Croup

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Croup
Other namesCroupy cough, subglottic laryngitis, obstructive laryngitis, laryngotracheobronchitis
Croup steeple sign.jpg
The steeple sign as seen on an AP neck X-ray of a child with croup
Pronunciation
Specialty Pediatrics
Symptoms "Barky" cough, stridor, fever, stuffy nose [2]
DurationUsually 1–2 days but can last up to 7 days [3]
CausesMostly viral [2]
Diagnostic method Based on symptoms [4]
Differential diagnosis Epiglottitis, airway foreign body, bacterial tracheitis [4] [5]
Prevention Influenza and diphtheria vaccination [5]
Medication Steroids, epinephrine [4] [5]
Frequency15% of children at some point [4] [5]
DeathsRare [2]

Croup ( /kruːp/ KROOP), also known as croupy cough, is a type of respiratory infection that is usually caused by a virus. [2] The infection leads to swelling inside the trachea, which interferes with normal breathing and produces the classic symptoms of "barking/brassy" cough, inspiratory stridor and a hoarse voice. [2] Fever and runny nose may also be present. [2] These symptoms may be mild, moderate, or severe. [3] Often it starts or is worse at night and normally lasts one to two days. [6] [2] [3]

Contents

Croup can be caused by a number of viruses including parainfluenza and influenza virus. [2] Rarely is it due to a bacterial infection. [5] Croup is typically diagnosed based on signs and symptoms after potentially more severe causes, such as epiglottitis or an airway foreign body, have been ruled out. [4] Further investigations, such as blood tests, X-rays and cultures, are usually not needed. [4]

Many cases of croup are preventable by immunization for influenza and diphtheria. [5] Most cases of croup are mild and the patient can be treated at home with supportive care. Croup is usually treated with a single dose of steroids by mouth. [2] [7] In more severe cases inhaled epinephrine may also be used. [2] [8] Hospitalization is required in one to five percent of cases. [9]

Croup is a relatively common condition that affects about 15% of children at some point. [4] It most commonly occurs between six months and five years of age but may rarely be seen in children as old as fifteen. [3] [4] [9] It is slightly more common in males than females. [9] It occurs most often in autumn. [9] Before vaccination, croup was frequently caused by diphtheria and was often fatal. [5] [10] This cause is now very rare in the Western world due to the success of the diphtheria vaccine. [11]

Signs and symptoms

Gnome-mime-sound-openclipart.svg
Stridor
Inspiratory and expiratory stridor in a 13-month child with croup.
Problems playing this file? See media help.
Gnome-mime-sound-openclipart.svg
Croupy cough
Croup cough in an 11-month child with croup.
Problems playing this file? See media help.

Croup is characterized by a "barking" cough, stridor, hoarseness, and difficult breathing which usually worsens at night. [2] The "barking" cough is often described as resembling the call of a sea lion. [5] The stridor is worsened by agitation or crying, and if it can be heard at rest, it may indicate critical narrowing of the airways. As croup worsens, stridor may decrease considerably. [2]

Other symptoms include fever, coryza (symptoms typical of the common cold), and indrawing of the chest wall–known as Hoover's sign. [2] [12] Drooling or a very sick appearance can indicate other medical conditions, such as epiglottitis or tracheitis. [12]

Causes

Croup is usually deemed to be due to a viral infection. [2] [4] Others use the term more broadly, to include acute laryngotracheitis (laryngitis and tracheitis together), spasmodic croup, laryngeal diphtheria, bacterial tracheitis, laryngotracheobronchitis, and laryngotracheobronchopneumonitis. The first two conditions involve a viral infection and are generally milder with respect to symptomatology; the last four are due to bacterial infection and are usually of greater severity. [5]

Viral

Viral croup or acute laryngotracheitis is most commonly caused by parainfluenza virus (a member of the paramyxovirus family), primarily types 1 and 2, in 75% of cases. [3] Other viral causes include influenza A and B, measles, adenovirus and respiratory syncytial virus (RSV). [5] Spasmodic croup is caused by the same group of viruses as acute laryngotracheitis, but lacks the usual signs of infection (such as fever, sore throat, and increased white blood cell count). [5] Treatment, and response to treatment, are also similar. [3]

