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Special Lecture รพ.ชัยภูมิ Lower Respiratory tract Infection Rattapon Uppala, MD Division of Pulmonology and critical care Faculty of Medicine Khon Kaen University Lung protective mechanism Intrinsic lung defenses • Aerodynamic filtering • Humidification • Airway reflexes –Sneezing –Bronchoconstriction –Cough reflex • Mucus and airway surface liquid –Respiratory mucus –Mucocilliary clearance Aerodymanic Filtering Very large particles: Nasal hair Particles > 10 μm: Surfaces of turbinate & septum Particles 2 - 10 μm: walls of the branching airways beyond the nose, sedimentation Particles 0.2 - 2 μm: Surface of the alveoli Particles < 0.2 μm may not sediment and are exhaled Stark JM, Colasurdo GN. In Kendig's Disorders of the Respiratory Tract in Children;2006:205-23. Abnormalities of Cough Mechanism Abnormalities of cough mechanism Decreased cough center sensitivity Decreased cough receptor sensitivity Abnormality of efferent nerves Abnormality of muscle Ineffective laryngeal closure Conditions Unconsciousness, Drugs e.g. opiates Recurrent aspiration ,GER Poliomyelitis, Infantile botulism Neuromuscular diseases e.g. SMA, muscular dystrophy Vocal cord paralysis Presence of a tracheostomy tube Sinus • Moist air space • Four pairs of sinuses : ethmoid, maxillary, frontal, sphenoid – – – – – Ethmoid and maxillary sinuses form, present at birth Only ethmoid sinuses are pneumatized at birth Maxillary sinuses are pneumatized by 4 years of age Sphenoid sinuses are pneumatized by 5 years of age Frontal sinuses appear at age 7 - 8 years, completely developed in late adolescence Nelson Textbook of Pediatrics, 19th edition Nelson Textbook of Pediatrics, 19th edition Pathogenesis • Ostia obstruction hypoxic environment within sinus • Retention of secretion inflammation and bacterial infection • Secretion stagnate obstruction increases cilia and epithelial damage Nelson Textbook of Pediatrics, 19th edition Criteria for the Diagnosis of Sinusitis • Presence of at least 2 Major or 1Major and ≥ 2 Minor IDSA Guideline for ABRS. Clin Infect Dis. 2012 ; 54(8): e72 – e112 Antimicrobial Regimens for ABRs in Children Not azithromycin, clarithromycin, co-trimoxazole for empiric Rx for ABRS Variable susceptibilities to oral 2nd, 3rd cephalosporins IDSA Guideline for ABRS. Clin Infect Dis. 2012 ; 54(8): e72 – e112 Treatment • Amoxicillin (45 mg/kg/day) for uncomplicated case • Penicillin-allergic : TMP-SMX, cefuroxime axetil, cefpodoxime, clarithromycin, or azithromycin • Recommend for 7 days after resolution of symptoms • High-dose amoxicillin-clavulanate (80-90 mg/kg/day of amoxicillin) PRSP group – – – – – Antibiotic treatment in the preceding 1-3 mo Daycare attendance Age <2 yr Presence of resistant bacterial species Failed to respond to initial therapy with amoxicillin within 72 hr • intranasal corticosteroids for allergic rhinitis co-morbidity • Nasal irrigation Nelson Textbook of Pediatrics, 19th edition Croup • Parainfluenza virus 1, 2, 3 (75%), RSV, Adenovirus, Herpesviruses (severe), Measle, Mycloplasma • Preschool age, Peak 18 - 24 months Pathogenesis • Swelling and inflammation in the subglottic area • Secretions in the airway lumen • Leukocytes infiltrate the subepithelium vascular congestion and airway wall edema • Spasmogenic mediators Diagnosis • Croup is clinical diagnosis : dose not required a radiograph of neck, AP neck : steeple sign Clinical 0 1 2 Cough None Hoarse cry Barking cough Stridor None Inspiration Inspiration and expiration Breath sound Normal Harsh with rhonchi delay Retraction None Nasal flaring, suprasternal Subcostal, intercostal Cyanosis None In room air In 40% oxygen Assess croup score <4 4-7 >7 -รักษาแบบผู ้ป่ วยนอก -พ่น adrenaline (1:1000) 0.05-0.5 มก./กก./ครัง้ -Intubation -ให ้การรักษาแบบประคับประคอง (อายุ <4ปี ขนาดสูงสุด 2.5 มล.) -Dexamethasone -ติดตามการรักษาภายใน 24 ขม. (อายุ >4ปี ขนาดสูงสุด 5 มล.) - No other underlying Dz -Dexamethasone 0.6 มก./กก./dose IV./IM.OD max dose10mg/dose ดีขน ึ้ ไม่ดข ี น ึ้ ให ้ adrenaline ซ้าได ้ทุก 2-6 ชม. ดูอาการต่ออีก > 24ชม. ดีขน ึ้ ดีขน ึ้ ดูอาการต่ออย่างน ้อย 24 ชม. ให ้ adrenaline ซา้ ได ้ทุก 2-6 ชม. ไม่ Intubation Bacterial tracheitis • Staphylococcus aureus : most common, HiB, streptococcus, pneumococcus, M. catarrhalis, Gram