CHAPTER 5: THE CHEST

5.0 OVERVIEW: CONGENITAL LUNG LESIONS

There are multiple echogenic lung lesions that must await neonatal assessment to determine a specific diagnosis. The generic term congenital lung lesion (CLL) should be used, instead of trying to make a histologic diagnosis based on specific sonographic criteria.

There has been a rise in the number of CLLs over the past 20 years to the current rate of 4.15 cases per 10,000 births. This appears to be a true rise in incidence rather than increased antenatal recognition because of the prevalence of second- and third-trimester ultrasound examinations.

Fetal assessment/management should be based on the sonographic criteria that can be evaluated on serial examinations: gestational age at first detection, the size of the mass, mediastinal deviation, eversion of the diaphragm, cystic and solid components, detection of a feeding vessel to the mass, and signs of hydrops.

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5.1 CONGENITAL HIGH AIRWAY OBSTRUCTION SYNDROME

EPIDEMIOLOGY/GENETICS

Definition Laryngeal atresia is the most common etiology of congenital high airway obstruction syndrome (CHAOS). Other etiologies of CHAOS include tracheal agenesis, tracheal atresia, subglottic stenosis, laryngeal web, tracheal membrane, and laryngeal cyst.

Epidemiology True incidence is unknown.

Embryology Tracheal or laryngeal atresia is thought to result from failure of recanalization of the upper airway. CHAOS occurs with Fraser syndrome (autosomal recessive), which has laryngeal atresia, urogenital abnormalities, and syndactyly. Fetal hydrops or polyhydramnios may occur. It has also been reported with cri du chat (5p-) syndrome, short-rib polydactyly syndrome, and the velocardiofacial syndrome.

Inheritance Patterns Inheritance is sporadic in most cases and autosomal recessive in the case of Fraser syndrome. One case of autosomal dominant inheritance has been reported with an affected father and two children.

Teratogens None are described.

Prognosis The absence of hydrops is associated with survival but with significant morbidity. Respiratory function is rarely normal due to long-term exposure to high airway pressure. The presence of other anomalies worsens the prognosis with CHAOS.

SONOGRAPHY

FREQUENT FINDINGS

• Large diffusely echogenic lungs

• Dilated airways distended with fluid

• Inverted diaphragms

• Heart compression from lung expansion

• Splaying of the ribs due to enlarged fetal lungs

• Ascites

LESS FREQUENT

• Hydrops

  • Pericardial effusion

  • Pleural effusion

  • Anasarca

  • Placentomegaly

• Polyhydramnios

• Mirror ...