Chronic atelectasis of the left lower lobe: a clinicopathological condition equivalent to middle lobe syndrome

Abstract

Chronic atelectasis of the left lower lobe is a clinicopathological condition equivalent to middle lobe syndrome. Impaired collateral ventilation together with airway plugging with secretion is an accepted explanation. Surgical resection is indicated for bronchiectatic lobe or failure of 2-month intensive medical therapy to resolve lobar atelectasis.

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

“…MLS was first described in 1948 by Graham et al [3] as a chronic or recurrent collapse of the middle lobe due to hypoventilation resulting from mechanical obstruction or transient mucosal inflammation [2] . Limited collateral ventilation and the specific anatomy of the bronchus, which is narrow, long and has an acute take-off angle, are physiopathologically decisive [1, 7, 13] . There are two types of MLS, obstructive and non-obstructive, with the first subdivided into intrinsic or extrinsic, according to the nature of the obstruction [2] .…”

“…The recurrent location suggested the latter, as did the examinations showing persistent atelectasis of the RML, consistent with MLS, and the exclusion of common chronic infections and immunodeficiencies. The second phase was to determine the type of MLS and search for a treatable cause [4, 5, 7] . The investigations did not suggest an obstruction in accordance with the previous bronchofibroscopy.…”

Postsplenectomy left lower lobe bronchiectasis

“…15 The third explanation may be chronic atelectasis postsplenectomy, which can be considered a clinicopathological condition equivalent to middle lobe syndrome, causing impaired collateral ventilation which together with airway plugging and secretion can cause left lower lobe bronchiectasis. 16 The main presenting symptoms were expectoration of foul-smelling purulent fetid sputum more in the morning and related to posture. The responsible organisms were usually Pseudomonas aeruginosa and Haemophilus influenzae.…”

Pulmonary Arteriovenous Malformation : A Culprit of Middle Lobe Syndrome ?

“…It is important to utilize bronchoscopic therapeutic options early in the course of the obstructive MLS to halt the progress of the disease into advanced bronchiectasis and recurrent pneumonitis. Approximately one to two-thirds of MLS patients sustain cure or show improvement in response to conservative treatment especially when bronchoscopy is utilized early in the course of treatment 10 . Best response occurs in the pediatric age group and the non-obstructive type of MLS.…”