neg: Pseudomonas aeruginosa • Primary bacterial infection or secondary to viral croup • Deteriorate rapidly, high fever, toxic appearance, respiratory distress and airway obstruction • Not respond to corticosteroid or nebulized epinephrine Pathophysiology • Subglottic edema with ulceration, erythema • Pseudomembranous formation on tracheal surface • Thick, mucopurulent secretion and sloughed mucosa frequently obstruct the lumen • Lateral neck X-ray – hazy tracheal air column – Irregularities of the trachea wall Treatment • Diagnostic endoscopy under GA; enable removal of secretion and sloughed tissue • Many patient required ET intubation, usually 3-7 days • Frequent tracheal suction • IV broad spectrum antibiotics 10-14 days Bronchitis • Nonspecific inflammation of bronchus • Usually viral in origin, follows upper respiratory tract infection • Cough prominent feature, Vomiting (swallowed sputum), Chest pain, Low grade fever (or absent) • Common in younger children(< 6 yrs) and males Nelson Textbook of Pediatrics, 19th edition Management Supportive treatment • Adequate hydration, rest, and proper humidification of the ambient air • Frequent shifts in position can facilitate pulmonary drainage in infants • Avoided cigarette smoke • Cough suppressant is contraindicated • Wheezing trial of a β agonist • Antibiotic if indicated • Steroids, either inhaled or systemic: poorly defined Nelson Textbook of Pediatrics, 19th edition Bronchiolitis • Younger than 2 years of age, 1st episode of wheezing • RSV(50-80%), HMPV (19%), other viruses • Clinincal viral infection, followed by onset of tachypnea, chest retraction, wheezing or prolong expiratory phase, apnea • Peak symptom around day 3-4 of illness • Diagnose by history and physical examination • Virology: viral culture, IFA, EIA, PCR, NP aspiration Kendig& Chernick’s disorders of the respiratory tract inchildren . 8th edition 2012 Pathogenesis • RSV binds to TLR-4 on epithelium • Cellular and ciliary damage, inflammatory effect • Mucus secretion combining with desquamated epithelial cells “Thick mucus plug” Bronchiolar obstruction air trap or collapse • Mucous plugs are removed by macrophages • Recovery after regeneration of the bronchiolar epithelium 3-4 days, cilia 15 days • RSV: Viral shedding time 8 days Kendig& Chernick’s disorders of the respiratory tract inchildren . 8th edition 2012 Severity assessment • Poor feeding and respiratory distress • Severity factors – Toxic or ill appearance – O2 < 95% with room air – Age younger than 3 mo. – RR ≥ 70 breath per min – Atelectasis on chest radiography Kendig’s disorders of the respiratory tract inchildren . 7th edition 2006 Treatment • Supportive treatment – Humidified oxygen – Adequate hydration, Beware SIADH – Nasal suctioning • Symptomatic treatment – – – – – – Antipyretic drug + Tepid sponge Trial nebulized adrenaline, salbutamol Systemic corticosteroid, Leukotriene Modifiers Hypertonic saline Heliox inhalation therapy CPAP or high flow oxygen • Specific treatment – Ribavirin and anti RSV medication – RSV Immunoglobulins prophylaxis (RSV Ig and Palivizumab) Kendig’s disorders of the respiratory tract inchildren . 7th edition 2006 Complication • Early – – – – Respiratory failure (esp. <6 mo, preterm) AOM (50-60%) Myocarditis SIADH • Late – Asthma / reactive airway disease recurrent wheezing >50% and abnormal PFT – Bronchiolitis obliterans Most common : adenovirus, especially serotypes 1, 3, 7 and 21, RSV Kendig& Chernick’s disorders of the respiratory tract inchildren . 8th edition 2012 • CXR : hyperinflation and bilateral interstitial markings • HRCT : mosaic perfusion, vascular attenuation • Anti-inflammatory drug : Azithromycin • Corticosteroids have not been shown to improve outcome • Lung transplantation Kendig& Chernick’s disorders of the respiratory tract inchildren . 8th edition 2012 Pneumonia • Inflammation of lung tissue caused by infectious agent resulting in damage to lung tissue • Thailand : 45-50% of LRTI children below 5 years of age, most common cause of death Kendig& Chernick’s disorders of the respiratory tract inchildren . 8th edition 2012 40% are caused by viral infections (WHO 2008) Kendig& Chernick’s disorders of the respiratory tract inchildren . 