Pneumonia is inflammatory process developed after entry of infectious agent in respiratory portions of airway tract. Entry routes of foreign agents in respiratory system (lungs) may be via inhalation or hematogenous. Inflammatory cascade is disease trigger and causes plasma exudation and loss of surfactant, causing difficult air exchange and consolidation.
Viral pneumonia is named generally as "Pneumonitidis" also called atypical pneumonia in the past when bacterial etiology was excluded and antibiotic therapy was useless.
Viral pneumonias vary from mild clinical forms to severe life threatening forms with dangerous hypoxemia.
Viral pneumonias are categorized according pneumonia caused by them is primary or part of multi-symptomatic disease syndrome.
Viral pathogens causing primary pneumonias are: Influenza type I and II, RSV, Adenovirus; those viral pathogens whose pneumonias are part of multi symptomatic syndrome are: Paramyxoviruses (Measles virus), Varicella zoster virus, EBV, HSV.
Disease spread aerial depends on the type of the virus. There are two forms of disease spread:
1) via big droplets on a short distances (<1m), examples are contaminated durty hand contact, vomiting, nasal discharge or conjunctiva “inoculation” (Rhinovirus, RSV).
2) spread via small droplets characteristic of Influenza and Adenoviruses.
Causative agents and their pathogenicity depends on the age of the patient, concerning
Three main age groups: neonates, preschool and school children. Age specifity of the pathogens is determined by maturity of immune system and anatomic, functional and physiologic peculiarities.
Newborn lung infection is discussed separately, because its development is associated with the perinatal period.
* Bacterial pneumonia.
Newborn pneumonia is part of generalized infection or septic process. Most commonly caused by group B streptococci, gram negative rods (E.coli), less often Klebsiella spp. or Pseudomonas spp.
* Viral pneumonia
Transplacental passage of Rubella virus, CMV and HSV may cause interstitial pneumonia and sometimes hepatosplenomegaly.
* Chlamydial pneumonia
Chlamydia is an obligate intracellular bacterial parasite. Chlamydia trachomatis mainly seen in newborns. In adults it is transmitted via sexual route, in newborns infected birth canal is the source. Those children born through passing infected vagina develop illness in 50% of cases. The infection may enter via conjunctiva or respiratory tract. 60% of infected newborns develop conjunctivitis and 10-20% develop pneumonia, in 10-15% disease is asymptomatic. Chlamydial pneumonia develops during first two months of life, roughly from 3rd week to 2 months of life.
Etiology of pre-school children pneumonia
60% of preschool children with respiratory infection go to doctor and 80% of cases are of viral origin. More than 200 viruses can damage respiratory system. Before 4 years of age 5% of pneumonias are caused by Mycoplasma pneumoniae.
Etiology of pneumonias in school children
- Mycoplasma pneumoniae -one of the most common respiratory pathogens of children. Infection transmits via respiratory droplets and is characterized by high transmissibility.
Mycoplasma pneumoniae disease have no geographic and seasonal variations, but occur more often in autumn when other respiratory pathogens are dormant.
- Chlamydia pneumoniae
According to modern classification it is new member of Chlamydia genera. Humans are the sole reservoirs and disease spreads by person-to-person contact. It is infrequent in children <5 years, mostly seen at ages of 8-9. 30-50% of adult population have serologically proved infection, but most are subclinical. Chlamydia pneumoniae causes 6-10% of total pneumonias.
Age related etiology of pneumonia
Before 1 months
1 months – 2 years
Main signs of pneumonia:
- Cough (recently started)
- Chest wall retractions
- Nasal flaring
- Auscultatory changes
Pneumonia indications in children younger 5 years of age:
- Nasal flaring (before 12 months)
- Oxygen saturation <94%
- Chest wall retractions
Absent of these following factors excludes pneumonia:
- Other signs of respiratory disease: cough, labored breathing, etc.
Risk factors for pneumonia development:
- Upper respiratory tract infections
- Tobacco smoke
- Children community buildings
- Co-morbidities: cardio-pulmonary, nervous, connective tissue, immune and others
- 3 months prior hospitalization episode
- Low social economic status
- Preterm Infants (before 1 years)
- Cystic fibrosis (mucoviscidosis)
- Failed immunizations
- Antibiotic therapy in previous months
- Contact with infected patient
Pneumonia diagnosis always includes detecting patchy infiltrative changes in the lung parenchyma with other signs of lower respiratory tract infection. X-ray study gives opportunity to evaluate pathologic process in dynamic. X-ray changes like spread of infiltration, pleural exudates, cavity destruction coincides with the severeness of the process and aids in choosing proper treatment plans.
