Croup

Croup has an infectious etiology and can be caused by bacteria or viruses, less often by fungal flora. Infectious agents enter the larynx by airborne droplets through the nasopharynx when inhaling infected air. True croup occurs when infected with Diphtheria bacillus. False croup often develops against the background of rhinitis, pharyngitis or laryngotracheitis of viral genesis in acute respiratory viral infections, influenza, adenovirus infection, scarlet fever, measles, chickenpox. Bacterial etiology of false croup is usually caused by non-specific microflora: Staphylococcus, Streptococcus, Hemophilus bacillus. In rare cases, there is a croup caused by a specific infection with laryngitis that has arisen against the background of mycoplasmosis, chlamydia, syphilis, tuberculosis, etc.

The development of croup against the background of an infectious disease is facilitated by a weakened state of the body, which is more often observed in children who have suffered fetal hypoxia, birth trauma, rickets; suffering from chronic diseases or diathesis.

Croup occurs as a result of several components accompanying the inflammatory process in the larynx: significant swelling of the larynx, reflex spasm of the muscles constricting the larynx, accumulation of thick secretions (sputum) and fibrinous films in its lumen. Depending on the prevalence of inflammatory lesions of the upper respiratory tract, laryngitis, laryngotracheitis or laryngotracheobronchitis may occur. In all these cases, the stenosis characterizing the croup occurs precisely at the level of the subclavian space of the larynx, since the area of the vocal cords is the narrowest point of the respiratory tract.

The obstruction causing croup leads to difficulty in inhaling and a decrease in the amount of air entering the respiratory tract during inhalation. Accordingly, the amount of oxygen entering the body decreases, which causes the development of hypoxia - oxygen starvation. At the same time, the condition of the patient with croup directly depends on the degree of obstruction. At the initial stage, the difficulty of passing air into the respiratory tract is compensated by the increased work of the respiratory muscles. Pronounced narrowing of the larynx leads to disruption of compensatory mechanisms and the appearance of paradoxical breathing. Croup at this stage can result in a complete cessation of air intake into the respiratory tract (asphyxia) and death.

True croup is distinguished by the fact that in its pathogenesis the leading role belongs to the steadily progressive swelling of the larynx, while false croup is characterized by the sudden appearance of reflex spasm of the laryngeal muscles or obstruction of the laryngeal lumen by thick mucus accumulated in it. As a result, in patients with diphtheria croup, there is a gradually increasing aggravation of respiratory disorders, and in patients with false croup, respiratory obstruction occurs paroxysmally.

The most important thing in clinical practice is the division of croup into true and false. Due to the occurrence of false croup, it is classified into bacterial and viral.

True croup is characterized by a gradual flow with a sequential transition from one stage to another. Depending on this, there are: croup of the dysphonic (catarrhal) stage, croup of the stenotic stage and croup of the asphyxic stage. False croup is classified according to the degree of laryngeal stenosis. There are croup with compensated stenosis (I degree), croup with subcompensated stenosis (II degree), croup with decompensated stenosis (III degree) and croup in the terminal stage of stenosis (IV degree).

Regardless of the etiology, croup is manifested by a cough of a specific barking nature, noisy breathing (stridor), hoarseness of voice and general symptoms. Narrowing of the laryngeal lumen causes the presence of inspiratory dyspnea, typical for patients with croup — breathing with difficulty breathing. Pronounced shortness of breath is accompanied by retraction of the intercostal and jugular fossa. With decompensation of laryngeal stenosis, mixed inspiratory-expiratory dyspnea and paradoxical breathing may occur. The latter is characterized by the fact that the chest incorrectly participates in the respiratory act: during the exhalation phase it expands, and during the inhalation period it decreases.

