Laryngitis is a group of disorders in which the inflammatory process covers the mucous membrane of all or particular levels of the larynx. These disorders have a different course in children under 4 years old than in children above 4 years old. According to numerous reports laryngitis in small children is more frequently, but not only, a viral infection. Lone articles discuss the role of the allergic factor in the etiopathogenesis of laryngitis.

The most frequent etiopathogenetic factor of laryngitis in small children is the parainfluenza virus [1]. American books describe the influenza virus, rubella virus and varicella-zoster virus as casual factors of laryngitis [2]. Epiglottitis should be described separately. It is caused almost always by Haemophilus influenzae.

The differences mentioned above in the course of laryngitis in children under 4 years old and in children above 4 years old arise from specific variations of the structure of the larynx in these two groups of children. The larynx of a small child is located higher, and the mucous is thicker and contains a large amount of soft tissue. This soft tissue is mainly located under the mucous of the aryepiglottic folds, and especially in the subglottic region. The specific reactivity of the mucous membrane in small children makes them prone to infections, especially viral. Some of these infections may cause oedema of the mucus. The respiratory tract in children is relatively narrow in this region and the chondrous ring limits the size of the subglottic region. So, oedema in this region may have a dramatic course, leading even to acute respiratory distress [3].

Laryngitis does not always lead to such dramatic situations. So, according to the literature and many years of our own experience the disorder was divided into various types [3].

1. Diffuse laryngitis – laryngitis diffusa.

2. Acute subglottic laryngitis – laryngitis subglottica acuta.

3. Laryngotracheobronchitis – LTB.

4. Laryngotracheobronchitis malignant – LTB maligna.

5. Acute epiglottitis – Epiglottitis acuta.

Diffuse laryngitis is inflammation of the mucous of the vestibule of the larynx, subglottic region and eventually adjacent parts of the respiratory tract with a low tendency to oedema. This type of laryngitis occurs most often in patients above 4 years old, in young children occurs rarely. The virus is an etiopathogenic factor. The viral infection at the same time or heterochronously usually involves the nose or pharynx. Symptoms include hoarseness even to aphonia, and a scraping or burning sensations in the pharynx. In the case when the infection involves other levels of the respiratory tract, additional symptoms, characteristic for these levels, occur: serous discharge from the nose, dry cough, fever. This type of laryngitis usually does not lead to dyspone, but may lead to subglottic form and then dyspnoea is the dominant symptom.

The treatment of diffuse laryngitis is analogous to the treatment of other viral infections of the respiratory tract and includes: anti-inflammatory drugs, inhalations with pine or eucalyptus oil, and vitamins. Antibiotics should be avoided, except in situations when symptoms of bacterial infection develop. Glycocortycosteroids should be avoided too. They are indicated for others types of laryngitis with dyspnoea.

Acute subglottic laryngitis it is a type of laryngitis in which cushion-like, symmetrical oedema develops in the subglottic region. Erythema of the mucosa of this part and exudations sometimes may be seen. In patients under 4 years old this type of laryngitis is caused more frequently by parainfluenza virus, rarely by adenovirus, ECHO virus and influenza virus. The symptoms of this type of laryngitis include: dyspnoea, inspiratory stridor, hoarseness and a characteristic barking cough. In the case of laryngeal dyspnoea the stridor is inspiratory and differs from dyspnoea of obturation at other levels. Laryngeal dyspnoea is generally inspiratory. In younger children hoarseness is not rare. On examination symptoms of inflammation of other parts of the respiratory tracts or ears are usually seen. Sometimes the infection may spread to the bronchi and lungs. To properly assess pathological changes of the larynx beside the general and laryngological examinations direct visualization of the larynx on endoscopy, fiberoscopy and laryngoscopy is indicated. The most general symptoms of laryngitis occur also in other disorders of the larynx which occur with dyspnoea like the foreign body of the larynx. So the precise diagnosis is a good base for planning of further treatment. When the symptoms of laryngitis occur at under 6 months of age or are prolonged or recurrent, a congenital defect of the larynx should be suspected, i.e. laryngeal web or haemangioma of the larynx. In these cases direct examination of the larynx is an urgent necessity, because the treatment of these disorders varies.

Acute subglottic laryngitis is a disease which has episodes of deterioration. Episodes of dyspnoea usually develop at night, last several hours and resolve spontaneously. Dyspnoea may recur in the same night or through several subsequent nights. It is impossible to foresee the degree of the episodes and their frequency. So, all small children with laryngitis should be hospitalised, especially because up to now there is, except intubation, no sufficient management to prevent patency of the airways. The treatment of subglottic laryngitis includes, as in other viral infections, systemic anti-inflammatory drugs, humidification and cooling the air in the room. In the case of increasing respiratory problems administration of hydrocortisone in high dose (10 mg per kg b. w.), preferably i.v., may be necessary. [4]. Because of the risk of acute respiratory distress of the child, in spite of proper treatment, hospitalization is indicated in all cases suspected for subglottic laryngitis [2]. Only intubation is a good method which protects the child from asphyxiation. Formerly, tracheotomy was performed, but now it is not often performed in this disease. Antibiotics are administrated in those patients in whom bacterial complications develop. It should be underlined that the antibiotics given for uncomplicated laryngitis in small children do not bring improvement, so should be avoided [5]. In patients older than 4 years of age etiologic factors may be different e.g. allergy. In these cases administration of anti-histaminic drugs and calcium may be suitable.

