Tuberk Toraks 2021;69(1):111-113
Satoh H, Nishino K.
111
Diaphragm thinning due to phrenic nerve palsy
doi • 10.5578/tt.20219915 Tuberk Toraks 2021;69(1):111-113
Geliş Tarihi/Received: 05.12.2020 • Kabul Ediliş Tarihi/Accepted: 22.12.2020
Hiroaki SATOH(ID)
Kengo NISHINO(ID) Division of Respiratory Medicine, Mito Medical Center, University of Tsukuba, Mito, Japan
Tsukuba Üniversitesi Mito Tıp Merkezi, Solunum Tıbbı Bölümü, Mito, Japonya
EDİTÖRE MEKTUP LETTER TO THE EDITOR
To the Editor,
Phrenic nerve palsy is a relatively rare disease caused by several conditions that impair the phrenic nerve (1,2). Among them, patients with “idiopathic” phrenic nerve palsy, whose causative condition are unknown, is the most common (1,2). Neurological examinations such as electromyography are known as accurate diagnostic methods for phrenic nerve palsy (3). Since these exam- inations are complicated, many reports have used “lack of vertical movement of the diaphragm during inspiration and expiration” as a diagnostic method (1,2). The thinning of the diaphragm seems to be a consequence of the palsy, related to secondary muscle atro- phy (4,5). We show, herein, a patient with idiopathic phrenic nerve palsy of the right, which was accompanied with diaphragm thinning on the affected side.
A 53-year-old man was referred to our hospital because of eleva- tion of right diaphragm on chest radiograph and restrictive respi- ratory impairment on respiratory function test. The forced vital capacity was 3.59 L a year ago, but this year it was 2.44 L. On chest X-ray of inspiration and exhalation, no vertical movement of the right diaphragm was shown (Figure 1). On CT scan, no atelec- tasis due to obstructive lesion in central airway was found. There were no lesions that impaired the phrenic nerve. The right dia- phragm was thinner than the left diaphragm (Figure 2). Since there was no medical history and imaging findings that caused phrenic Dr. Hiroaki SATOH
Division of Respiratory Medicine,
Mito Medical Center, University of Tsukuba, Miya-machi 3-2-7,
Ibaraki, 310-0015, MITO - JAPAN e-mail: hirosato@md.tsukuba.ac.jp
Yazışma Adresi (Address for Correspondence) Cite this article as: Satoh H, Nishino K. Diaphragm thinning due to phrenic nerve palsy. Tuberk Toraks 2021;69(1):111-113.
©Copyright 2021 by Tuberculosis and Thorax.
Available on-line at www.tuberktoraks.org.com
Tuberk Toraks 2021;69(1):111-113 Diaphragm thinning due to phrenic nerve palsy
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nerve palsy, the patient was diagnosed as having an idiopathic phrenic nerve palsy.
Atelectasis due to lesions in the central airways may cause elevation of the diaphragm may involve periph- eral (6). Therefore, it is necessary to pay attention to the presence or absence of endobronchial lesion in central airway even if there is apparent cancerous lesion adjacent to central airway. If there is no vertical movement of the diseased diaphragm during breath- ing, phrenic nerve palsy must be suspected. The majority of patients with phrenic nerve palsy are considered those with idiopathic clinical conditions (1,2). However, several diseases such as trauma, sur- gery, infections, and neurological disorders may cause phrenic nerve palsy, and head and neck can-
cers and lung cancers that damage the phrenic nerve from the C3-C5 nerve root may also cause phrenic nerve palsy (1,2). It should be noted that phrenic nerve palsy may be accompanied by the develop- ment of hypoventilation, basal pulmonary atelectasis, and can progress to the risk of hypercapnic respirato- ry failure (7). Therefore, when encountering a patient suspected of having phrenic nerve palsy, it is clinical- ly important to search for the presence of the patho- logical condition causing the palsy rather than simply diagnosing it as “idiopathic”. In the present patient, thinning of the diaphragm on the affected side was observed. The effect of diaphragm thinning on dia- phragm atrophy and respiratory function is unknown, but it was reported that thinning had already observed 48 hours after the start of mechanical ventilation in the ICUs (4). Guinard et al. have reported a case of diaphragmatic paralysis with a thinning diaphragm muscle (5). Diaphragmatic vertical movement during respiration is the most important finding in phrenic nerve palsy, in addition to this, thinning of the affect- ed diaphragm might also be a noteworthy finding.
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Figure 1. Chest radiograph on inspiration A. and expiration B. demonstrating paradoxical elevation of the right hemidiaphragm on inspiration. No vertical movement of the right diaphragm was observed.
Figure 2. Chest CT scan revealed that the right diaphragm (arrows) was thinner than the left diaphragm (arrow heads).
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