Pneumonia Flashcards
Define pneumonia.
Infection of the lung parenchyma.
What are causative organisms of pnuemonia in neonates?
Organisms from the female genital tract: Group B haemolytic streptococcus, E. coli, and gram-negative bacilli, chlamydia trachomatis.
What are causative organisms of pnuemonia in infants and pre-school children?
Viral (most common):
Parainfluenza, influenza, adenovirus and RSV.
RSV can be particularly dangerous to expreterm infants and infants with underling chronic lung disease (CLD) of prematurity.
Bacterial:
Streptococcus pneumonia (90% of bacterial pneuomonia). Staphylococcus aureus is uncommon but causes severe infection.
What are causative organisms of pnuemonia in older children and adolescents?
As previous, but also atypical organism such as Mycoplasma pneumonia and chlamydia pneuominae.
TB should be considred at any age.
What are causative organisms of aspiration pneumonia?
Enteric gram-negative bacteria +/- Strep. Pneumonia, Staph aureus
What are causative organisms of pneumonia in non-immunised children?
Haemophilus influenza
Bordetella pertussis
Measles
What are causative organisms of pneumonia in immunocompromised children (acquired or inherited)?
Viral: CMV, VZV, HSV, measles and adenoviruses
Bacterial: Pneumpcystis carinii, TB.
What are risk factors for pneumonia?
CLD: Ex-preterm, CF, sickle cell disease
Congenital cardiac abnormality: Especially with large left to right intracardiac shunt
Chronic aspiration: Cerebral palsy, TOF, GORD
Kartagner syndrome: Ciliary dysfuntion, bhronciectasis and dextrocardia
What are the stages of lobar pneumonia?
- Congestion with vascular engorgement, intra-alveolar bacteria
- Red hepatisation: Alveolar spaces fill with neutrophils, fibrin and RBCs.
- Grey hepatisation: RBC disintegrates with fibrin and suppurative inflammation.
- Resolution: Exudate in alveolar spaces is degraded and removed by macrophages.
What are stages of bronchopneumonia?
Macro: Patchy areas of consolidation with grey/yellowish appearance.
Micro: Neutrophil inflammatory infiltrate in bronchi, bronchioles and adjacent alveoli.
Summarise the epidemiology of pneumonia.
29/10,000 children < 5 years of age. 12/10,000 children < 14 years of age.
Decreasing since the introduction of the conjugate pneumococcal vaccine in all children.
What are the signs and symptoms of pneumonia?
General: Fever, tachycardia, tachypnoea, cough, sputum (yellow, green or rusty in Strep pneuomoniae), vomiting particularly post-coughing, poor feeding, diarrhoea, preceding URTI (especially viral infections).
Signs of consolidation: Decreased breath sounds, dullness to percuss, increased tactile/vocal fremitus, bronchial breathing, coarse crepitations.
What are appropriate investigations for pneumonia?
CXR: Focal consolidation suggests a bacterial cause; diffuse consolidation bronchopneumonia suggests a viral cause.
Bloods: Increase WCC, Increase ESR/CRP, U&Es (SIADH), mycoplasma serology.
Urine: Pneumococcal antigen.
Microbiology: Blood and sputum MC&S.
Blood film: RBC agglutination by Mycoplasma (cold agglutinins; See haemolytic anaemia).
Immunofluorescence/PCR: Can detect RSV on nasopharyngeal aspirate.
What is the management for pneumonia?
Supportive treatment: Maintain oxygen saturation > 92%, IV resuscitation in dehydration or shock.
Antibiotic: Determined by presentation, i.e. viral/bacterial aetiology, severity and CXR appearance; normally oral amoxicillin or erythromycin. If severe, IV cefuroxime +/- erythromycin, metronidazole for aspiration pneumonia
Respiratory failure: CPAP/BiPAP; may require PICU transfer
Immunisation: HiB and pneumococcal (all infants), influenza (at-risk infants).
What are complications associated with pneumonia?
Pleural effusion, empyema, lung abscess, septic shock, ARDS, ARF.
