Introduction
The pathology of lung development is manifold and the spectrum goes from the absence of whole parts of the lungs up to small intrapulmonary abnormalities that have no functional consequences.
Pulmonary atresia
This abnormality is fatal. Probably this defect arises from a fundamental disorder of the epithelio-mesenchymal interaction, upon which the entire development of the lungs is based.
Laryngotracheal fistulas
Laryngotracheal fistulas are relatively frequent. They arise from a disturbed separation of the lung buds from the esophagus during the early development of the respiratory tract. There are numerous variations in the form of this disorder but all have in common a stenosis or atresia of a segment of the trachea or the esophagus with variable connections in between.
Attacks of coughing in a direct association with the intake of nutriments and uncontrollable bronchitis indicate clinically a disordered swallowing with aspiration.
- A
- Atresia of the esophagus with
the rudiment of a fistula - B
- Atresia of the esophagus
- C
- Atresia of the esophagus with
fistula of the lower esophagus-
stump towards trachea - D
- Atresia of the esophagus with
fistula of the upper esophagus-
stump towards trachea - 1
- Trachea
- 2
- Esophagus
There are many variations of abnormalities between the trachea and the esophagus.
Respiratory Distress Syndrome (RDS)
This disorder appears mainly in premature newborns. It manifests on the 2nd day of life at the latest with the formation of a hyaline membrane in the pulmonary alveoli. The cause is a disorder in the unfolding of the alveoli due to a deficiency of surfactant. Clinically the infants exhibit superficial, rapid breathing (tachypnoea) and cyanosis.
Surfactant is only produced in sufficient quantities from the 34th /35th week of pregnancy. Without the surfactant the lungs collapse, this being known as atelectasis. Breathing is thereby strongly confined and no uptake of oxygen occurs. Therapeutically surfactant obtained from animal lungs or manufactured artificially, can be introduced into the afflicted lungs as an emulsion and thereby increase the chances of survival.
The surfactant consists to 90% of dipalmitoyl-phosphatidylcholine (= lecithin, esterized with two palmitic acid molecules). In order to determine fetal lung maturity in a case of impending premature birth, the lecithin/sphingomyelin quotient in the amniotic fluid is measured; with a value > 2 a newborn RDS is unlikely to develop.
Congenital cysts in the lungs
One distinguishes between bronchogenic cysts and pulmonary cysts. The latter arise later during gestation so they can also contain alveolar structures. They are to be found more often in the lung periphery and, in contrast to the bronchogenic cysts, have as a rule a connection with the bronchial tree, so that they are filled with air.
| |
Bronchogenic cysts | Pulmonary cysts | |
|
Localization
|
Interpleural | intrapulmonary |
lung periphery
|
| Air-filled | very rarely | seldom |
as a rule
|
| Symptom | dyspnea | ||
| Diagnostic | thorax x-ray, computer tomography | ||
|
Therapy
|
surgical resection | ||
Tracheomalacia
Tracheomalacia in the newborn is a congenital stenosis of the trachea due to pressure from the outside as a result of aberrant vessels (arteria lusoria, doubled aortic arches) or cysts (esophagus diverticulum, neck cysts). Cartilaginous ring anomalies can also lead to a tracheomalacia.
The main symptom is an inspiratory - partially also expiratory - stridor (wheeze). The diagnosis is made by bronchoscopic visualization.
Therapy: wait and see with tracheomalacia and light stenosis; proceed surgically with vascular anomalies, cysts, compression due to tumors, lymph nodes, etc.
The benign connatal stridor "happy wheezer", caused by an under-developed, infantile larynx or cartilage bridges that are too soft, mostly disappears by the 18th month, because at that age the cartilaginous bridges also stabilize.