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UDC 616.24-007
MORPHO-FUNCTIONAL ANALYSIS OF LUNG HYPOPLASIA IN
CHILDREN.
Ruziev Farkhod Kurbanovich.
Tashkent Medical Academy.
farxodroziyev69@gmail.com
According to the literature, there is a continuous increase in the number of
children suffering from chronic pneumonia, the pathogenesis and pathomorphology of
which are based on congenital anomalies and malformations of the bronchopulmonary
structures [1,3]. Among the malformations, pulmonary hypoplasia is the most
common, accounting for 75-80% and characterized by a steady increase in morbidity
among children, an increase in the incidence of extensive, advanced and severe forms
of damage [5,6].
The difficulties of early detection of HL are associated with the fact that the
disease occurs under the guise of a chronic suppurative process in the lung. Recognition
of pulmonary hypoplasia at the stages of primary diagnosis is difficult due to the lack
of clear clinical and morphological changes that are smoothed out against the
background of a long-term inflammatory process, in connection with which the number
of erroneous diagnoses ranges from 73 to 94.5%. [4, 6 ]
The purpose of this work was to study the morpho-functional changes in various
forms of pulmonary hypoplasia in children. The work is based on the results of
examination and treatment of 93 children with pulmonary hypoplasia aged from 3
months to 15 years, who were hospitalized for the period from 2013 to 2023 in the
clinic of TashPMI and TMA.
The distribution of patients by age was as follows: up to 1 year - 12 children, from
1 year to 5 years - 2 children, from 6 to 10 years - 36, from 11 to 15 years - 24 patients.
There were 55 boys, 33 girls. Lesions of 1 lobe on one side were observed in 53
(56.9%) patients, lesions of 2 lobes on one side - in 14 (15%) patients, lesions of
individual segments in 10 (10.7%) patients, bilateral lesions in 16 (172%) patients.
The examined groups included children with pulmonary hypoplasia: severe form
(SF), simple form (SF), cystic form (CF), congenital lobar emphysema (CLE),
postnatal hypoplastic bronchiectasis (PHB). Congenital lobar emphysema and
postnatal hypoplastic bronchiectasis are described in textbooks and manuals on
pediatric surgery as separate nosological entities. We included them in the pulmonary
hypoplasia group. According to the classification of the Research Institute of
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Pulmonology of the Russian Federation (2000), this is justified by the fact
that all forms of lung underdevelopment are based on hypoplasia of the bronchial wall,
bronchioles and alveoli as a whole or in a limited area of the lung [7,8].
The morphological picture of HL was studied in 39 patients, including 18 (46.1%)
with CF, 3 (7.6%) with VLE, 11 (28.2%) with PF, and 7 (18%) with GSD.
The functional characteristics of external respiration and hemodynamics in the
pulmonary circulation in HL were studied using spirography, echocardiography, and
ECG in 58 (62.3%) children with HL aged 5 to 15 years; the examined children were
divided into 2 groups[9,10]..
The first group
(41 children) included children with antenatal HL (RF, PF, CF,
VLE). The duration of the disease in these children was more than 4 years, the course
was characterized by frequent relapses, occurring with the phenomena of severe
intoxication and respiratory failure.
The second
group (GB, 17 (18.2%) children)
included children whose disease progressed more favorably than in group 1, although
these children suffered from colds quite often. The disease duration exceeded 2 years,
relapses were rare.
Results and discussion
: In cystic hypoplasia of the lungs, the results of
microscopic studies conventionally divided the results into two morphological types:
impaired development of the proximal sections of the bronchial tree and 2)
impaired development as a result of reduction of its distal sections. The first
morphological type of CF could be evidence of an ontogenesis disorder that occurs as
a result of pneumomeres, "amputation" of the bronchial tree, which ceases to divide in
the first generations (the first type of bronchographic variants of cystic hypoplasia).
