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| {{DiseaseDisorder infobox | | | __NOTOC__ |
| Name = Status asthmaticus|
| | {{status asthmaticus}} |
| ICD10 = {{ICD10|J|46||j|40}} |
| | '''For patient information click [[{{PAGENAME}} (patient information)|here]]''' |
| ICD9 = {{ICD9|493.01}}, {{ICD9|493.91}} |
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| }}
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| {{Asthma}}
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| {{CMG}}; {{AOEIC}} {{LG}} | | {{CMG}}; {{AOEIC}} {{LG}} |
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| ==Overview== | | ==[[Status asthmaticus overview|Overview]]== |
| '''Status asthmaticus''' is an [[Acute (medical)|acute]] exacerbation of [[asthma]] that does not respond to standard [[Bronchodilator|bronchodilator]] and [[corticosteroid]] therapy. Symptoms include [[chest tightness]], [[dyspnea|rapidly progressive dyspnea]], [[cough|non-productive cough]] and [[Wheeze|wheezing]]. Status asthmaticus if left untreated may result in severe [[bronchospasm]], mucus plugging and rapidly develops [[acidosis]] and [[respiratory failure]] as a consequent of [[carbon di oxide]] retention and [[hypoxemia]].
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| ==Epidemiology== | | ==[[Status asthmaticus pathophysiology|Pathophysiology]]== |
| Approximately 10% of the US population is affected by asthma with status asthmaticus requiring highest rates of hospitalization.<ref name="pmid18955910">Gorelick M, Scribano PV, Stevens MW, Schultz T, Shults J (2008) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=18955910 Predicting need for hospitalization in acute pediatric asthma.] ''Pediatr Emerg Care'' 24 (11):735-44. [http://dx.doi.org/10.1097/PEC.0b013e31818c268f DOI:10.1097/PEC.0b013e31818c268f] PMID: [http://pubmed.gov/18955910 18955910]</ref>
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| ==Predisposing factors== | | ==[[Status asthmaticus causes|Causes]]== |
| *Increase use of [[bronchodilator]] despite resistance,
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| *Frequent exacerbations despite the use of [[corticosteroids]],
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| *Despite adhering to therapy, a peak flow rate of less than 10% from baseline,
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| *Frequent hospitalization for acute attacks,
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| *History of [[syncope]] or [[seizure]] during an acute asthmatic attack,
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| *Oxygen saturation lower than 92% despite supplemental oxygen,
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| *Airway obstruction is significantly reduced, resulting in severe impairment of air motion that leads to a '''silent chest''' with the absence of [[wheeze]] suggestive of an [[respiratory failure|imminent respiratory arrest]].
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| ==Diagnosis== | | ==[[Status asthmaticus differential diagnosis|Differentiating Status Asthmaticus from other Diseases]]== |
| ===History and Symptoms===
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| *[[dyspnea|Rapidly progressive dyspnea]]
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| *[[cough|Non-productive cough]]
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| *[[sweating|Profuse sweating]]
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| *[[Cyanosis]]
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| *[[Loss of consciousness]] and/or [[seizure]] secondary to [[hypoxia|severe hypoxia]] may be observed
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| *Inability to speak more than one or two words may be observed with severe airway obstruction
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| ===Physical Examination=== | | ==[[Status asthmaticus epidemiology and demographics|Epidemiology and Demographics]]== |
| ====Vital Signs====
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| *[[Tachypnea|Increased respiratory rate]] greater than 30 cycles per minute
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| *[[Tachycardia|Increased heart rate]]
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| *[[Pulsus paradoxus]] (is a fall in [[Systolic blood pressure|SBP]] greater than 20-40 mmHg during inspiration)
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| ====General Physical Examination====
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| *Sit upright with arms extended to support the upper chest ('''tripod position''') that assist the use of accessory muscles of respiration
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| *[[Asthma pulmonary function test#Peak Expiratory Flow Rate|Peak flow rate]] is a simple bedside measurement of airway obstruction and a '''red zone''' indicates less than 50% of the usual or normal peak flow reading signifying severe airway obstruction.
