Pneumonia Flashcards
annual incidence in developed countries is:
- 40 / 1000 children per year for children under 5 years
- 20 /1000 children per year for children over 5 years of age
- Developing countries:
-more frequent than in Europe / North America;
-more severe
-leading cause of mortality in children along with diarrheal
diseases
MORPHOLOGY:
- inflammation of the lung parenchyma
(alveoli, interstitial, small caliber lower respiratory tract - small bronchi, bronchioles) most often due to infection
Clinical practice - term pneumonia
- Child with fever and respiratory signs and symptoms who has evidence af consolidation (parenchymal infiltrates) on CXR (chest X-Ray)
- where a CXR is not performed / the diagn is based on
symptoms and signs alone – the term acute LRTI (lower
respiratory tract infection) is prefered.
PNEUMONIA - DEFINITION
Chest- X-Ray is essential for:
- Supporting diagnosis
- Clinical and radiological accurate form
- in practice it is not always recommended (guidelines)
- alveolary infiltrate / consolidation – lobar or segmental
= alveolar disease (pneumococcal pneumonia
characteristics)
2. Interstitial infiltrate= interstitial pneumonia
-characteristic for viral infections, mycoplasma,
Chlamydia
3. bronchopneumonia type – multifocal/multilobar pneumonia
PATOPHYSIOLOGY
The development of pneumonia requires a causative pathogen to reach the alveoli / to overcome the hosts protective immunity
1. most pneumonia is acquired by inhalation of infected particles
* from exogenous sources
* from colonization of the nasopharynx or sinuses
2. most rarely - following aspiration
3. hematogenous spread (10-15%) / generalized infection(sepsis)
4. contiguity (rarely)
Lower respiratory airway - are normally sterile
Filtering and fixing of pathogens in the environment in upper respiratory airway → first barrier
Local host defence mechanisms include:
- innate responses
- mucociliary clearance and coughing,
- mucus layer, IgAs,
- phagocytosis by alveolar macrophages and neutrophils
- antiviral and antibacterial molecules: defensins,
interferons, lysosime- produced by the airway epithelium - acquired immunity:
surface antibodies and rapid T-cell responses
Inflammatory response
Neutrophils influx
The release of mediators of inflammatory reaction
Oxidative enzymes
Plasma transudation
The loss of surfactant
MECHANISMS
- The deficit means of defense of the lung
A. Shorting upper airway (intubation, tracheostomy)
B. Depressed epiglottis reflex / ineffective ⇒ suction
(oral secretions, gastric contents - neurology disease)
C. Alteration of mucociliary clearance
(chronic pulmonary disease : FC, PCD)
D. Depression / inefficiency of cough reflex
E. Cell immunodeficiency / humoral immunodeficiency local or general
F. Immunosuppression (drugs, illness) - Viral infection - facilitates bacterial invasion
Factors that predispose to pneumonia are:
- exposure to virulent organisms
- high inoculum
- impaired innate response
- impaired acquired immunity
- Viral infections are more infectious and transmissible than bacterial pneumonias
- most community - acquired bacterial pneumonias arise
following the endogenous spread of organisms from the upper airway, after local host responses have been damaged by a recent / concurrent viral respiratory infection!
CLASIFICATION CRITERIA
Most times - etiologyc diagnosis is made on the basis of
probability criteria:
- Age group
- Presence / absence of comorbidities
- Clinical exam
- Radiological appearance
- Biological status / reactivity
- Epidemiological context, vaccination status
ETIOLOGY
- Viruses
Respiratory syncytial virus
Parainfluenza viruses 1,2,3,4
Influenza A and B viruses
Human- Metapneumovirus
Adenoviruses, Enteroviruses
Rhinoviruses
Measles virus, VZV, CMV - Bacterial atypical
Mycoplasma - Mycoplasma pneumoniae
Chlamydia - Chlamydia trachomatis (neonates)
Chlamydia pneumoniae
Legionella pn., Moraxella sp.
