Croup
 | The English used in this article or section may not be easy for everybody to understand. (April 2012) |
| Croup | |
|---|---|
| Classification and external resources | |
 The steeple sign as seen on an AP neck X-ray of a child with croup | |
| ICD-10 | J05.0 |
| ICD-9 | 464.4 |
| DiseasesDB | 13233 |
| MedlinePlus | 000959 |
| eMedicine | ped/510 emerg/370 radio/199 |
| MeSH | D003440 |
Croup (or laryngotracheobronchitis) is caused by a viral infection of the upper airway. The infection causes swelling inside the throat. This swelling causes problems with normal breathing. People with croup may have a "barking"cough, stridor (a high-pitched wheezing sound), and hoarseness. Croup symptoms often get worse at night. A single dose of oral steroids can treat the condition. Sometimes epinephrine is used in more severe cases. Hospitalization is rarely required.
Doctors decide if a person has croup based on signs and symptoms once more severe causes of symptoms have been excluded (for example, epiglottitis or an airway foreign body). Blood tests, X-rays, and cultures are usually not needed. Croup is common. About 15% of children, usually between 6 months and 5–6 years of age get croup. Teenagers and adults rarely get croup.
Signs and symptoms
Croup symptoms include a "barking" cough, stridor( a high pitched sound typically when breathing in), hoarseness, and difficult breathing that usually are worse at night.[1] The "barking" cough is often described as resembling the call of aseal or sea lion.[2] Crying can make the wheezing worse; wheezing can mean that the airways are narrowed As croup gets worse, the wheezing may decrease.[1]
Other symptoms include fever, coryza (symptoms typical of the common cold), and indrawing of the skin between the ribs.[1][3] Drooling or a sick appearance typically indicate other medical conditions.[3]
Causes
Croup is usually caused by a viral infection.[1][4] Some people call severe laryngotracheitis croup. This disease is caused by a virus is milder. Croup may also be laryngeal diphtheria, bacterial tracheitis, laryngotracheobronchitis, and laryngotracheobronchopneumonitis. These diseases are caused by bacteria and are usually more severe.[2]
Viral
In 75% of cases parainfluenza virus, mainly types 1 and 2, is the virus that causes croup.[5] Other viruses that can cause croup include influenza A and B, measles, adenovirus and respiratory syncytial virus (RSV).[2] Spasmodic croup (croup with barking) is caused by the same viruses that cause acute laryngotracheitis, but it does not have the usual signs of infection such as fever, sore throat, and increased white blood cell count).[2] Treating spasmodic croup is the same as regular croup.[5]
Bacterial
Bacterial croup includes laryngeal diphtheria, bacterial tracheitis, laryngotracheobronchitis, and laryngotracheobronchopneumonitis.[2] Laryngeal diphtheria is caused by Corynebacterium diphtheriae while bacterial tracheitis, laryngotracheobronchitis, and laryngotracheobronchopneumonitis come from a virus infection, followed by a bacteria infection. The most common bacteria that cause croup areStaphylococcus aureus, Streptococcus pneumoniae, Hemophilus influenzae, and Moraxella catarrhalis.[2]
Changes in the body
The virus infection leads to swelling of the larynx, trachea, and large airways with white blood cells.[4] Swelling can make breathing difficult.[4]
Diagnosis
| Feature | Number of points assigned for this feature | |||||
|---|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 | |
| Chest wall retraction |
None | Mild | Moderate | Severe | ||
| Stridor | None | With agitation |
At rest | |||
| Cyanosis | None | With agitation |
At rest | |||
| Level of consciousness |
Normal | Disoriented | ||||
| Air entry | Normal | Decreased | Markedly decreased | |||
Croup is diagnosed based on signs and symtoms.[4] The first step is to exclude other conditions that can block the upper airway, especially epiglottitis, something in the airway, subglottic stenosis, angioedema, retropharyngeal abscess, and bacterial tracheitis.[2][4]
An X-ray of the neck is not routinely performed,[4] but if it is done, it can show a narrowing of the trachea, called the steeple sign, because the shape of the narrowing looks like a church steeple. The steeple sign does not appear in half of cases.[3]
Blood tests and viral cultures (tests for the virus) can cause unnecessary irritation to the airway.[4] While viral cultures, obtained via nasopharyngeal aspiration (a procedure using a tube to suck mucus out of the nose), can be used to confirm the exact cause. These cultures are usually restricted to those doing research.[1] If a person does not improve with standard treatment, further tests can be done to check for bacteria.[2]
- Severity
The most common system for describing the severity of croup is the Westley score. This test is used for research purposes not for helping patients.[2] The score is the sum of points for five factors: level of consciousness, cyanosis, stridor, air entry, and retractions.[2] The points given for each factor is listed in the table to the right, and the final score ranges from 0 to 17.[6]
- A total score of ≤ 2 indicates mild croup. The person can have barking cough and hoarseness, but there is no stridor (wheezing) when the person is resting.[5]
- A total score of 3–5 is moderate croup — the person has wheezing, with few other signs.[5]
- A total score of 6–11 is severe croup. The patient has obvious stridor and chest wall indrawing.[5]
- A total score of ≥ 12 means respiratory failure is possible. The barking cough and wheezing may no longer be present at this stage.[5]
85% of children going to the emergency department have mild disease. Severe croup is rare–less than 1% of cases.[5]
Prevention
Immunization (vaccines) for influenza and diphtheria can prevent croup.[2]