Bacteria and cocci

Croup caused by a bacterial infection is rare. [13] Bacterial croup may be divided into laryngeal diphtheria, bacterial tracheitis, laryngotracheobronchitis, and laryngotracheobronchopneumonitis. [5] Laryngeal diphtheria is due to Corynebacterium diphtheriae while bacterial tracheitis, laryngotracheobronchitis, and laryngotracheobronchopneumonitis are usually due to a primary viral infection with secondary bacterial growth. The most common cocci implicated are Staphylococcus aureus and Streptococcus pneumoniae , while the most common bacteria are Haemophilus influenzae , and Moraxella catarrhalis . [5]

Pathophysiology

The viral infection that causes croup leads to swelling of the larynx, trachea, and large bronchi [4] due to infiltration of white blood cells (especially histiocytes, lymphocytes, plasma cells, and neutrophils). [5] Swelling produces airway obstruction which, when significant, leads to dramatically increased work of breathing and the characteristic turbulent, noisy airflow known as stridor. [4]

Diagnosis

Croup is typically diagnosed based on signs and symptoms. [4] The first step is to exclude other obstructive conditions of the upper airway, especially epiglottitis, an airway foreign body, subglottic stenosis, angioedema, retropharyngeal abscess, and bacterial tracheitis. [4] [5]

A frontal X-ray of the neck is not routinely performed, [4] but if it is done, it may show a characteristic narrowing of the trachea, called the steeple sign, because of the subglottic stenosis, which resembles a steeple in shape. The steeple sign is suggestive of the diagnosis, but is absent in half of cases. [12]

Other investigations (such as blood tests and viral culture) are discouraged, as they may cause unnecessary agitation and thus worsen the stress on the compromised airway. [4] While viral cultures, obtained via nasopharyngeal aspiration, can be used to confirm the exact cause, these are usually restricted to research settings. [2] Bacterial infection should be considered if a person does not improve with standard treatment, at which point further investigations may be indicated. [5]

Severity

Westley score: Classification of croup severity [3] [14]
FeatureNumber of points assigned for this feature
012345
Chest wall
retraction		NoneMildModerateSevere
Stridor NoneWith
agitation		At rest
Cyanosis NoneWith
agitation		At rest
Level of
consciousness 		NormalDisoriented
Air entryNormalDecreasedMarkedly decreased

The most commonly used system for classifying the severity of croup is the Westley score. It is primarily used for research purposes rather than in clinical practice. [5] It is the sum of points assigned for five factors: level of consciousness, cyanosis, stridor, air entry, and retractions. [5] The points given for each factor is listed in the adjacent table, and the final score ranges from 0 to 17. [14]

85% of children presenting to the emergency department have mild disease; severe croup is rare (<1%). [3]

Prevention

Croup is contagious during the first few days of the infection. [13] Basic hygiene including hand washing can prevent transmission. [13] There are no vaccines that have been developed to prevent croup, [13] however, many cases of croup have been prevented by immunization for influenza and diphtheria. [5] At one time, croup referred to a diphtherial disease, but with vaccination, diphtheria is now rare in the developed world. [5]

Treatment

Most children with croup have mild symptoms and supportive care at home is effective. [13] For children with moderate to severe croup, treatment with corticosteroids and nebulized epinephrine may be suggested. Steroids are given routinely, with epinephrine used in severe cases. [4] Children with oxygen saturation less than 92% should receive oxygen, [5] and those with severe croup may be hospitalized for observation. [12] In very rare severe cases of croup that result in respiratory failure, emergency intubation and ventilation may be required. [15] With treatment, less than 0.2% of children require endotracheal intubation. [14] Since croup is usually a viral disease, antibiotics are not used unless secondary bacterial infection is suspected. [2] The use of cough medicines, which usually contain dextromethorphan or guaifenesin, are also discouraged. [2]

Supportive care

Supportive care for children with croup includes resting and keeping the child hydrated. [13] Infections that are mild are suggested to be treated at home. Croup is contagious so washing hands is important. [13] Children with croup should generally be kept as calm as possible. [4] Over the counter medications for pain and fever may be helpful to keep the child comfortable. [13] There is some evidence that cool or warm mist may be helpful, however, the effectiveness of this approach is not clear. [4] [5] [13] If the child is showing signs of distress while breathing (inspiratory stridor, working hard to breathe, blue (or blue-ish) coloured lips, or decrease in the level of alertness), immediate medical evaluation by a doctor is required. [13]

