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Infant Respiratory Distress Syndrome

Last updated Oct. 9, 2018

Approved by: Maulik P. Purohit MD, MPH

Infant Respiratory Distress Syndrome (IRDS) is a breathing disorder in newborns, which results primarily due to premature delivery of the baby. The condition arises owing to reduced amounts of surfactants in immature lungs.

What are the other Names for this Condition? (Also known as/Symptoms)

  • Hyaline Membrane Disease in Newborns
  • Neonatal Respiratory Distress Syndrome
  • Surfactant Deficiency in Newborns

What is Infant Respiratory Distress Syndrome? (Definition/Background Information)

  • Infant Respiratory Distress Syndrome (IRDS) is a breathing disorder in newborns, which results primarily due to premature delivery of the baby. The condition arises owing to reduced amounts of surfactants in immature lungs
  • Surfactants are complex substances that help lower the surface tension of fluids in the lung. This helps keep the alveolar sacs (the sites of oxygen exchange) from collapsing. Thus, a deficiency of surfactants leads to non-compliant and stiff lungs
  • It is estimated that about half of the babies born between weeks 28 and 32 of gestation develop Infant Respiratory Distress Syndrome, which is typically manifested as breathing trouble and bluish discoloration of the skin
  • The diagnosis of Infant Respiratory Distress Syndrome may require chest X-rays and lab tests, apart from physical examination and symptom assessment
  • Treatment options for a newborn with Infant Respiratory Distress Syndrome are geared toward easing breathing difficulties, which may involve the use of artificial surfactants, oxygen therapy, and the use of a breathing machine (if warranted)
  • If the condition does not get resolved in early infancy, it could develop into a more chronic form known as bronchopulmonary dysplasia. In addition, air or gas build-up might occur around the lungs and between the heart and its outer layer. In serious cases, developmental abnormalities affecting the lungs, eyes, and brain might ensue
  • In case of premature labor, treating the pregnant woman with steroids is reported to aid in lung maturity in the fetus. Taking steps to avoid premature deliveries by good prenatal care is a known preventive method for Infant Respiratory Distress Syndrome
  • If diagnosed and treated promptly, the prognosis of Infant Respiratory Distress Syndrome is considered good. However, the prognosis also depends upon the severity of the condition

Who gets Infant Respiratory Distress Syndrome? (Age and Sex Distribution)

  • Infant Respiratory Distress Syndrome occurs primarily in preterm babies. The majority of cases are seen in babies born before the 37th week of gestation
  • Approximately, 50% of babies born between gestational ages of 28-32 weeks develop IRDS
  • Most babies born before the 29th week of gestation have a 60% probability of developing the condition, which may occur within 24 hours of birth
  • IRDS is known to affect both genders, although some studies show that it is more commonly observed in newborn boys than girls, especially among Caucasians
  • The condition is seen across all racial and ethnic groups worldwide

What are the Risk Factors for Infant Respiratory Distress Syndrome? (Predisposing Factors)

The following are some known risk factors for developing Infant Respiratory Distress Syndrome:

  • Premature delivery of the baby i.e., the baby is born before 37 weeks of gestation
  • Newborn baby boys of Caucasian descent have a higher risk for IRDS
  • Being delivered by Cesarean section
  • Having siblings in the past with IRDS
  • Multiple pregnancies (a mother carrying twin babies or more)
  • Mother with conditions such as diabetes during pregnancy
  • Birth following a rapid (precipitated) labor

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your health care provider.

What are the Causes of Infant Respiratory Distress Syndrome? (Etiology)

Infant Respiratory Distress Syndrome is known to occur due to inadequate quantity of surfactants in the lungs. The surfactant is a wetting agent, which

  • Is secreted by the cells in the air sacs of lungs, known as the alveoli
  • Is slippery, and it aids in decreasing the surface tension of fluids in the lungs
  • Helps keep the lungs filled with air, and prevents the alveoli from collapsing or deflating (referred to as atelectasis)

There are two main causes for inadequacy in the amount of surfactants that leads to an Infant Respiratory Distress Syndrome:

  • Premature birth of a baby
    • The surfactant develops late in prenatal life. It is either absent or present in insufficient quantities in fetuses, before 36 weeks of gestation
    • Due to this, when a baby is born before full term, his/her lungs are immature and lacking in surfactants
    • This leads to improper functioning of the lungs and thus, to IRDS
  • A genetic defect leading to abnormal lung development
    • The pulmonary surfactant B gene codes for surfactant protein B (SP-B)
    • A mutation in this gene can lead to abnormal SP-B, and a resultant loss of functional SP-B, leading to the rare genetic IRDS
    • The genetic form of IRDS is inherited in an autosomal recessive manner

Autosomal recessive inheritance: In this type of inheritance, an individual must possess both copies of the causative gene in the defective form in every cell of the body for the condition to manifest itself. Affected individuals inherit a single defective copy of the gene from each parent, who are typically unaffected.

