Infectious Pneumonia Review - Dr. Mendoza PDF

Infectious Pneumonia V.C.D.Mendoza II, M.D. FPPS, DPAPP Date Viral Pneumonia  leading cause of mortality  children < 5 years of age  68% cause of death  40% viral pneumonia  Respiratory syncitial virus, Metapneumo virus, Parainfluenza virus Pathogenes...

Infectious Pneumonia V.C.D.Mendoza II, M.D. FPPS, DPAPP Date Viral Pneumonia  leading cause of mortality  children < 5 years of age  68% cause of death  40% viral pneumonia  Respiratory syncitial virus, Metapneumo virus, Parainfluenza virus Pathogenesis  Infection of cells surrounding the alveolar space  Alveolar walls thicken  occlusion of alveolar space with exudates, sloughed cells, macrophages  poor gas exchange, poor oxygenation, CO2 retention Clinical Disease  Fever  Influenza - most frequent cause of high grade fever  Increase respiratory rate, nasal flaring  grunting, retractions  Crackles & wheeze  RSV mixed presentation  Colds/coryza, otitis media Radiographic findings  principal diagnostic test  hyperaeration  prominent lung markings  bronchial wall thickening  focal areas of atelectasis Laboratory Examinations  Culture in cell monolayer  Rapid diagnostic tests for RSV and Influenza A & B  expertise? and fresh specimen  Polymerase chain reaction (PCR) Co-infections  secondary bacterial infection may occur  abrupt changes in signs & symptoms  appearance of toxicity  changes in chest x-ray findings  leukocytosis  Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus Therapy  Symptomatic treatment  O2 support  grunting, flaring, severe tachypnea, retractions  O2 sats 40/minute Diagnosis  suspected in any child with  cough, fever  tachypnea, repiratory distress, grunting  retractions, crackles Differential diagnosis  viral pneumonia  bronchial asthma  chemical pneumonitis secondary to aspiration  cardiogenic causes of tachypnea  interstitial lung diseases  Tuberculosis Laboratory test  leukocytosis  CRP  culture of specimen from lung biopsy or BAL - GOLD standard  sputum examination  serologic test  PCR - mostly for research chest radiograph  No need - > 2 months old and managed as OPD  alveolar pneumonia - common in bacterial etiology  still not definitive for etiologic cause! Streptococcus pneumoniae  most frequent cause  1/2 of cases for admissions  1 million deaths in developing countries  can be prevented with appropriate antibiotics  increasing penicillin resistant cases  due to changes in penicillin binding sites Haemophilus influenzae  gram negative cocobacilli  once a frequent cause of pneumonia in the < 5yrs  chest xray  linear infiltrates, hyperaeration  pleural effusion - common feature GABS & Strep. pyogenes  usually associated with bacteremia  scarlet fever  commonly seen after Measles and Varicella infection Staphylococcus aureus  inhalation of agent  rarely - spread from catheter and IV sites  acute and severe manifestations  chest x ray: alveolar pattern, unilateral  may coalesce, form large consolidation or cavitations  50% may form pneumatocoele  90% - pneumothorax or pyoneumothorax Management of bacterial pneumonia General management  mild to moderate symptoms - OPD  MUST be re-examined w/in 48 hrs  British Thoracic Society: indications for admission  SaO2 < 92%, cyanosis, RR > 70  DOB, apnea  grunting  inability to fed General management  antipyretics  Intravenous fluids  O2 support  mechanical ventilator  NGT?  CPT? Lung injury from Hydrocarbon Aspiration and Smoke Inhalation Hydrocarbon toxicity Petroleum solvents Liquid polishes Dry cleaning fluids Waxes Lighter fluids Furniture polishes Kerosene Gasoline Hydrocarbon toxicity  CNS ( weakness, confusion, coma)  GIT  cardiomyopathy  renal toxicity  pneumonitis - most common and most serious complication  respiratory insufficiency - common cause of death Pathology  Dissolves the cell wall/lipid lining layers  desquamation and fluid infiltration  Necrosis of bronchial, bronchiolar and alveolar tissue  atelectasis  Hemorrhagic pulmonary edema  Interstitial inflammation, vascular thromboses  necrotizing bronchopneumonia, hyaline membrane formation Pathophysiology  Risk for aspiration depends