Pneumonia is inflammation of the lung's alveoli (i.e. microscopic air sacs). Prognosis is that in the very young and very old, and chronically ill, pneumonia is a leading cause of death.

Patient information

People usually say pneumonia is a lung infection, is that correct?
Sort of. It's specifically of the alveoli in the lungs. Bronchioles are also in the lungs, but inflammation of that is called bronchiolitis! So to say it's a lung infection is correct but imprecise !

What are alveoli?
Air sacs that look a bit like grapes! They are the interface of the lung and the blood system, in a spherical shape to maximize the surface area over which gas can be exchanged.

I'm feeling hungry

• Fever → infection
• Productive cough (bacterial pneumonia is green, yellow, or red-brown; in viral/mycoplasma is thin and whitish) → LRTI
• SOB → LRTI
• Chest pain → LRTI
• Fatigue → overcompensation for SOB

• Infections, by:
  • Bacteria, the most common cause of CAP (community-acquired pneumonia). The most common include:
    • Strep penumoniae (50%)
    • Haemophilus influenzae (20%)
    • Chlamydophila pneumoniae (13%)
    • Mycoplasma pneumoniae (3%) (mycoplasma is considered a tween of viruses and bacteria)
  • Viruses, including:
    • Rhinovirus
    • Coronaviruses
    • Influenza virus
    • RSV
    • Adenovirus
    • Parainfluenza
  • Even other microorganisms
• Certain drugs

Predisposing factors:

• Extremities of age (newborns<2yo, old>65yo)
• Smoking
• Immunocompromised, as in autoimmune diseases (HIV, diabetes), asthma, COPD, kidney disease, liver disease, or premature or sick newborns
• Alcoholism
• Acid suppressing medications (PPI's, H2 blockers)

• Microorganisms (usually bacteria), defeating immune responses, cause inflammation of the lung's alveoli → chest pain, fever
• Inflammation causes exudate to fill the alveoli sacs → productive cough
• The exudate reduces the surface area over which gas can be exchanged → SOB

• Classification by acquisition, including:
  • Community-acquired pneumonia (CAP), which is contracted outside of the healthcare system
  • Hospital-acquired pneumonia (HAP), is more serious because it is in addition to a pre-existing condition
    • Ventilator-associated pneumonia (VAP), which occurs in Pt's on a ventilator (i.e. breathing machine)
• Classification by cause:
  • Aspiration pneumonia, is a caused by entrance of foreign materials into the lungs, usually oral or gastric contents (including food, liquid, or even vomit). If the aspirate is acidic, it can cause chemical pneumonitis
  • Opportunistic pneumonia, which occurs in immunocompromised Pt's, such as AIDS, organ transplant, chemotherapy, and can be caused by agents that are usually healthy for the body
• Anatomical distribution of consolidation:
  • Broncopneumonia, affects patches of the bronchiole tubes
  • Lobar pneumonia, affects a continuous area of the lung's lobes [the right lung has 3 lobes, and the left one has 2 lobes due to the cardiac notch]
• Historically, divided into typical and atypical, where atypical pneumonia (aka walking penumonia) is pneumonia not caused by the traditional pathogens (e.g. strep pneumoniae), which was thought to present less typically (respiratory Sx, lobar pneumonia), and more atypically with "generalized" Sx (fever, headache, myalgia, bronchopneumonia)

• CURB-65 score, can help determine need for admission in adults, if the score is 0-1 Pt's can be Mx at home, 2 a short hospital stay or close follow up needed, and 3-5 hospitalization is recommended. It is an acronym for:
  • Confusion
  • Urea (BUN) >7mmol/L
  • RR >30
  • Systolic BP <90mmHg, diastolic BP <60mmHg
  • Age 65+

• Stethescope:
  • Inspiratory crackles (over affected areas)
  • Dull percussion (over affected areas)
• CXR → consolidation (especially anatomical distribution)

Source: 2010/04/CXR-Pneumonia-lobar.jpg">Life in the Fast Lane

• CT scan → 3D version of CXR
• Sputum culture → growth
• Blood test [prior to administration of abx] → growth (if organism spread by blood)
• Bronchoscopy (endoscopic)
• Bronchoalveolar lavage (bronchoscopy + fluid squirted, which is then collected and tested for organisms)

• Prevention, including:
  • Lifestyle factors, including hand hygiene, exercise, quit smoking
  • Vaccinations, including:
    • Flu shot
    • Pneumococcal vaccine, which is a vaccination against streptococcus pneumoniae that can protect from 7-23 strains
    • Hib vaccine, against haemophilus influenzae
• If presumed bacterial, antibiotics: → useful for both fungal and bacterial pneumonia
  • Empiric Tx w/ amoxicillin is 1st line for CAP, including kids w/ mild ot moderate Sx, w/ doxycycline or clarithromycin as alternatives
  • In USA where atypical forms of CAP are more common, macrolides (e.g. azithromycin, erythromycin), and doxycycline has displaced amoxicillin as 1st line outpatient Tx in adults
  • Use of fluoroquinolones in uncomplicated cases is DISCOUARGED due to concerns about side effects and generating resistance in light of no greater clinical effects
  • HAP (hospital-acquired pneumonia), involves often giving abx IV, and used in combination, w/ >90% improve w/ the initial abx, including 3rd and 4th generation cephalosporins, carbapenems, fluoroquinolones, aminoglycosides, and vancomycin
  • Duration of Tx has typically been 7-10 days, but evidence shows shorter courses of 3-5 days are similarly effective
• Corticosteroids, improves outcomes, in those who require hospitalization and have CAP
• ABC's, including:
  • Oxygen
  • Fluids → hydration, thin secretions
• Analgesics
• If severe, admission to hospital
• Insufficient evidence for chest physiotherapy (CPT, i.e. removal of mucus by percussing the chest and back)

• Bacteremia → bacteria affects other organs
• Lung abscess (cavity is formed inside the lung, containing pus and other necrotic tissue)
• Empyema (abscess occuring in a naturally occuring cavity, e.g. in the pleural cavity)

• Usually resolves after 3-5 days of antibiotics, but Sx can last to a month
• There is however a 30% mortality for severe pneumonia in ICU

• Asthma
• LRTI (category)