Search :     
Cases
2002-03-14-12 Answer to the case of the week #68 © Brodaty http://www.thefetus.net/

Answer to case #68

February 22-March 714 2002

Geneviève Brodaty, MD, Bettina Bessières, MD, Luc Gourand, MD

Service du Dr Fernand Daffos, Médecine Foetale, Institut de Puériculture, Paris.

A 30-year old patient with unremarkable anamnesis was referred at 24 weeks for a second opinion. The pregnancy was uncomplicated but at 22 weeks a routine ultrasound examination discovered ascites.

At 24 weeks the following images were obtained. The thoracic cavity was filled with a solid echogenic mass resembling liver. The heart was shifted to the left side. No normal lung could be clearly visualized on the left side.

 

 

 

 

 

 

 

An amniocentesis revealed a normal 46XX standard karyotype. Parental counseling led to termination of pregnancy at 25 weeks. At autopsy, there was no other finding (i.e.: no thymus aplasia, no cardiopathy)

Findings:

  • Large right-sided thoracic mass
  • Downwards displacement of the diaphragm
  • Ascites

This is the fetus after delivery:

Note the intact diaphragm and the enlarged right lung

The tracheobronchial tree and the right main stem bronchus with its obstruction distal to the carena

 

Differential diagnosis:

This was not a right diaphragmatic hernia because the liver was in place in the abdomen surrounded by ascites.

This was not a cystic adenomatoid malformation of the lung type III (CCAML III) because energy Doppler indicated a normal distribution of the pulmonary vessels into the right thoracic mass.

Thus tracheal stenosis was thought of. But, because the heart was completely shifted to the left, the diagnosis of right bronchus atresia was proposed prenatally and was confirmed by pathology.

To our knowledge, this is the first reported case of unilateral bronchial atresia diagnosed by ultrasound in the second trimester of pregnancy.

Discussion:

The first prenatal diagnosis of laryngo-tracheal obstruction was reported in1989 [1]. This is a rare anomaly. In 2000, only 12 such prenatally diagnosed cases had been reported [2].

Upper respiratory tract obstruction is usually associated with bilateral enlarged uniformly hyperechogenic lungs. The diaphragmatic is inverted, bulging downwards into the abdomen. 

The presence of fluid-filled trachea and bronchi indicates laryngeal atresia.

Kalache & al. [3­] studied ultrasound measurements of the trachea, larynx and pharynx throughout gestation, as a mean to diagnose upper respiratory obstructive anomalies tract. He noted that in fetuses with laryngeal atresia only the tracheal diameter was significantly higher compared with that of normal fetuses.

As in our case, Okamura & al. [4] reported color Doppler findings as the most important characteristic for distinguishing fetal upper respiratory obstruction from other echogenic changes in the fetal chest such as CCAML III. They underlined the increased blood flow but they did not emphasize, as we do, the integrity of the pulmonary vessels architecture into the thoracic mass. We believe this point essential to eliminate two differential diagnoses: CCAML III and lung sequestration.  

In all published cases, upper respiratory obstruction was associated with ascites or fetal hydrops, which were interpreted as a sign of congestive (right) heart failure. Doppler flow measurements to the inferior vena cava, umbilical vein and ductus venosus showed signs of compromised fetal circulation [6].

The volume of amniotic fluid can be normal, as in our case.

Kassanos & al. [5] suggest that oligohydramnios (due to the obstructed drainage of lung liquid) may be helpful in distinguishing the upper respiratory tract obstruction from CCAML III.

In some cases, polyhydramnios might result from esophagus compression.

Associated syndromes:

Laryngo-tracheal atresia may be part of different syndromes: Fraser, Di George, VATER association, and rhizomelic chondrodysplasia punctata.

  • Fraser syndrome: autosomal recessive, cryptophthalmia, syndactyly and other anomalies like laryngeal atresia, genito-urinary tract anomalies. In a review [6] of 16 Fraser cases, 8 were diagnosed prenatally with hyperechoic lungs, oligohydramnios, and ascites.

  • Di George: 22q11 microdeletion, conotruncal-cardiopathy with thymus aplasia or hypoplasia, parathyroid hypoplasia. Laryngeal atresia has been described in 3 neonates with DiGeorge anomaly [7]. 

  • The combination of a VATER-association with tracheal atresia has only been reported twice [8].

Conclusions:

Upper respiratory tract obstruction is uncommon in fetal life. Yet, the diagnosis is feasible prenatally by ultrasound: enlarged hyperechoic lungs associated with ascites or hydrops.

Energy Doppler, by demonstrating the integrity of the pulmonary vessels architecture into the thoracic mass, may be helpful to eliminating two differential diagnoses: CCAML III and lung sequestration for which the prognosis might be quite different.

References  

1         Ariziwa M, Imai S, Suehara N, Nakayama M,.Prenatal diagnosis of laryngeal atresia. Acta    Obstet Gynecol Jpn 1989; 41:907-10

2         Haugen G, Jenum P.A., Scheie D, Sund S, Stray-Pedersen B,.Prenatal diagnosis of tracheal obstruction: possible association with maternal pertussis infection . Ultrasound Obstet Gynecol 2000; 15:69-73

3         Kalache KD, Franz M, Chaoui R, Bollmann R . Ultrasound measurements of the diameter of the fetal trachea, larynx and pharynx  throughout gestation applicability to prenatal diagnosis of obstructive anomalies of the upper respiratory-digestive tract. Prenat diagnosis 1999 Mar; 19(3): 211-8

4         Okumura M, Itakura A, Kurauchi O; Nakagawa A, Mizutani S. Color doppler sonographic findings of fetal upper respiratory tract obstruction.. Ultrasound Obstet gynecol  2000; 16: 667-668.

5         Kassanos D, Christodoulou CV, Agapitos E, Pavlopoulos PM, Pagalos N .Prenatal ultrasonographic detection of the tracheal atresia sequence. Ultrasound  Obstetric Gynecol 1997; 10: 133-6

6         Berg C, Geipel A, Germer U, Petersen-Hansen A, Korch-D?ffler M, Gembruch U.  Prenatal detection of Fraser syndrome without cryptophtalmy: case report and review of the literature. Ultrasound Obstet Gynecol 2001; 18:76-80

7         Moerman P, de Zegher F, Vandenberghe K, Devlieger H, Petit P, Lauweryns JM, Fryns JP. Laryngeal atresia sequence as part of the DiGeorge developmental field defect. Genet Couns 1992; 3: 133-7

8         Baarsma R, Bekedam DJ, Visser GH. Qualitative abnormal fetal breathing movements associated with tracheal atresia. Early hum Dev 1993 Feb; 32(1): 63-9

Back to case
Help Support TheFetus.net :