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

Status Asthmaticus: Differential Diagnoses & Workup

Author: Adam J Schwarz, MD, Consulting Staff, Critical Care Division, Pediatric Subspecialty Faculty, Children's Hospital of Orange County
Contributor Information and Disclosures

Updated: Apr 8, 2009

Differential Diagnoses

Airway Foreign Body
Inhalation Injury
Aspiration Syndromes
Lymphadenopathy
Bronchiectasis
Pulmonary Artery Sling
Bronchiolitis
Respiratory Syncytial Virus Infection
Cystic Fibrosis
Tracheomalacia
Gastroesophageal Reflux
Vascular Ring, Double Aortic Arch
Heart Failure, Congestive

Workup

Laboratory Studies

  • Selection of laboratory studies depends on historical data and patient condition.
  • Pulse oximetry provides a continuous evaluation of oxygen saturation, which is vitally important because the primary cause of death in status asthmaticus is hypoxia.
    • The advantages of pulse oximetry are that pulse oximetry is readily available, it is noninvasive, it provides continuous monitoring, and it is a good indicator of hypoxemia resulting from V/Q mismatch.
    • The disadvantages of pulse oximetry are that movement artifact can be significant and pulse oximetry may provide an erroneous reading when pulsatile flow is inadequate (ie, shock with poor perfusion) or in the presence of anemia.
  • The use of blood gas determination is controversial. The information generated by a blood gas measurement may be helpful in making a determination of whether to intubate a patient with asthma. However, such decisions are usually made on the basis of clinical grounds in a patient who is either in respiratory arrest or impending respiratory arrest. If a patient with acute asthma has adequate peripheral oxygen saturation, is receiving further therapy, and does not warrant immediate intubation, then the use of the blood gas information should be considered against the potential pain and agitation that it may cause in the child. Improvement or deterioration in acute asthma can generally be followed clinically. Indwelling arterial catheters reduce the pain issue and generate highly reliable and reproducible information.
  • Serum electrolyte measurement is important, particularly to monitor serum potassium levels. Medications used to treat status asthmaticus may cause hypokalemia. A low pH may result in a transient elevation of potassium.
  • Serum glucose levels may become elevated from stress, use of beta-agonist agents, such as epinephrine, and from the use of corticosteroids. However, because of poor stores, hypoglycemia may develop in younger children in response to stress.
  • A CBC count and differential may demonstrate an elevated white blood cell count, with or without a shift to the left. CBC count may also indicate a bacterial infection; however, beta-agonists and corticosteroids may result in demargination of white cells with an increase in the peripheral white cell count.
  • Blood theophylline levels provide an important monitoring component in patients taking theophylline (either at home or while hospitalized) and especially in those who have received a bolus infusion of theophylline followed by continuous intravenous infusion. The volume of distribution of theophylline is 0.56 mg/L in children and adults. A dose of 1 mg/kg of theophylline raises the serum level by approximately 2 mg/dL.
  • If theophylline is used in the management of asthma, monitor serum levels. If the patient has been receiving theophylline at home, obtain a serum theophylline level before therapy. Following a loading dose (if needed), obtain a serum level 30 minutes after the end of the infusion. For serum theophylline steady-state levels, obtain a serum sample at 24-36 hours in children younger than 6 months, at 12-24 hours for those aged 6 months to 12 years, and at 24 hours for children aged 12 years and older.
    • Factors that decrease theophylline clearance (increase levels) include cimetidine, erythromycin and other macrolide antibiotics, viral infections, cirrhosis, fever, propranolol, and ciprofloxacin.
    • Factors that increase theophylline clearance (decrease levels) are intravenous isoproterenol, phenobarbital, smoking, phenytoin, and rifampin.
  • Peak flow monitoring provides an objective measure of airflow obstruction in children old enough and able to tolerate this maneuver without exacerbating their reactive airways disease.

Imaging Studies

  • Chest radiography is indicated in children who have an atypical presentation or in those who do not respond to therapy.
  • In children with a known diagnosis of asthma, chest radiography is indicated when pneumonia, pneumothorax, pneumomediastinum, or significant atelectasis is suspected.

Other Tests

Pulmonary function testing can be useful to quantify the severity of disease and response to therapy; it should be performed in children who are old enough and who are capable of cooperating.

  • FEV 1  is used to monitor the degree of airway obstruction. In patients who are acutely ill, peak flow monitoring is more commonly performed.
  • Findings may be diminished in other pulmonary function tests (eg, maximum expiratory flow rate, mid-maximum expiratory flow rate, forced vital capacity). Functional residual capacity and residual volume increase because of air trapping; however, these tests require the child being in a body plethysmograph, which is impractical in the severely ill child.

Procedures

  • Tracheal intubation and mechanical ventilation are indicated for respiratory failure. Noninvasive ventilation may be tried to reduce the work of breathing and fatigue in order to avoid intubation.
  • Placement of an indwelling arterial catheter is indicated for blood gas sampling and continuous blood pressure measurement in patients with mechanical ventilation. The arterial waveform can also be used for measurement of pulsus paradoxus.
  • Chest tube placement may be necessary in the management of pneumothorax.

More on Status Asthmaticus

Overview: Status Asthmaticus
Differential Diagnoses & Workup: Status Asthmaticus
Treatment & Medication: Status Asthmaticus
Follow-up: Status Asthmaticus
Multimedia: Status Asthmaticus
References
Further Reading
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References

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  2. National Asthma Education and Prevention Program (NAEPP) Expert Panel. Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. 2007. National Heart, Lung, and Blood Institute; August 28, 2007. [Full Text].