Bacterial typical
Streptococcus pneumoniae
Haemophilus influenzae type b/ nontypable strains
Staphylococcus aureus
Streptococcus pyogenes (group A)
Klebsiella sp
Mycobacterium tuberculosis
Atypical mycobacteria (M.avium intracellulare complex, M.abscessus,
M. kansasii and several others)
ETIOLOGY
- New born - intrauterine or intrapartum origin
- etiology ≈
early neonatal sepsis
Group B Streptococcus
Listeria monocytogenes
Haemophilus influenzae type b
Gram-negative bacilli
Etiology * < 3 wk
- increased risk of nosocomial pneumonia
- favorable factors :
small weight new born ,
peripartum complications
(respiratory distress, mechanical
ventilation, invasive maneuvers, etc)
E.coli and other enteric gram-negative bacilli
Staphylococcus aureus /S. epidermidis
Streptococcus pneumoniae
Etiology
3 wk - 4 mo
- viruses (RSV, influenza, parainfluenza, adenovirus)
-S.pneumoniae, H. influenzae b, - Staph.aureus, Staph.epidermidis, Chlamydia trachomatis, Bordetella pertussis
Etiology
4 mo - 5 years -
- viruses (RSV, influenza, parainfluenza, adenovirus)
- S.pneumoniae, H. influenzae b / non-typable
- Streptococi Gr A, Staph. aureus
- Bordetella pertussis
- Moraxella catarrhalis
- Klebsiella pneumoniae
- enteric bacilli, anaerobic
ETIOLOGY
> 5 years
Viruses (influenza, parainfluenza, adenoviruses)
Mycoplasma pneumoniae
Chlamydia pneumoniae
Streptococcus pneumoniae
H. influenzae b (unvaccinated), non-typable H. influenzae
Legionella pneumophilla
most important bacterial
cause in all age group
Streptococcus pneumoniae
In all age groups - etiology is dominated by viruses
The high incidence of mixed infections is usually a combination of viral and bacterial pathogens, reflecting the prior role that viral infection has in establishing bacterial pneumonia
* The contribution of viral infection to pneumonia will increase significantly during influenza epidemics
CLINICAL MANIFESTATION
It differs by:
- age
- etiology
- presence / absence of comorbidity
In infants the clinical signs may be less relevant or even missing
It is possible a normal clinical exam, but with chest X-Ray changes / and the reverse situation
CLINICAL EXAM
- The likely symptoms and signs of pneumonia depend on the age and the extent of the disease
- Widespread bilateral disease is more likely to cause breathlessness and signs of respiratory distress
- Focal infection may cause fever and lethargy/ often - nothing specific to find on examination to suggest a pneumonia
Abnormal respiratory rate by age group:
> 60 breaths / min in infants less than 2 months
50 breaths / min in infants between 2 - 12 months
40 breaths / min in children 1-5 years
˃30 breaths / min in children over 5 years
CLINICAL MANIFESTATION
Infant / toddler
- fever, tachycardia
- irritability
- anorexia
- decreased activity / lethargy
- drowsiness
- vomiting / diarrhea,
- tachypnea, cough, chest wall recession, wheeze
=> General non-specific symptoms in infant!
CLINICAL MANIFESTATION
older child
- fever, chills
- productive cough
- chest pain (twinge or pleuritic)
- tachypnea, shortness of breathe
- headache, tachycardia
- abdominal pain-usually- lower lobe ( may be severe, mimic appendicitis),
- nausea,vomitting
CLINICAL EXAMINATION
in general
- The presence of:
- respiratory distress syndrome
- tachypnea, chest wall recession
- expiratory groan, nasal flaring, use of accesory muscle of
respiration, dyspnea, cough , cyanosis +/- - dullness on percussion, localized decreased breath sounds ,bronchophony
- abnormal findings on ascultation: bronchial breathing , crackles (crepitations), wheeze
- Crepitations- indicates small airway or alveolar disease
CLINICAL MANIFESTATION
- Other possible signs:
- neurological
- cardiovascular
- digestive (flatulence, diarrhea, toxic ileus)
- stigmata of viral infection(rash)
Hypoxemia
- tachypnea, chest recession
- Nasal flaring
- central type of cyanosis
- lethargy
Bacteriemia
- high fever > 39 o and persistent
- Sensory alteration (low reactivity, not feeding, no longer receives liquid p.o.)
Possible - “toxic” abdominal ileus, seizures
BACTERIAL PNEUMONIA
- Rapid onset, high fever, chills
- Signs / symptoms of sepsis ± severe respiratory symptoms localized chest pain (pleural effusion)
- crackles or decreased breath sounds in the setting of
consolidation - Evidence of infection of other sites - due to the same
organism causing their pneumonia :meningitis, otitis media, sinusitis, pericarditis, epiglotitis, abscess
VIRAL PNEUMONIA
- Slower onset, upper respiratory tract infection prodrome- coryza, fever, cough, hoarseness !!
