Community Acquired Pneumonia [CAP]

DR. HARDIK SHAH

Introduction Pneumonia is the leading killer of children,

causing an estimated 1.9 million deaths worldwide under the age of 5 years.

Pneumonia is an inflammation of the parenchyma of the lungs.

In developed countries, the diagnosis is usually made on the basis of radiographic findings.

The WHO has defined pneumonia solely on the basis of clinical findings obtained by visual inspection and counting the respiratory rate, for developing countries.

Etiology

Pathogenesis The lower respiratory tract is normally kept

sterile by physiologic defense mechanisms, including mucociliary clearance, the properties of normal secretions such as secretory immunoglobulin A (IgA), and clearing of the airway by coughing.

Immunologic defense mechanisms of the lung that limit invasion by pathogenic organisms include macrophages that are present in alveoli and bronchioles, secretory IgA, and other immunoglobulins.

Viral pneumonia usually results from spread of infection along the airways, accompanied by direct injury of the respiratory epithelium, which results in airway obstruction from swelling, abnormal secretions, and cellular debris.

M. pneumoniae attaches to the respiratory epithelium, inhibits ciliary action, and leads to cellular destruction and an inflammatory response in the submucosa.

S. pneumoniae produces local edema that aids in the proliferation of organisms and their spread into adjacent portions of lung, often resulting in the characteristic focal lobar involvement.

S. aureus pneumonia manifests in confluent bronchopneumonia, which is often unilateral and characterized by the presence of extensive areas of hemorrhagic necrosis and irregular areas of cavitation of the lung parenchyma, resulting in pneumatoceles, empyema, or, at times, bronchopulmonary fistulas.

Clinical presentation Any patient presenting with cough and

difficult or rapid breathing should be considered as a case of pneumonia.

Neonates Neonates present with tachypnea, and signs of

respiratory distress such as grunting, flaring and retractions.

Fever and cough may be absent; however hypothermia and temperature instability may be observed.

Nonspecific complaints, such as irritability or poor feeding may be the presenting symptoms

Cyanosis may be present in severe cases Chlamydia trachomatis pneumonia should be

considered in infants aged 2–4 wks and is often associated with conjunctivitis.

Infants After the first month of life, cough is the most common

presenting symptom. Infants may have a history of antecedent upper

respiratory symptoms. Depending upon the degree of illness, tachypnea,

grunting, and retractions may be noted. Vomiting, poor feeding, and irritability are also common. Infants with bacterial pneumonia often are febrile, but

those with viral or atypical pneumonia may have lowgrade fever or could be afebrile.

Wheezing or noisy breathing. Wheeze suggests a viral cause.

Toddlers and Preschool Children A history of antecedent upper respiratory illness is

common. Cough is the most common presenting symptom. The presence and degree of fever is dependent

upon the organism involved. Vomiting, particularly post-tussive, may be

present. Chest pain may be observed with inflammation of

or near the pleura. Abdominal pain or tenderness is often seen in

children with lower lobe pneumonia.

Older Children and Adolescents Atypical organisms, such as Mycoplasma are

common in this age group. In addition to the symptoms observed in

younger children, adolescents may have other constitutional symptoms, such as headache, pleuritic chest pain, and vague abdominal pain.

Headache, fever and myalgia are associated with M. pneumoniae.

Vomiting, diarrhea, pharyngitis, and otalgia/otitis are also common symptoms.

Assess for Contributing Etiology Contact with person(s) having respiratory infection Possibility of foreign body aspiration Possibility of primary aspiration Stools consistent with malabsorption (may suggest

cystic fibrosis) Sinusitis Asthma Growth and nutritional status Dysmorphic syndromes Neuromuscular weakness Cardiac failure

Risk Factors of CAP Malnourished state, young age (<6 months), post-measles state, absence of (or inadequate) breastfeeding, solid fuel use. Hospital acquired infection/pneumonia include

hospitalization for ≥48 h, broad spectrum antibiotic therapy for ≥7 days in the preceding 30 days, immunosuppressive therapy including glucocorticoid therapy, neutropenia and severe structural lung disease.

Severity Assessment Any infant with age ≤2 months with

symptoms suggestive of pneumonia should be considered as having severe pneumonia. Such a child needs immediate hospitalization

Tachypnea (respiratory rate >60/min) in this age group is often associated with hypoxemia.

There is no validated criteria for severity assessment in children >5 years.