  3. [Best Evidence] Castro-Rodriguez JA, Rodrigo GJ. Efficacy of inhaled corticosteroids in infants and preschoolers with recurrent wheezing and asthma: a systematic review with meta-analysis. Pediatrics. Mar 2009;123(3):e519-25. [Medline].

  4. Ciarallo L, Brousseau D, Reinert S. Higher-dose intravenous magnesium therapy for children with moderate to severeacute asthma. Arch Pediatr Adolesc Med. Oct 2000;154(10):979-83. [Medline].

  5. Stephanopoulos DE, Monge R, Schell KH, et al. Continuous intravenous terbutaline for pediatric status asthmaticus. Crit Care Med. Oct 1998;26(10):1744-8. [Medline].

  6. Ream RS, Loftis LL, Albers GM, et al. Efficacy of IV theophylline in children with severe status asthmaticus. Chest. May 2001;119(5):1480-8. [Medline]. [Full Text].

  7. Wheeler DS, Jacobs BR, Kenreigh CA, et al. Theophylline versus terbutaline in treating critically ill children with statusasthmaticus: a prospective, randomized, controlled trial. Pediatr Crit Care Med. Mar 2005;6(2):142-7. [Medline].

  8. [Best Evidence] Kim IK, Phrampus E, Venkataraman S, Pitetti R, Saville A, Corcoran T. Helium/oxygen-driven albuterol nebulization in the treatment of children with moderate to severe asthma exacerbations: a randomized, controlled trial. Pediatrics. Nov 2005;116(5):1127-33. [Medline].

  9. Kudukis TM, Manthous CA, Schmidt GA, Hall JB, Wylam ME. Inhaled helium-oxygen revisited: effect of inhaled helium-oxygen during the treatment of status asthmaticus in children. J Pediatr. Feb 1997;130(2):217-24. [Medline].

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  15. Scarfone RJ, Loiselle JM, Joffe MD, et al. A randomized trial of magnesium in the emergency department treatment of childrenwith asthma. Ann Emerg Med. Dec 2000;36(6):572-8. [Medline].

  16. Schuh S, Johnson DW, Callahan S, et al. Efficacy of frequent nebulized ipratropium bromide added to frequent high-dosealbuterol therapy in severe childhood asthma. J Pediatr. Apr 1995;126(4):639-45. [Medline].

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  18. Werner HA. Status asthmaticus in children: a review. Chest. Jun 2001;119(6):1913-29. [Medline]. [Full Text].

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  20. Zorc JJ, Pusic MV, Ogborn CJ, et al. Ipratropium bromide added to asthma treatment in the pediatric emergency department. Pediatrics. Apr 1999;103(4 Pt 1):748-52. [Medline]. [Full Text].

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Further Reading

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Keywords

asthma, asthma unresponsive to treatment with bronchodilators, wheezing, dyspnea, cough, reactive airways disease, RAD, severe asthma, status asthmaticus, airway hyperresponsiveness, emesis, ventilation/perfusion mismatch, V/Q mismatch, hyperventilation, respiratory alkalosis, respiratory distress, air trapping, hyperinflation, hypoxemia, hypercarbia, atopy, tachyphylaxis, bronchospasm, airway inflammation, mucus plugging, carbon dioxide retention, respiratory failure, obstructed airway, mast cell degranulation, acute asthma, bronchopulmonary dysplasia, respiratory syncytial virus, RSV, atopy, allergies, bradycardia, hypoventilation, cardiorespiratory arrest, hypotension, bronchiolitis, cystic fibrosis, congestive heart failure, CHF, tension pneumothorax, gastroesophageal reflux disease

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Contributor Information and Disclosures

Author

Adam J Schwarz, MD, Consulting Staff, Critical Care Division, Pediatric Subspecialty Faculty, Children's Hospital of Orange County
Adam J Schwarz, MD is a member of the following medical societies: American Academy of Pediatrics and Phi Beta Kappa
Disclosure: Nothing to disclose.

Medical Editor

G Patricia Cantwell, MD, Associate Clinical Professor, Department of Pediatrics, University of Miami; Director of Pediatric Critical Care Medicine, Miller School of Medicine, Jackson Children's Hospital
G Patricia Cantwell, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Emergency Physicians, American Heart Association, American Trauma Society, National Association of EMS Physicians, Society of Critical Care Medicine, and Wilderness Medical 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 financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner

Managing Editor

Barry J Evans, MD, Assistant Professor of Pediatrics, Temple University Medical School; Director of Pediatric Critical Care and Pulmonology, Associate Chair for Pediatric Education, Temple University Children's Medical Center
Barry J Evans, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Chest Physicians, American Thoracic Society, and Society of Critical Care Medicine
Disclosure: Nothing to disclose.

CME Editor

Mary E Cataletto, MD, Associate Director, Division of Pediatric Pulmonology, Winthrop University Hospital; Professor of Clinical Pediatrics, State University of New York at Stony Brook; Director of Children's Sleep Services, Winthrop University Hospital
Mary E Cataletto, MD is a member of the following medical societies: American Academy of Pediatrics and American College of Chest Physicians
Disclosure: Shering Plough Pharmaceuticals Honoraria Consulting

Chief Editor

Michael R Bye, MD, Professor of Clinical Pediatrics, Division of Pulmonary Medicine, Columbia University College of Physicians and Surgeons; Attending Physician, Pediatric Pulmonary Medicine, Morgan Stanley Children's Hospital of New York Presbyterian, Columbia University Medical Center
Michael R Bye, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Chest Physicians, and American Thoracic Society
Disclosure: Merck Honoraria Speaking and teaching

 
 
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