Meconium aspiration syndrome: Difference between revisions
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==Background== | ==Background== | ||
*May cause meconium aspiration syndrome (MAS) in a newborn infant that was born through meconium-stained amniotic fluid (MSAF) | *May cause meconium aspiration syndrome (MAS) in a newborn infant that was born through meconium-stained amniotic fluid (MSAF) | ||
* | *Presentation ranges from mild respiratory distress to life-threatening respiratory failure | ||
*Incidence is 2-10% of infants born through MSAF | *Incidence is 2-10% of infants born through MSAF | ||
*Causes hypoxemia and acidosis via airway obstruction, chemical irritation/inflammation, infection, and surfactant inactivation | *Causes hypoxemia and acidosis via airway obstruction, chemical irritation/inflammation, infection, and surfactant inactivation | ||
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==Differential Diagnosis== | ==Differential Diagnosis== | ||
*Transient tachypnea of the newborn | *Transient tachypnea of the newborn (TTN) | ||
*Sepsis | *Sepsis | ||
*Pneumonia | *Pneumonia | ||
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==Evaluation== | ==Evaluation== | ||
*Workup | |||
**CXR | |||
**ABG | |||
**Echocardiogram | |||
**Blood and sputum cultures | |||
*Clinical diagnosis based on the following: | *Clinical diagnosis based on the following: | ||
**Evidence of meconium on infant | **Evidence of meconium on infant | ||
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***Finally, diffuse patchy opacities (may appear similar to ARDS if severe) | ***Finally, diffuse patchy opacities (may appear similar to ARDS if severe) | ||
**If intubation required, meconium visualized in trachea | **If intubation required, meconium visualized in trachea | ||
*Ways to differentiate between other causes of respiratory distress in a neonate: | |||
**TTN is more common in late preterm infants (34-37 weeks) and RDS in preterm infants, whereas MAS more common in postmature infants (>41 weeks) | |||
**Delayed transition from fetal circulation symptoms improve more quickly than those of MAS | |||
**Congenital cyanotic heart disease is differentiated by physical exam (murmurs, hepatomegaly), CXR (cardiac size/shape), and echocardiogram (cardiac anatomy and function) | |||
==Management== | ==Management== | ||
*Empiric antibiotics while awaiting culture results (because of difficulty differentiating between pneumonia initially) | |||
==Disposition== | ==Disposition== | ||
Revision as of 18:26, 11 October 2017
Background
- May cause meconium aspiration syndrome (MAS) in a newborn infant that was born through meconium-stained amniotic fluid (MSAF)
- Presentation ranges from mild respiratory distress to life-threatening respiratory failure
- Incidence is 2-10% of infants born through MSAF
- Causes hypoxemia and acidosis via airway obstruction, chemical irritation/inflammation, infection, and surfactant inactivation
- Associated with persistent pulmonary hypertension of the newborn (PPHN)
Clinical Features
- Tachypnea
- Cyanosis
- Accessory muscle use (intercostal/subxiphoid retractions, paradoxical breathing, grunting, nasal flaring)
- Barrel-shaped chest
- Rales and rhonchi on lung auscultation
- Pneumothorax
- Pneumomediastinum
- Usually develop symptoms immediately after birth, but sometimes are born asymptomatic and develop symptoms as meconium moves into lower tracheobronchial tree
Differential Diagnosis
- Transient tachypnea of the newborn (TTN)
- Sepsis
- Pneumonia
- Delayed transition from fetal circulation
- Pneumothorax
- Pulmonary edema
- Blood aspiration
Evaluation
- Workup
- CXR
- ABG
- Echocardiogram
- Blood and sputum cultures
- Clinical diagnosis based on the following:
- Evidence of meconium on infant
- Respiratory distress shortly after birth
- Characteristic CXR findings
- Initially, streaky, linear densities
- Next, development of hyperinflated lungs and flattened diaphragm
- Finally, diffuse patchy opacities (may appear similar to ARDS if severe)
- If intubation required, meconium visualized in trachea
- Ways to differentiate between other causes of respiratory distress in a neonate:
- TTN is more common in late preterm infants (34-37 weeks) and RDS in preterm infants, whereas MAS more common in postmature infants (>41 weeks)
- Delayed transition from fetal circulation symptoms improve more quickly than those of MAS
- Congenital cyanotic heart disease is differentiated by physical exam (murmurs, hepatomegaly), CXR (cardiac size/shape), and echocardiogram (cardiac anatomy and function)
Management
- Empiric antibiotics while awaiting culture results (because of difficulty differentiating between pneumonia initially)