Steroids

Corticosteroids, such as dexamethasone and budesonide, have been shown to improve outcomes in children with all severities of croup, however, the benefits may be delayed. [7] Significant relief may be obtained as early as two hours after administration. [7] While effective when given by injection, or by inhalation, giving the medication by mouth is preferred. [4] A single dose is usually all that is required, and is generally considered to be quite safe. [4] Dexamethasone at doses of 0.15, 0.3 and 0.6 mg/kg appear to be all equally effective. [16]

Epinephrine

Moderate to severe croup (for example, in the case of severe stridor) may be improved temporarily with nebulized epinephrine. [4] While epinephrine typically produces a reduction in croup severity within 10–30 minutes, the benefits are short-lived and last for only about 2 hours. [2] [4] If the condition remains improved for 2–4 hours after treatment and no other complications arise, the child is typically discharged from the hospital. [2] [4] Epinephrine treatment is associated with potential adverse effects (usually related to the dose of epinephrine) including tachycardia, arrhythmias, and hypertension. [15]

Oxygen

More severe cases of croup may require treatment with oxygen. If oxygen is needed, "blow-by" administration (holding an oxygen source near the child's face) is recommended, as it causes less agitation than use of a mask. [5]

Other

While other treatments for croup have been studied, none has sufficient evidence to support its use. There is tentative evidence that breathing heliox (a mixture of helium and oxygen) to decrease the work of breathing is useful in those with severe disease, however, there is uncertainty in the effectiveness and the potential adverse effects and/or side effects are not well known. [15] In cases of possible secondary bacterial infection, the antibiotics vancomycin and cefotaxime are recommended. [5] In severe cases associated with influenza A or B infections, the antiviral neuraminidase inhibitors may be administered. [5]

Prognosis

Viral croup is usually a self-limiting disease, [2] with half of cases resolving in a day and 80% of cases in two days. [6] It can very rarely result in death from respiratory failure and/or cardiac arrest. [2] Symptoms usually improve within two days, but may last for up to seven days. [3] Other uncommon complications include bacterial tracheitis, pneumonia, and pulmonary edema. [3]

Epidemiology

Croup affects about 15% of children, and usually presents between the ages of 6 months and 5–6 years. [4] [5] It accounts for about 5% of hospital admissions in this population. [3] In rare cases, it may occur in children as young as 3 months and as old as 15 years. [3] Males are affected 50% more frequently than are females, and there is an increased prevalence in autumn. [5]

History

The word croup comes from the Early Modern English verb croup, meaning "to cry hoarsely." The noun describing the disease originated in southeastern Scotland and became widespread after Edinburgh physician Francis Home published the 1765 treatise An Inquiry into the Nature, Cause, and Cure of the Croup. [17] [18]

Diphtheritic croup has been known since the time of Homer's ancient Greece, and it was not until 1826 that viral croup was differentiated from croup due to diphtheria by Bretonneau. [11] [19] Viral croup was then called "faux-croup" by the French and often called "false croup" in English, [20] [21] as "croup" or "true croup" then most often referred to the disease caused by the diphtheria bacterium. [22] [23] False croup has also been known as pseudo croup or spasmodic croup. [24] Croup due to diphtheria has become nearly unknown in affluent countries in modern times due to the advent of effective immunization. [11] [25]

One famous fatality of croup was Napoleon's designated heir, Napoléon Charles Bonaparte. His death in 1807 left Napoleon without an heir and contributed to his decision to divorce from his wife, the Empress Josephine de Beauharnais. [26]

Related Research Articles

<span class="mw-page-title-main">Pneumonia</span> Inflammation of the alveoli of the lungs

Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severity of the condition is variable.