- Moderate fever, irritable child without toxic condition
- Signs of respiratory distress
- tachypneea,
retractions,
grunting,
nasal flaring - Rales , decreased breath sounds
- Conjunctivitis, otitis media, rash, stridor , cough
± headache, myalgia , +/- wheezing
CHEST X- RAY
VIRAL / ATYPICAL PNEUMONIAS
- hyperinflation
- perihilar streaking
- increased interstitial markings
- peribronchial infiltrates
- patchy bronchopneumonia
- rare : lobar consolidation/atelectasis, pleural effusion
It is an etiological orientation element, but there are overlaps !! - to be interpreted in the clinical context
- only chest X-Ray- is not sensitive to etiological differentiation
- may be “normal” in early stages
CHEST X-RAY
- Clinical and radiological aspects do not allow the affirmation of a
specific etiology other than with a considerable degree of
approximation!
CT - scan, ultrasound chest – may be useful (confirm
diagnosis, differential diagn,
CHEST XRAY
BACTERIAL PNEUMONIA
- Alveolary consolidation process with lobar / segmental / lobular distribution
- Air bronchogram on the pulmonary condensation area
- Frequent pleural participation (pleural effusion)
- Possible pneumatoceles / abscesses (necrotizing pneumonia)
DIAGNOSIS - INVESTIGATION (1)
*1. Blood count - WBC / differential white blood cell count ( etiological orientation), intrainfectious anemia
2. ESR, CRP, procalcitonin,
3. Blood cultures ( ˂ 10% are positive)
4. Urea, electrolytes – SIADH
5. Sputum culture , IDR 5uPPD
6. Pleural fluid (smear, chemistry, culture)
7. Pulse oximetry, blood gas dosing, pH
8. Ag microbial detection in urine (limited value)
DIAGNOSIS - INVSTIGATIONS (2)
- Determination of specific Ac in serum (viral infections, atypical germs – late diagnosis)
- Immunological techniques :
Ag determinations by contraimmunoelectrophoresis, agglutination latex, PCR - polymerase chain reaction- molecular diagnosis –on blood or respiratory secretions for viruses, Mycoplasma, Chlamydia, Pneumococcus - nasopharyngeal aspirate - Viral cultures (high cost, results
belatedly)
INVESTIGATIONS (3)
- naso pharyngeal cultures, sputum cultures - bacterial
superinfection, false pos / neg (not differ by carrier status) - if in cultures→-bK germ, Pseudomonas, nosocomial germs →of considered and supplemented by other investigations
- Bronchoscopy- tracheobronchial aspirate, bronchoalveolar lavage + exam bacteriological and culture (Gram pos / neg, aerobic / anaerobic, fungi, bK)
- Lung Biopsy (immunosuppressed)
- Investigations for possible underlying pathologies (sweat test, immunogram, IDR 5u PPD etc) or complications(thoracic US, chest CT)
BACTERIAL OR VIRAL (1)
- In many children the diagnosis is made clinically in the primary care setting, investigations is unnecessary
- For sicker children requiring hospital treatment – poor feeding, oxygen requirement, severe malaise- investigations are indication
- It is difficult to distinguish bacterial from viral pneumonia in many children
- Mycoplasma, chlamydia can cause focal consolidation
- Invasive viruses such as influenza and adenovirus can cause high neutrophil counts and elevated acute phase reactants !
- Mixed infection occurs in up to 30% of children
BACTERIAL OR VIRAL (2)
SOS
- Bilateral wheeze is perhaps the strongest indicator that any LRTI that may be present is atypical or viral in etiology
- A truly focal disease confined to a single lobe is not likely
to be due to a virus
SOS * Unilateral pleural effusion with adjacent consolidation indicates a bacterial cause ! SOS
- Empyema can occur frequently with Staphylococcal, pneumococcal, group A – β hemolytic Streptococcal pneumonia
- Procalcitonin and C-reactive protein are not specific for
bacterial pneumonia / but if the values are high may be helpful !!!
