Croup natural history, complications and prognosis
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Luke Rusowicz-Orazem, B.S.
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Overview
Croup symptoms typically manifest after 2-7 days of human parainfluenza virus infection. Symptoms will typically last between 24-48 hours; very rarely they will last up to 7 days. They will typically resolve without treatment, excepting the most severe cases that pose the threat of respiratory failure. Prognosis is good in mild and moderate croup with and without treatment. Severe croup and impending respiratory failure classifications have poor prognosis, if left untreated, due to life-threatening airway obstruction. With treatment, all manifestations of croup have a good prognosis. Complications of croup stem from airway obstruction, including respiratory failure and respiratory distress. They also stem from infections due to immunocompromise from the causative human parainfluenza virus and corticosteroid therapy; these include bacterial tracheitis, atelectasis, pneumonia, pulmonary edema, and epiglottitis.
Natural History
- The incubation period for human parainfluenza virus (HPIV), causing croup, is typically 2 to 7 days upon infection.[1]
- Croup symptoms will usually develop abruptly post-incubation, often overnight, including simultaneous manifestation of "barking" cough, stridor, hoarseness, and difficulty breathing.[2]
- Without treatment, mild and moderate croup symptoms will usually resolve within 1 to 2 days of manifestation.[3]
- 50% of childrens' symptoms resolve within 24 hours.
- 80% of childrens' symptoms resolve within 48 hours.
- Croup is usually self-limited and usually does not require treatment for symptom resolution.
- Threat of respiratory failure in the most severe cases requires treatment.[2]
Complications
- Complications that can develop as a result of croup are primarily based on the resultant airway obstruction and include the following:[2]
- Croup complications that can result from immunocompromise from the causative human parainfluenza virus include the following:[2]
- Immunosuppressive effects from corticosteroid therapy can also lead to infection-based complications.[4]
Prognosis
- Croup is usually self-limiting and prognosis for croup is usually good, but can vary due to severity of symptoms and complications.
Mild and Moderate Croup
- Symptoms are not life threatening and will resolve without treatment.[2]
- Treatment can shorten the duration of croup and lower the severity of symptoms.[4]
Severe Croup and Impending Respiratory Failure
- Symptoms can be life threatening if the severity indicates a possibility of respiratory failure and will require emergency intubation for resolution.[2]
- Prognosis without treatment, in the presence of possible respiratory failure, is poor.
- Prognosis with proper intubation in severe croup is good.
- The mortality rate for croup is very low at <1 per 100,000 individuals.[2]
References
- ↑ "Human Parainfluenza Viruses | Symptoms and HPIV Illnesses | CDC".
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Johnson D (2009). "Croup". BMJ Clin Evid. 2009. PMC 2907784. PMID 19445760.
- ↑ Thompson M, Vodicka TA, Blair PS, Buckley DI, Heneghan C, Hay AD (2013). "Duration of symptoms of respiratory tract infections in children: systematic review". BMJ. 347: f7027. PMC 3898587. PMID 24335668.
- ↑ 4.0 4.1 Cherry, James D. (2008). "Croup". New England Journal of Medicine. 358 (4): 384–391. doi:10.1056/NEJMcp072022. ISSN 0028-4793.