Histologically, this type was characterized by the formation of large cystic cavities,
which were undivided pneumomeres immersed in a stroma poor in vessels. At the same
time, an unordered type of branching was revealed with the transition of large, sharply
dilated and deformed bronchi into cystic cavities. Cystic-altered large-caliber bronchi
are closely located among the fields of fibrous, hyalinized connective tissue, areas of
proliferation of adenomatous structures and muscular sclerosis. Segmental, as well as
interlobular and intralobular bronchi, were not expressed. The cartilaginous framework
of the bronchi was sharply reduced (Fig. 1). In the presence of large cysts, the above-
mentioned signs of cystic hypoplasia are determined in the tissue surrounding them.
Mucous glands, a lining of cylindrical or cubic epithelium, clusters of cartilaginous
islands of various sizes, as well as daughter cysts are constantly visible in the walls of
such cysts. Also characteristic of the first type of CF was the absence of formed alveolar
tissue (Fig. 2).
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The second type was characterized by a simplification of the bronchial
tree structure due to the reduction of small bronchi and partial underdevelopment of
the alveolar tissue. Histologically, cystic cavities were determined, located among the
alveolar parenchyma, which was reduced in quantity. The bronchi were cystically
dilated, their wall was represented by hyalinized connective tissue. The cystic cavities
were lined with columnar epithelium, the flask-shaped cells were atrophied, the walls
of the cavities contained bundles of smooth muscles and fibrous structures without
elements of the bronchial wall. Areas of atelectasis with adenomatous structures and
randomly located fields of muscular sclerosis alternated with foci of emphysema,
sharply dilated respiratory bronchioles and alveoli. A mosaic histological picture was
noted - underdeveloped and cystically altered areas of the lung tissue were presented
along with normally developed bronchi and respiratory sections. The presence of
alveolar structures in areas of cystic hypoplasia can be explained by the fact that when
some bronchial buds stopped developing, others developed up to the respiratory
sections. In this case, the developmental defect of a certain area of the lung was not
continuous, but mosaic in nature. Respiratory sections among bronchial cysts arose not
only when the development of the bronchial tree stopped, but also when the
development processes were distorted, which we have repeatedly seen in histological
studies, when cystically altered bronchi did not end blindly, but continued to divide,
resulting in a branched system of interconnected cysts related to several successive
generations of bronchi. Thus, the presence of respiratory structures, including alveoli,
does not contradict the idea that this defect occurs in the early antenatal period.
Fig. 1. The cystically dilated bronchus has a lumen of a bizarre shape. Its inner surface is
lined with high cylindrical epithelium lying on the basement membrane. Stained with
hematoxylin and eosin. Magnification x 120
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Fig. 2. Small cysts are represented by terminal bronchioles with pronounced lymphoid
peribronchiolar infiltration. Hematoxylin and eosin staining. Magnification x 12
In congenital lobar emphysema, macroscopic examination did not reveal any violations of the
anatomical patency of the lobar and segmental bronchi. The removed lobes were sharply swollen,
pale pink formations of a consistency tightly packed with feathers, without individual emphysematous
bubbles. After cutting off from the root, the lobe did not subside. Histological studies revealed sharply
swollen respiratory bronchioles and alveolar ducts with a noticeable decrease and underdevelopment
of the elastic framework in the respiratory sections (Fig. 3), uneven expansion of the alveoli, without
ruptures of the interalveolar septa, and parenchyma sclerosis. In none of our observations were signs
of malformation of the leading large bronchi found, which indicates the localization of the main
pathology in the respiratory sections (Fig. 4). Macroscopic examination of PF hypoplasia shows that
the lung volume is reduced, the visceral pleura is thickened, the interlobar fissure is obliterated, and
the normal lobar anatomical structure of the lung is absent. The section shows dilated and deformed
segmental and subsegmental bronchi that end blindly with the formation of multiple bronchiectasis.
The microscopic examination allowed us to divide them into 2 conditional types: the first type
included morphological changes around large bronchi - pronounced fibrous changes. The lumen of
small bronchi is narrowed, the mucous and muscular layers are thickened, in some places small
bronchi are dilated with the formation of bronchiectasis. In the defect area, the absence of twisted
bundles of elastin and collagen was found, which gives grounds to speak of the absence of alveolar
tissue. The pulmonary vessels are deformed. Arteriovenous shunts are detected in the root area. In
atelectatic lung tissue, small vessels are narrowed and obliterated due to the proliferation of
connective tissue (Fig. 5).
