As pseudocroup or pseudocroup (synonyms: [acute] stenosing laryngotracheitis , laryngitis subglottica , simplistic sometimes also " croup " , from Scottish croup , "hoarseness") is a non-specific inflammation of the upper respiratory tract in the area of the larynx below the glottis ( Glottis), which is characterized by a characteristic barking cough ("sheep cough"), hoarseness and, in severe cases, shortness of breath. Infants and toddlers between the ages of six months and six years are mainly affected, adolescents and young adults only in very rare cases.
The disease is not to be confused with the so-called "real croup", which is the inflammation of the larynx in diphtheria . Since the "real croup" has become very rare in Europe due to the diphtheria vaccination , one nowadays often no longer speaks of pseudo croup (or, as in the past, of false croup ), but simply of croup or the croup syndrome . Although the disease is often self-limiting, the administration of glucocorticoids is recommended even in mild cases . In severe cases, inhalation of adrenaline and hospital monitoring may be necessary.
Pseudocroup usually occurs as a result of viral infections . The most common pathogens are parainfluenza (mostly type 1), influenza (type A or B), RS , rhino , adeno and metapneumoviruses , and occasionally measles , chickenpox , herpes simplex and Epstein-Barr viruses . Heavy air pollution, weather influences and passive smoking can have negative effects, although these are not causative factors.
Due to the viral infection, the mucous membrane in the area of the larynx and below the vocal cords becomes inflamed . The inflammation causes the mucous membrane to swell, causing the airways to narrow . In children, the airways are still very small, so that the narrowing is more pronounced than in older children or adults. In the case of a 1 mm thick ring edema in the area of the cricoid cartilage , the airway resistance in small children increases 16-fold; in adults only three times as much (see illustration).
In rare cases, pseudo croup can also occur in older children. Usually the larynx area is already so large that the swelling only leads to hoarseness.
Pseudocroup occurs mainly and more intensely at night. The reason for this is probably the circadian cortisol rhythm , which has a minimum between midnight and 4 a.m. During this period of decreased endogenous cortisol production , the body is less able to react to inflammation.
Pseudo croup shows a seasonal accumulation in the months of October to March. It can be assumed that the damp, cold weather prevailing at this time of year also weakens the defenses of those affected and that those affected are generally exposed to more viruses from the environment.
Pseudocroup usually occurs between the ages of six months and three years. The disease is very rare under the age of six months and over six years. Pseudocroup has an incidence of 1.5% to 6% under six years of age , which reaches its maximum in the second year of life. With a ratio of around 1.4: 1, boys are more likely to be affected by pseudo croup than girls. Around 10–15% of all children develop a viral croup once in their life.
The symptoms are expressed in the typical dry barking cough, hoarseness and loud whistling noises when inhaling ( inspiratory stridor ). In higher-grade stenosis can cause shortness of breath with signs of strained breathing as recoveries of the intercostal spaces (intercostal) and the jugular notch come (jugular fossa).
If an adequate oxygen supply is no longer guaranteed due to the obstruction of the airways, rapid heartbeat ( tachycardia ) and a blue discoloration of the lips and fingernails ( cyanosis ) occur. The transition to such a life-threatening clinical picture is possible at any time and cannot be foreseen. Symptoms often appear suddenly in the middle of the night in previously perfectly healthy children. The subjective feeling of shortness of breath often leads to fear and restlessness in the children, which can exacerbate the symptoms.
The disease is also often associated with fever, rhinopharyngitis, and fatigue.
The diagnosis is made clinically based on symptoms. Since it is sometimes difficult to differentiate it from other diseases (see differential diagnosis), the anamnesis and examination must be carried out particularly carefully. Educating parents also plays an important role, as the disease can sometimes take on severe and possibly life-threatening forms. Due to the uncertain course, the start of an immediate therapy has a high urgency compared to further diagnostics.
Whether X-ray diagnostics should be carried out is discussed and handled differently, since this does not make a decisive contribution to the diagnosis itself. However, the case of a foreign body aspiration can be recorded by the X-ray. The church tower sign may appear on an X-ray . Microbiological diagnostics, however, are superfluous.
Further diagnostic steps should be taken in atypical clinical courses.
The severity is usually classified using the Westley score. The Westley Score is the sum of the points given to describe the following symptoms: stridor , retractions, ventilation, cyanosis, and consciousness (see table).
Retraction is understood as the inward falling of the skin between the ribs or the skin in the zygomatic cavity or under the costal arch.
|1||audible with a stethoscope at rest|
|2||Can be heard at rest without a stethoscope|
- Sum of points ≤2: mild pseudo croup
- Sum of points 3–5: moderate pseudo croup
- Sum of points 6–11: severe pseudo croup
- Sum of points> 12: impending respiratory failure
In most cases (85%), mild pseudocroup is present, while severe pseudocroup occurs in <1% of cases.
An important first measure is the calming effect of the parents on the child. The less fear the child experiences and the calmer it behaves, the lower the oxygen consumption, which in turn relatively reduces the shortage of breath.
Since the prognosis is uncertain, a doctor should always be consulted and an inpatient admission should be considered. If the course is severe (pronounced shortness of breath or abnormal breathing noises despite therapy), it must be done in any case.
In the older literature it is sometimes recommended to inhale moist air (possibly with a nebuliser) . However, an extensive evaluation of randomized controlled studies has shown that this measure does not lead to any improvement in symptoms.
The therapy of choice for all degrees of severity is a single administration of glucocorticoids . It can be administered intravenously , intramuscularly , orally , rectally or by inhalation . A meta-analysis has shown that of the available glucocorticoids and dosage forms, the single oral administration of dexamethasone is preferable. The administration of prednisone or prednisolone suppositories is still common in Germany, but has the disadvantage of uncertain absorption , which can fluctuate between 20 and 80%. In addition, no randomized controlled studies are available on the effectiveness of rectal administration of glucocorticoids (prednisolone and prednisone). The glucocorticoids usually start to work after 30–60 minutes, depending on the active ingredient. The effect lasts for many hours ( biological half-life of dexamethasone: 36–72 hours, prednisolone / prednisone 12–36 hours).
In the case of moderate to severe courses ( dyspnoea , cyanosis) or if there is no effect, adrenaline (epinephrine) should also be used for inhalation. The decongestant effect sets in after ten minutes, but only lasts for about two hours. The recommendation for inhaled adrenaline was confirmed in a meta-analysis.
Other causes of airway obstruction in the larynx area can include:
Epiglottitis : (Notes: salivation, poor general condition , high fever, no Haemophilus influenza B vaccination)
Since the introduction of the specific vaccination against Haemophilus influenzae type B, this disease has become rare.
Diphtheria ("real croup"): (Notes: lack of vaccination, sweet smell, reduced general condition, anamnesis - cave : Eastern Europe)
Due to the high vaccination rate in western industrial nations against diphtheria, this disease occurs only very rarely.
- Inhaled foreign bodies (laryngeal, pharyngeal or tracheal): (Notes: very sudden appearance, possibly when playing, without previous symptoms and without fever)
- bacterial tracheitis : (Notes: previous mild to moderate illness for 2–7 days, which then gets worse, lack of response to inhaled adrenaline)
- Peritonsillar and retropharyngeal abscess : (Notes: cervical lymph nodes swollen, difficulty swallowing)
- Pre- existing stenoses such as infantile larynx, laryngeal membranes or cysts
- soft subglottic stenosis
- subglottic hemangioma
- Whooping cough : (Notes: lack of vaccination, attack-like staccato-like cough with 10-20 coughs in a row and subsequent whistling inhalation)
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