Congenital Anomalies of the Respiratory Tract

Introduction:

Congenital pulmonary anomalies are structural deformities or abnormalities in the developing baby’s lungs when present inside the womb. The respiratory system consists of a respiratory tract divided into two parts: the upper and lower respiratory tract. The upper respiratory tract has three parts: the nose, nasal cavity, and pharynx. In addition, the upper respiratory tract consists of the larynx, trachea, bronchi, and lungs.

What Are the Congenital Anomalies of the Larynx?

The congenital malformations of the larynx are:

• Laryngomalacia: The laryngeal tissues above the vocal cord are soft and floppy. This floppiness causes the tissue to move inwards and partially obstructs the airway. The most common clinical feature is stridor or noisy breathing on inhalation. The epiglottis becomes ‘omega shaped.’

• Laryngeal Cyst: It is a sac-like pouching formed anywhere along the larynx but most frequently above the glottis, on the glottis and vallecula. The cyst consists of fluid or semi-fluid material. The clinical features are voice hoarseness and dyspnea.

• Laryngocele: It is a rare condition in which the saccule of the laryngeal ventricle shows an outward dilation or extension that communicates with the larynx’s lumen. The patient is asymptomatic or shows signs of voice hoarseness, cough, stridor, sore throat, and neck swelling.

• Bifid Epiglottis: It is a very rare condition of the presence of an aperture in the epiglottis, which has failed to fuse during its development. Patients are usually asymptomatic or rarely present with aspiration, airway obstruction, difficulty feeding, and stridor. Bifid epiglottis is one of the signs of Pallister-Hall syndrome.

• Laryngeal Webs: The larynx is made up of a thick fibrous layer of tissues called laryngeal webs that restrict laryngeal movements. So there is a narrowing of the larynx and breathing problems.

• Laryngeal Atresia: This is a rare congenital abnormality where the larynx fails to open and lacks a lumen. The opening is closed by tissue or cartilage. The newborn will have complete airway obstruction and requires immediate tracheostomy to breathe.

• Vocal Cord Paralysis: Vocal cord paralysis is due to loss of control of the muscles that help in phonation. The nerves that supply the muscles do not work properly; hence, the vocal folds do not open or close to produce a voice. It can be an acquired condition and can be unilateral or bilateral. The symptoms are hoarseness and low pitch in voice, shortness of breath, choking while swallowing food, and inability to clear the throat properly.

• Subglottic Stenosis: This means the upper airway is narrowed in part below the vocal cord and above the trachea. The symptoms are shortness of breath, wheezing, and hoarseness.

• Subglottic Hemangioma: It is a mass of blood vessels present below the vocal cords leading to airway obstruction. The symptoms include stridor, cough, and noisy breathing.

• Laryngotracheal Clefts: It is also a rare condition with an abnormal opening between the larynx and esophagus through which the contents of the food pipe can enter the windpipe.

What Are the Congenital Anomalies of the Trachea?

The congenital abnormalities of the trachea are:

• Congenital Tracheal Stenosis: There is a narrowing of the cartilage supporting the trachea leading to airway obstruction. It can be congenital or acquired. The clinical features are wheezing, stridor, pneumonia, and cyanosis.

• Tracheomalacia: It is a rare condition wherein the cartilaginous walls of the trachea are weak at birth and collapses when the baby tries to breathe. The trachea does not develop properly, leading to its floppiness and symptoms like noisy cough, high-pitched breathing, and frequent airway infections.

• Tracheoesophageal Fistula: It is one of the most common congenital anomalies associated with esophageal atresia in most cases. It is an abnormal connection between the esophagus and the trachea. As a result, babies show signs like vomiting, frothing from the mouth, difficulty breathing, and bluish skin while feeding, coughing, or choking.

• Tracheal Agenesis: It is a rare and fatal condition of complete absence of the trachea. It is also known as tracheal atresia, where the trachea is underdeveloped.

What Are the Congenital Anomalies of Bronchi and the Lungs?

The congenital structural anomalies of the bronchi and the lungs are:

• Bronchomalacia: It is a compromised cartilage support of the small airways present below the trachea. The airways collapse during exhalation easily and prevent the clearing of secretions. The symptoms include apnea, recurrent infections, chronic cough, and exercise intolerance.

• Lung Agenesis: A complete absence of the lung, bronchi, and pulmonary artery is called lung agenesis. It is extremely uncommon and lethal. It may be unilateral or bilateral.

• Pulmonary Hypoplasia: It is a condition of underdeveloped lungs, deficient tissue, and blood flow, and less branching in bronchi and alveoli. It is mostly seen in children with diaphragmatic herniation.

• Pulmonary Sequestration: It is a mass of lung tissue without communication with the rest of the tracheobronchial tree. It has two types - intralobar sequestration and extralobar sequestration. It is supplied by an abnormal blood vessel.

• Bronchogenic Cysts: They are cystic malformations derived from the foregut and located in the lungs or the mediastinum. Their symptoms include infection, fever, difficulty swallowing, and other breathing problems.

• Congenital Lobar Emphysema: It is also called congenital lobar overinflation and is characterized by an enlarged or overinflated lobe of the lungs. The upper left lobe is mostly affected. It shows symptoms like wheezing, ronchi, difficulty feeding, cyanosis, and respiratory distress. It has two types- intrinsic and extrinsic lobar emphysema.

• Congenital Adenomatoid Lung Malformation: Also known as congenital pulmonary airway malformation, this condition is characterized by a lung lesion that develops in a fetus. It is a mass of lung tissue on the chest that does not function normally but continues to grow in size. It is the most common type of lung lesion in the fetus. Small lesions do not cause serious problems and can be removed after birth, but large lesions can cause heart problems like fetal heart failure and need immediate treatment. Symptoms include tachycardia and cyanosis.

Conclusion:

Babies born with congenital anomalies of the respiratory system require special care and treatment during the first few years of life. An interprofessional approach and appropriate regular follow-ups are important to lower short and long-term complications. No treatment is required for asymptomatic babies, and an emergency tracheostomy is performed for babies with severe respiratory distress. The prognosis varies from excellent to poor depending on the severity of the anomaly and whether appropriate treatment was provided.