Cough (pediatrics)

Cough is a repeated violent loud exhalation maneuver aimed at clearing the airways or eliminating their irritation. Together with other defensive and protective reflexes of the airways, it helps physiologically maintain free airway patency. Cough, along with shortness of breath is one of the most common symptoms of respiratory diseases.

Pathophysiology cough
It is a nociceptive reflex, ie a physiological response to irritation of nerve endings (receptors) located in reflexogenic (tussigenic) zones , the most sensitive of which are in the larynx (glottis, vocal cords and subglottis), trachea and bronchi (most near the branches large bronchi), other zones are in the mucosal areas of the paranasal sinuses, nasopharynx, Eustachian tubes, inner ear, external auditory canal and other localizations. Receptors are located just below the airway epithelium and respond to mechanical stimuli (secretion, foreign body), thermal (cold or hot air), chemical(vapors, gases, acidic gastric juices) and inflammatory (edema, hyperemia). The cough reflex is completed in the first six weeks of life.

The cough begins with a deep breath, then when the glottis is closed, the activation of the exhaled muscles increases the pressure in the chest. The high alveolar pressure after opening the glottis leads to a high flow rate of the air exhaled during coughing and thus to the entrainment and expectoration of the airway contents. The cough is accompanied by a sharp fluctuation in intrathoracic pressure, which is transmitted to the circulatory system.

Cough reflex


 * 1) irritation (chemical, thermal or mechanical);
 * 2) receptors: mucous membranes of the upper and lower respiratory tract, tussigenic zones in the areas of the vagus nerve endings (pleura, spleen, outer ear, stomach, pericardium);
 * 3) afferent fibers: sensitive fibers of the nervus vagus (nervus laryngeus superior);
 * 4) cough center: elongated spinal cord (n. ambiguus, n. retroambigularis), cortex (affecting the will);
 * 5) efferent fibers: motor fibers of the vagus nerve;
 * 6) effect muscles: respiratory muscles;
 * 7) pressure gradient over 10 kPa;
 * 8) air flow 150–280 m / s (cough).

Cough becomes a pathological phenomenon if, due to its quantity or quality, unfavorable aspects outweigh positive aspects.

Classification of cough
By duration:


 * acute - regardless of treatment does not last longer than 1 week;
 * subacute - regardless of treatment does not last longer than 3-4 weeks;
 * chronic - lasting more than 4 weeks.

By character:


 * dry (non-productive);
 * moist (productive);


 * barking (acute subglottic laryngitis)
 * paroxysmal (whooping cough).

Clinical picture

 * coughing in nasopharyngeal secretion - pharyngeal cough;
 * barking cough in the larynx - laryngeal cough;
 * coarse, irritating cough - tracheal;
 * suffocating cough with or without expectoration - cough from lower respiratory tract disorders..

Warning signs of acute cough: cyanosis, suffocation, sudden onset of symptoms

Warning signs of chronic cough: failure to thrive, vomiting, dyspnoea, night cough..

Differential diagnosis of cough in children

 * very wide

Acute cough

 * Acute cough is most often a manifestation of an upper respiratory tract infection. It is usually associated with colds and slightly elevated temperatures. It is mostly of viral origin and tends to be uncomplicated. Treatment is not necessary, mucolytics and secretolytics are not suitable because they increase the production of mucus. In newborns and infants, it is important to maintain nasal patency to avoid food intake problems. Excessive swallowing of mucus (especially in young children who cannot blow and cough) can lead to loss of appetite, oral rejection and vomiting. This can lead to dehydration and metabolic breakdown.


 * acute laryngitis;
 * a sudden, rough, barking cough that develops in a constriction between the subglottic mucosal valleys (dry, unproductive);
 * inspirational stridor, or other signs of dyspnoea;
 * it typically begins at night with either full health or a mild respiratory infection;
 * mucus secretion gradually increases and the cough turns wet;
 * predominantly viral etiology;
 * treatment: cold nebulization, inhalation of adrenaline (dilution 1: 4 with saline), administration of corticoids parenterally (dexamethasone 0.4-0.6 mg / kg / dose), oral or rectal administration is not recommended due to the slow onset of action (only in case of impossibility of intravenous administration), careful sedation in case of restlessness of the child, in case of progression of dyspnea, early transfer to the intensive care unit to ensure artificial lung ventilation; administration of antitussives or mucolytics has no therapeutic significance.


 * acute bronchitis;
 * inhalation of irritants;
 * inflammation of the paranasal sinuses;
 * aspiration.

Chronic cough
The most common causes are viral cough, rhinitis syndrome, bronchial asthma and gastroesophageal reflux.


 * Pulmonary causes – bronchial asthma, cystic fibrosis, primary ciliary dyskinesia, foreign material aspiration, tracheoesophageal fistula, family smoking, post-infection cough, postnasal drip syndrome, tuberculosis, interstitial lung process, tumor, postinfection (RS viruses, parainfluenza, mykoplasmas, chlamydia, cytomegaloviruses, pertussis, parapertus), nasopharyngeal obstruction (adenoid vegetation), chronic bronchitis, hypotonic tracheal dyskinesia, congenital malformations,  unknown aspiration of a foreign body wedged in the bronchial tree.
 * Extrapulmonary causes – gastroesophageal reflux, cardiac cause, use of ACE inhibitors, psychogenic cough.

Cough with hemoptysis

 * rarer in children than in adults;
 * causes: lung and airway tumors, cardiovascular aneurysms, tuberculosis;
 * prodromes of fullness or warmth in the chest and cough irritation;
 * the blood is usually bright red, foamy, alkaline.

Pseudohemoptysis

 * hemorrhagic diathesis, bleeding during anticoagulant treatment, after ENT procedures, most often epistaxis;
 * rather coughing, with dark red or brownish and unfoamed blood.
 * in hematemesis, the blood is dark red to black (coffee grounds color), unfoamed, with a sour smell, and leftover food.

The most common causes according to age
Infnts: aspiration,  obstructive bronchitis laryngotracheomalacie, compression of the airway vessels (ring loop and. Lusoria - aberrant distance right subclavian artery beyond the distance left subclavian artery - it is usually in the esophagus, but rarely can go well between the esophagus and trachea), cystic fibrosis, viral infections (RSV, parainfluenza, adenoviruses), rarely pertussis, pneumocystosis, tuberculosis (from mother),  congenital heart defects with left-sided short circuit, idiopathic cardiac hemosiderosis, influence of passive smoking…

Children under 5 years of age : aspiration,bronchial asthma, bronchiectasis, cystic fibrosis, primary ciliary dyskinesia, imunodeficiency, acute resp. infection, chronic sinusitis and otitis, tuberculosis…

School children and adolescents: bronchial asthma, bronchiectasis, primary ciliation dyskinesia, immunodeficiency, cystic fibrosis, chronic sinusitis, otitis, active or passive smoking, working environment, lung tumors and mediastinum, psychogenic cough.

Medical examination

 * Anamnes
 * family anamnesis: atopy, bronchial asthma, eczema or immunodeficiency;
 * personal anamnesis: neonatal period, type of nutrition, previous illness, incidence of eczema;
 * current diseases: cough duration, its daily variability, exercise tolerance, the effect of temperatures on cough, the occurrence of previous infections, the occurrence of rhinitis, snoring in the child's sleep, the effect of food on the onset of cough;
 * the child's social environment and overall regime may affect the onset and duration of the disorder.
 * Clinical examination.
 * Basic laboratory tests: sedimentation of red blood cells (FW), blood count with differential budget, C reactive protein.
 * Serology: chlamydia, mycoplasma, pertussis, viruses - adenoviruses.
 * Sweat test - to rule out cystic fibrosis.
 * Mantoux II test - to rule out tuberculosis.
 * 24-hour esophageal pH measurement, or X-ray contrast examination of the esophagus - to exclude GER.
 * Bronchomotor tests.


 * Skiagram of the chest
 * indicated for both acute and chronic cough;
 * anterior and possibly lateral projection, in case of suspicion of foreign body aspiration, focal finding (abscess, cyst, pneumocele,…), atelectasis, focal pneumonia,…


 * Spirometry - functional examination of the lungs
 * indicated for chronic cough;
 * requires patient cooperation, is performed on children from about 3 years of age;
 * baby co-plethysmography may be performed on non-cooperating children;
 * it is performed at rest;
 * flow-volume curve determines ventilation parameters (functional vital capacity, one second expiratory capacity, maximum expiratory rate,…)..


