Pneumonia is infection of the lungs. Other lower respiratory tract infections seen in children are croup (laryngotracheobronchitis), bronchitis, and bronchiolitis.

Pneumonia results from direct inflammation of the lung tissue. Most commonly, it is the result of infections (bacterial, viral or fungal), but it can occur as a result of chemical injury (gastric acid/ aspiration of food/ hydrocarbon and lipoid pneumonia/ radiation induced pneumonia). The causative agent may reach the lung via the blood stream or from direct inhalation

The incidence of pneumonia in developing countries in children less than 5 years old is almost 30% with a high mortality rate.

Clinical features:

Neonates: Refusal of feeds, lethargy. Tachypnea, grunting, retractions, cyanosis.

Infants: Cough, fever, Refusal of feeds, lethargy.Tachypnea, grunting, retractions, cyanosis, wheezing, noisy breathing.

Preschoolers: cough, post tussive vomiting, fever, chest pain, abdominal pain.In severe cases: Tachypnea, grunting, retractions, cyanosis,

Older Children: fever, cough, chest pain, dyspnea. Pharyngitis and otalgia/otitis are other common symptoms.

The pathognomic sign of pneumonia is the presence of crackles (also called as crepitations). Localized crepitations in a febrile child without underlying lung disease is pneumonia until proven otherwise. However, not all children with pneumonia have crepitations. Decreased breath sounds with dull note on percussion and presence of bronchial breathing are also suggestive of pneumonia.

Common causes of pneumonia:

Newborns:group B Streptococcus (GBS), respiratory syncytial virus (RSV).

Infants:
Viruses: parainfluenza viruses, influenza virus, adenovirus, and respiratory syncytial virus (RSV). cytomegalovirus

Atypical organisms: Chlamydia trachomatis, Ureaplasma urealyticum, and Pneumocystis carinii (PCP). PCP is especially seen in children with immunodeficiencies.

Bacterial: B. pertussis, Streptococcus pneumoniae, Haemophilus influenzae, Haemophilus influenzae, mycobacterial tuberculosis.

Young children:
Viruses: parainfluenza viruses, influenza virus, adenovirus, and respiratory syncytial virus (RSV).

Atypical organisms: Mycoplasma pneumoniae.

Bacterial: Pneumococcus, mycobacterial tuberculosis.

Older children and adolescents:
Atypical organisms: Mycoplasma pneumoniae, Chlamydia trachomatis.

Bacterial: Pneumococcus, B. pertussis, mycobacterial tuberculosis.


Other rare causes of pneumonia: