Infection Diseases of Respiratory System in Children

Introduction High Morbidity Rate

High Mortality Rate

Each year, respiratory infection diseases cause about 15 million deaths among children younger than age 5 year through the world. This is a significant cause of mortality in childhood. Pediatric pulmonary infection accounts for about 63.89% of all hospitalizations of children, in which 44.6 percent are pneumonia.Acute and Chronic InfectionRheumatic DiseasePleural DiseaseForeign Body of AirwayNeoplasmCongenital Anomalies

Cricoid cartilage Venting, Warming, Humidificationand conditioningventilationUpper respiratory tract nose, paranasal sinuses pharynx, eustachian tube, epiglottis, larynxLower respiratory tract: trachea, bronchi, bronchioles, alveolus Anatomy and Physiology

Anatomy and Physiology Short Nasal passages, nasolacrimal duct and eustachian tubeUpper respiratory tract

Anatomy and PhysiologyNarrowed airwaySoft mucous menbraneMore vascularSofter and more compliant pulmonary alveolisIgA on Respiratory Mucosaalveolar surfactantClinical significance:Easy to become hyperemia, edema, and congestion which will induce infectionComplication: Pulmonary emphysema and atelectasisLower respiratory tractSmall amounts

Anatomy and PhysiologyThe younger the child The quicker the frequencyThe less regular the rhythmVital capacity (VC) Tidal volumeTotal lung capacity (TLC) Respiratory frequency and rhythm The respiratory frequency is inversely related to age . neonate : 4050 bpm612mo: 30-35 bpm 1-3 yr : 2530 bpm49 yr : 20-25 bpm 8-14 yr :1820 bpm(2) Some young infants present with irregular rhythm or apnea due to immature respiratory center. Small

Anatomy and PhysiologyThoracic cage The thorax is barrel shaped. The ribs are in horrizontal position which are almost perpendicular to the spinal column. The location of diaphragm is oppositely superior, which make the size of thoracic cavity decrease, and the size of lung increase.

Respiratory immune function The specific and nonspecific immune function are poor.

Acute Upper Respiratory Tract Infection AURI

commonly called common coldAcute Upper Respiratory Infection

IntroductionThe common cold is the most common pediatric disease and accounts for 80-90% proportion of visit to clinic.Local infection may spread to nearby organs and tissues which will likely to cause otitis media, conjunctivitis, lymphadenitis, lymphadenitis and pneumonia.Bronchial asthma, nephritis, myocarditis, measles and pertussis may also follow AURI

90% of AURI are caused by viral infectionEtiology RhinovirusEcho virusCoxsackievirusParainfluenzaInfluenzaAdenovirusRSV(Respiratory Syncytial Virus)

PneumococcusMoraxelle catarrhalis Haemophilus influenzaeStaphylococcus aureusBacteria

MycoplasmaChlamydia Other Microorganisms

Others

Mild symptom Nasal congestion, rhinorrhea, sneezing, sore throatSevere symptom High fever, convulsion, anorexia,frequency cough

Clinical Manifestation

Symptoms of URI in children of different ages

< 3 moInfantsAdolescentsSystemicsymptomUsually mildLow grade feverUsually severeHigh feverConvulsionIrritabilityUsually mildLow grade feverRespiratory SymptomsNasal congestion DyspneaAbsent or mildor severe Nasal congestionRhinorrheaSneezingSore throat Gastrointestinal Symptoms DiarrheaVomitingDiarrheaVomitingAnorexiaAbdominal Pain

Physical Sign

The pharynx is red Retropharyngeal folliculosisErythematous enlarged tonsils Enlarged lymph nodesEnterovirus illnesses may be associated with a wide variety of skin rashes

Two Special TypeHerpanginaCoxsackievirus AMost often occurs in summer and autumnMore often in infants0-3 yr of ageCharacterized by sudden onset of fever, sore throat and dysphagia Characteristic lesions, present on the posterior pharynx, are discrete vesicles and ulcersDuration of illness is usually 7 days

