Infectious Causes of Right Middle Lobe Syndrome

Rashid, Aatif; Nanjappa, Sowmya; Greene, John N.

doi:10.1177/107327481702400110

Cited by 9 publications

(7 citation statements)

References 33 publications

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“…Anatomically, the right middle lobe is unique from other lobes, with a long, narrow, pliable bronchus, acute-angle bronchi takeoffs, and clusters of peribronchial lymph nodes (44a). Clinical studies have noted the vulnerability of the right middle lobe to aspiration pneumonia and atelectasis (13,38). Additionally, the deep fissures of the right middle lobe hinder collateral ventilation (1,30), and the relative anatomical isolation of the right middle lobe reduces the chances of reinflation in the case of atelectasis (10,30).…”

Section: Discussionmentioning

confidence: 99%

Heavy upright exercise increases ventilation-perfusion mismatch in the basal lung: indirect evidence for interstitial pulmonary edema

Tedjasaputra

Sá

Anderson

et al. 2019

Journal of Applied Physiology

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Ventilation-perfusion (V̇a/Q̇) mismatch during exercise may result from interstitial pulmonary edema if increased pulmonary vascular pressure causes fluid efflux into the interstitium. If present, the increased fluid may compress small airways or blood vessels, disrupting V̇a/Q̇ matching, but this is unproven. We hypothesized that V̇a/Q̇ mismatch would be greatest in basal lung following heavy upright exercise, consistent with hydrostatic forces favoring edema accumulation in the gravitationally dependent lung. We applied new tools to reanalyze previously published magnetic resonance imaging data to determine regional V̇a/Q̇ mismatch following 45 min of heavy upright exercise in six athletes (V̇o2max = 61 ± 7 mL·kg−1·min−1). In the supine posture, regional alveolar ventilation and local perfusion were quantified from specific ventilation imaging, proton density, and arterial spin labeling data in a single sagittal slice of the right lung before exercise (PRE), 15 min after exercise (POST), and in recovery 60 min after exercise (REC). Indices of V̇a/Q̇ mismatch [second moments (log scale) of ventilation (LogSDV) and perfusion (LogSDQ) vs. V̇a/Q̇ distributions] were calculated for apical, middle, and basal lung thirds, which represent gravitationally nondependent, middle, and dependent regions, respectively, during upright exercise. LogSDV increased after exercise only in the basal lung (PRE 0.46 ± 0.06, POST 0.57 ± 0.14, REC 0.55 ±0.14, P = 0.01). Similarly, LogSDQ increased only in the basal lung (PRE 0.40 ± 0.06, POST 0.51 ± 0.10, REC 0.44 ± 0.09, P = 0.04). Increased V̇a/Q̇ mismatch in the basal lung after exercise is potentially consistent with interstitial pulmonary edema accumulating in gravitationally dependent lung during exercise. NEW & NOTEWORTHY We reanalyzed previously published MRI data with new tools and found increased ventilation-perfusion mismatch only in the basal lung of athletes following 45 min of cycling exercise. This is consistent with the development of interstitial edema in the gravitationally dependent lung during heavy exercise.

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Section: Discussionmentioning

confidence: 99%

Heavy upright exercise increases ventilation-perfusion mismatch in the basal lung: indirect evidence for interstitial pulmonary edema

Tedjasaputra

Sá

Anderson

et al. 2019

Journal of Applied Physiology

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“…MLS is typically divided into two categories: obstructive and non-obstructive. The obstructive type is characterized by a blockage in the airway, while the non-obstructive type involves a clear right middle bronchus 20 . In our four cases, all patients exhibited the obstructive type, with mucus obstructing the bronchus.…”

Section: Discussionmentioning

confidence: 99%

“…The etiologies lying behind obstructed MLS include enlarged peribronchial lymph nodes, cardiovascular anomalies, inspissated mucus as in our four cases, and aspirated foreign bodies, particularly in children. On the other hand, the aetiology of the non-obstructive form is not fully understood, but inefficient collateral ventilation, infection, and inflammation in the middle lobe or lingula, along with bronchiectasis, are thought to play a role 1 , 20 .…”

Section: Discussionmentioning

confidence: 99%

Unveiling the complexity of right middle lobe syndrome: a case series highlighting the association with asthma

