eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Neonatology

Meconium Aspiration Syndrome: Differential Diagnoses & Workup

Author: Melinda B Clark, MD, Assistant Professor of Pediatrics, Department of Pediatrics, Albany Medical College
Coauthor(s): David A Clark, MD, Chairman, Professor, Department of Pediatrics, Albany Medical College
Contributor Information and Disclosures

Updated: Dec 2, 2008

Differential Diagnoses

Aspiration Syndromes
Pulmonary Hypertension, Persistent-Newborn
Congenital Diaphragmatic Hernia
Sepsis
Pneumonia
Transient Tachypnea of the Newborn
Pulmonary Hypertension, Idiopathic
Transposition of the Great Arteries

Other Problems to Be Considered

Surfactant deficiency
Congenital heart disease with pulmonary hypertension

Workup

Laboratory Studies

The following studies are indicated in suspected meconium aspiration syndrome (MAS):

  • Acid-base status
    • Ventilation-perfusion (V/Q) mismatch and perinatal stress are prevalent and assessment of acid-base status is crucial.
    • Metabolic acidosis from perinatal stress is complicated by respiratory acidosis from parenchymal disease and persistent pulmonary hypertension of the newborn (PPHN).
    • ABG measurement of pH, partial pressure of carbon dioxide (pCO2), partial pressure of oxygen (pO2), and continuous measurement of oxygenation by pulse oximetry are necessary for appropriate management.
  • Serum electrolytes: Obtain sodium, potassium, and calcium concentrations when the infant with MAS aged 24 hours because the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) and acute renal failure are frequent complications of perinatal stress.
  • CBC count
    • In utero or perinatal blood loss, as well as infection, contributes to postnatal stress.
    • Hemoglobin and hematocrit levels must be sufficient to ensure adequate oxygen-carrying capacity.
    • Thrombocytopenia increases the risk for neonatal hemorrhage.
    • Neutropenia or neutrophilia with left shift of the differential may indicate perinatal bacterial infection.
    • Polycythemia may be present secondary to chronic or acute fetal hypoxia. Polycythemia is associated with decreased pulmonary blood flow and may exacerbate the hypoxia associated with meconium aspiration syndrome and PPHN.

Imaging Studies

  • Chest radiography is essential for the following:
    • To confirm the diagnosis of meconium aspiration syndrome and determine the extent of intrathoracic pathology
    • To identify areas of atelectasis and air block syndromes
    • To assure appropriate positioning of the endotracheal tube and umbilical catheters
  • Later in the course of meconium aspiration syndrome, when the infant is stable, imaging procedures of the brain (eg, MRI, CT scanning, cranial ultrasonography) are indicated, if the infant's neurologic examination findings are abnormal.

Other Tests

  • Echocardiography is necessary to ensure normal cardiac structure and assess cardiac function, as well as determine the severity of pulmonary hypertension and right-to-left shunting.

More on Meconium Aspiration Syndrome

Overview: Meconium Aspiration Syndrome
Differential Diagnoses & Workup: Meconium Aspiration Syndrome
Treatment & Medication: Meconium Aspiration Syndrome
Follow-up: Meconium Aspiration Syndrome
Multimedia: Meconium Aspiration Syndrome
References
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References

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Further Reading

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Keywords

meconium aspiration syndrome, MAS, meconium-stained amniotic fluid, fetal hypoxic distress, intrauterine distress, placental insufficiency, maternal hypertension, preeclampsia, oligohydramnios, maternal drug abuse, neonatal respiratory distress, airway obstruction, surfactant dysfunction, chemical pneumonitis, pulmonary hypertension, atelectasis, persistent pulmonary hypertension of the newborn, PPHN, pneumothorax, pneumomediastinum, pneumopericardium, pulmonary interstitial emphysema, respiratory acidosis, metabolic acidosis, syndrome of inappropriate secretion of antidiuretic hormone, SIADH

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Contributor Information and Disclosures

Author

Melinda B Clark, MD, Assistant Professor of Pediatrics, Department of Pediatrics, Albany Medical College
Melinda B Clark, MD is a member of the following medical societies: Alpha Omega Alpha, Ambulatory Pediatric Association, American Academy of Pediatrics, and Medical Society of the State of New York
Disclosure: Nothing to disclose.

Coauthor(s)

David A Clark, MD, Chairman, Professor, Department of Pediatrics, Albany Medical College
David A Clark, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American Pediatric Society, Christian Medical & Dental Society, Medical Society of the State of New York, New York Academy of Sciences, and Society for Pediatric Research
Disclosure: Nothing to disclose.

Medical Editor

Steven M Donn, MD, Professor of Pediatrics, Director, Neonatal-Perinatal Medicine, Department of Pediatrics, University of Michigan Health System
Steven M Donn, MD is a member of the following medical societies: American Pediatric Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from broker recommendation; Avanir Pharma Stock Investment from broker recommendation

Managing Editor

Brian S Carter, MD, FAAP, Professor of Pediatrics (Neonatology), Vanderbilt University School of Medicine; Co-director, Pediatric Advance Comfort Team, Monroe Carell Jr Children's Hospital at Vanderbilt
Brian S Carter, MD, FAAP is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, National Hospice and Palliative Care Organization, and National Perinatal Association
Disclosure: Nothing to disclose.

CME Editor

Carol L Wagner, MD, Professor of Pediatrics, Medical University of South Carolina
Carol L Wagner, MD is a member of the following medical societies: American Academy of Pediatrics, American Chemical Society, American Medical Women's Association, American Public Health Association, American Society for Bone and Mineral Research, American Society for Clinical Nutrition, Massachusetts Medical Society, National Perinatal Association, and Society for Pediatric Research
Disclosure: Nothing to disclose.

Chief Editor

Ted Rosenkrantz, MD, Professor, Departments of Pediatrics and Obstetrics/Gynecology, Division of Neonatal-Perinatal Medicine, University of Connecticut School of Medicine
Ted Rosenkrantz, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, American Pediatric Society, Connecticut State Medical Society, Eastern Society for Pediatric Research, and Society for Pediatric Research
Disclosure: Nothing to disclose.

 
 
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