X-ray picture improves slowly and lags behind clinical improvement. Absolute resolution of changes occur in 51% of cases after 2 weeks, and in 49% after 4 weeks.
Complete blood count (CBC) doesn’t tell about cause of pneumonia, but leukocytosis > 12-15 X 109/L indicates more about bacterial origin. Leukopenia < 3 X 109/L and leukocytosis > 25 X 109/L are poor prognostic signs.
Serology studies include taking patient sera in acute and reconvalescence periods (few weeks after start of the disease). Serologic studies are mandatory for inpatients. On an outpatient basis biochemical tests should be done (blood urea nitrogen, electrolytes and liver function tests) in order to evaluate severity of liver and kidney disorders.
Should be done in every inpatient and if it is <92% arterial blood gases should be also done (ABG).
Blood cultures should be done in each outpatients, and it is better to be done before start up of antibiotic therapy. Sputum culture – in patients who can expectorate sputa and haven’t been on prior antibiotic therapy, also in those patients for whom prior therapy was ineffective.
Invasive diagnostic methods (bronchoscopy, trans-tracheal aspiration, transthoracic biopsy, etc) are carried out in hospital when Tuberculosis or bronchogenic cancer is suspected.
C reactive protein
Determination of C reactive protein can be beneficial for outpatient treatment. During initial hospitalization period C reactive protein is more selective marker of pneumonia than high body temperature or leukocytosis. Only 5% of patients have CRP >50mg/L, in other clinic studies it was shown that all pneumonia patients have CRP> 50mg/L. It is higher in those patients who didn’t have prior antibiotic therapy and during Pneumococcal pneumonia relative to Mycoplasma or viral pneumonias.
Evaluation severity of pneumonia in infants
1 t < 38,50 C
1 RR < 50/min
1 Feeds well
1 t > 38,50 C
1 RR > 70/min
1 Mild or strong retractions
1 Nasal flaring
1 Periodic apnoea ”grunting” (gasping respiration)
1 Poor feeding
General principles of pneumonia treatment
Childhood pneumonia treatment includes:
- Antibiotic therapy
- Oxygen therapy
- Temperature and pain management
Choosing proper antibiotic therapy depends on child age, pneumonia etiology and disease severity. Treatment decision depends on the following main subjects:
- Necessity of antibiotics
- Choosing proper drugs
- Choosing intake method of drugs
- Duration of treatment
β-lactam drugs are main choice of pneumonia treatment, especially ,,protected” amino-penicillins because of their strong bactericidal(especially against S.aureus) activity with low toxic effects, high safety margins, efficiency and resistance against bacterial β -lactamase, very crucial factor. Clavomed is combination of amoxicillin and clavulanic acid. It has marked activity against S.pneumoniae and H.influenzae strains. Compared with ampicillin it has higher bioavailability, absorption isn’t influenced by food and less gastric irritation and other systemic effects occur. Clavomed maintains bactericidal activity against Penicillin resistant strains.
For pneumonia treatment, antibiotics are mainly chosen empirically, regarding age group of the patient, probable etiologic agent and its prevalence, also specific signs and symptoms pathognomic for the disease induced by particular causative agent (if applicable).
Patients from 2months to 5 years of age
Clavomed 5-7 day therapy is recommended for this age group patients, if suspicion of bacterial etiology is high. S.pneumonia main causative in such pediatric patients has high sensitivity for Clavomed.
Patients >5 years
In this age group, Macrolides are first line treatment options. Main pneumonia causatives are S.pneumoniae and C.trachomatis sensitive to Marcolides. Duration of Macrolide therapy is also 7-10 days, 5 day Azythromycin course can also be undertaken.
During mild forms of pneumonias peroral antibiotics can be satisfactory with temperature normalization in 3-4 days. Treatment duration lasts for 7-10 days.
In case of Mycoplasma or Chlamydia induced pneumonias treatment lasts for 14 days.
Some clinical data about short term effective treatment also exists.
With severe forms of pneumonia treatment must be started promptly with parenteral antibiotic therapy, after diagnosis. Initially broad spectrum antibiotics like Bactamed can be used, after patient stabilization treatment can be continued with Clavomed according to the Step-down therapy principles.