Shhada,

Nahle,

Hamdar

et al. 2024

Annals of Medicine &Amp; Surgery

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Introduction and Importance: Right middle lobe syndrome (MLS) is a rare lung disorder primarily affecting children with a history of asthma or atopy. It encompasses a range of pathological and clinical conditions, from recurrent collapses of the middle lobe to bronchiectasis. In this study, we present a case series featuring four individuals with MLS associated with asthma, aiming to deepen our understanding of this uncommon condition. Case Presentation: Four pediatric patients with right MLS exhibited symptoms of persistent cough, dyspnea, and recurrent asthma exacerbations. Radiographic evaluations confirmed features consistent with right MLS, and bronchoscopy revealed mucus plugs and edematous airways obstructing the right middle lobe bronchus. Treatment with bronchodilators, antibiotics, and corticosteroids led to symptom improvement and resolution of atelectasis. Clinical Discussion: MLS is a rare condition characterized by chronic collapse of the right middle lobe and bronchiectasis. It is challenging to diagnose MLS, but CT scans provide detailed lung images for confirmation. Treatment focuses on addressing the underlying cause, such as infections or mucus obstruction. Lobectomy may be considered in severe cases. This case series emphasizes the need for further research on MLS, as its rarity and characteristics remain unclear. Conclusion: Our cases exhibited obstructive MLS with and without asthma. Accurate diagnosis is challenging, requiring imaging techniques. MLS has clinical implications, particularly in asthma patients. Future studies should focus on understanding the etiology of non-obstructive MLS.

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“…Consideration must be given to chronic immunosuppressive medication. HIV, complement and immunoglobulin deficiencies should be excluded and the effect of diabetes, neoplasia or autoimmune diseases must be taken into account [8–11] .…”

Section: Discussionmentioning

confidence: 99%

Non-Obstructive Middle Lobe Syndrome: An Unusual Cause of Recurrent Pneumonia in an Elderly Woman

Rua

Marques

Silva

et al. 2017

European Journal of Case Reports in Internal Medicine

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How to cite this article: Rua J, Marques R, Silva R, Gomes B, Fortuna J. Non-obstructive middle lobe syndrome: an unusual cause of recurrent pneumonia in an elderly woman. EJCRIM 2017;4: doi:10.12890/2017_000737. Conflicts of Interests:The Authors declare that there are no competing interests. This article is licensed under a Commons Attribution Non-Commercial 4.0 LicenseABSTRACT An 84-year-old woman had five episodes of pneumonia in 4 months. Despite extensive comorbidities and advanced age, her health status was good and the recurrence seemed unjustified. Exhaustive background investigation revealed 14 episodes of right-sided pneumonias during the 3 previous years and an inconclusive investigation with CT of the thorax and bronchofibroscopy, despite some fibrotic and atelectasic alterations in the right middle lobe. A new right-sided x-ray showed a wedge-shaped density extending anteriorly and inferiorly from the hilum, and CT of the thorax revealed aggravated middle lobe abnormalities with thickening of the bronchial wall and segment atelectasis, without any visible airway obstruction. After extensive work-up had excluded other causes of recurrent pneumonia and immunodeficiency, a non-obstructive middle lobe syndrome (MLS) was deemed responsible for the repeated episodes of pneumonia. MLS is characterised by chronic hypoventilation and atelectasis of the middle lobe, facilitating secretion accumulation, chronic inflammation and repeated infection. After treatment with bronchodilators and immunostimulants was initiated, the patient experienced no recurrences for several months. LEARNING POINTS• Recurrent pneumonia is common and has several possible causes. Investigation should be directed by whether or not the location of the episodes varies, suggesting a systemic condition or a local abnormality, respectively. • Middle lobe syndrome (MLS) is characterised by chronic hypoventilation of the right middle lobe resulting in atelectasis and secretion accumulation, sometimes causing recurrent pneumonia, and should therefore be considered in the differential diagnosis.• MLS is not unusual in children with asthma but is quite uncommon in the elderly despite age-related changes in the characteristics of airways with reduced elastic recoil and mucociliary clearance.

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Infectious Causes of Right Middle Lobe Syndrome

Cited by 9 publications

References 33 publications

Heavy upright exercise increases ventilation-perfusion mismatch in the basal lung: indirect evidence for interstitial pulmonary edema

Heavy upright exercise increases ventilation-perfusion mismatch in the basal lung: indirect evidence for interstitial pulmonary edema

Unveiling the complexity of right middle lobe syndrome: a case series highlighting the association with asthma

Non-Obstructive Middle Lobe Syndrome: An Unusual Cause of Recurrent Pneumonia in an Elderly Woman

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