Hodgkin's lymphoma presenting as chylothorax. Lung India. 2014 Apr-Jun; 31(2):184-6. [CrossRef] [PubMed]
7. Kuan YC, How SH, Ng TH, Abdul Rani MF. Intrapleural streptokinase for the treatment of chylothorax. Respir Care. 2011 Dec;56(12):1953-5. [CrossRef] [PubMed]
8. Nair SK, Petko M, Hayward M. Aetiology and management of chylothorax in adults. Eur J Cardiothorac Surg. 2007 Aug;32(2):362-9. [CrossRef] [PubMed]
9. Pillay TG, Singh B. A review of traumatic chylothorax. Injury. 2016 Mar;47(3):545-50. [CrossRef] [PubMed]
10. Tu CY, Chen CH. Spontaneous bacterial empyema. Curr Opin Pulm Med. 2012 Jul;18(4):355-8. [CrossRef] [PubMed]
11. Skouras V, Kalomenidis I. Chylothorax: diagnostic approach. Curr Opin Pulm Med. 2010 Jul;16(4):387-93. [CrossRef] [PubMed]
12. Tsauo J, Shin JH, Han K, Yoon HK, Ko GY, Ko HK, Gwon DI.Transjugular intrahepatic portosystemic shunt for the treatment of chylothorax and chylous ascites in cirrhosis: a case report and systemic review of the literature. J Vasc Interv Radiol. 2016 Jan;27(1):112-6. [CrossRef] [PubMed]
13. Bensoussan AL, Braun P, Guttman FM. Bilateral spontaneous chylothorax of the newborn. Arch Surg. 1975 Oct;110(10):1243-5. [CrossRef] [PubMed]
14. Asnis DS, Saltzman HP, Iakovou C, Byrns DJ. Anaerobic empyema and chylothorax. Inf Dis Clin Pract. 1994;3(5):368-70. [CrossRef]
15. Natrajan S, Hadeli O, Quan SF. Infected spontaneous chylothorax. Diagn Microbiol Infect Dis. 1998 Jan;30(1):31-2. [CrossRef] [PubMed]
16. Guarracino JF, Murruni A; Basílico H, Villasboas RM, Halabe K, Barroso S, Demirdjian G. Chylothorax: Unusual complication presented in a burned child with an inflation injury under the effects of mechanical ventilation (Originial title Quilotórax: Complicación pocofrecuente en un ni-o quemado en asistencia respiratoria mecánica por síndrome inhalatorio). Revista Argentina de Burns 2000:15 (1). Available at: http://www.medbc.com/meditline/review/raq/vol_15/num_1/text/vol15n1p30.htm  (accessed 8/24/18).
17. Wang JT, Hsueh PR, Sheng WH, Chang SC, Luh KT. Infected chylothorax caused by Streptococcus agalactiae: a case report. J Formos Med Assoc. 2000 Oct;99(10):783-4. [PubMed]
18. Biswas A, Ghosh JK, Chatterjee A, Basu K, Chatterjee S. Infected chylothorax caused by escherichia coli in a non-immunocompromised child. Indian J Pediatr. 2008 Feb;75(2):192-3. [CrossRef] [PubMed]
19. Alkassis SH, Bou Khalil BK. Infected chylothorax [abstract]. Presented at American Thoracic Society international meeting 2010 https://www.atsjournals.org/doi/abs/10.1164/ajrccm-conference.2010.181.1_MeetingAbstracts.A4591 (accessed 8/24/18).
20. Epelbaum O, Kazianis J. Chylous empyema or empyematous chylothorax? [Abstract] Presented at American Thoracic Society international meeting 2011. https://www.atsjournals.org/doi/pdf/10.1164/ajrccm-conference.2011.183.1_MeetingAbstracts.A6460 (accessed 8/24/18)
21. Wright RS, Jean M, Rochelle K, Fisk D. Chylothorax caused by paragonimus westermani in a native Californian. Chest. 2011 Oct;140(4):1064-6. [CrossRef] [PubMed]
22. Bakar B, Pampal K, Tekkok IH. Infected bilateral chylothorax in a problematic case. Curr Surg. 2012 April;2(2):62-5. [CrossRef]
23. Di Marco Berardino A, Inchingolo R, Smargiassi A, Re A, Torelli R, Fiori B, d'Inzeo T, Corbo GM, Valente S, Sanguinetti M, Spanu T. Empyema cause by prevotella bivia complicating an unusual case of spontaneous chylothorax. J Clin Microbiol. 2014 Apr;52(4):1284-6. [CrossRef] [PubMed]
24. Geerlings SE, Hoepelman AI. Immune dysfunction in patients with diabetes mellitus. FEMS Immunol Med Microbiol. 1999 Dec;26(3-4):259-65. [CrossRef] [PubMed]
25. Boule LA, Ju C, Agudelo M, et al. Summary of the 2016 Alcohol and Immunology Research Interest Group (AIRIG) meeting. Alcohol. 2018 Feb;66:35-43. [CrossRef] [PubMed]
26. Milner JJ, Beck MA. The impact of obesity on the immune response to infection. Proc Nutr Soc. 2012 May;71(2):298-306. [CrossRef] [PubMed]
27. Schild HH, Strassburg CP, Welz A, Kalff J. Treatment options in patients with chylothorax. Dtsch Arztebl Int. 2013 Nov 29;110(48):819-26. [CrossRef]
28. Rudrappa M, Paul M. Chylothorax. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2018 Jan. [PubMed]
29. Nadolski G. Nontraumatic Chylothorax: diagnostic algorithm and treatment options. Tech Vasc Interv Radiol. 2016 Dec;19(4):286-90. [CrossRef] [PubMed]
30. Misthos P, Kanakis MA, Lioulias AG. Chylothorax complicating thoracic surgery: conservative or early surgical management? Updates Surg. 2012 Mar;64(1):5-11. [CrossRef] [PubMed]
31. Sahn SA. Diagnosis and management of parapneumonic effusions and empyema. Clin Infect Dis. 2007 Dec 1;45(11):1480-6. [CrossRef] [PubMed]

