10- pneumonia

• Pneumonia

  Inflammation of the substance of the lungs, usually caused by bacteria
• Pneumonia

  • Can be classified anatomically (e.g. lobar and bronchopneumonia)
  • Can be classified according to the setting where infection contracted (community versus hospital acquired)
  • Can be classified by etiology
• Types of pneumonia

  • Community acquired pneumonia
  • Hospital acquired pneumonia
• Community acquired pneumonia

  Occurs in community or within first 48 hours of hospitalization, can be typical or atypical, most common bacteria is streptococcus pneumonia
• Hospital acquired pneumonia

  Occurs during hospitalization after first 48 hours, most common pathogens are gram-negative (E. coli and pseudomonas) and staph. aures
• Symptoms & signs of pneumonia

  • Fever, rigors (if swinging may indicate empyema)
  • Cough with sputum
  • Pleurisy, chest pain
  • Shortness of breath
  • Signs of consolidation (reduced expansion, dull to percussion, bronchial breathing, increase vocal resonance)
  • Pleural effusion, and plural rub may also be present
• Risk factors for pneumonia

  • Extremes of age (less than 16, more than 65)
  • Underlying lung disease
  • Smoking, alcohol, IV drugs
  • Immunosuppressive drugs, prolonged steroids, HIV, DM, CKD, malnutrition
  • Recent viral resp infection
• Causes of community acquired pneumonia

  • #1: Strept. pneumoniae
  • #2: viruses
  • H.influenzae
  • Moraxellacatarrhalis
  • Staph aureus
  • Aerobic gram – (E. coli, klebsiella)
  • Anaerobes (associated with aspiration)
  • Mycoplasma pneumoniae
  • Legionella
  • Chlamydia pneumonia
  • Chlamydia psittaci
  • Coxiella burnetti
• Complications of pneumonia

  • Abscess
  • Pleural effusion
  • Empyema
  • Septicemia
• Differential diagnoses for pneumonia

  • PE
  • Pulmonary edema or hemorrhage
  • Bronchial carcinoma
  • Hypersensitivity pneumonitis
  • Diffuse parenchymal lung disease with acute onset
• Investigations for pneumonia

  • Chest x-ray: Confirms area of consolidation, Must be repeated after 6 weeks (to check for underlying lung malignancy)
  • Sputum: Gram stain, Culture and sensitivity
  • CBC: WBC more than 15*109 suggests bacterial origin, Lymphopenia associated with legionella
  • Specific etiology: Urine for legionella and pneumococcal antigens, Cold agglutinins in mycoplasma pneumonia, Serology (mycoplasma: raised IgM)
  • ABG: Done if SpO2 < 92% or rising PaCO2
• Infecting agents and clinical circumstances

  • Streptococcus pneumonia, Mycoplasma pneumonia, Influenza A, Chlamydia pneumonia - Community acquired and usually previously fit
  • Hemophilus influenza - COPD
  • Chlamydia psittaci - Contact with birds
  • Staphylococcus aureus - Children, IV drug abusers, complicated influenza virus infections
  • Legionella pneumophila - Hospitals and hotels (institutional outbreaks)
  • Coxiella burnetti - Animal-hide workers
  • Pseudomonas aeruginosa - Cystic fibrosis and bronchiectasis
  • Enteric gram-negative bacilli - Acutely ill
  • Pneumocystis jiroveci, Nocardia asteroids, Cytomegalovirus, Aspergillus fumigatus - Immunocompromised (AIDS, lymphoma, leukemias, use of cytotoxic drugs and corticosteroids)
• CURB-65 scoring system

  1 point for each: Confusion, Urea>7mmol, Respiratory rate > 30/min, BP < 90 systolic / 60 diastolic, Age > 65
• Management

  1. 0-1 (low risk) - oral antibiotics/home treatment

  2. ≥ 3 (severe pneumonia) - admit to ICU esp. if 4 or 5 points
• Severe pneumonia management

  • Analgesia for pleuritic pain
  • Humidified oxygen if hypoxemic
  • IV Fluids
• Antibiotic therapy for CAP - Outpatient treatment

  1. Macrolide (clarithromycin) - covers S. pneumo and atypical organisms

  2. If resistance is suspected - supplement with B-lactam (amoxicillin)

  3. Risk factors for drug resistance: Age more than 65, Comorbidities, Immunosuppressive drug or disease, B-lactam, fluroquinolone, or macrolide therapy in the last 3-6 months

  4. Outpatient Tx is used when CURB score 0-1

  5. Duration of Tx: 1 week to 10 days

  6. Review Tx if still febrile within 72 hours
• Antibiotic therapy for CAP - Inpatient

  1. Macrolide + Ceftriaxone (anti-pneumococcal B-lactam)

  2. OR respiratory fluroquinolones (levofloxacin or moxifloxacin)
• Antibiotic therapy for Pseudomonal risk

  Fluroquinolone (cipro or dose levo) + one of: Piperacillin/tazobactam, Imipenem or meropenem, Cefepime
• Antibiotic therapy for MRSA risk

  Vancomycin or linezolid
• Influenza treatment started only if it is confirmed
• Metronidazole in patients with risk of anaerobic infection, e.g. Prolonged ICU stay or aspiration pneumonia
• Rules before stopping antibiotics

  1. Patient afebrile 48-72 hours

  2. Breathing without supplemental oxygen

  3. No more than 1 clinical instability factor (HR > 100, RR > 24, SBP ≤ 90)
• Strept pneumo

  • Sputum: rusted color
  • High fever, pleuritic chest pain
  • Acute onset, preceded by flu-like symptoms
  • Urine antigen test
  • WBC > 15 (90% polymorphic leukocytosis)
  • High ESR & CRP
  • +ve blood cultures indicate severe disease with higher mortality
  • Associated with herpes labialis
• Mycoplasma

  • Mild disease in young patient
  • X-ray does not correlate to the clinical picture (patient signs and symptoms are mild while x-ray looks very bad)
  • Prominent extra-pulmonary features (headache, malaise, myalgia)
  • Hemolytic anemia (cold agglutinins; thrombocytopenia)
  • Erythema multiforme
  • Hepatitis
  • Meningoencephalitis
  • Myocarditis and pericarditis
  • Serology: high IgM
  • WBC usually normal
• Legionella

  • More severe disease with need for early intensive care
  • Inhaling water-mist bacteria
  • Headache and neurological symptoms
  • GI involvement, hepatitis, high CK
  • More common in young, males, smokers
  • Urinary antigen
  • Lymphopenia with no marked leukocytosis
  • Hyponatremia
  • Hypoalbuminemia
  • High liver enzymes
• Risk factors for pneumonia

  • Alcohol: klebsiella or TB
  • Smoking/COPD: Hemophilus influenzae, Moraxella, Strept pneumo
  • Aspiration: gram –ve
  • Abscess: fungal, atypical, TB, MRSA
  • Cavitation: staph aureus, klebsiella, anaerobes, TB
  • Staph aureus: recent influenza
  • Chlamydophila pneumonia: hoarseness