Pharyngoconjunctival FeverOccurs typically with type 3,7 adenovirus Most often occurs in spring and summerChildren >3 yr more often affectedFeatures include: A high temperature that lasts 45 days, pharyngitis, conjunctivitis, cervical lymphadenopathy, and rhinitis. Duration of illness is usually 1-2 weeks

Complication Otitis mediaCervical lymphadenitisBronchitisPneumoniaSepticemiaViral Infection Viral Myocarditis Viral EncephalitisBacterial Infectionsstreptococcus)) Acute Nephritis Rheumatic Fever

DiagnosisClinical manifestationsSymptoms and sighs

The differential diagnosis of the URl includes other acute infectious disease.In patient with febrile convulsion, central nervous system Infections should also considered.Patients with abdominal pain may have acute abdomen. Differential diagnosis

Difference Between Mesenteric Lymphadenitis and Acute appendicitis

Clinical ManifestationMesenteric lymphadenitisAcute appendicitis

Symptom of URIexistabsentFever andAbdominal Pain1st present with: feverFollow : pain (mild)1st present with : pain (severe)Follow : Low grade feverAbdomen signsDiffuse tendernessNo rebound tenderness and guardingProgressive localized abdominal tendernessWith rebound tenderness and guardingBlood routineWBC is usually normal or elevatedWBC is elevatedhigher level of neutrophils

Prophylaxis Increase outdoor activities. Improve physical fitness. Enhance immunity function. Patients in collective institutions should be isolated.

TreatmentGeneral treatment Etiological treatment Anti-virusRibavirin Avoid the abuse of antibioticsSymptomatic treatment Severe nasal obstruction Irritability-restlessness High fever Pharyngeal portion ulcer Conjunctivitis

Summary Upper respiratory infection is the most common disease in childhood most of which are caused by viral infections. The severity of clinical manifestations is related to age of the patients. Infants present mild local symptoms and severe systemic symptoms, while older children present on the contrary. A stuffy, congested nose may exist in infants younger than 3 months of age. Treatment for the common cold should be mainly symptomatic. Antibiotics should not be used unless in those young, infant patients which are suspected to complicate bacterial infections.

Acute BronchitisAcute bronchitis is inflammation of the tracheobronchial epithelium .Trachea is usually involvedso acute bronchitis is also called acute tracheobronchitis.Acute bronchitis is commonly secondary to an acute viral infection, or just one manifestation of acute infectious disease.

EtiologyInfectious factorsviral, bacterial or other pathogen infectionsCharacters of respiratory tract of infants: The mucous become edema and hyperemia which make the bronchus narrower when inflammation.Other factorsimmunodeficiency, nutritional diseases, specific body constitution.

Clinical Manifestation Begins as an URICough is a significant signs nonproductive cough productiveThe systemic symptoms is usually serve in infants including fever, vomiting and diarrheaMedical examination Respiratory rudeness Diffuse or scattered rales No dyspneaCXR : may be normal or thickening lung markings

Summary Acute bronchitis is an inflammation of the major conducting airways within the lung which caused by viral or bacteria, and is most often in infants. Cough is the most significant clinical manifestation. Fever, vomiting and diarrhea are frequent in infants. Respiratory sounds are rough and scattered rales are heard on auscultation. Radiographic examination of the chest may show a mild increase in bronchovascular markings. Antibiotics are indicated if a bacterial infection of the airway is suspected or proven. Corticosteroids are recommended in severe cases.