Cite as: Eubank L, Gabe L, Kraft M, Billheimer D. Infected chylothorax: a case report and review. Southwest J Pulm Crit Care. 2018;17(2):76-84. doi: https://doi.org/10.13175/swjpcc097-18 PDF

August 2018 Pulmonary Case of the Month

Arooj Kayani, MD

Richard Sue, MD

Banner University Medical Center Phoenix

Phoenix, AZ USA

Pulmonary Case of the Month CME Information

Completion of an evaluation form is required to receive credit and a link is provided on the last page of the activity. 

0.25 AMA PRA Category 1 Credit(s)™

Estimated time to complete this activity: 0.25 hours

Lead Author(s): Arooj Kayani, MD. All Faculty, CME Planning Committee Members, and the CME Office Reviewers have disclosed that they do not have any relevant financial relationships with commercial interests that would constitute a conflict of interest concerning this CME activity.

Learning Objectives: As a result of completing this activity, participants will be better able to:

1. Interpret and identify clinical practices supported by the highest quality available evidence.
2. Establish the optimal evaluation leading to a correct diagnosis for patients with pulmonary, critical care and sleep disorders.
3. Translate the most current clinical information into the delivery of high quality care for patients.
4. Integrate new treatment options for patients with pulmonary, critical care and sleep related disorders.

Learning Format: Case-based, interactive online course, including mandatory assessment questions (number of questions varies by case). Please also read the Technical Requirements.

CME Sponsor: University of Arizona College of Medicine at Banner University Medical Center Tucson

Current Approval Period: January 1, 2017-December 31, 201

Financial Support Received: None

History of Present Illness

A 59-year-old woman referred because of worsening dyspnea over the past 2 months along with cough and wheezing. She has a history of chronic obstructive pulmonary disease (COPD) and is on continuous oxygen @ 2 L/min.

PMH, SH, and FH

In addition to her COPD she has a history of hypothyroidism, pneumonia, tonsillectomy, hip lipoma resection, hysterectomy, and a herniorrhaphy. She has a 30 pack-year history of smoking. She currently smokes half pack/day. No family history of lung disease or cancer.

Medications

• Fluticasone/salmeterol
• Tiotropium
• Albuterol
• Levothyroxine

Physical Examination

• Vitals: HR 79/min, BP 100/69 mmHg, RR 16/min, SpO2 92% on 2 L/min.
• General: Alert and oriented. Healthy appearing in no distress.
• Lungs: Expiratory stridor and expiratory wheezing loudest over left lung. No crackles.
• Cardiac: Regular rhythm with no murmurs. No edema.
• The remainder of physical examination was unremarkable.