What are the Signs and Symptoms of Infant Respiratory Distress Syndrome?

The signs and symptoms of Infant Respiratory Distress Syndrome typically appear within 24 hours following birth and peak at 2-3 days post-birth. The following are some symptoms of IRDS:

  • Difficulty in breathing, which may be presented as:
    • Shallow breathing
    • A brief stop/pause while breathing
    • Rapid breathing
    • Grunting sounds
    • Abnormal muscle movement of chest when breathing
    • Flaring of nostrils
  • Cyanosis or bluish tinge in skin and mucous membrane
  • Low birth weight
  • Low muscle tone
  • Reduced urination
  • Immature development of genitalia

How is Infant Respiratory Distress Syndrome Diagnosed?

The diagnosis of Infant Respiratory Distress Syndrome is made by the following tools:

  • A thorough physical examination and assessment of symptoms
  • Blood gas analysis to check for oxygen levels: The blood of the infant will show low oxygen and increased acidity of body fluids, if the test is positive for IRDS
  • Chest X-ray of the newborn baby: A “ground glass” appearance of the lungs is indicative of the condition. If a newborn does have IRDS, this typical appearance of the lungs is reported to develop between 6-12 hours after birth
  • Tests to rule out lung infection, which may produce symptoms similar to IRDS
  • Prenatal testing: A sample of amniotic fluid may be drawn to check for the lung maturity of a fetus. Typically, the lecithin-sphyngomyelin ratio (also known as phosphatidylglycerol) is tested. A ratio less than 1%, may be indicative of IRDS after birth
  • Fetal lung maturity fluorescence polarization amniotic fluid test: It helps determine the level of pulmonary surfactant in the lungs of a developing fetus, by measuring its levels in the amniotic fluid

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Infant Respiratory Distress Syndrome?

Infant Respiratory Distress Syndrome can potentially lead to the following complications: 

  • Bronchopulmonary dysplasia, or growth and developmental abnormalities in the lungs
  • Air/gas build-up around the lungs (pneumothorax), between the lungs (pneumomediastinum), and between the heart and its outer layer (pneumopericardium)
  • Developmental abnormalities involving the eyes
  • Bleeding in the brain and lungs, as well as formation of blood clots
  • Bleeding in the lungs because of treatment with surfactants (is a possibility)
  • Brain damage and intellectual deficiency

How is Infant Respiratory Distress Syndrome Treated?

The treatment of Infant Respiratory Distress Syndrome may require the involvement of medical professionals who specialize in newborn care, as well as those who have expertise in pulmonary conditions. The following are some treatment methods for IRDS:

  • Use of warm, moist oxygen to help ease breathing
  • Artificial surfactant therapy, delivered into the baby’s airway
  • Mechanical breathing machines (ventilators) or positive end expiratory pressure (PEEP) may be used, if a baby develops the following:
    • Low blood oxygen levels
    • Elevated blood carbon-dioxide levels
    • Increased acidity of blood
    • Repeat episodes of apnea (interrupted breathing)
  • Maintaining proper body temperature of the affected neonate
  • Addressing infections promptly, if they develop
  • Making sure that the baby’s nutritional and fluid intake needs are met

How can Infant Respiratory Distress Syndrome be Prevented?

The following are some methods and guidelines for the prevention of Infant Respiratory Distress Syndrome:

  • Proper prenatal care during pregnancy, so that premature labor and delivery is avoided
  • If opting for a Cesarean method of delivery, choosing an optimal time for delivery, preferable at full term
  • If inducing labor, or a Cesarean surgery becomes medically necessary, checking the maturity of the fetal lungs with a lab test
    • If a pregnant woman goes into pre-term labor between 24-34 weeks of pregnancy, treating with corticosteroids is reported to aid in hastening lung maturity in the premature baby, as well as help in reducing the severity of IRDS after birth
    • Steroid medication takes time to show benefits. These are typically begun a week prior to delivery

What is the Prognosis of Infant Respiratory Distress Syndrome? (Outcome/Resolutions)

  • The prognosis of Infant Respiratory Distress Syndrome is determined by weeks of gestation, birth weight, and severity of the condition. If IRDS is diagnosed and treated promptly, the outcome is good
  • Infants with low birth weight (under 1000 g or 2.2 lbs) may develop severe IRDS, and the mortality rate in underweight infants is reported to be nearly 50%
  • Additionally, if serious complications occur, developmental delays and intellectual deficiency may take place

Generally, the symptoms of Infant Respiratory Distress Syndrome begin within 24 hours following birth, then worsen and peak in 2-3 days. With appropriate treatment, IRDS stabilizes by the 5th day following birth, and improves thereafter.

Additional and Relevant Useful Information for Infant Respiratory Distress Syndrome:

In the United States, about 10% of the preterm babies are reported to develop Infant Respiratory Distress Syndrome.

What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: July 12, 2017
Last updated: Oct. 9, 2018