Treatment
It is important to keep children with croup as calm as possible.[4] Doctors often give children steroids, but epinephrine is used in severe cases.[4] If the amount of oxygen in the child's blood is under 92%, they need to be given oxygen.[2] People with severe croup can be hospitalized for observation.[3] If oxygen is needed, "blow-by" administration (holding an oxygen source near the child's face) is better, because it is less likely to upset a child than an oxygen mask is.[2] With treatment, less than 0.2% of people require endotracheal intubation(a tube placed into the airway).[6]
Steroids
Corticosteroids, such as dexamethasone and budesonide, can be used to treat croup.[7] Patients may begin to improve a lot within six hours after taking steroids.[7] Steroids work when given by mouth, injection, or inhalation, but taking them by mouth is best.[4] A single dose is usually enough, and is usually safe.[4] Dexamethasone at doses of 0.15, 0.3 and 0.6 mg/kg appear to be all equally good.[8]
Epinephrine
Moderate to severe croup can be helped with nebulized epinephrine(an inhaled solution that widens the airway).[4] While epinephrine usually reduces croup severity within 10–30 minutes, the benefits last for only about 2 hours.[1][4] If the condition remains improved for 2–4 hours after treatment and no other complications arise, the child typically can leave the hospital.[1][4]
Other
Other treatments for croup have been studied, but there is not enough evidence to support their use. Breathing hot steam or humidified air is a traditional self-care treatment, but clinical studies have failed to show effectiveness[2][4] and currently it is rarely used.[9] The use of cough medicines, which usually containdextromethorphan and/or guiafenesin, is also discouraged.[1] While breathing heliox (a mixture of helium and oxygen) to decrease the work of breathing has been used in the past, there is very little evidence to support its use.[10] Since croup is usually a viral disease, antibiotics are not used unless bacteria are also suspected.[1] The antibiotics vancomycin and cefotaxime are recommended for bacterial infections.[2] In severe cases associated with influenza A or B, theantiviral neuraminidase inhibitors can be administered.[2]
Likely outcome
Viral croup is usually a short-term disease. Croup rarely causes death from respiratory failure and/or cardiac arrest.[1] Symptoms usually improve within two days, but can last for up to seven days.[5] Other uncommon complications include bacterial tracheitis, pneumonia, and pulmonary edema.[5]
Epidemiology
About 15% of children, usually between the ages of 6 months and 5–6 years, will get croup.[2][4] Croup accounts for about 5% of hospital admissions for this age group.[5] In rare cases, children as young as 3 months and as old as 15 years have croup.[5] Males are affected 50% more frequently than are females; croup is more common in autumn (fall).[2]
History
The word croup comes from the Early Modern English verb croup, meaning "to cry hoarsely"; the name was first used for the disease in Scotland and became popular in the 18th century.[11] Diphtheritic croup has been known since the time of Homer's Ancient Greece. In 1826, Bretonneau distinguished viral croup and croup due to diphtheria.[12] The French called viral croup "faux-croup," using "croup" for a disease caused by the diphtheria bacteria.[9] Croup due to diphtheria has become nearly unknown due to the advent of effective immunization.[12]
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 Rajapaksa S, Starr M (2010). "Croup – assessment and management". Aust Fam Physician. 39 (5): 280–2. PMID 20485713.
{{cite journal}}: Unknown parameter|month=ignored (help) - ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 2.15 2.16 2.17 Cherry JD (2008). "Clinical practice. Croup". N. Engl. J. Med. 358 (4): 384–91. doi:10.1056/NEJMcp072022. PMID 18216359.
- ↑ 3.0 3.1 3.2 3.3 "Diagnosis and Management of Croup" (PDF). BC Children’s Hospital Division of Pediatric Emergency Medicine Clinical Practice Guidelines.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 4.13 4.14 4.15 Everard ML (2009). "Acute bronchiolitis and croup". Pediatr. Clin. North Am. 56 (1): 119–33, x–xi. doi:10.1016/j.pcl.2008.10.007. PMID 19135584.
{{cite journal}}: Unknown parameter|month=ignored (help) - ↑ 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 5.10 5.11 Johnson D (2009). "Croup". Clin Evid (Online). 2009. PMC 2907784. PMID 19445760.
- ↑ 6.0 6.1 6.2 Klassen TP (1999). "Croup. A current perspective". Pediatr. Clin. North Am. 46 (6): 1167–78. doi:10.1016/S0031-3955(05)70180-2. PMID 10629679.
{{cite journal}}: Unknown parameter|month=ignored (help) - ↑ 7.0 7.1 Russell KF, Liang Y, O'Gorman K, Johnson DW, Klassen TP (2011). Klassen, Terry P (ed.). "Glucocorticoids for croup". Cochrane Database Syst Rev. 1 (1): CD001955. doi:10.1002/14651858.CD001955.pub3. PMID 21249651.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ↑ Port C (2009). "Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary. BET 4. Dose of dexamethasone in croup". Emerg Med J. 26 (4): 291–2. doi:10.1136/emj.2009.072090. PMID 19307398.
{{cite journal}}: Unknown parameter|month=ignored (help) - ↑ 9.0 9.1 Marchessault V (2001). "Historical review of croup". Can J Infect Dis. 12 (6): 337–9. PMC 2094841. PMID 18159359.
{{cite journal}}: Unknown parameter|month=ignored (help) - ↑ Vorwerk C, Coats T (2010). Vorwerk, Christiane (ed.). "Heliox for croup in children". Cochrane Database Syst Rev. 2 (2): CD006822. doi:10.1002/14651858.CD006822.pub2. PMID 20166089.
- ↑ Online Etymological Dictionary, croup. Accessed 2010-09-13.
- ↑ 12.0 12.1 Feigin, Ralph D. (2004). Textbook of pediatric infectious diseases. Philadelphia: Saunders. p. 252. ISBN 0-7216-9329-6.