Which of the following should be performed? (Click on the correct answer to proceed to the second of four pages)

1. Spirometry
2. Sputum Gram stain, AFB stain, and fungal stain with cultures
3. Thoracic CT scan
4. 1 and 3
5. All of the above

Cite as: Kayani A, Sue R. August 2018 pulmonary case of the month. Southwest J Pulm Crit Care. 2018;17(2):47-52. doi: https://doi.org/10.13175/swjpcc093-18 PDF 

July 2018 Pulmonary Case of the Month

Anjuli M. Brighton, MB, BCh, BAO

Mayo Clinic Arizona

Scottsdale, AZ USA

Pulmonary Case of the Month CME Information

Completion of an evaluation form is required to receive credit and a link is provided on the last page of the activity. 

0.25 AMA PRA Category 1 Credit(s)™

Estimated time to complete this activity: 0.25 hours

Lead Author(s): Anjuli M. Brighton, MB. All Faculty, CME Planning Committee Members, and the CME Office Reviewers have disclosed that they do not have any relevant financial relationships with commercial interests that would constitute a conflict of interest concerning this CME activity.

Learning Objectives: As a result of completing this activity, participants will be better able to:

1. Interpret and identify clinical practices supported by the highest quality available evidence.
2. Establish the optimal evaluation leading to a correct diagnosis for patients with pulmonary, critical care and sleep disorders.
3. Translate the most current clinical information into the delivery of high quality care for patients.
4. Integrate new treatment options for patients with pulmonary, critical care and sleep related disorders.

Learning Format: Case-based, interactive online course, including mandatory assessment questions (number of questions varies by case). Please also read the Technical Requirements.

CME Sponsor: University of Arizona College of Medicine at Banner University Medical Center Tucson

Current Approval Period: January 1, 2017-December 31, 2018

Financial Support Received: None

History of Present Illness

An 81-year-old gentleman was admitted for syncope. He had felt unwell for one month. His recent illness started with the “flu”. He had lingering productive cough, low volume hemoptysis and felt very fatigued. After a coughing episode he apparently lost consciousness and was taken to the emergency department.

Past Medical History, Social History and Family History

He has a past medical history of hypertension, glaucoma, diverticulosis and COPD. He was taking only antihypertensives including a diuretic. He has a 30 pack-year history of smoking but quit 10 years ago.

Physical Examination

• Normotensive
• Tachypneic
• SpO2 96% on 2L NC
• Afebrile
• Diffuse wheezing, diminished at L base
• Irregularly irregular heart rate

Which of the following are indicated at this time? (Click on the correct answer to be directed to the second of six pages)

1. Chest x-ray
2. Complete blood count (CBC)
3. Electrocardiogram (EKG)
4. 1 and 3
5. All of the above

Cite as: Brighton AM. July 2018 pulmonary case of the month. Southwest J Pulm Crit Care. 2018;17(1):1-6. doi: https://doi.org/10.13175/swjpcc073-18 PDF 

Phrenic Nerve Injury Post Catheter Ablation for Atrial Fibrillation

Payal Sen, MD¹ 

Uddalak Majumdar, MD² 

Ali Imran Saeed, MD¹

¹University of New Mexico

Albuquerque, NM USA

²Cleveland Clinic Foundation

Cleveland, Ohio USA

Abstract

Objective: Phrenic nerve injury (PNI) is a complication of catheter ablation treatment of atrial fibrillation (AF). This condition can mimic that of comorbid conditions like congestive heart failure (CHF) and chronic obstructive pulmonary disease (COPD).

Case details: A 77-year-old woman with past medical history of heart failure with preserved ejection fraction and mild COPD, presented with dyspnea for 8 days. One week ago, she had undergone radiofrequency catheter ablation for persistent symptomatic AF. After the ablation, she reported dyspnea during PCP and pulmonary office visits and was given increasing doses of diuretics and inhalers since her symptoms were attributed to acute exacerbation of heart failure in the setting of COPD. However, a chest x-ray showed elevation of the right hemidiaphragm, and she had a positive sniff test. She was thus diagnosed with right sided phrenic nerve palsy and was treated with oxygen therapy.