Pneumonia is an inflammation of the parenchyma of the lungs. Most cases of pneumonia are caused by microorgnanisms, but there are several noninfectious causes, which include aspiration of food or gastric acid, foreign bodies and so on. Acute Pneumonia

EpidemiologySeason of onset Age of onsetMorbidity rateMortality rate

Classified according to the infecting organism: Viral pneumonia, bacterial Pneumonia, mycoplasma Pneumonia.Classified according to Pathology: Bronchopneumonia, lobar pneumonia,interstitial pneumonia.Classified according to duration of disease: Acute pneumonia( 3mo).Classified according to severity of disease: Mild pneumonia and severe pneumonia.Category

Etiology

AgeMore often in infantsDiseaseEnvironmentMalnutrition, Congenital heart disease, Immunodeficiency diseaseThe recidence is wetness, stuffiness and crowding. InducementPatients with the following problems are particularly predisposed to this disease:

Hyperemia, edema and inflammatory infiltration of lung tissuesAlveolar exudate Patchy Inflammation focus, and consolidation Atelectasis and emphysema of lungPathology

FevercoughtachypneaRalesfoursymptomsClinical Manifestionpneumonia

Apart from the general features of bronchopneumonia, severe pneumonia also present with systemic toxic symptoms in respiratory system, circulatory system, nervous system and digestive system.Severe Pneumonia

Circulatory systemMyocarditis, heart failureMicrocirculation disturbanceDigestive systemGastrointestinal dysfunction, enteroplegiaAlimentary tract hemorrhageNervous systemIntracranial hypertensionEncephaledemaWater-Electrolyte BalanceMixed acidosis, dehydrationHyponatremiaExtrapulmoanry presentations

Myocardial failure Suddenly onset of tachypnea, R>60 bpm, increased pulmonary rales. Tachycardia that can not be explained by high fever or tachypnea, HR>180 bpm Irritability and cyanosis Gallop rhythm or dull heart sound , distension of jugular vein and enlarged cardiac Increased liver with tenderness, > 1.5cm.Oliguria or anuria that present with edema of eyelid or lower extremities.

Complication

Empyema of pleura Purulent pneumothorax Bullae of lung

OthersSepticemia Purulent pericarditis

Laboratory ExaminationPeripheral blood examination White cell count CRP (C-reactive protein) Nitroblue tetrazolium testEtiological examination Bacteriological examination Bacterial culture Virological examination Viral isolation Examination of mycoplasma Specific immunity examination

Lobular pneumonia (Bronchopneumonia)Pathogen Streptococcus pneumoniae Haemophilus influenzaePathology Pathological changes such as hyperemia and edema of bronchiolar wall, exudation of pulmonary lobule, and bronchiolar obstruction are scattered surround bronchus.Clinical manifestation Hyperpyrexia, cough, tachypnea and dyspnea More common in infants, aged people and weak people

Increase lung markingsDiffuse bilateral Patchy infiltrates and consolidation scattered throughout both lungsAtelectasis, hyperinflation, bullae of lung and pyothoraxChest radiographic findings in bronchopneumonia

Chest radiographic findings in bronchopneumoniaFrontal views :Patchy infiltrates and consolidation at the inner zone and middle zone of bilateral lower lobes, with or without hyperinflation

Segmental atelectasisFrontal views :It is a segmental atelectasis at the right superior lobe. The transversa fissure is displaced toward the airless lobe. There is a sector high density shadow with the apex toward the hilum of lung. The diaphragm is elevated and the mediastinum is shifted to the side of involvement.

Lobar pneumoniaPathogen: maily streptococcus pneumoniaePathology : inflammtion infiltrates throughout a whole lobe or segment of the lung. Main clinical manifestation: More common in adolescence, rare in young children.Hyperpyrexia, cough, and rusty sputumX-ray findings Change after changes of clinical symptoms.

Lobar pneumonia at middle lobe of right lungFrontal views :A consolidation within the transverse fissure and oblique fissure can be seen at the middle lobe of right lung,

viral disease, RSV (85%). aged 2-6 months. airway obstruction is due to pathological changes include swelling and distension of bronchioles, secretions blockage.Bronchiolitis

expiratory wheezing tachypnea, nasal flaringCyanosis fine rales emphysemaThe duration of illness is 4 ~ 7 days Clinical Manifestation

Hyperexpansion is commonly present Peribronchial cuffingIncreased interstitial markings Patchy infiltrates Chest radiographic findings

RSV PneumoniaFrontal views of CXR:

Ground-glass opacity Decreased lung markingsPatchy infiltrates in innner and middle zoneAcquired hyperinflation

Escherichia coli is the most common pathogen in neonate. In young infants > 1 week, mainly pathogen are staphylococcus aureus and hemolytic streptococcus. Some patients may present only with signs of generalized toxicity. Patient uauslly present no cough or fever. Rales are seldom heard on ausculation. Clinical manifestation may be milk-resistant, drowsiness, low response, and tachypnea.Cyanosis, foaming at mouth, nodding respiration or apnea may present in severe cases.Respiratory signs is rare.

Pneumonia of newborn

Chest X-rayFrontal views :There is patchy shadows and infiltrates at right lung field.

Adenovirus pneumonia Type 3,7 adenovirusYoung children6 mo-2 yr are more often affectedAcute onset of high fever, toxic symptoms and pale face. Sometimes present with cardiac dysfunction and symptom of nervous system Severe cough, dyspnea and wheezing Respiratory signs such as fine rales occur after 3-4 daysPatchy infiltrates and consolidation with hyperinflation.

Adenovirus pneumoniaFrontal views :Chest radiographs reveals diffuse interstitial and patchy alveolar infiltrates, peribronchial thickening, and focal consolidation throughout both lung field.

Staphylococcal pneumonia

More common in neonate and infantsPresent a sudden onset and progress quicklySigns include: rashes, severe toxic symptoms, digestive symptoms, convulsion and shockSigns vary with stage of diseaseConsolidation of lung is obviousChest X-ray reveals infiltrates, abscess and bullae of lung

Abscess of lungFrontal views :Multiple round high density shadow in both sides

Pyopneumothorax

Encapsulated pleural effusion

Pulmonary BullaFemale7 dayhyperpyrexia and no cryingCXR: multiple giantair-containing cavity

Mycoplasma pneumoniaCommon cause of symptomatic pneumonia in older children Fever, dry cough are common symptoms Extrapulmonary complications sometimes occurChest radiographs are untypical, usually demonstrate interstitial or bronchopneumonic infiltrates

Interstitial infiltrates in Mycoplasma pneumonia A 5-year-old boycomplain of fever and cough.MP antibody (+)Frontal views of CXR:Increased lung markingsDiffuse patchy infiltratesVolume loss of lower lobes of bilateral lungEnlarged hilar shadow

Diagnosis Peak age of onset Clinical manifestation Laboratory examination X-ray examination Others

Differential DiagnosisAcute bronchitisPulmonary tuberculosisForeign body in bronchus

TreatmentNursing and supporting therapySymptomatic treatment Oxygen supply Conscious sedation Pyretolysis Cough suppressants Eliminate sputum Antimicrobial therapy Treatment of complicationEnhance immunity functionphysical treatment

Antimicrobial treatment Principle of antibiotic treatment: Sensitive Early treatment Sufficiency Drug combination

Antibiotic treatment

Antiviral treatmentThere is no ideal drug in antiviral therapy.Ribovirininterferon (IFN)Human Immunoglobulin Traditional chinese drug therapy Yuxingcao, Double coptis

Severe toxic symptom that include shock, ultrahyperpyrexia and toxic encephacopathy

Increased secretions and bronchial spasm

Complicated with pleural effusion in early period

Indication of Systemic corticosteroids

Heart failure cardiotonic, sedative diuresis and oxygen supplyRespiratory Failure suctioning, oxygen supply intubation and artificial respiratorToxic encephacopathy anti-infection, oxygen supplY, correct acidosis Treatment of severe pneumonia

SummaryFever, cough, tachypnea and fine rales are four major symptoms of pneumonia. Besides, severe pneumonia present circulatory, neurological and digestive symptoms Diagnosis mainly depends on clinical manifestations and X-ray examination.According to the characteristics of clinical symptoms, signs and auxiliary examination, we classify different type and severity. Treatment should emphasize comprehensive treatment. Choose different antibiotics according to different pathogens.Pay attention to the importance of nursing, supporting therapy, and symptomatic therapy.

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