Respiratory System - Abnormalities

From Embryology
Revision as of 08:11, 28 February 2012 by S8600021 (talk | contribs) (Search Pubmed)


Abnormalities of the respiratory system include not only lung development but also the upper respiratory tract, the supporting musculoskeletal system and the vascular system. In addition, some respiratory problems arise from prematurity of birth or difficulty with the birth process itself.

Respiratory Links: respiratory | Science Lecture | Lecture Movie | Med Lecture | Stage 13 | Stage 22 | upper respiratory tract | diaphragm | Histology | Postnatal | respiratory abnormalities | Respiratory Quiz | Respiratory terms | Category:Respiratory
Historic Embryology  
1902 The Nasal Cavities and Olfactory Structures | 1906 Lung | 1912 Upper Respiratory Tract | 1912 Respiratory | 1914 Phrenic Nerve | 1918 Respiratory images | 1921 Respiratory | 1922 Chick Pulmonary Vessels | 1934 Right Fetal Lung | 1936 Early Human Lung | 1937 Terminal Air Passages | 1938 Human Histology

Abnormality Links: abnormal development | abnormal genetic | abnormal environmental | Unknown | teratogens | ectopic pregnancy | cardiovascular abnormalities | coelom abnormalities | endocrine abnormalities | gastrointestinal abnormalities | genital abnormalities | head abnormalities | integumentary abnormalities | musculoskeletal abnormalities | limb abnormalities | neural abnormalities | neural crest abnormalities | placenta abnormalities | renal abnormalities | respiratory abnormalities | hearing abnormalities | vision abnormalities | twinning | Developmental Origins of Health and Disease |  ICD-11
Historic Embryology  
1915 Congenital Cardiac Disease | 1917 Frequency of Anomalies in Human Embryos | 1920 Hydatiform Degeneration Tubal Pregnancy | 1921 Anencephalic Embryo | 1921 Rat and Man | 1966 Congenital Malformations

Some Recent Findings

  • Surfactant Metabolism Dysfunction and Childhood Interstitial Lung Disease (chILD).[1] "Surfactant deficiency and the resultant respiratory distress syndrome (RDS) seen in preterm infants is a major cause of respiratory morbidity in this population. Until recently, the contribution of surfactant to respiratory morbidity in infancy was limited to the neonatal period. It is now recognised that inborn errors of surfactant metabolism leading to surfactant dysfunction account for around 10% of childhood interstitial lung disease (chILD)."

Tracheoesophageal Fistula

(Tracheo-Oesophageal Fistula, Oesophageal Atresia) - Oesophageal Atresia with or without tracheo-oesophageal fistula

Lobar Emphysema (Overinflated Lung)

Congenital lobar emphysema
  1. There is an overinflated left upper lobe
  2. There is a collapsed lower lobe
  3. The left lung is herniating across the mediastinum

Congenital Diaphragmatic Hernia

File:Adult diaphragm.jpg
Normal Adult Diaphragm

Failure of the pleuroperitoneal foramen (foramen of Bochdalek) to close allows viscera into thorax. Intestine, stomach or spleen can enter the pleural cavity, compressing the lung.

Australian Statistics

A recent Western Australian study[2] of congenital diaphragmatic hernia (CDH) outcomes showed:

  • 35% of live-born infants died before referral or transport.
  • population of infants reaching center represented only 40% of the total cases
  • 92% percent of postoperative infants survived beyond 1 year of age
  • 80% of infants who reached the surgical referral center
  • only 52% of live-born infants, 32% of all cases, and 16% of all prenatally diagnosed cases survived.
  • the overall mortality rate for this condition remains high
  • 33% of all cases of CDH and 49% of prenatally diagnosed fetuses underwent elective termination of pregnancy
  • the number of fetal terminations confounds the accurate assessment of the true outcomes of this condition

Links: Musculoskeletal System - Abnormalities | GeneReviews

Azygos Lobe

Lung azygos lobe in the adult.

Lung Azygos Lobe 02.jpg

Common anatomical variation occurring in about 0.5% of the population. The right lung upper lobe expands either side of the posterior cardinal. There is also some course variability of the phrenic nerve in the presence of an azygos lobe.

Congenital Laryngeal Webs

Laryngeal abnormality due to embryonic (week 10) incomplete recanalization of the laryngotracheal tube during the fetal period. Rare abnormality occuring mainly at the level of the vocal folds (glottis).

Meconium Aspiration Syndrome

Newborn X-ray Meconium aspiration syndrome

(MAS) Meconium is the gastrointestinal contents that accumulate in the intestines during the fetal period. Fetal stress in the third trimester, prior to/at/ or during parturition (birth) can lead to premature meconium discharge into the amniotic fluid and sunsequent ingestion by the fetus and damage to respiratory function. Damage to placental vessels meconium myonecrosis may also occur.

