Lung sequestration: Epidemiology, Symptoms & Diagnosis
Lung sequestration is characterized by a non-functioning lung tissue with lower airway congenital abnormality. This non-functioning lung tissue is not normally associated with the tracheobronchial tree, and is supplied by the systemic circulation rather than the pulmonary artery. One congenital lower respiratory tract abnormality is found in 10,000 to 35,000 people, the most common being congenital cystic adenomatoid malformation, and lung sequestration is found in 0.15 to 6.4%.
Classification of lung sequestration
Lung sequestration is divided into two types according to location. The standard of location is visceral pleura.
1) Intralobar sequestration: Located in the same visceral pleura as the normal lung, accounting for 75% of the total lung sequestration. They are mainly adolescents and adults, who experience repetitive pneumonia while experiencing the same rate of men and women. Approximately 60% of the cases occur in the left lower lobe, mainly hemoptysis and recurrent pneumonia. The blood supply is mainly supplied from the lower thoracic and upper abdominal aorta, and venous blood flows through the pulmonary vein to the left atrium. Sometimes vena cava, azygous vein, right atrium can also be connected. Unlike extralobar sequestration, other deformities do not accompany well.
2) Extralobar sequestration refers to when a lung lesion has a distinctive visceral pleura that is different from that of a normal lung. It accounts for 25% of the total lung sequestration. It usually occurs in 80% of males, and it is often found incidentally because it is asymptomatic. 80% of extralobar sequestration occurs between the left diaphragm and the left lower lobe. Diaphragmatic hernia, or other dysplasia such as colonic duplication, vertebral abnormalities, and pulmonary hypoplasia. The blood supply is mainly supplied by aberrant vessels from thoracic aorta, which are generally small and have low flow. Venous blood flows through the aberrant vessel, vena cava, and azygous system, which enter the right atrium. Infection does not work well because it has its own visceral pleura.
Clinical manifestation & diagnosis
Overall, there is a decrease in the euphinia and a tingling sensation in the lesion area. If there is an infection, crackle can be heard. , There may be continuous systolic noises.
Diagnosis mainly uses images. It is well known in prenatal ultrasonography. Prenatal ultrasonography shows mainly homogenous echogenic thoracic mass, which is well found in the lower hemithorax near the diaphragm. At this time, even if arterial supply is seen, it is difficult to differentiate it from congenital cystic adenomatoid malformation.
The process of birth evaluation is as follows.
What is symptomatic here?
- Any symptoms (eg, respiratory distress)
- Large LS (occupying> 20 percent of the lobe on ultrasonography or plain radiographs)
- Risk factors for pleuropulmonary blastoma (bilateral or multifocal cysts, pneumothorax, or a family history of pleuropulmonary blastoma)
And the like.
There are four types of images.
X-ray: Uniformly dense mass is seen in thoracic cavity or pulmonary parenchyma. Repeated infections can increase the cystic area and air-fluid levels can be seen at 26%. Most are located in the lower lobe.
CT: Images showing the best lung sequestration can be distinguished by homogenous or heterogeneous solid mass. Sometimes there are occasions when various cystic changes appear. It is good to take contrast CT or helical CT because small blood vessels can not be recognized.
MRI: MRI is a good image to confirm lesion location, aberrant artery, and venous drainage. In particular, MRA can be used to better identify.
US: Ultrasound does not help much in diagnosing lung sequestration. CT, and MRI are better for examining the vessel supply. Doppler US can help to view aberrant systemic artery, venous drainage, and US can help with biopsy.
Classification of lung sequestration
Lung sequestration is divided into two types according to location. The standard of location is visceral pleura.
1) Intralobar sequestration: Located in the same visceral pleura as the normal lung, accounting for 75% of the total lung sequestration. They are mainly adolescents and adults, who experience repetitive pneumonia while experiencing the same rate of men and women. Approximately 60% of the cases occur in the left lower lobe, mainly hemoptysis and recurrent pneumonia. The blood supply is mainly supplied from the lower thoracic and upper abdominal aorta, and venous blood flows through the pulmonary vein to the left atrium. Sometimes vena cava, azygous vein, right atrium can also be connected. Unlike extralobar sequestration, other deformities do not accompany well.
2) Extralobar sequestration refers to when a lung lesion has a distinctive visceral pleura that is different from that of a normal lung. It accounts for 25% of the total lung sequestration. It usually occurs in 80% of males, and it is often found incidentally because it is asymptomatic. 80% of extralobar sequestration occurs between the left diaphragm and the left lower lobe. Diaphragmatic hernia, or other dysplasia such as colonic duplication, vertebral abnormalities, and pulmonary hypoplasia. The blood supply is mainly supplied by aberrant vessels from thoracic aorta, which are generally small and have low flow. Venous blood flows through the aberrant vessel, vena cava, and azygous system, which enter the right atrium. Infection does not work well because it has its own visceral pleura.
Clinical manifestation & diagnosis
Overall, there is a decrease in the euphinia and a tingling sensation in the lesion area. If there is an infection, crackle can be heard. , There may be continuous systolic noises.
Diagnosis mainly uses images. It is well known in prenatal ultrasonography. Prenatal ultrasonography shows mainly homogenous echogenic thoracic mass, which is well found in the lower hemithorax near the diaphragm. At this time, even if arterial supply is seen, it is difficult to differentiate it from congenital cystic adenomatoid malformation.
The process of birth evaluation is as follows.
What is symptomatic here?
- Any symptoms (eg, respiratory distress)
- Large LS (occupying> 20 percent of the lobe on ultrasonography or plain radiographs)
- Risk factors for pleuropulmonary blastoma (bilateral or multifocal cysts, pneumothorax, or a family history of pleuropulmonary blastoma)
And the like.
There are four types of images.
X-ray: Uniformly dense mass is seen in thoracic cavity or pulmonary parenchyma. Repeated infections can increase the cystic area and air-fluid levels can be seen at 26%. Most are located in the lower lobe.
CT: Images showing the best lung sequestration can be distinguished by homogenous or heterogeneous solid mass. Sometimes there are occasions when various cystic changes appear. It is good to take contrast CT or helical CT because small blood vessels can not be recognized.
MRI: MRI is a good image to confirm lesion location, aberrant artery, and venous drainage. In particular, MRA can be used to better identify.
US: Ultrasound does not help much in diagnosing lung sequestration. CT, and MRI are better for examining the vessel supply. Doppler US can help to view aberrant systemic artery, venous drainage, and US can help with biopsy.