In patients with croup, air noisily passes through the stenosed larynx, causing stridor. Croup, the pathogenesis of which is dominated by laryngeal edema, is manifested by wheezing. With pronounced hypersecretion and accumulation of sputum in the lumen of the larynx, breathing becomes bubbling and wheezing. If the spastic component of obstruction dominates, then the sound characteristic of breathing is variable. A decrease in the intensity of the noise accompanying breathing may indicate an aggravation of stenosis.

The general symptoms, depending on the type of pathogen and the state of reactivity of the patient's body with croup, can be expressed to varying degrees. Diphtheria croup is characterized by a high rise in temperature and significant intoxication: headache, loss of appetite, weakness, fatigue. False croup caused by adenovirus or parainfluenza infection often occurs with a subfebrile temperature. Depending on the degree of airway obstruction, a patient with croup has signs of hypoxia: restlessness or lethargy, pallor of the skin, perioral or diffuse cyanosis, tachycardia, followed by bradycardia in the decompensation stage. The course of the croup can be complicated by the development of bronchitis, pneumonia, otitis, conjunctivitis, sinusitis, meningitis.

Croup can be diagnosed by a pediatrician, therapist or otolaryngologist. With the development of bronchopulmonary complications of infection, a consultation with a pulmonologist is necessary. Croup with syphilis is diagnosed together with a venereologist, with laryngeal tuberculosis - together with a phthisiologist. The characteristic clinic, anamnesis of the disease, data of auscultation, laryngoscopy and additional studies allow to diagnose croup.

During auscultation, dry wheezing of a whistling nature is heard in the lungs. The appearance of wet wheezing indicates an aggravation of the disease. The laryngoscopic picture allows to determine the degree of narrowing of the larynx and the prevalence of the process, to identify fibrinous films characteristic of diphtheria. Verification of the pathogen is carried out by microscopy and back-seeding of smears from the throat, PCR examination, ELISA and RIF diagnostics. To detect syphilis, an RPR test is mandatory. The degree of hypoxia is judged by the results of the analysis of the gas composition of the blood and its acid-base state.

With the development of complications, depending on their nature, the patient undergoes pharyngoscopy, otoscopy, rhinoscopy, radiography of the lungs and paranasal sinuses, lumbar puncture. Differential diagnosis of croup is carried out with whooping cough, a foreign body of the larynx, a pharyngeal abscess, epiglotitis, bronchial asthma, laryngeal tumors, in infants - with congenital stridor.

Differential diagnosis of true and false croup

True and false croup occur against the background of the underlying disease on the 2nd-3rd day from the rise in temperature and the appearance of common symptoms. A similar beginning is replaced by a noticeable difference in the further course of the disease. Thus, true croup is characterized by a gradual increase in the degree of laryngeal obstruction and the corresponding gradual development of respiratory disorders. In its course, there is a dysphonic stage that proceeds without signs of obstruction, stenotic and asphyxic stages. With false croup, there is no stage of the course, the degree of narrowing of the larynx changes during the day, pronounced obstruction develops suddenly in the form of an attack (more often at night).

The swelling of the vocal cords accompanying the true croup leads to a gradual aggravation of voice disorders (dysphonia) up to complete aphonia. It is characterized by the absence of voice amplification during coughing, screaming or crying. At the onset of aphonia, there is a silent cough and crying. False croup is usually accompanied by hoarseness of voice, but never leads to aphonia. The amplification of the voice when shouting and coughing persists.

During laryngoscopy, catarrhal changes of the laryngeal mucosa (edema and hyperemia), narrowing of its lumen and characteristic diphtheria attacks are detected in patients with true croup. Diphtheria attacks are often detected during the examination of the pharynx. They are poorly removed and often expose small ulcerative defects. With false croup, laryngoscopy determines catarrhal inflammation, laryngeal stenosis and accumulation of a large amount of thick mucus in it. There may be easily removable plaque. Bacteriological examination of smears from the pharynx helps to finally differentiate the true and false croup. The detection of diphtheria bacillus 100% confirms the diagnosis of true croup.

