|LETTER TO EDITOR
|Year : 2022 | Volume
| Issue : 3 | Page : 122-123
High attenuation mucus
Vishnu Sharma Moleyar, Nisha Thomas
Department of Respiratory Medicine, A. J. Institute of Medical Sciences and Research Centre, Mangalore, Karnataka, India
|Date of Submission||10-Jun-2022|
|Date of Acceptance||22-Jun-2022|
|Date of Web Publication||17-Aug-2022|
Dr. Vishnu Sharma Moleyar
Department of Respiratory Medicine, A. J. Institute of Medical Sciences and Research Centre, Kuntikana, Mangalore, Karnataka
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Moleyar VS, Thomas N. High attenuation mucus. J Adv Lung Health 2022;2:122-3
High-attenuation mucus (HAM) if present in computed tomography (CT) scan of thorax is diagnostic of allergic bronchopulmonary aspergillosis (ABPA). Attenuation value more than 70 Hounsfield units indicates HAM. Awareness of this radiological sign is essential to avoid further evaluation in these patients. If radiologists and clinicians are not aware, HAM may be misinterpreted as endobronchial lesion. This may lead to further unnecessary invasive tests for diagnosis. We hereby present a case where chest CT scan showed HAM.
A 35-year-old female was admitted for the evaluation of recurrent mild hemoptysis. She had bronchial asthma for the past 15 years. Her asthma was uncontrolled with frequent exacerbations over the past 2 years. Chest X-ray [Figure 1] and CT scan thorax [Figure 2] and [Figure 3] were done which was diagnostic.
|Figure 2: CT scan thorax lung window axial image, CT = Computed tomography|
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|Figure 3: CT scan thorax mediastinal window axial image, CT = Computed tomography|
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Chest X-ray [Figure 1] and CT scan thorax lung window axial view [Figure 2] show “finger in glove sign.” CT scan thorax mediastinal window axial image [Figure 3] shows “High-attenuation mucus” which is considered to be diagnostic of ABPA.
Finger in glove sign is due to obstructed bronchus getting dilated by distally filled mucus. The most common cause for this sign is mucus plug obstruction due to ABPA. Other causes include cystic fibrosis, bronchial asthma, endobronchial obstructive lesions such as carcinoid, lipoma, foreign body, bronchial stricture, and rarely obstruction due to slow-growing bronchogenic carcinoma.
HAM in ABPA wasfirst described by Goyal et al. HAM may occur in up to 28% of patients with ABPA. It is more common in patients with long-standing ABPA with localized bronchial involvement than in patients with extensive lesions. Usually, bronchial mucus is visualized as hypo attenuation in CT scan. The cause for the hyper attenuation of mucus in some cases of ABPA may be due to the presence of calcium salts and metals (the ions of iron and manganese) or desiccated mucus. In CT scan, when visually the shadow is denser than the chest wall or paraspinal skeletal muscles, HAM should be suspected. Attenuation value more than 70 Hounsfield units indicate HAM.
Most of the patients with ABPA respond well to systemic steroids. ABPA patients with HAM may have poorer outcomes. This may be because most of these patients have long standing and more severe disease, which may lead to permanent changes in the affected bronchial segments and surrounding lungs. Bronchiectasis and parenchymal fibrosis may persist when diagnosis and treatment is delayed. Early diagnosis and treatment may improve the outcome.
While interpreting the chest CT scan of a patient with suspected ABPA, proper attention should be given to record the presence or absence of HAM. Awareness of ABPA, as a common cause for uncontrolled asthma and recurrent hemoptysis and the characteristic radiological sign of finger-in-glove appearance and HAM will avoid further investigations in these patients. If radiologists and clinicians are not aware, HAM may be misinterpreted as an endobronchial lesion. This may lead to further unnecessary invasive diagnostic tests like bronchoscopy/percutaneous biopsy.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Sharma VM, Walikar BA. Recurrent hemoptysis in a patient with bronchial asthma. J Adv Lung Health 2021;1:70-4. [Full text]
Goyal R, White CS, Templeton PA, Britt EJ, Rubin LJ. High attenuation mucous plugs in allergic bronchopulmonary aspergillosis: CT appearance. J Comput Assist Tomogr 1992;16:649-50.
Agarwal R. High attenuation mucoid impaction in allergic bronchopulmonary aspergillosis. World J Radiol 2010;2:41-3.
[Figure 1], [Figure 2], [Figure 3]