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Fig. 3. Elements of the bronchiole wall are
hypoplastic and dilated, interalveolar septa are
thinned. Hematoxylin and eosin staining.
Magnification x 200
Fig. 4. Enlarged alveoli, thinned interalveolar
septa, sclerosis and fibrosis in places.
Hematoxylin
and
eosin
staining.
Magnification x 200
In the second type, narrow bronchi continue to the subpleural sections, where they are
arranged in spirals and disintegrate into small trunks; a decrease in the number of bronchial
generations and hypoplasia of the respiratory section were detected in them. In general, these
structures resemble randomly located small bronchi and bronchioles. Their walls are thinned, the
mucous membrane is smoothed, fibrously changed, the number of mucous glands is reduced. Alveoli
are found near them, and it is possible to find communications between them. Signs of inflammation,
expressed to varying degrees, and small bronchioloectasias are also noted (Fig. 6).
Fig. 5. Bronchial wall with dilated bronchial glands, plethora of vessels of the proper plate of
the mucous membrane. Hematoxylin and eosin staining. Enlargement x 200
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Fig. 6. Inflammatory infiltration of the bronchiole wall, in the lumen - secretion with a large number
of neutrophils, cellular detritus. Hematoxylin and eosin staining. Enlargement x 200
Fig. 7. Obliterating bronchiolitis with
adenomatous structures in the bronchial lumen.
Hematoxylin and eosin staining. Magnification x 80
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Fig.8.Bronchioloectasis with pronounced lymphoid peribronchiolar infiltration. Hematoxylin and
eosin staining. Magnification x 120
Сonclusions.
Types of Morphological Changes in Cystic Hypoplasia of the Lungs
:
The results are divided into two types: impaired development of the proximal sections
of the bronchial tree (Type 1) and reduction of the distal sections (Type 2). Type 1 is
characterized by large cystic cavities and the absence of alveolar tissue, while Type 2
involves a simplified bronchial tree structure and partial underdevelopment of alveolar
tissue.
Histological
Features
of
Type
1
Cystic
Hypoplasia
:
This type shows large cystic cavities lacking alveolar tissue, thickened bronchial walls,
and disordered branching of the bronchial tree. Microscopically, cyst walls consist of
hyalinized connective tissue with smooth muscle bundles and fibrous structures, but
no typical bronchial wall elements.
Macroscopic and Microscopic Characteristics of Congenital Lobar
Emphysema
:
Macroscopically, lobar and segmental bronchi remain patent, while the affected lobes
are overinflated. Histologically, there is swelling of respiratory bronchioles and
alveolar ducts, underdevelopment of the elastic framework, and areas of emphysema
and parenchymal sclerosis.
Pathology
of
Pulmonary
Vessels
and
the
Bronchial
Tree
:
Pulmonary vessels are deformed, with arteriovenous shunts in the root zone and
obliteration of small vessels due to connective tissue proliferation. Large cystically
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altered bronchi are surrounded by adenomatous structures, hyalinized
connective tissue, and areas of muscular sclerosis.
Mosaic Histological Pattern
:
Underdeveloped and cystically altered lung tissue alternates with normally
developed bronchi and respiratory sections. This mosaic development suggests that
certain areas of the lung stopped developing early in the antenatal period, with the
presence of branched cystic structures linked to multiple bronchial generations.
Thus, morphological studies indicate that various forms of pulmonary
hypoplasia are characterized by a common feature: underdevelopment, insufficient
differentiation and various disorders of all structural elements of the lung. In the second
type and the third "A" type of HL, morphological changes in the form of alternation of
sections occur, there is a reduction in the branching of the bronchial tree, agenesis of
the respiratory sections and preservation of the alveolar structure of the lung
parenchyma, due to a developmental defect of the organ in the early stages of
embryogenesis. In the third "B" type of HL, the basis of the developmental defect of
the lung is a decrease in the branching of the bronchial tree with preservation of the
pulmonary parenchyma, which can be repatriated.
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8. Chernov A.S., Trofimov V.V. Modern approaches to the treatment of
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