Evaluating pneumonia severity
INFANTS
MILD SEVERE
TEMPERATURE - ˂ 38,5o ˃ 38,5o
RESP RATE -≤ 70 ˃ 70
SpO2 in room air - ˃ 94 % ˂ 90-93
Chest recession - mild moderate to severe
Breathing difficulty nasal flaring,cyanosis,apnea
Other symptoms - taking full meal not eating
Evaluating pneumonia severity
OLDER CHILDREN
MILD SEVERE
TEMPERATURE - ˂ 38,5o ˃ 38,5o
RESP RATE -≤ 50 ˃ 50
SpO2 in room air - ˃ 94 % ˂ 90-93%
Chest recession- mild breathlessness severe difficulty
Breathing difficulty nasal flaring,cyanosis,apnea
Other symptoms-no vomiting grunting respiration signs of
dehydration
COMPLICATIONS
- Pleural effusion, Empyema – SA, SP, STR
- Pneumatocelle – SA
- Pericarditis- SA, SP
- Bacteremia –SA, SP, HI
- Meningitis, suppurative arthritis, osteomielitys – SP, HI
- Sepsis, shoc septic
- ARDS- acute respiratory distress syndrome (viral, bacterial)
- SIADH – innapropriate secretion antidiuretic syndrome
- SHU (hemolytic uremic syndrome) – acute renal failure, anemia,
thrombocytopenia - CID (coagulation intravascular diseminate)
TREATMENT
- Whether a child should be hospitalised depends – age, the severity of ilness, the suspected organism
- All children younger than 3 months are generally admitted to the hospital
- Children older than 3 months with febrile pneumonia require admission
- moderate to severe respiratory distress , apnea, hypoxemia, poor feeding, clinical deterioration on treatment
- Associated complications- large effusions, empyema, abscess
SUPORTIVE TREATMENT
- Keep upper airways clear – frequent suctioning nasal and oral
secretions - Oxygenotherapy
- Hydration po / parenteral fluids/ electrolyte supplementation
- Infants with severe disease – should not be fed
- The decision to use antibiotics or not, depends on the clinical
picture and the age of the child - It is important
– epidemiological context - chest X-Ray
- imunisation
TREATMENT
Bacterial pneumonia
- If a bacterial pneumonia is suspected – empiric antibiotic
therapy should be considered - Children less than 5 years old an abnormal chest X-Ray,
suggestive clinical findings- the most likely bacterial pathogen is S.
Pneumoniae and the antibiotic of choice is amoxicillin for
outpatient management - second generation cephalosporins or macrolide – for children allergic to penicillin
- Children older than 5 years are more likely to have atypical pneumonia and a macrolide might be the best empiric antibiotic choice
- When its posible - therapy can be guided by the antibiotic
sensitivity of the organisms isolated
TREATMENT
Bacterial pneumonia
BIRTH - 1 month
– ampicillin i.v + aminoglycoside i.v
or
- cefotaxime i.v. + ampiciln i.v. +/- antistaphilococal MRSA
TREATMENT
BACTERIAL PNEUMONIA
1- 3 months
ampicillin i.v. or oral amoxicilin (90-100 mg/kg/day, 7- 10 days
- amoxicillin – clavulanate (90 mg/kg /day for amoxi)
- erythromycin – 40 mg/kg/day
- ceftriaxone – 100 - 150 mg/kg/day
- cefotaxime - 100-150 mh/kg/day
TREATMENT
BACTERIAL PNEUMONIA
* 4 months – 4 years
– oral amoxicillin or ampicillin i.v.
- oral amoxicillin – clavulanate (90 mg/kg/day)
- oral or parenteral clarithromycin (15mg/kg/day)
- oral azithromycin
- cefuroxime oral 30 mg/kg/day
- benzylpenicilin i.v. 200 000 units/kg/day
- ceftriaxone i.v. 50-100 mg/kg/day
- cefotaxime i.v. + vancomicyn i.v. / linezolid i.v.
- cefotaxime i.v. + clindamycin
TREATMENT
BACTERIAL PNEUMONIA
* 5 – 18 years
- Oral amoxicillin or ampicillin i.v.
- Erythromycin oral or parenteral
- Clarithromycin oral or parenteral
- Oral Azithromycin
- Ceftriaxone i.v.
- Cefotaxime i.v. +/- vancomycin, cloxacilin, cephazoline i.v.
- Bezylpencillin i.v.
CONCLUSIONS
- In developed countries, for the immunocompetent host in whom bacterial pneumonia is adequately recognised and treated, the survival rate is high
- LRTI are a major cause of childhood mortality in disadvantaged areas of the world
- In developed countries the majority are caused by viral agents and bacterial pneumonias is a less common cause
- The most common cause of bacterial pneumonia in children of all ages is S.pneumoniae
- Children at high risk for bacterial pneumonia are those with compromised pulmonary defense systems