<span class="mw-page-title-main">Diphtheria</span> Bacterial disease

Diphtheria is an infection caused by the bacterium Corynebacterium diphtheriae. Most infections are asymptomatic or have a mild clinical course, but in some outbreaks, the mortality rate approaches 10%. Signs and symptoms may vary from mild to severe, and usually start two to five days after exposure. Symptoms often develop gradually, beginning with a sore throat and fever. In severe cases, a grey or white patch develops in the throat, which can block the airway, and create a barking cough similar to what is observed in croup. The neck may also swell, in part due to the enlargement of the facial lymph nodes. Diphtheria can also involve the skin, eyes, or genitals, and can cause complications, including myocarditis, inflammation of nerves, kidney problems, and bleeding problems due to low levels of platelets.

<span class="mw-page-title-main">Trachea</span> Cartilaginous tube that connects the pharynx and larynx to the lungs

The trachea, also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all animals lungs. The trachea extends from the larynx and branches into the two primary bronchi. At the top of the trachea, the cricoid cartilage attaches it to the larynx. The trachea is formed by a number of horseshoe-shaped rings, joined together vertically by overlying ligaments, and by the trachealis muscle at their ends. The epiglottis closes the opening to the larynx during swallowing.

<span class="mw-page-title-main">Cough</span> Sudden expulsion of air from the lungs as a reflex to clear irritants

A cough is a sudden expulsion of air through the large breathing passages which can help clear them of fluids, irritants, foreign particles and microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three phases: an inhalation, a forced exhalation against a closed glottis, and a violent release of air from the lungs following opening of the glottis, usually accompanied by a distinctive sound.

<span class="mw-page-title-main">Pharyngitis</span> Inflammation of the back of the throat

Pharyngitis is inflammation of the back of the throat, known as the pharynx. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, difficulty swallowing, swollen lymph nodes, and a hoarse voice. Symptoms usually last 3–5 days, but can be longer depending on cause. Complications can include sinusitis and acute otitis media. Pharyngitis is a type of upper respiratory tract infection.

Atypical pneumonia, also known as walking pneumonia, is any type of pneumonia not caused by one of the pathogens most commonly associated with the disease. Its clinical presentation contrasts to that of "typical" pneumonia. A variety of microorganisms can cause it. When it develops independently from another disease, it is called primary atypical pneumonia (PAP).

<span class="mw-page-title-main">Bronchiolitis</span> Inflammation of the small airways in the lungs

Bronchiolitis is inflammation of the small airways also known as the bronchioles in the lungs. Acute bronchiolitis is caused by a viral infection, usually affecting children younger than two years of age. Symptoms may include fever, cough, runny nose or rhinorrhea, and wheezing. More severe cases may be associated with nasal flaring, grunting, or respiratory distress. If the child has not been able to feed properly due to the illness, signs of dehydration may be present.

<span class="mw-page-title-main">Respiratory syncytial virus</span> Species of virus

Respiratory syncytial virus (RSV), also called human respiratory syncytial virus (hRSV) and human orthopneumovirus, is a contagious virus that causes infections of the respiratory tract. It is a negative-sense, single-stranded RNA virus. Its name is derived from the large cells known as syncytia that form when infected cells fuse.

<span class="mw-page-title-main">Laryngitis</span> Inflammation of the larynx (voice box)

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<span class="mw-page-title-main">Upper respiratory tract infection</span> Infection of the nose, sinuses, pharynx, larynx or trachea

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<span class="mw-page-title-main">Epiglottitis</span> Inflammation of the epiglottis

Epiglottitis is the inflammation of the epiglottis—the flap at the base of the tongue that prevents food entering the trachea (windpipe). Symptoms are usually rapid in onset and include trouble swallowing which can result in drooling, changes to the voice, fever, and an increased breathing rate. As the epiglottis is in the upper airway, swelling can interfere with breathing. People may lean forward in an effort to open the airway. As the condition worsens, stridor and bluish skin may occur.

<span class="mw-page-title-main">Human parainfluenza viruses</span> Viruses that cause human parainfluenza

Human parainfluenza viruses (HPIVs) are the viruses that cause human parainfluenza. HPIVs are a paraphyletic group of four distinct single-stranded RNA viruses belonging to the Paramyxoviridae family. These viruses are closely associated with both human and veterinary disease. Virions are approximately 150–250 nm in size and contain negative sense RNA with a genome encompassing about 15,000 nucleotides.