Patients with true croup are necessarily hospitalized in an infectious hospital. Their treatment, depending on the severity of the condition, is carried out by intramuscular or intravenous administration of anti-diphtheria serum. Detoxification treatment is used: drip administration of glucose solution, cocarboxylase, according to indications — glucocorticosteroids (prednisone). With the development of severe intoxication, methods of extracorporeal hemocorrection (discrete and membrane plasmophoresis, hemosorption) are used.

Treatment of false croup is carried out with antihistamines, antispasmodics, sedatives. With a dry debilitating cough, antitussive agents (glaucin, prenoxdiazine, oxeladine, codeine) are indicated, with a wet cough, mucolytics (carbocysteine, acetylcysteine, ambroxol) are indicated. In severe cases, with sub- and decompensated laryngeal stenosis, glucocorticosteroids may be prescribed. Croup of viral etiology is treated with drugs with antiviral effect (interferon alpha-2b, proteflazide). Patients with bacterial croup or the threat of secondary infection are treated with antibiotic therapy. The drug is selected in accordance with the results of the antibioticogram performed during the back-sowing. Inhalation therapy with alkaline solutions is carried out, with signs of hypoxia — oxygen therapy. Pronounced laryngeal stenosis with the threat of asphyxia is an indication for tracheotomy.

False croup is an acute inflammatory process of the larynx, accompanied by swelling of its subclavian region, which leads to laryngeal stenosis and obstruction of the upper respiratory tract. False croup is manifested by a dry "barking" cough, hoarse voice and inspiratory shortness of breath, causing noisy breathing. The severity of the condition of patients with false croup depends on the degree of laryngeal stenosis and often changes throughout the day. False croup is diagnosed due to the characteristic clinic and auscultative picture in the lungs, as well as data from the analysis of blood CBS, blood gas composition studies, laryngoscopy, radiography, bakposev, PCR and ELISA diagnostics. Treatment of patients with false croup is carried out with antibiotics, antitussive, sedative, antihistamine and glucocorticoid drugs.

The most common cause of false croup is a viral infection. These are mainly parainfluenza viruses, influenza and adenoviruses, less often measles virus, herpes simplex, chickenpox, whooping cough. False croup of bacterial etiology (hemophilic bacillus, streptococci, staphylococci, pneumococci) is observed quite rarely and is characterized by a more severe course. As a rule, false croup occurs as a complication of acute rhinitis, pharyngitis, adenoiditis, ARVI, measles, chickenpox, scarlet fever and other infections. False croup may be a consequence of exacerbation of chronic tonsillitis. The weakened state of the child's body contributes to the appearance of the disease as a result of birth trauma, fetal hypoxia, rickets, diathesis, artificial feeding, vitamin deficiency, reduced immunity.

Depending on the etiology, viral and bacterial false croup are isolated. According to the presence or absence of complications, false croup is divided into complicated and uncomplicated.

But most often in clinical practice, false croup is classified according to the degree of laryngeal stenosis. With compensated stenosis (grade I), inspiratory shortness of breath (difficulty breathing) is noted with anxiety or physical exertion. False croup with subcompensated stenosis (grade II) is accompanied by inspiratory dyspnea not only during exercise, but also at rest. Decompensated stenosis (grade III) is characterized by severe inspiratory or mixed dyspnea, paradoxical breathing may be observed. With a false croup with a terminal degree of stenosis (IV degree), severe hypoxia occurs, leading to the death of the patient.

In most cases, false croup develops on the 2-3 day of acute infectious disease of the upper respiratory tract. A triad of signs typical of croup appears: a cough of a barking nature, hoarseness of voice and stridor - noisy breathing due to narrowing of the laryngeal lumen. There is an inspiratory type of shortness of breath. The child is excited and restless. The degree of increase in body temperature depends on the type of pathogen and the state of reactivity of the body. This may be subfebrility (more often with a parainfluenza infection) and a rise in temperature to 40 ° C (mainly with the flu). Examination of a child with a false croup often reveals an increase in cervical lymph nodes (lymphadenitis). When inhaling, dry wheezing can be heard.