Discussion: Phrenic nerve injury can be diagnosed via clinical exam, chest x-ray and sniff test. A sniff Test which shows paradoxical elevation of the paralyzed hemidiaphragm with inspiration, compared with the rapid descent of the normal hemidiaphragm.

Conclusion: Phrenic nerve palsy is a complication which occurs in 6.6 percent of cases, post catheter ablation procedure for atrial fibrillation. This condition can mimic pulmonary conditions like acute exacerbation of COPD. Not keeping this complication in mind can lead to biased diagnostic reasoning and missed or delayed diagnosis.

Introduction

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia (1). In the past decade, catheter ablation of AF has evolved from an investigational procedure to a frequent therapeutic one (2). Phrenic nerve injury (PNI) is a complication of ablation that pulmonologists should be familiar with, due to its increasing incidence (3). This condition can mimic that of comorbid conditions like congestive heart failure (CHF) and chronic obstructive pulmonary disease (COPD). Hence it is important to develop clinical suspicion of phrenic nerve injury, and correlate onset of symptoms to the ablation, to prevent missed or delayed diagnosis, and to avoid falling prey to availability bias.

Case Report

History of Present Illness: A 77-year-old Caucasian woman with past medical history of heart failure with preserved ejection fraction and mild COPD (GOLD Stage 1), presented with dyspnea and right sided chest discomfort for 7 days. One week ago, she had undergone radiofrequency catheter ablation at the University of New Mexico, for persistent symptomatic AF. After the ablation, she reported dyspnea during PCP and pulmonary office visits, which was attributed to acute exacerbation of heart failure in the setting of COPD. She had been given increasing doses of diuretics which did not relieve her symptoms. A short course of azithromycin and prednisone had also been prescribed for possible acute exacerbation of COPD, but her symptoms had remained unchanged. Review of systems were negative for fever, chills, cough, leg swelling and hemoptysis. She led an active lifestyle, did not require oxygen, and had quit smoking 10 years ago. There was no history of cardio- respiratory diseases in the family.

Physical Examination:

Vitals: Temperature: 97.1°F, Pulse – 88/minute, RR 22/minute, BP –

140/70 mm Hg., Spo2 – 90% in Room air (baseline >95 percent).

She appeared to be in mild distress. Baseline dry weight had not increased. She had no clinical signs of heart failure- no peripheral edema, no JVD, no S3, no bibasilar crackles. There were decreased breath sounds in the base of the right lung but no rales or rhonchi. No significant wheezing was heard in any of the lobes of the lungs.

No clubbing or cyanosis was noted. The rest of the exam was unremarkable with a normal abdominal, and skin exam. There was no lymphadenopathy.

Laboratory: White blood cell count 10,000/mm³, hemoglobin 11 g/dL, with normal electrolytes, liver function tests and negative troponins. Arterial blood gases on room air showed a pH 7.38, paO2 of 62 mm Hg, pCO2 41 mm Hg and HCO3^- 25.

EKG: negative for signs of ischemia.

Radiography: Chest radiography showed an elevated right diaphragm (Figure 1).

Figure 1. A: PA chest radiograph and B: 3 weeks earlier for comparison.

Sniff test performed under fluoroscopy showed paradoxical elevation of the right hemidiaphragm with inspiration, compared with rapid descent of the left hemidiaphragm, confirming right hemidiaphragm paralysis (Figure 2).

Figure 2. Static images from sniff test under fluoroscopy: A: pre-sniff. B: post-sniff. When the patient sniffs in, the left hemidiaphragm moves downwards but right hemidiaphragm does not (actually moves upwards very slightly).

After obtaining proper imaging, the patient was finally diagnosed with right-sided diaphragmatic paralysis due to phrenic nerve injury from the catheter ablation procedure done to treat AF. She was discharged with home oxygen and her symptoms have resolved. Follow up clinic visits revealed complete resolution of symptoms.