  • meconium is formed from gut and associated organ secretions as well as cells and debris from the swallowed amniotic fluid.
  • Meconium accumulates during the fetal period in the large intestine (bowel). It can be described as being a generally dark colour (green black) , sticky and odourless.
  • Normally this meconium is defaecated (passed) postnatally over the first 48 hours and then transitional stools from day 4.
  • Abnormally this meconium is defaecated in utero, due to oxygen deprivation and other stresses. Premature discharge into the amniotic sac can lead to mixing with amniotic fluid and be reswallowed by the fetus. This is meconium aspiration syndrome and can damage both the developing lungs and placental vessels.

Australian Statistics

The following Australia and New Zealand (1995 - 2002) data is from a recent (2009) study, the epidemiology of meconium aspiration syndrome: incidence, risk factors, therapies, and outcome.[3]

  • Data were gathered on all of the infants in Australia and New Zealand who were intubated and mechanically ventilated with a primary diagnosis of MAS (MASINT) between 1995 and 2002, inclusive.
  • MASINT occurred in 1061 of 2,490,862 live births (0.43 of 1000), with a decrease in incidence from 1995 to 2002.
  • A higher risk of MASINT was noted at advanced gestation, with 34% of cases born beyond 40 weeks, compared with 16% of infants without MAS.
  • Fetal distress requiring obstetric intervention was noted in 51% of cases, and 42% were delivered by cesarean section.
  • There was a striking association between low 5-minute Apgar score and MASINT.
  • Risk of MASINT was higher where maternal ethnicity was Pacific Islander or indigenous Australian and was also increased after planned home birth.
  • Uptake of exogenous surfactant, high-frequency ventilation, and inhaled nitric oxide increased considerably during the study period, with >50% of infants receiving > or =1 of these therapies by 2002.
  • Risk of air leak was 9.6% overall, with an apparent reduction to 5.3% in 2001-2002.
  • The duration of intubation remained constant throughout the study period (median: 3 days), whereas duration of oxygen therapy and length of hospital stay increased.
  • Death related to MAS occurred in 24 infants (2.5% of the MASINT cohort; 0.96 per 100,000 live births).

Newborn Respiratory Distress Syndrome

(Hyaline Membrane Disease) medline plus | eMedicine

Surfactant Metabolism

(pulmonary surfactant metabolism dysfunctions, surfactant dysfunction disorders) For review of genetic disorders of surfactant dysfunction[4]

Mutations in the genes encoding:

  • surfactant protein B (SP-B)
  • surfactant protein C ( SP-C)
  • phospholipid transporter ABCA3

Bronchopulmonary Dysplasia

A chronic lung disease which can occur following premature birth and related lung injury. The definition of bronchopulmonary dysplasia (BPD) has in recent years changed from a severe lung injury and associated repair, to more of a disruption of lung growth in older infants.[5]

Most infants who develop BPD are born more than 10 weeks before their due dates, weigh less than 1,000 grams (about 2 pounds) at birth, and have breathing problems. Infections that occur before or shortly after birth also can contribute to BPD.

Links: NIH - NHLBI

Cystic Fibrosis

UK deaths from cystic fibrosis [6]

Cystic Fibrosis (CF) is a serious genetic disease due to abnormal chloride channel synthesis (cystic fibrosis transmembrane conductance regulator, CFTR), the impact occurs postnatally. Mucus accumulates mainly in the passages of the lungs and in the pancreas.

Links: PubMed Health | OMIM | USA National Heart Lung and Blood Institute | Cystic Fibrosis Australia


List of respiratory related abnormalities Respiratory and Diaphragmatic Hernia.


  1. <pubmed>19252722</pubmed>
  2. <pubmed>16140678</pubmed>
  3. <pubmed>16651329</pubmed>
  4. <pubmed>19220077</pubmed>
  5. <pubmed>19712501</pubmed>
  6. PMID 21862532 | BMJ


<pubmed>20727133</pubmed> <pubmed>17272782</pubmed> <pubmed>15819986</pubmed>


<pubmed>19381312</pubmed> <pubmed>20004027</pubmed> <pubmed>20318245</pubmed> <pubmed>2017954</pubmed> <pubmed>6787889</pubmed> <pubmed>19436785</pubmed>

Search Pubmed

Search Pubmed: Respiratory System Developmental Abnormalities | Tracheoesophageal Fistula | Bronchopulmonary Dysplasia | Congenital Laryngeal Webs | Hyaline Membrane Disease | Meconium Aspiration Syndrome

External Links

External Links Notice - The dynamic nature of the internet may mean that some of these listed links may no longer function. If the link no longer works search the web with the link text or name. Links to any external commercial sites are provided for information purposes only and should never be considered an endorsement. UNSW Embryology is provided as an educational resource with no clinical information or commercial affiliation.

Glossary Links

Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link

Cite this page: Hill, M.A. (2019, October 16) Embryology Respiratory System - Abnormalities. Retrieved from

What Links Here?
© Dr Mark Hill 2019, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G