on the inherent properties of the substance  Aspiration is more likely to occur if the substance has:  Low surface tension  Low viscosity  High volatility  Increases surface tension Clinical findings  Cough  Hemoptysis and Pulmonary edema  Radiographic signs of chemical pneumonitis:  punctate, mottled densities  pneumonitis, atelectasis  dependent portions  air trapping, pneumatocoeles, effusion Clinical findings  Radiographic changes - peak at 72 hours  lasts for days - weeks  Xrays changes are more prominent than physical exam  pneumatocoeles - months before resolution PFT  blood gas - hypoxemia  V/Q mismatch  Diffusion block  Spirometry - Airway obstruction  increased residual volume  increased slope of phase III  reduced FEV1 Management  History and P.E.  Chest X-ray  Avoid emetics and gastric lavage  - if no symptoms and with normal xray - observe for 6-8 hours  - if history, P.E. or with abnormal xray do Blood gas repeat xray after 24 hours. If normal may discharge Management  O2 support  Intravenous fluids  trial of bronchodilator  Mechanical ventilator  ECMO  Antimicrobials? EDUCATION FOR PREVENTION!!! Lung injury from Smoke Inhalation Smoke Inhalation  In the U.S.  Death from fire - 5th leading cause  morbidity and mortality from fire - pulmonary injuries  Severity of injury depends on 1. Nature of materials involved and by products of combustion 2. Confinement in a closed space Pathogenesis  Thermal factor  supraglottic airways  if with steam or with prolonged exposure to heat may reach intrathoracic airways  Chemical factors  oxides of sulfur & nitrogen, acetaldehydes  hydrocyanic acid & carbon monoxide Chemical factors  Nitrous oxide & sulfur dioxide  combines with lung water - corrosive acid  Aldehydes from furniture and cotton  denaturation of CHON, cellular damage & pulmonary edema  COmbustion of woods  generate CO2 & CO Chemical factors  Polyvinyl chloride (PVC)  chlorine & hydrochloric acid  Polyethylene  hydrocarbons, aldehydes  ketones & acids  Polyurethane  isocyanate & hydrogen cyanide Carbon monoxide poisoning  serious complication of smoke inhalation  binds to hemoglobin (hgb)  displaces oxygen from hgb  CO > O2 in terms of affinity  shifts Oxyhemoglobin dissociation curve to the left  poor delivery of oxygen to tissues Oxyhemoglobin dissociation curve Treatment  O2 support  CO levels reduced to half w/in 1 hour with 100% O2  Hyperbaric therapy?  Endotracheal intubation  Mechanical ventilation  IV fluids  Proper Management of burns (extrapulmonary) Indications for intubation  severe burns of the face, nose and/or mouth  edema of vocal cords with laryngeal obstruction  difficulty handling secretions  progressive respiratory insufficiency  altered mental status Infectious causes of upper airway obstruction Infectious cause of UAO  common in infants and children  viral laryngotracheobronchitis (LTB)  bacterial infections - epiglottitis, tracheitis, retropharyngeal abscess & peritonsillar abscess  usually presents with stridor  Stridor - rapid, turbulent flow of air through a narrow segment of a large airway laryngeal anatomy  larynx is high in the neck  epiglottis is narrow, vertically positioned & omega shaped  narrowest segment of the airway - subglottic region  non fibrous, loosely attached mucosa  cartilages are still soft and compliant  large head, lax neck muscles  tongue is relatively large than the oropharynx Laryngomala cia  most common congenital abnormality of the upper airway  underlying mechanism is still misunderstood Variable abnormalities 1. Aryepiglottic folds are short & vertical curling the epiglottis into omega shape 2. Prominent cuneiform and corniculate cartilages lie over the arytenoid cartilages 3. A loose redundantmucosal covering of the aryepiglottic fold prolapses into the airway. Clinical presentation  inspiratory stridor  onset usually on the 1st week of life  feeding problems - regurgitation, distress during sucking  symptoms tend to resolve w/in the 2nd year of life  mild symptoms may persist until adulthood Management  majority of cases thrive very well  confirmation of diagnosis through flexible nasopharyngoscopy 