Discussion

Ectopic discharges from pulmonary veins are an important cause of atrial fibrillation, the most common sustained cardiac arrhythmia (1). Calkins et al. (4) carried out a study in 2009, where they showed statistically significant improvement in symptoms and quality of life in patients receiving ablation therapy versus those patients who received anti arrhythmic drugs (4). Traditionally, isolating the pulmonary vein by point-by-point radiofrequency catheter ablation was the cornerstone of catheter ablation strategies for the treatment of atrial fibrillation (2). However, this procedure had various complications such as thromboembolism, cardiac perforation, injury to adjacent structures and pulmonary vein stenosis (5). Hence, with the hope of finding an effective alternative approach with less complications, cryothermal ablation was started. This particular procedure involves electrically isolating pulmonary veins, by creating circumferential lesions by means of a cryoballoon catheter (6). Nonetheless, in both techniques, the most common complication is hemi‐diaphragmatic paralysis, due to phrenic nerve injury. This especially occurs whilst trying to isolate the right superior pulmonary vein (3). The approximate incidence of this complication is close to 3–11% (7). It is thought that the phrenic nerve gets injured due to the close anatomic relationship of the phrenic nerve to the heart (Figure 3).

Figure 3. Thoracic CT scan showing anatomical relationships (yellow star is the right phrenic nerve).

Both the right and the left phrenic nerves can get damaged - the right phrenic nerve is specifically at risk when ablations are carried out in the superior caval vein and the right superior pulmonary vein, and the left phrenic nerve is liable to damage during lead implantation into the great cardiac and left obtuse marginal veins (8). In our patient, the right phrenic nerve, which runs along the lateral surfaces of the superior vena cava and right atrium, was injured by energy delivered to the adjacent area during ablation.

In 2005 Bunch et al. (9) investigated the specific mechanism of phrenic nerve injury. Their study revealed that the phrenic nerve tended to retain heat after ablation. This phenomenon resulted in higher local temperatures with subsequent energy deliveries, causing early transient injury. Andrade et al. (3) in 2014, were the first to define this phrenic nerve injury histopathologically. According to them, phrenic nerve injury consisted of Wallerian degeneration characterized by loss of large myelinated axons with variable degrees of endoneural edema, vacuolated macrophages, myelin ovoids, and myelin digestion chambers (6).

Phrenic nerve injury can be diagnosed on clinical exam, and via a chest X-ray. Thereafter one can confirm the diagnosis with the sniff test or phrenic nerve stimulation/diaphragm electromyography. An upright chest x-ray will reveal an elevated diaphragm on the affected side. This test is sensitive, but not specific for the diagnosis of unilateral diaphragmatic paralysis (10). Another frequently done test is the sniff test which shows paradoxical elevation of the paralyzed hemidiaphragm with inspiration, compared with the rapid descent of the normal hemidiaphragm (11). The sniff test has more than 90 percent sensitivity (11). In 2014, Linhart et al. (12) performed studies to show that fluoroscopic assessment of diaphragm movement during spontaneous breathing was more sensitive for the diagnosis of phrenic nerve injury as compared to SVC pacing (12). It has also been seen that EMG‐guided approach results in less damage to the phrenic nerve and a significant reduction in hemi‐diaphragmatic paralysis as compared to current methods of abdominal palpation and fluoroscopy (13).

In unilateral diaphragmatic paralysis, patients are usually asymptomatic, have good prognosis and do not always need treatment. This is specifically true in the absence of underlying lung disease (14). Another procedure often done is the surgical plication of the affected hemidiaphragm (15). In bilateral diaphragm paralysis, ventilatory failure often occurs and these patients may require continuous positive airway pressure or mechanical ventilation and tracheostomy (16). According to Kauffman (17) in 2014, functional restoration of the paralyzed diaphragm should also be part of the standard treatment algorithm in managing symptomatic patients.

Conclusion

Phrenic nerve palsy is a complication which occurs in about 6 percent of cases post catheter ablation procedure for atrial fibrillation. This condition can mimic pulmonary conditions like acute exacerbation of COPD. It is important to develop clinical suspicion and correlate onset of symptoms to the ablation. Not keeping this complication in mind can lead to biased diagnostic reasoning and missed or delayed diagnosis.

References

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Cite as: Sen P, Majumdar U, Saeed AI. Phrenic nerve injury post catheter ablation for atrial fibrillation. Southwest J Pulm Crit Care. 2018;16(6):362-7. doi: https://doi.org/10.13175/swjpcc070-18 PDF