Croup: Wikis


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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 is a group of respiratory diseases that often affects infants and children[1] under age 6. It is characterized by a barking cough; a whistling, obstructive sound (stridor) as the child breathes in; and hoarseness due to obstruction in the region of the larynx. It may be mild, moderate or severe, and severe cases, with breathing difficulty, can be fatal if not treated in a hospital.[2] Another type of croup is known as spasmodic croup. People with spasmodic croup first catch a cold, rarely with fever, and then the croupy cough begins. In some cases spasmodic croup may begin suddenly without any preceding cold symptoms. Unlike viral croup, spasmodic croup usually recurs, can occur in older children, and rarely even in adults. Spasmodic croup is thought to be related to allergies.



Croup affects 5% of children in the second year of life; the peak incidence is 3 months to 3 years. The group of respiratory diseases consists of spasmodic croup, acute laryngotracheitis, laryngotracheobronchitis (LTB), laryngotracheobronchopneumonitis (LTBP), and laryngeal diphtheria. LTB and LTBP, which usually involve a bacterial infection, are usually severe.[2]

The first step in diagnosis is to exclude other acute obstructive illnesses in the region of the larynx, such as epiglottitis, a foreign body, or angioneurotic edema of the epiglottis. Misdiagnosing an obstructive airway disease can be fatal.[2]

Signs and symptoms

Croup is characterized by a harsh "barking" cough and sneeze, inspiratory stridor (a high-pitched sound heard on inhalation), nausea/vomiting, and fever. Hoarseness is usually present. More severe cases will have respiratory distress.

The "barking" cough (often described as seal-like)[3] of croup is diagnostic. Stridor will be provoked or worsened by agitation or crying. If stridor is also heard when the child is calm, critical narrowing of the airway may be imminent.

In diagnosing croup, it is important for the physician to consider and exclude other causes of shortness of breath and stridor, such as foreign body aspiration and epiglottitis.

On a frontal X-ray of the cervical vertebrae, the steeple sign suggests the diagnosis of croup.


One tool for measuring the severity of croup is the Westley croup score, which describes specific features of physical examination[4]

The Westley Score: Classification of croup severity
Feature Severity
Chest wall retraction None = 0 Mild = 1 Moderate = 2 Severe = 3
Stridor None = 0 With agitation = 1 At rest = 2
Cyanosis None = 0 With agitation = 4 At rest = 5
Level of consciousness Normal = 0
(including sleep)
Disoriented = 5
Air entry Normal = 0 Decreased = 1 Markedly decreased = 2
  • A Westley score of ≤ 2 designates mild croup. The characteristic barking cough and hoarseness may be present but without resting stridor.
  • A score of 3 to 7 is classed as moderate croup, and typically there will be signs of increased respiratory effort, including accessory muscle recruitment and sternal recession.
  • A score of ≥ 8 indicates severe croup, and these children are at the greatest risk of respiratory failure. There is marked in drawing of the sternum, and the child may become fatigued and distressed.

One alarming feature is the reduction of stridor in a child previously demonstrating severe obstructive signs. With worsening airway obstruction, air movement is so limited that the characteristic sound is lost.


Croup is most often caused by parainfluenza virus, primarily types 1 and 2 (some definitions limit the term "croup" to this pathogen).[5] However, other viral and possibly bacterial infections can also cause it. Approximately 75% of cases are caused by parainfluenza virus. Influenza A and B, Measles, adenovirus and respiratory syncytial virus (RSV) are other viruses that sometimes cause croup. It is most common in the fall and winter but can occur year-round, with a slight predilection for males.

The respiratory distress is caused by the inflammatory response to the infection, rather than by the infection itself. It usually occurs in young children as their airways are smaller and differently shaped than adults', making them more susceptible. There is some element of genetic predisposition as children in some families are more susceptible than others.

An entity known as spasmodic croup also occurs, distinct from the infectious variety, due to laryngeal spasms.


The treatment of croup depends on the severity of symptoms.

The Alberta Clinical Practice Guideline Working Group has developed guidelines for diagnosing and treating croup, including a scoring system for classifying severity.[6] The severe form (which affected less than 1% of children seen in the emergency department) involves breathing difficulties, indicated by stridor, chest retractions, agitation and distress. Lethargy or decreased level of consciousness is a sign of impending respiratory failure, and requires emergency medical treatment. LTB and LTBP are usually severe, and require treatment in the intensive care unit, with an endotracheal (ET) tube to assist breathing and antibiotics.[2]

The routinely recommended treatment is with corticosteroids, although corticosteroids suppress the immune system and can predispose the child to infection. There is a debate over how many doses to give, but Cherry in the New England Journal of Medicine recommends one dose, and has observed that children with viral, bacterial and fungal complications have had multiple doses. Epinephrine produces a significant reduction in the croup severity score but the benefit only lasts for 2 hours. Children who have moderate or severe croup with blood oxygen saturation under 92% should receive oxygen.[2]

Since laryngotracheitis is a viral disease (most commonly parainfluenza virus 1) antibiotics have no value.

Croup can be prevented by immunization for influenza and diphtheria. At one time, croup referred to a diphtherial disease, but with vaccination diphtheria is rare.[2]

One of the traditional ways to treat croup is to inhale hot steam. However, studies have found that this is not effective.[2] This was the sole treatment for croup throughout the nineteenth and most of the twentieth century. Hospitals today use a "blowby" apparatus for this purpose. Simpler remedies include taking the child outside in moist night air, or alternatively exposing the child to steam from a hot bath or a humidifier. There is little or no evidence to support their efficacy.

Mild croup with no stridor, or stridor only on agitation, and just a cough may simply be observed, or a dose of inhaled, oral, or injected steroids may be given. When steroids are given, dexamethasone is often used, due to its prolonged physiologic effects.

Moderate to severe croup may require nebulized adrenaline in addition to steroids. Oxygen may be needed if hypoxia develops. Children with moderate or severe croup are typically hospitalized for observation, usually for less than a day. Intubation is rarely needed (less than 1% of hospitalized patients).


Viral croup is a self-limited disease, but can very rarely result in death from complete airway obstruction. Symptoms may last up to 7 days, but typically peak around the second day of illness. Rarely, croup can be complicated by, (or confused with) an acute bacterial tracheitis, which is more dangerous.


External links

1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

CROUP, a name formerly given to diseases characterized by distress in breathing accompanied by a metallic cough and some CH 2 :C< C02H' Methacrylic Acid.

hoarseness of speech. It is now known that these symptoms are often associated with diphtheria, spasmodic laryngitis, and a third disease, spasmodic croup, to which the term is now alone applied. This occurs most frequently in children above two years of age; the child goes to bed quite well, and a few hours later suddenly awakes with great difficulty in inspiration, the chest wall becomes markedly retracted, and there is a metallic cough. The child becomes cyanosed, and, to the inexperienced nurse, seems in an almost moribund condition. In the course of four or five minutes, normal respiration starts again, and the attack is over for the time being; but it may recur several times a day. The seizure may be accompanied by convulsions, and death has occurred from dyspnoea. The best treatment is to plunge the child into a warm bath, and sponge the back and chest with cold water. Subsequently this can be done two or three times a day. Should the cyanosis become very severe, respiration can be restarted by making the child sick, either with a dose of ipecacuanha wine, or by forcing one's finger down the throat. Generally the bowels should be attended to; and the throat carefully examined for enlarged tonsils or adenoids, which if present should be treated.

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