8th edition 2012 Pathogenesis • Viral pneumonia – Interstitial inflammation – Alveolar walls thicken, occluded with exudates, sloughed cells, and macrophages – Inflammation of the bronchioles, and air trapping • Bacterial pneumonia – Organisms colonize the trachea access to the lungs or direct seeding after bacteremia – Alveolar inflammation Kendig& Chernick’s disorders of the respiratory tract inchildren . 8th edition 2012 Tachypnea : useful sign for the diagnosis of childhood pneumonia Pediatrics in Review 2008;29;147 Diagnosis • Gold standard : lung puncture specimen or performing a bronchoalveolar lavage • Chest radiograph – Viral : hyperaeration, prominent lung markings (bronchiolar thickening) and focal atelectasis – Bacterial : alveolar infiltration, lobar consolidation, linear filtration, pleural effusion, pneumatocele Kendig& Chernick’s disorders of the respiratory tract inchildren . 8th edition 2012 Recommended Microbiological investigations Blood culture For all hospitalized, positive less than 10% Nasopharyngeal aspirate (NPA) for viral antigen detection For all under 18 months of age, highly specific and sensitive for RSV, influenza and adenovirus Nasopharyngeal aspirate viral culture if virus not detected by antigen detection, highly specific and sensitive Serology Acute and convalescent serology for viruses, Mycoplasma and Chlamydia Pleural aspirate (if present) Microscopy, culture and bacterial antigen detection (pneumococcal) Bacterial antigen in urine NOT recommended due to poor specificity Nasopharyngeal aspirate (NPA) bacterial culture NOT recommended as not of diagnostic value Serum antigens (bacterial) NOT recommended as tests are less sensitive and specific Review of BTS guidelines for the management of community acquired pneumonia in children. Journal of Infection (2004) 48, 134–138 Criteria for admission • Age < 3 mo • SpO2 at room air < 92% • Respiratory distress : retraction, grunting difficult breath,apnea • Sign of dehydration, poor feeding • Drowsiness or sign of shock • Suspected S.aureus pneumonia • Underlying CHD, CLD, immune deficiency • Not response in OPD treatment 48 hr and clinical progression • Poor childcare attendance ชมรมโรคระบบหายใจและเวชบาบัดวิกฤตในเด็กแห่งประเทศไทย 2556 Treatment • Supportive & Symptomatic treatment - Oxygen therapy Adequate hydration Bronchodilator Expectorant or mucolytic Chest physical therapy Antipyretic • Specific treatment - Antiviral, Antibiotic • Prevention - Vaccine - Infectious control : isolation, hand hygiene ชมรมโรคระบบหายใจและเวชบาบัดวิกฤตในเด็กแห่งประเทศไทย 2556 Kendig& Chernick’s disorders of the respiratory tract inchildren . 8th edition 2012 Complication • • • • • • Parapneumonic effusion Pneumatocele, pneumothorax Lung abscess Septicemia and metastatic infection Hemolytic uremic syndrome Extrapulmonary in M.pneumoniae : rash, SJS, hemolytic anemia, polyarthritis, hepatitis, pancreatitis, myocarditis, encephalitis, aseptic meningitis and transverse myelitis • Long term : chronic lung disease, bronchiectasis ชมรมโรคระบบหายใจและเวชบาบัดวิกฤตในเด็กแห่งประเทศไทย 2556 Pulmonary abscess • Thick walled purulent material, result of infection destructing lung parenchyma, cavitating and central necrosis – Primary lung abscess – Secondary lung abscess • Predispose conditions : aspiration (most common in children), pneumonia, cystic fibrosis, GER, TE fistula, immunodeficiency, postoperative complication T&A, seizure, neurologic disease Nelson Textbook of Pediatrics, 19th edition Aspiration • Effected sites – Recumbent position : RUL, LUL, apical segment of RLL – Upright position : posterior segment of RUL • Organism : Mixed organism – Anaerobes (Bacteroides, Fusobacterium, Peptostreptococcus) – Aerobes (Strep, Staph, E.coli, Klebsiella, Pseudomonas) – Fungus particularly immunocompromised patients Nelson Textbook of Pediatrics, 19th edition Diagnosis • CXR abcess = parenchymal inflamation with cavity containing air-fluid level • CXR pneumatoceles = thin and smooth walled, localized air collection with or without air-fluid level • Sputum C/S : mixed organism, not reliable • CT-guided percutaneous or transtracheal aspiration or BAL Nelson Textbook of Pediatrics, 19th edition Treatment • ATB : IV 2-3 wks, then oral for total 4-6 wks • Initial broad spectrum ATB with aerobic (S.aureus) and