special lecture รพ. ชัยภูมิ rattapon uppala, md division of pulmonology and...

Special Lectureรพ.ชั�ยภู�มิ

Rattapon Uppala, MD

Division of Pulmonology and critical care

Faculty of Medicine

Khon Kaen University

Lower Respiratory tract Infection

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 < 0.2 μm may not sediment and are exhaled

Particles 2 - 10 μm: walls of the branching airways beyond the nose, sedimentation

Particles 0.2 - 2 μm: Surface of the alveoli

Particles > 10 μm: Surfaces of turbinate & septum

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

Conditions

Decreased cough center sensitivity

Unconsciousness, Drugs e.g. opiates

Decreased cough receptor sensitivity

Recurrent aspiration ,GER

Abnormality of efferent nerves

Poliomyelitis, Infantile botulism

Abnormality of muscle

Neuromuscular diseases e.g. SMA, muscular dystrophy

Ineffective laryngeal closure

Vocal cord paralysisPresence 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

Pathogenesis

• Ostia obstruction hypoxic environment within sinus

• Retention of secretion inflammation and bacterial infection

• Secretion stagnate obstruction increases cilia and epithelial damage


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

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


Croup

• Parainfluenza virus 1, 2, 3 (75%), RSV, Adenovirus, Herpesviruses (severe), Measle, Mycloplasma

• Preschool age, Peak 18 - 24 months

• Swelling and inflammation in the subglottic area

• Secretions in the airway lumen

• Leukocytes infiltrate the subepithelium vascular congestion and airway wall edema

• Spasmogenic mediators

Pathogenesis

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

rhonchidelay

Retraction None Nasal flaring, suprasternal

Subcostal, intercostal

Cyanosis None In room air In 40% oxygen

Assess croup score

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• 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

Bacterial tracheitis

• 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

Pathophysiology

• 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

Treatment

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


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


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

aspirationKendig& Chernick’s disorders of the respiratory tract inchildren . 8 th 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 . 8 th 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


• 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


• 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

Pneumonia



40% are caused by viral infections (WHO 2008)

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


Tachypnea : useful sign for the diagnosis of childhood pneumonia

• 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

Diagnosis


Recommended Microbiological investigationsRecommended 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 communityacquired pneumonia in children. Journal of Infection (2004) 48, 134–138

• 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

Criteria for admission

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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


• 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

Complication


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


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


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


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


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 ARespiratory Syncytial Virus (RSV) Human Metapneumovirus 4 Varicella-Zoster Virus (VZV - Chickenpox)AdenovirusPara-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

• Presentation Acute febrile illness, possibly preceded by typical viral URTI.

• Symptoms :

1. Cough

2. Breathlessness ( preventing feeding)

3. Irritability

4. Sleeplessness

5. Chest or abdominal pain in older patients Audible wheezing is rare in LRTI, but can occur

Physical Signs

1. Capillary blood oxygen saturation <95%2. Intercostal and supra-sternal recession3. Flushing4. Tachypnea5. High fever over 38.5 c6. Nasal flaring in children under 1 yr of age7. 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

special lecture รพ. ชัยภูมิ rattapon uppala, md division of pulmonology and...

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