Clinical manifestations of false croup directly depend on the degree of laryngeal stenosis.

I degree of stenosis is characterized by the presence of shortness of breath only with physical exertion and excitement of the child. Auscultation reveals an elongated inhalation and the presence of single wheezing wheezes in the lungs, appearing mainly on inspiration.

Grade II stenosis is characterized by the presence of shortness of breath and at rest. On inspiration, there is a retraction of the jugular fossa and intercostal spaces. Dry wheezing is heard auscultatively. There is a cyanotic coloration of the nasolabial triangle, indicating a slight oxygen starvation. Tachycardia, agitation, sleep disorders are noted.

III degree of stenosis. There is a strong inspiratory dyspnea with retraction during breathing of the jugular fossa, intercostal space and epigastric region. A patient with a false croup has a pronounced "barking" cough, dysphonia and paradoxical breathing appear. Shortness of breath of a mixed nature is possible, which is an unfavorable sign in terms of the prognosis of the disease. Cyanosis is diffuse. Pulse is individual with loss on inspiration, tachycardia. The child's anxiety is replaced by lethargy, drowsiness, confusion of consciousness occurs. In the lungs, dry and wet different-sized wheezes are heard on inhalation and exhalation, muffled heart tones are noted.

The IV degree of stenosis is characterized by the absence of a typical "barking" cough and noisy breathing for a false croup. There is arrhythmic shallow breathing, arterial hypotension, bradycardia. Convulsions are possible. The consciousness of a patient with a false croup is confused and goes into a hypoxic coma. False croup with IV degree of stenosis can be fatal as a result of the development of asphyxia.

A distinctive feature is that false croup proceeds with changes in the severity of obstructive syndrome and inspiratory dyspnea throughout the day from pronounced to almost imperceptible. However, the greatest severity of the condition is always noted at night. It is at night that false croup attacks occur, caused by severe laryngeal stenosis. They are manifested by a progressive feeling of suffocation, fear and motor anxiety on the part of the child, severe shortness of breath, characteristic cough, perioral cyanosis and pallor of the rest of the skin.

The main task of treating a child with a false croup is to prevent and stop attacks of laryngeal stenosis, relieve inflammation and swelling of the subcutaneous area. It is necessary to exclude the impact of factors that can provoke the occurrence of an attack. It is necessary to provide access to fresh air and abundant alkaline drink, cancel the intake of throat-irritating food, if possible, give the patient false croup medications in the form of syrups, apply throat-softening tablets for resorption, aerosols and inhalations. False croup, accompanied by an unproductive cough, is an indication for the appointment of antitussive medications (codeine, licorice root, thermopsis, oxeladin, prenoxdiazine).

Antihistamines (mebhydroline, diphenhydramine, hifenadine) are used, which have antitussive and decongestant effect. False croup with pronounced laryngeal stenosis is treated with the use of glucocorticoid drugs, sedatives and antispasmodics. Taking antibiotics is recommended from the first day of the disease with bacterial false croup or with the development of infectious complications. Therapy of false croup of viral nature is carried out with antiviral drugs.

Seizures accompanying false croup are caused by reflex spasm of the larynx and can be stopped by attempts to cause an alternative reflex. To do this, press on the root of the tongue, provoking a gag reflex, or tickle in the nose, causing reflex sneezing. They also use hot foot baths, warm compresses on the larynx and chest, cans on the back.

Specific prevention of diphtheria and true croup is carried out by mass vaccination of children, starting from three months of life. False croup has no specific preventive measures. In its prevention, an important role is played by increasing the body's defenses (proper nutrition, hardening and a healthy lifestyle), timely treatment of inflammatory diseases of the nasopharynx and upper respiratory tract infections.