<span class="mw-page-title-main">Tracheitis</span> Inflammation of the trachea

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<span class="mw-page-title-main">Airway obstruction</span> Blockage in the respiratory system

Airway obstruction is a blockage of respiration in the airway that hinders the free flow of air. Airway obstructions can occur either in the upper airway (UPA) or lower airway (LOA). The upper airway consists of the nose, throat, and larynx. The lower airway comprises the trachea, bronchi, and bronchioles.

<span class="mw-page-title-main">Adenovirus infection</span> Medical condition

Adenovirus infection is a contagious viral disease, caused by adenoviruses, commonly resulting in a respiratory tract infection. Typical symptoms range from those of a common cold, such as nasal congestion, coryza and cough, to difficulty breathing as in pneumonia. Other general symptoms include fever, fatigue, muscle aches, headache, abdominal pain and swollen neck glands. Onset is usually two to fourteen days after exposure to the virus. A mild eye infection may occur on its own, combined with a sore throat and fever, or as a more severe adenoviral keratoconjunctivitis with a painful red eye, intolerance to light and discharge. Very young children may just have an earache. Adenovirus infection can present as a gastroenteritis with vomiting, diarrhoea and abdominal pain, with or without respiratory symptoms. However, some people have no symptoms.

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<span class="mw-page-title-main">Subglottic stenosis</span> Medical condition

Subglottic stenosis is a congenital or acquired narrowing of the subglottic airway. It can be congenital, acquired, iatrogenic, or very rarely, idiopathic. It is defined as the narrowing of the portion of the airway that lies between the vocal cords and the lower part of the cricoid cartilage. In a normal infant, the subglottic airway is 4.5-5.5 millimeters wide, while in a premature infant, the normal width is 3.5 millimeters. Subglottic stenosis is defined as a diameter of under 4 millimeters in an infant. Acquired cases are more common than congenital cases due to prolonged intubation being introduced in the 1960s. It is most frequently caused by certain medical procedures or external trauma, although infections and systemic or autoimmune diseases can also cause it.

References

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  12. 1 2 3 4 "Diagnosis and Management of Croup" (PDF). BC Children's Hospital Division of Pediatric Emergency Medicine Clinical Practice Guidelines. Archived from the original (PDF) on 2020-06-23. Retrieved 2020-03-16.
  13. 1 2 3 4 5 6 7 8 9 10 Baiu I, Melendez E (2019-04-23). "Croup". JAMA. 321 (16): 1642. doi: 10.1001/jama.2019.2013 . ISSN   0098-7484. PMID   31012936. S2CID   242149254.
  14. 1 2 3 Klassen TP (December 1999). "Croup. A current perspective". Pediatr. Clin. North Am. 46 (6): 1167–78. doi:10.1016/S0031-3955(05)70180-2. PMID   10629679.
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  16. ↑ Port C (April 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. S2CID   6655787.
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  20. ↑ Cormack JR (8 May 1875). "Meaning of the Terms Diphtheria, Croup, and Faux Croup". British Medical Journal . 1 (749): 606. doi:10.1136/bmj.1.749.606. PMC   2297755 . PMID   20747853.
  21. ↑ Loving S (5 October 1895). "Something concerning the diagnosis and treatment of false croup". JAMA: The Journal of the American Medical Association . XXV (14): 567–573. doi:10.1001/jama.1895.02430400011001d. Archived from the original on 4 July 2014. Retrieved 16 April 2014.
  22. ↑ Bennett JR (8 May 1875). "True and False Croup". British Medical Journal . 1 (749): 606–607. doi:10.1136/bmj.1.749.606-a. PMC   2297754 . PMID   20747854.
  23. ↑ Beard GM (1875). Our Home Physician: A New and Popular Guide to the Art of Preserving Health and Treating Disease. New York: E. B. Treat. pp.  560–564. Retrieved 15 April 2014.
  24. ↑ Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases (8 ed.). Elsevier Health Sciences. 2014. p. 762. ISBN   978-0-323-26373-3. Archived from the original on 2017-09-08.
  25. ↑ Vanderpool P (December 2012). "Recognizing croup and stridor in children". American Nurse Today. 7 (12). Archived from the original on 16 April 2014. Retrieved 15 April 2014.
  26. ↑ Bruce E (1995). Napoleon and Josephine. London: Weidenfeld & Nicolson.
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