It should be emphasised that giving these drugs to patients under 4 years old may cause deterioration of the condition, because these drugs cause thickening of the secretion of the respiratory airways, so may lead to obstruction of the narrowed part of the respiratory tract by a close mucus and cause a life-threatening condition. Proper hydratation should be maintained in children with subglottic laryngitis.

Very often subglottic laryngitis develops in children with characteristic appearances: with pale skin, bulky, with red blush on cheeks. This appearance of the child may be associated with hyperalimentations of carbohydrates. In recent years most children with subglottic laryngitis have not demonstrated the above-mentioned symptoms [6, 7]. In the American literature acute subglottic laryngitis is called "croup” [2]. The term "krup” in Polish is preserved for diphteric laryngitis; translation of the American term "croup” into Polish "krup” is improper, because it suggests other aetiology and other treatment.

Acute laryngotracheobronchitis (LTB) – it is a form of laryngeal disease which through spreading of infection is associated with inflammation of the trachea and bronchi. This disorder is extremely rare now, affecting generally infants and small children. Most frequently it is a complication of subglottic laryngitis. In the beginning the causative factors are the same viruses which cause laryngitis, but later bacteria which are the most often responsible for infection of the respiratory tract add to the infection: Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus [1]. American books give as a pathogen Branhamella catarhallis [2].

The disease begins with symptoms similar to those of subglottic laryngitis, but the dyspnea does not disappear after a few hours. Except for inspiratory dyspnoea, mixed inspirator-expiratory dyspnoea may develop. The general symptoms are more severe too.

Laryngoscopic examinations reveal concentric oedema [in distinction to symmetric oedema in the subglottic laryngitis] in the subglottic region and stenosis of the lumen of the larynx, and the trachea is cone-shaped downwards. Treatment includes urgent hospitalisation; bronchoscopy should be performed to aspirate the thick secretion from the trachea. The bronchoscopy is not only diagnostic but also therapeutic. The treatment includes administration of high doses of the antibiotics, which act effectively on the above-mentioned bacteria. Glycocortycoseroids intravenously in high doses are necessary. The administration of mucolytic drugs should be taken into consideration. In the case of increase of dyspnoea intubation is necessary. The course of disease is severe, the prognosis uncertain in spite of the present therapeutic possibilities.

Malignant laryngotracheobronchitis – it is an entity in which to the symptoms of laryngtracheobronchitis bloody secretion is added, because of damage of the mucous membrane by the inflammatory process. This disorder is extremely rare. Recognition is based on endoscopic evaluation. Treatment includes analogous drugs like in laryngotracheobronchitis and mechanical removal of the crust from the airways. In the severe course tracheotomy may be advantageous to remove secretions [1].

Epiglottitis is an inflammatory process of the structures of the epiglottic region of the larynx. So it involves epiglottis and aryepigllotic folds [3, 8]. This type of laryngitis develops most often in children under 7 years of age. Haemophilus influenza is the etiologic factor in a significant number of cases [more than 90%]. Streptoccocus pneumoniae, Staphylococcus aureus and Mycoplasma pmeumoniae are found rarely [1]. The disease begins with sudden pain of the pharynx, which increases leading to dysphagia and sialorrhea. The voice changes, developing into the so-called sheep-like voice. Because of the toxic form of inflammation general symptoms increase: fever, diminished typical child motility, and coughing may be present. The dyspnea develops late, often at the terminal stage. The observation of hypokinesia is important because it is a signal that the child is seriously ill. On examination, even without a spatula, oedematous red epiglottis is seen. The use of a spatula must be gentle and limited to the distal part of the tongue, because forced pressure of the radix of the tongue may lead to collapse of the epiglottis and respiratory distress. American books indicate [2] in the case of epiglottitis to perform radiological examination as a safer method than using a spatula. Ordering an X-ray often necessitates moving patients to another building or even hospital in Polish conditions. This is not admissible because the patient during transport may asphyxiated. It is possible only in the situation when the radiological laboratory is close to the emergency room with the anaesthesiologist, and the child may be directed for X-ray with an anaesthesiologist. A child with epiglottitis requires absolute hospitalisation. The child should be monitored at the hospital. Cases of suspected problems of respiration should be immediately intubated. Because of the bacterial aetiology the treatment includes antibiotics acting on Haemophilus influenza. Cephalosporines of the 3^rd generation are indicated: cefotaxim, ceftriaxon, or ceftazidim at this time [1, 2]. In the case of hyperactivity on beta-lactamase antibiotics, treatment with chloramphenicol should be taken into consideration. This antibiotic was used in the past in the treatment of epiglottitis. In spite of good value in the treatment of infections caused by Heamophilus influenzae it was rejected because of depressing effect on the marrow. But the use of chloramphenicol may be explained in special cases.