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| ====Respiratory Examination==== | | ==[[Status asthmaticus risk factors|Risk Factors]]== |
| =====Inspection=====
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| *Use of accessory muscles of respiration correlates with the disease severity
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| *Intercostal retractions
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| *Paradoxical thoraco-abdominal breathing
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| =====Auscultation===== | | ==[[Status asthmaticus natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
| *High-pitch prolong polyphonic expiratory [[wheeze]]
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| *Bilateral crackles
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| *Air entry may or may not be reduced depending on the severity
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| *Absence of [[wheeze]], breath sounds secondary to severe airway obstruction may represent a silent chest which is an ominous sign of imminent [[respiratory failure]].
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| ====Cardiovascular Examination==== | | ==Diagnosis== |
| Progressive untreated airway obstruction and increased work of breathing eventually leads to worsening [[hypoxemia]], [[hypercarbia]] and increased [[air trapping]] with compromised [[stroke volume]] that results in [[bradycardia]], [[hypotension]], [[hypoventilation]] and subsequent [[cardiorespiratory arrest]].
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| ====Neurological Examination====
| | [[Status asthmaticus history and symptoms|History and Symptoms]] | [[Status asthmaticus physical examination|Physical Examination]] | [[Status asthmaticus laboratory findings|Laboratory Findings]] | [[Status asthmaticus electrocardiogram|Electrocardiogram]] | [[Status asthmaticus chest x ray|Chest X ray]] | [[Status asthmaticus CT|CT]] | [[Status asthmaticus MRI|MRI]] | [[Status asthmaticus other imaging findings|Other Imaging Findings]] | [[Status asthmaticus other diagnostic studies|Other Diagnostic Studies]] |
| *Level of consciousness ranges from lethargy, agitation to even [[loss of consciousness]] or [[seizure]], secondary to severe airway obstruction, [[hypoxia]] and carbon-di-oxide retention.
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| *Unable to speak in full sentences
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| ===Laboratory Tests=== | | ==Treatment== |
| *Measurement of oxygen saturation by pulse oximetry may be useful to identify patients with acute severe asthma who may rapidly progress to [[respiratory failure]] and thereby require more intensive therapy.<ref name="pmid1121560">Overall JE (1975) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=1121560 Rating session. Video taped interviews and BPRS ratings.] ''Psychopharmacol Bull'' 11 (1):15. PMID: [http://pubmed.gov/1121560 1121560]</ref>
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| *[[Arterial blood gas]] may reveal [[respiratory alkalosis]] that is consistent with the [[hypoxemia]] and/or [[hypercarbia]] secondary to significant [[hypoventilation]].
| | [[Status asthmaticus medical therapy|Medical Therapy]] | [[Status asthmaticus primary prevention|Primary Prevention]] | [[Status asthmaticus secondary prevention|Secondary Prevention]] | [[Status asthmaticus cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Status asthmaticus future or investigational therapies|Future or Investigational Therapies]] |
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| *CBC count may demonstrate an increase in [[white blood cell|peripheral WBCs]] secondary to the use of [[steroids]] and [[Bronchodilators|β-agonists]].
| | ==Case Studies== |
| | | [[Status asthmaticus case study one|Case #1]] |
| ===Pulmonary Function Test=== | |
| [[Spirometry#Explanation of common test values in FVC tests|FEV1]] lower than 60% predicted is strongly suggestive of severe airway obstruction | |
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| ===ECG===
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| The presence of [[supraventricular tachycardia]] on ECG should raise a suspicion of [[Bronchodilator#Theophylline|theophylline toxicity]].
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| ===Imaging Modalities===
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| [[Asthma CT|High-resolution CT]] may reveal several structural changes related to small-airway disease including [[Bronchiectasis|cylindrical bronchiectasis]], bronchial wall thickening, and [[air trapping]].<ref name="pmid1094668">Robards VL, Lubin EN, Medlock TR (1975) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=1094668 Renal transplantation and placement of ileal stoma.] ''Urology'' 5 (6):787-9. PMID: [http://pubmed.gov/1094668 1094668]</ref>
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| ==References==
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| {{reflist|2}}
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| [[Category:Asthma]] | | [[Category:Asthma]] |
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| [[Category:Disease]] | | [[Category:Disease]] |
| [[Category:Pulmonology]] | | [[Category:Pulmonology]] |
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| [[Category:Emergency medicine]] | | [[Category:Emergency medicine]] |
| [[Category:Intensive care medicine]] | | [[Category:Intensive care medicine]] |