 * CT / HRCT of the chest
 * allows the assessment of the structural integrity of small airways;
 * the disadvantage is the high radiation exposure, which carries the risk of malignancy;
 * indicated in case of suspicion of interstitial lung process, pulmonary embolism, congenital defect of lungs, respiratory tract, mediastinum or heart, suspicion of tumor event. evidence of metastases of extratoracal malignancies, pathological processes of the mediastinum, complicated pneumonia (necrotizing, abscessing).


 * Bronchoscopy - endoscopy of the lower respiratory tract
 * the range of the flexible bronchoscope is at the level of 6-8. bronchial branching order from a total of 23-24 (depending on the device used);
 * indicated for diagnostic reasons in chest skiagram abnormalities (atelectasis, atypical and unclear infiltrates), airway obstruction (stridor, persistent wheezing, localized hyperinflation), chronic cough (suspected foreign body aspiration, hemoptysis);
 * indicated for therapeutic reasons in the presence of a mucus and blood plug and to clear the airways;
 * special bronchoscopic methods: bronchoalveolar lavage, brush or mucosal biopsy, transbronchial biopsy, drug administration, endoscopic intubation.


 * Otorhinolaryngological examination (paranasal sinuses, adenoid vegetation);
 * Allergological examination;
 * Immunological testing;
 * Cardiac examination;
 * Psychological examination.

Therapy

 * Léčba základního onemocnění.
 * Symptomatická adenoidní vegetace – adenotomie.
 * Perzistující průduškové astma – inhalační kortikosteroidy (u těžších forem v kombinaci s dlouhodobými ß2-agonisty nebo montelukastem).
 * Cystická fibróza – komplexní léčba: mukolytika, antibiotika, pankreatické enzymy, inhalace – amilorid a rekombinantní DNasa, vitaminy, dechová rehabilitace a výživa se zvýšeným přívodem živin a minerálních látek).
 * Primární ciliární dyskineze – antibiotika, mukolytika, dechová rehabilitace.


 * Antibiotická léčba je indikovaná u bakteriální rinosinusitidy a bronchitidy, pneumonie a pertuse. Iniciální antibiotická terapie je u komunitní pneumonie empirická, proto nedojde-li ke zlepšení klinického stavu po 48 h antibiotické léčby, je třeba zvážit změnu farmakoterapie.
 * Děti do 6 let:
 * nejčastěji perorální penicilin se širokým antibakteriálním spektrem a inhibitorem β laktamáz (ampicilin/sulbaktam a amoxicilin/kyselina klavulanová);
 * nebo cefalosporiny stabilní vůči β-laktamázám (cefuroxim);
 * při podezření na mykoplazmovou nebo chlamydiovou pneumonii se používá makrolid (klaritromycin nebo azitromycin).
 * Děti ve věku 6–15 let:
 * makrolidová antibiotika (např. klaritromycin po dobu 14 dnů) vzhledem k vysoké prevalenci mykoplazmové pneumonie.


 * Symptomatologická léčba: expektorancia, antitusika.

Expektorancia

 * usnadňují odstraňování hustého hlenu z dýchacích cest;
 * podle mechanizmu se dělí na mukolytika, sekretolytika a sekretomotorika:
 * mukolytika snižují viskozitu bronchiálního sekretu ovlivněním jeho fyzikálně-chemických vlastností – štěpením chemických vazeb snižují vazkost hlenu a někdy vykazují i protizánětlivé a protiinfekční působení;
 * sekretomotorika (beta-sympatomimetika, rostlinné silice) usnadňují transport hlenu a jeho vykašlávání zvýšením aktivity řasinkového epitelu.


 * Acetylcystein - mukolytikum, které redukuje disulfidické vazby v bílkovinách hlenu;
 * účinek až po 2–3 dnech p.o. podávání;
 * NÚ gastrointestinální obtíže, cefalgie, kožní alergické reakce.


 * Karbocystein – výhodnější farmakokinetické vlastnosti a vyšší stabilita než acetylcystein;
 * KI u dětí do 2 let, při akutní vředové chorobě, akutní cystitidě a akutní glomerulonefritidě.