In this age group, pneumonia is considered severe if the following features (of severe respiratory distress) are present.

o Respiratory rate >30/mino Chest wall retractiono Use of accessory muscles of respirationo Altered sensorium

Investigations

CXR: Chest radiographs are not needed routinely in all children with

suspected pneumonia.Specific indications include:1. When the diagnosis is in doubt (bronchiolitis, asthma, developmental

malformation, foreign body inhalation, aspiration pneumonia etc.)2. Asymmetrical findings on chest examination3. Suspected complications of pneumonia (pleural effusion, empyema,

lung abscess etc.)4. Known case of recurrent chest infection (asthma,cystic fibrosis,

immunodeficiency etc.)5. Severe and very severe pneumoniaFindings to be looked for in chest radiograph include: Parenchymal infiltrates (evidence of consolidation) Features of atypical pneumonia (bilateral streaky infiltrate) Presence of pneumatocele Any evidence of foreign body inhalation Pleural spaces for pneumothorax, effusion

Arterial blood gas (ABG):The indications are:1. Severe and very severe pneumonia2. Hypoxemia on pulse oxymetry (SpO2 <94%

on 40% oxygen), cyanosis3. Shock

Other Investigations in Hospitalized Patients Hemogram with total and differential leukocyte count Serum electrolytes and renal function test Blood culture: These are positive in 10%–20% of children with

pneumonia Other diagnostic investigations: In atypical pneumonia: Serology—RSV, Mycoplasma,

Chlamydia CMV serology (if suspected like immune-compromised and TORCH group of infection) Atypical H1N1 (swine flu) testing during epidemics

CSF (if feasible) in case of i. Newborns ii. Infants presenting with altered sensorium iii. Seizures

The indications for hospitalization are: Age <2 months Severe and very severe pneumonia (as per WHO definition) Signs of shock Hypoxemia (requirement for supplemental oxygen) Moderate to severe malnutrition because it increases the

risk of mortality Recurrent chest infection (cardiopulmonary disease,

anatomical defects in airway, neurological disease) Immunocompromised state Not accepting orally, dehydration, vomiting No response or increased severity (treatment failure) on

appropriate oral antibiotic therapy Family unable to provide appropriate care at home.

Baseline Stabilization A-B-C Resuscitation if required as per the Pediatric Assessment Triangle and

Primary Assessment O2 inhalation by nasal prongs, at flow rate 1–5 l/min (depending on age) if

child has lower chest wall indrawing or SpO2 ≤92%. First dose of antibiotic as early as possible; preferably after obtaining a

sample for blood culture. However, administration of the first dose should not be delayed for this.

Hydration (intravenous or nasogastric tube feed) i. If child is accepting orally well—allow orally (ad libitum) ii. If not accepting well orally (but feeding not contraindicated)—Nasogastric

or orogastric feed can be started iii. Start 0.45 Saline in 5% dextrose as 2/3rd to 3/4th maintenance if there is

respiratory distress (where feed cannot be started) or underlying dehydration or ongoing losses through vomiting etc.

Treatment of other emergent co-morbidities i. Hypoglycemia ii. Electrolyte imbalance

Antibiotic TreatmentThe choice of first-line antibiotic therapy is guided by: Age of the child Severity of pneumonia Associated clinical features suggesting specific etiology

e.g. pustules suggesting Staphylococcal infection Immune-suppressed or immunocompromised state (such

as post-measles state) Underlying chronic lung disease e.g. cystic fibrosis Radiographic pointers towards a specific etiology

(necrotizing pneumonia, pneumatoceles suggest Staphylococcal infection, parahilar streaky infiltrates are more common in atypical pneumonia.)

Presence of complication such as pneumothorax/empyema.

Treatment of Non-severe Pneumonia (at home) Non-severe pneumonia can be treated at home with

oral antibiotics in most cases. Amoxicillin (50 mg/Kg/day) in 2 divided doses for 3– 5

days Advise to return immediately if the child develops

lower chest indrawing, is unable to drink/feed, is excessively sleepy or sick looking.

Follow-up after 2 days If the child has persistent raised respiratory rate but

no indication for admission, change to Amoxicillin-clavulanic acid (80–90 mg/kg of amoxicillin) in 2 divided doses for 5 days or add Azithromycin 5 mg/kg for 5 days if clinical and radiological features suggest atypical pneumonia.

If lower chest indrawing or a general danger sign appears, hospitalize urgently for treatment as severe / very severe pneumonia

Treatment of Severe Pneumonia Hospitalize, continue oxygen. Injectable ampicillin (50 mg/kg/dose) IV 6 hourly. Add Cloxacillin (100–200 mg/kg/day in 4 four divided

doses) if clinical features (presence of pustules, postmeasles state, severe malnutrition, empyema) and radiographic features (pneumatoceles, necrotizing pneumonia) suggest Staphylococcal infection.

Assess and monitor for oral intake/feeding, respiratory rate, chest indrawing, and oxygenation (by pulse oximetry) .

If at any time danger signs of very severe pneumonia develop treat as very severe pneumonia

After 48 h—if improved: continue: on oral amoxicillin for 5 more days, if not improved in 48 h/deteriorated: treat as very severe pneumonia

Treatment of very severe pneumonia

Treatment of Pneumonia in infants ≤2 months old

Indications for PICU TransferAt any stage, the following should be

considered for transfer to ICU: Very severe pneumonia Hypoxemia Patients requiring intubation/ventilation Presence of shocky failure

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