Transcript Kendig& Chernick`s disorders of the respiratory tract inchildren . 8 th

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
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–
–
–
–
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
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–
–
–
–
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
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–
–
–
–
–
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
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–
–
–
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
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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
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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
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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 