 * Erdostein – mukolytický i mírný protizánětlivý účinek, působí jako scavenger volných kyslíkových radikálů;
 * KI u dětí do hmotnosti 15 kg;
 * v současnosti považován za nejúčinnější mukolytikum, jeho efektivitu potvrdila i kontrolovaná klinická hodnocení, která u něho prokázala antioxidační a protizánětlivé působení, zvyšování imunoglobulinu A, lysozymu a laktoferinu v bronchiálním sekretu, snižování přilnavosti bakterií a potenciaci účinku antiastmatik salbutamolu a budesonidu i antibiotika amoxicilinu.


 * Ambroxol – metabolit bromhexinu, který má mukolytický a výrazný sekretomotorický účinek, urychluje tvorbu a sekreci surfaktantu a snižuje tak adhezivitu hlenu k povrchu dýchacích cest; podporuje aktivitu alveolárních makrofágů a má antioxidační účinek a nepřímý účinek protizánětlivý; zvyšuje penetraci antibiotik do plicní tkáně a patrně se podílí i na snižování bronchiální hyperreaktivity;
 * NÚ jediněle gastrointestinální obtíže.
 * Bromhexin – metabolizuje se na vlastní účinnou látku ambroxol;
 * dlouhodobá aplikace vede k nadměrné stimulaci pohárkových buněk, a tím nakonec k jejich atrofii.


 * Desoxyribonukleáza – enzym štěpící mimobuněčnou DNA, která zodpovídá za vysokou viskozitu hlenu u pacientů s cystickou fibrózou;
 * KI u dětí do 5 let, v době gravidity a laktace;
 * NÚ alergické kožní reakce.


 * Guaifenezin, mesna.

Expektorancia by neměla být podávána současně s antitusiky pro možné hromadění a stázu hlenu v bronších.

Antitusika

 * potlačují kašlací reflex;
 * indikována při úporných stavech suchého, dráždivého kašle, kdy předchozí podání expektorancií bylo neúčinné;
 * při dlouhodobém podávání hrozí riziko vzniku závislosti;
 * dle složení: kodeinová x nekodeinová;
 * dle mechanizmu účinku: centrální x periferní;
 * antitusika kodeinového typu mají centrální mechanizmus účinku; nekodeinová mohou mít centrální i periferní účinek.


 * centrální antitusika: kodein, dihydrokodein, etylmorfin a dextrometorfan;
 * inhibují nebo potlačují kašlací reflex útlumem centra kašle v prodloužené míše nebo vyšších centrech;
 * nepříznivé účinky morfiových antitusik: možný útlum dýchání a rozvoj obstipace;
 * Kodein – metylderivát morfinu; velmi účinné antitusikum s analgetickými účinky;
 * KI u dětí do 12 let a při obtížné expektoraci u CHOPN;
 * NÚ nauzea, zvracení, zácpa, útlum dechového centra, retence moči, palpitace, eventuálně mióza.
 * Folkodin – derivát kodeinu s výhodnějšími vlastnostmi než kodein – má silnější antitusický účinek, méně nežádoucích účinků a nižší riziko vzniku závislosti.
 * Dextrametorfan – syntetické antitusikum, které je velmi dobře snášeno, nemá analgetický účinek, netlumí dechové centrum, riziko vzniku závislosti je minimální, nevyvolává zácpu;
 * KI u dětí do 2 let a při astma bronchiale.


 * peripheral antitussives: butamirate, dropropizine and levodropropizine;
 * suppresses the reflex zones of cough in the airways and conduction of excitations in the afferent and efferent pathways of the cough reflex, does not suppress the respiratory center and does not lead to drug dependence
 * Butamyrate - central and peripheral effects (mild bronchodilator effects);
 * a well-acting and well-tolerated antitussive with minimal side effects..

Many studies have not shown a clinical effect of antitussives in children..

Comment:


 * Antihistamines have minimal or no effect in the treatment of cough.
 * Most children with acute cough recover spontaneously without medical intervention.
 * Treatment of the symptom itself can lead to an unnecessary delay in the correct diagnosis, and even to severe damage to the airways and lung parenchyma..