Early manifestation of ARDS in COVID-19 infection in a 51- year-old man affected by Mounier-Kuhn syndrome.

A 51-year-old man known to be affected by Mounier-Kuhn syndrome (MKS). presented to Accident & Emergecy (A&E) with fever, dyspnea and deterioration of his chronic coughs. Increased diameters of his trachea (39 mm), right (30 mm) and left (26 mm) main bronchi were revealed by chest computerized tomography (CT) scan. CT scan showed also ground-glass opacities (GGO) and bronchiectasis in the mid and lower zones of both lungs. COIVD-19 infection was eventually confirmed by RT-PCR. A severe form of COVID-19 could occur even in the early stages of the disease in presence of underlying co-morbidities including MKS, which increases the susceptibility to more recurrent and severe respiratory infections.

Introduction

COVID-19 as an emerging infectious disease of the human respiratory system, with a broad clinical pattern ranging from asymptomatic to a critical life threatening condition.1, 2, 3 A severe form of COVID-19 can develop quickly in a minority of patients, with the onset of acute respiratory distress syndrome (ARDS), septic shock, pleural effusion and other organ dysfunction/failure. , 4, 5 –

Mounier–Kuhn Syndrome (MKS, a form of tracheo-broncho-megaly), is a clinical idiopatic yet extremely rare disorder, featured by abnormal dilatation of the trachea and main bronchi due to atrophy or lack of elastic fibers and smooth muscle cells. Since it is a significant risk factor for recurrent lower respiratory infections, MKS needs to be detected as early as possible to prevent potential complications. –

We report a patient affected by MKS admitted to Baqiyatallah hospital in Tehran (Iran) for COVID-19, who subsequenty developed a form of the disease with acute respiratory distress syndrome (ARDS).

Case presentation

A 51-year-old man, known to be affected by MKS was admitted to our accident & emergency (A&E) service of the Baqiyatallah hospital in Tehran (Iran), with a new onset of fever, dyspnea and deterioration of his chronic coughs. On physical examination the patient was ill, febrile, tachycardic, hypoxic with O2 saturation of about 80% and diffuse rhonchi at chest auscultation. The most significant laboratory finding was a notable leukopenia.

A chest CT scan revealed increased diameter of his trachea (39 mm), right (30 mm) and left (26 mm) main bronchi, due to MKS. Furthermore, the CT scan showed bilateral ground-glass opacities (GGO) and bronchiectasis in the mid and lower zones of both lungs, with small air cysts in the lower zone of the right lung at coronal bronchiectasis in the mid and lower zones of both lungs, with small air cysts in the lower zone of the right lung at coronal (Fig 1 ) and axial (Fig 2 ) imaging's, compatible with an early stage ARDS.

Fig. 1

Coronal reconstructed ct scan shows trachea-bronchomegaly (Mounier-Kuhn syndrome) . The diameter of trachea measures 39 mm, the right main bronchus 30 mm and the left main bronchus 26 mm. Ground-glass opacities (GGO) and bronchiectasis in the mid and lower zone of both lungs, with small air cysts in the lower zone of the right lung due to early stage ARDS in COVID-19 pneumonia can be noted.

Fig. 2

Four axial CT scan show ill–defined bilateral ground-glass opacities (GGO) and bronchial dilatation within areas of GGO bilaterally and a small air cyst in the right middle lung lobe, suggestice of an early stage ARDS due to COVID-19 pneumonia subsequently confirmed by PCR test.

In a few hours the patient became cyanotic, with altered mental status, shortage of breath and drop in O2 saturation to about 45%. In compliance with Iran's treatment protocols, the patient was promptly intubated and transferred to the intensive care unit (ICU) for further diagnostic and therapeutic procedures, his clinical and radiological pattern being compatible with ARDS. He was placed under O2 therapy mechanical ventilation, with a tracheostomy also performed. The patient health conditions progressively improved over time and after about two weeks he was weaned and discharged from hospital.

Although the patient conditions was unusual for an early stage of the disease, COVID-19 was still our first differential diagnosis, given we were in the middle of the COIVD-19 epidemic. COIVD-19 infection was eventually confirmed by real time reversed polymerase chain reaction (RT-PCR). A severe form of COVID-19 could in fact occur even in the early stages of the disease in presence of underlying co-morbidities, including MKS which increases the susceptibility to more recurrent and severe respiratory infections.

Discussion

MKS is a are congenital disorder more common in men and manifesting with tracheo-bronchial dilation. Although the exact etiology of MKS is unknown, familial susceptibility and genetic predisposition seem to play a role. MKS is supposedly sustained by lack of musculo-elastic tissue at different levels of the trachea and main bronchi, causing diverticular structures and sacculationar outpouchings especially in the posterior membranous trachea.7, 8 , –

The clinical presentations of MKS are not specific and include a wide spectrum of clinical features ranging from asymptomatic or minimal disease to progressive manifestations leading to respiratory failure. Common presentations are chronic productive cough, dyspnea and recurrent respiratory infections due to of mucociliary dysfunction and accumulation of secretions. , ,

MKS’ diagnosis relies on detection of enlarged diameter of the trachea, right and left main bronchi by CT scan. – In the presented case the diameter of trachea, right and left bronchi were 39 mm, 30 mm and 26 mm, respectively. However, considerable variations in the enlargement of the lower respiratory tract tree have been documented. For instance, Woodring reported the diameter of right and left main bronchi being larger than 21 mm and 18 mm respectively in men affected by MKS. Similar radiological features were confirmed by Nobrega and Menon, with the diameter of trachea, right and left brochi being larger than 30 mm, 24 mm and 23 mm, respectively. , A remarkable trachea larger than 40 mm was reported by Bastos in a 33 year old man with MKS. Likewise, Abdelghani described a 53 old man affected by MKS with a diameter of his trachea, right and left bronchi being of 50 mm, 38 mm and 34 mm respectively.

The above variability in the anatomical presentations of MKS can translate into different risk of acquiring respiratory tract infections and should be taken into account when managing COVID-19 patients, as they may influence the course of the disease. COVID-19 can present with mild, moderate and severe symptoms. Whilst the vast majority of patients develop a mild form of the disease, underlying co-morbidities such as diabetes, hypertension, cardiovascular disorders and malignancies can significantly increase the risk of developing a severe form of COVID-19, especially among patients older than 50. ,

Conclusion

All possible underlying co-morbidities, even rare conditions as MKS, should be therefore carefully considered when managing a COIVD-19 patient, because they can significantly influence the course of the disease.