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

Medical Image of the Month: Mucinous Adenocarcinoma of the Lung Mimicking Pneumonia

Figure 1. A contrasted, coronal-reformatted CT image of the chest demonstrates unilateral ground glass opacification of the right lung with superimposed interlobular septal thickening (blue arrows). There is also volume loss of the left lung with elevation of the left hemidiaphragm (red arrow).

Clinical Scenario: A 60-year-old man with a history of chronic obstructive pulmonary disease presented to the hospital with worsening shortness of breath over a period of 3 days. He had a 50-pack-year history of smoking, coronary artery disease, and a previous history of a left lung mass of unknown pathology status post left upper lobectomy. He was bought to the emergency room via ambulance after being found at home with oxygen saturations in the 60s. Upon arrival to the emergency room, he required continuous oxygen at 15 L/min to maintain his oxygen saturations above 88%. He had a progressive, markedly productive cough over the last few weeks prior to presentation. He had been treated for pneumonia with multiple courses of antibiotics over the last two months without any significant improvement. His blood work was significant for a leukocytosis with neutrophilia and an elevated D-dimer. He underwent a CTA of the chest in the emergency room to evaluate for a pulmonary embolism. The CTA of the chest had no evidence of pulmonary thromboembolic disease. However, there was unilateral ground glass opacification of the right lung with interlobular septal thickening along with volume loss of the left lung and associated elevation of the left hemidiaphragm (Figure 1). He was admitted to the medical ICU and started on broad-spectrum antibiotics. He underwent a bronchoscopy which demonstrated mucinous adenocarcinoma of the lung. His oxygen requirement was eventually weaned after multiple days in the ICU. He was discharged with follow up in the oncology clinic.

Discussion: Mucinous adenocarcinoma of the lung is the rarest type of adenocarcinoma of the lung. It is characterized as mucinous adenocarcinoma in situ, minimally invasive adenocarcinoma, and invasive mucinous adenocarcinoma. Mucinous adenocarcinoma of the lung is morphologically characterized by tall columnar cells with abundant cytoplasm that contain varying amounts of mucin. Mucus secreted by these cells can commonly be discharged as sputum. However, if airway obstruction occurs secondary to excessive mucus production, a post-obstructive pneumonia may develop. The prognosis of mucinous adenocarcinoma of the lung is poor.

Nicholas Blackstone MD¹, Tammer El-Aini MD²

¹Department of Internal Medicine and ²Department of Pulmonary and Critical Care, South Campus, Banner University Medical Center – Tucson, Tucson, AZ USA

References

1. Liu Y, Zhang HL, Mei JZ, Guo YW, Li RJ, Wei SD, Tian F, Yang L, Wang H. Primary mucinous adenocarcinoma of the lung: A case report and review of the literature. Oncol Lett. 2017 Sep;14(3):3701-3704. [CrossRef] [PubMed]
2. Marchetti A, Buttitta F, Pellegrini S, Chella A, Bertacca G, Filardo A, Tognoni V, Ferreli F, Signorini E, Angeletti CA, Bevilacqua G. Bronchioloalveolar lung carcinomas: K-ras mutations are constant events in the mucinous subtype. J Pathol. 1996 Jul;179(3):254-9. [CrossRef] [PubMed]
3. Travis WD, Brambilla E, Noguchi M, Nicholson AG, Geisinger KR, Yatabe Y, Beer DG, Powell CA, Riely GJ, Van Schil PE, Garg K, Austin JH, Asamura H, Rusch VW, Hirsch FR, Scagliotti G, Mitsudomi T, Huber RM, Ishikawa Y, Jett J, Sanchez-Cespedes M, Sculier JP, Takahashi T, Tsuboi M, Vansteenkiste J, Wistuba I, Yang PC, Aberle D, Brambilla C, Flieder D, Franklin W, Gazdar A, Gould M, Hasleton P, Henderson D, Johnson B, Johnson D, Kerr K, Kuriyama K, Lee JS, Miller VA, Petersen I, Roggli V, Rosell R, Saijo N, Thunnissen E, Tsao M, Yankelewitz D. International association for the study of lung cancer/American Thoracic Society/European Respiratory Society international multidisciplinary classification of lung adenocarcinoma. J Thorac Oncol. 2011 Feb;6(2):244-85. [CrossRef] [PubMed]
4. Cai D, Li H, Wang R, Li Y, Pan Y, Hu H, Zhang Y, Gong R, Pan B, Sun Y, Chen H. Comparison of clinical features, molecular alterations, and prognosis in morphological subgroups of lung invasive mucinous adenocarcinoma. Onco Targets Ther. 2014 Nov 18;7:2127-32. [CrossRef] [PubMed].
5. Xie GD, Liu YR, Jiang YZ, Shao ZM. Epidemiology and survival outcomes of mucinous adenocarcinomas: A SEER population-based study. Sci Rep. 2018 Apr 17;8(1):6117. [CrossRef] [PubMed]

Cite as: Blackstone N, El-Aini T. Medical image of the month: mucinous adenocarcinoma of the lung mimicking pneumonia. Southwest J Pulm Crit Care. 2021;22(1):8-10. doi: https://doi.org/10.13175/swjpcc072-20 PDF