anaerobic coverage : Clindamycin or BL/BI or PGS + Metronidazole • Severely ill or fails medication after 7-10 days of appropiate ATB : minimal invasive percutaneous aspiration – rare for thoracotomy with surgical drainage or lobectomy and/or decortication • Excellent prognosis – Fever can persist for 3 wk – CXR resolve in 1-3 mo, can persist for year Nelson Textbook of Pediatrics, 19th edition Lower Respiratory Tract Infections in Children Summary Definition & Etiology There is no hard and fast definition of lower respiratory tract infection (LRTI), that is universally adopted. Essentially, it is inflammation of the airways/pulmonary tissue, due to viral or bacterial infection, below the level of the larynx. Viral causes Influenza A Respiratory Syncytial Virus (RSV) Human Metapneumovirus 4 Varicella-Zoster Virus (VZV - Chickenpox) Adenovirus Para-influenza virus Bacterial Agents Streptococcus pneumoniae Hemophilus Influenzae Staphylococcus aureus M Klebsiella pneumoniae Enterobacteria e.g. E. coli Anaerobes Atypical Agents Mycoplasma pneumoniae Legionella pneumophila Chlamydia sp. Coxiella burnetii Clinical Picture • • 1. 2. 3. 4. 5. Presentation Acute febrile illness, possibly preceded by typical viral URTI. Symptoms : Cough Breathlessness ( preventing feeding) Irritability Sleeplessness Chest or abdominal pain in older patients Audible wheezing is rare in LRTI, but can occur Physical Signs 1. 2. 3. 4. 5. 6. 7. Capillary blood oxygen saturation <95% Intercostal and supra-sternal recession Flushing Tachypnea High fever over 38.5 c Nasal flaring in children under 1 yr of age Dullness to percussion over zones of pneumonia consolidation. 8. Cyanosis in severe cases. Investigations • Chest radiography if fever and tachypnea, oxygen saturation to monitor condition. • In hospital consider capillary or arterial blood gases. • Culture of sputum or nasopharyngeal discharge/aspirate may be used in hospital but has little to add in primary care. • Blood cultures if evidence of septicemia. • Blood urea and electrolytes Management • Admission for children under 5 years with fever and breathlessness is mandatory. • Older children can be managed with close observation at home if not distressed • Physiotherapy has no place in treatment of uncomplicated pneumonia in children without pre-existing respiratory disease. Essential consideration • • • • Oxygen IV fluids if unable to feed Respiratory support in severe cases Cough medicines are not indicated and may be used if cough interferes with feeding or sleep. Honey with lemon may be helpful. • Antihistamines are dangerous in young children & should be avoided. Medications • Antipyretics (avoid aspirin in young children due to danger of Reye's syndrome). • Antibiotic treatment for bacterial pneumonias. • Pneumonia or LRTI following URTI is likely to be viral and will not respond to antibiotic therapy. However, it is difficult to distinguish between viral and bacterial infection and young children can deteriorate rapidly. so consider antibiotic therapy depending on presentation and the clinical judgment of the concerned child. Antibiotics • Streptococcal pneumonia is treated with oral penicillin V, or synthetic penicillin such as amoxicillin as first line drugs. • Recent research indicates that children with non-severe pneumonia on amoxicillin for 3 days do as well as those who receive it for 5 days • If a child is genuinely allergic to penicillin, consider using a macrolide or quinolone. • Cephalosporin often cross-react with penicillin. Antibiotics • For Hemophilus influenzae cephalosporins or Amoxicillin/Calvulenic acid combination are useful. • For Staph pneumonia cloxacillin is used and in severe cases parenteral vancomycin is required. • Injectable antibiotics are indicated in severe cases Complications Bacterial invasion of the lung tissue can cause: – pneumonic consolidation – septicemia – empyema – lung abscess (esp. S. Aureus) – pleural effusion – Mycoplasma P. can cause hemolysis – Rarely, respiratory failure, hypoxia and death. Prevention • It is achieved with pneumococcal vaccine and influenza vaccine • Stop indoor smoking. Smoking at home or school is a major risk factor. • Zinc supplementation reduces the incidence of pneumonia by over 40% in malnourished children. Thank you