January 2023 Medical Image of the Month: Abnormal Sleep Study and PFT with Supine Challenge Related to Idiopathic Hemidiaphragmatic Paralysis

Figure 1. Results of a sleep study demonstrating a correlation between body position and oxygen saturation.  When the patient moved into right lateral decubitus positioning, their SaO2 dropped (red), when they moved into left lateral decubitus positioning, their SaO2 recovered (Green).  This position-dependent change in SaO2 during sleep suggests right hemidiaphragmatic paralysis.

Figure 2.  Flow-volume loop from pulmonary function testing demonstrates a significant reduction in forced vital capacity (FVC) and forced expiratory volume 1s (FEV1) with supine positioning (green line) compared to upright baseline (red line) suggestive of diaphragmatic dysfunction. 

Figure 3.  Fluoroscopic images from a sniff test at end tidal (A) and “sniffing” (B) portions of exam demonstrating normal depression of the left hemidiaphragm (down arrowhead) and paradoxical elevation of the right hemidiaphragm (up arrowhead) consistent with right hemidiaphragmatic paralysis. Sagittal reconstruction from a noncontrast chest CT (C) demonstrating an elevated but otherwise normal appearing right hemidiaphragm (arrows).

A 71-year-old man presented to our pulmonary clinic with a complaint of worsening dyspnea, which seems to be positional in nature.  Symptoms were exacerbated by bending over or laying down too quickly.  The patient was known to our practice, having had a kidney transplant 17 years ago, a left upper lobectomy for squamous cell carcinoma 6 years ago (no recurrence), and has been on fluconazole for 4 years due to disseminated coccidioidomycosis (cocci) with cavitary pulmonary involvement.  The patient had recurrent DVTs 2 years ago and is on Eliquis.  On top of that, the patient had COVID 1 year ago, but had recovered.  An outside sleep study was remarkable for overnight hypoxia.  Outside pulmonary function testing (PFTs) demonstrated a combined restrictive and obstructive picture.  An outside chest CT failed to demonstrate any findings that would suggest COVID-related changes or progression of cocci as a potential cause.  A V/Q scan was low probability for pulmonary embolism.

 The positional nature of the patient’s symptoms and suspicious physical exam findings suggested abnormal diaphragmatic motion as a potential etiology.  The astute pulmonologist ordered a home sleep study to evaluate for any positional nature to the overnight hypoxia (Fig. 1), PFTs with supine challenge (Fig. 2) and a fluoroscopic sniff test to evaluate diaphragmatic motion (Figure 3).  The sleep study did indeed demonstrate a strong correlation between patient position and SaO2 (dropped when right side down or supine).  The PFTs demonstrated a significant drop in pulmonary function with supine challenge.  The sniff test demonstrated an elevated right hemidiaphragm with paradoxical motion during sniffing maneuvers (Fig. 3A,3B).  Results were consistent with right hemidiaphragmatic paralysis.  Of note, several months later repeat PFTs and sniff test demonstrated some interval improvement in right hemidiaphragmatic paralysis suggesting a reversible process, probably inflammatory and perhaps related to a viral neuritis.

Diaphragmatic paralysis can be further categorized into unilateral or bilateral with these entities each having a somewhat different set of potential etiologies. Distinguishing between unilateral vs. bilateral paralysis is important. Potential causes of unilateral hemidiaphragmatic paralysis can be separated into trauma/iatrogenic causes (such as following CABG), compression (such as cervical spondylosis or tumor along phrenic nerve), neuropathic (such as in multiple sclerosis) or inflammation (such as in the setting of a viral neuritis) (1).  Viral neuritis affecting the phrenic nerve has been reported with COVID-19 (2).  Up to 20% of cases of unilateral hemidiaphragmatic paralysis may be considered idiopathic (3).

The diagnostic approach to suspected hemidiaphragmatic paralysis is actually pretty well demonstrated by this case report.  CXR, in combination with physical exam, is often good as an initial screening exam.  Diaphragmatic motion can be assessed with sniff testing using fluoroscopy (or ultrasound if there is a desire to limit exposure to ionizing radiation).  Evaluation for causes of compression can be done with cross-sectional imaging, particularly CT or MRI.  Pulmonary function testing with supine challenge and a sleep study can also provide useful information, as demonstrated by this case.

Clinton Jokerst MD¹, Carlos Rojas MD¹, Michael Gotway MD¹, and Philip Lyng MD²

Department of Radiology¹

Mayo Clinic Arizona, Scottsdale, AZ USA

Division of Pulmonology²

Mayo Clinic Arizona, Scottsdale, AZ USA

References

1. O'Toole SM, Kramer J. Unilateral Diaphragmatic Paralysis. [Updated 2022 Jun 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557388/ (accessed 12/12/22).
2. FitzMaurice TS, McCann C, Walshaw M, Greenwood J. Unilateral diaphragm paralysis with COVID-19 infection. BMJ Case Rep. 2021 Jun 17;14(6):e243115. [CrossRef] [PubMed]
3. Kokatnur L, Vashisht R, Rudrappa M. Diaphragm Disorders. 2022 Aug 1. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–. [PubMed] 

Cite as: Jokerst C, Rojas C, Gotway MB, Lyng P. January 2023 Medical Image of the Month: Abnormal Sleep Study and PFT with Supine Challenge Related to Idiopathic Hemidiaphragmatic Paralysis. Southwest J Pulm Crit Care Sleep. 2023;26(1):5-7. doi: https://doi.org/10.13175/swjpccs057-22 PDF

July 2018 Imaging Case of the Month

Michael B. Gotway, MD

Department of Radiology

Mayo Clinic Arizona

Scottsdale, AZ USA

Imaging Case of the Month CME Information  

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

0.25 AMA PRA Category 1 Credit(s)™

Estimated time to complete this activity: 0.75 hours

Lead Author(s): Michael B. Gotway, 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 the Arizona Health Sciences Center.

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

Clinical History: An 81–year old non-smoking woman presented with complaints of shortness of breath for one month, more so when laying down. The patient had a history of Sjögren syndrome established 13 years earlier. She notes a history of dryness of the eyes and upper airways. Her medications included 5 mg prednisone daily as well as various vitamins and supplements. While she complained of several medication “allergies,” none were serious and most appeared to represent side effects or untoward reactions to medications as opposed to true allergic reactions. Her past medical history included arthritis, possible obstructive sleep apnea, kidney stones, and orthostatic hypotension, the latter thought to be related to her Sjögren syndrome. Her surgical history included a sternotomy for thymoma resection years earlier.

Her physical examination was unremarkable except for diminished breath sounds at the left base; her vital signs were within normal limits.

Frontal and lateral chest radiography (Figure 1) was performed.

Figure 1. Frontal (A) & lateral (B) chest radiography.

Which of the following represents the most accurate assessment of the chest radiographic findings? (click on the correct answer to be directed to the second of eleven pages)

1. Chest radiography shows an elevated left hemidiaphragm
2. Chest radiography shows bibasilar fibrotic-appearing opacities
3. Chest radiography shows cavitary pulmonary lesions
4. Chest radiography shows multifocal bronchiectasis
5. Chest radiography shows small pulmonary nodules

Cite as: Gotway MB. July 2018 imaging case of the month. Southwest J Pulm Crit Care. 2018;17(1):15-27. doi: https://doi.org/10.13175/swjpcc086-18 PDF