🎯 Pathology

• infection of the alveoli

• alveolus = one unit of lung function

​

⚡️ Types

• community-acquired pneumonia (CAP)

  • pneumonia acquired outside of hospital

• hospital-acquired pneumonia (HAP)

  • pneumonia acquired >48 hours following admission to hospital

• ventilator-associated pneumonia (VAP)

  • pneumonia acquired >48 hours following endotracheal intubation

​

🧐 Assessment

• primary care —> CRB-65 score

  • Confusion (abbreviated mental test ≤ 8)

  • Respiratory rate (≥ 30/min)

  • Blood pressure (< 90 systolic and/or < 60 diastolic)

  • ≥ 65 years

• secondary care (hospital setting) —> CURB-65

  • Confusion (abbreviated mental test ≤ 8)

  • Urea > 7 mmol/L

  • Respiratory rate (≥ 30/min)

  • Blood pressure (< 90 systolic and/or < 60 diastolic)

  • ≥ 65 years

​

• the CURB-65 scoring system predicts mortality as well as helps with the decision regarding whether the patient should be managed on an outpatient basis, admitted to hospital, or managed in an intensive care unit (ICU) setting

  • score 0-1: outpatient

  • score ≥ 2: admit to hospital

  • score ≥ 3: manage in the ICU

​

🩺 Clinical features

• symptoms

  • shortness of breath

  • pleuritic chest pain

• signs

  • fever, tachypnoea, tachycardia, hypotension, confusion

  • productive cough

  • signs of consolidation

    • ​dullness to percussion

    • reduced breath sounds

    • reduced chest expansion

    • bronchial breathing

    • increased vocal resonance/fremitus

    • focal coarse crackles

​

🕵️‍♂️ Investigations

• bloods

  • FBC, U&E, LFTs, CRP

• blood cultures

• sputum cultures

• urinary antigen testing

  • pneumococcal or legionella antigens

• chest x-ray

​

💆‍♂️ Management​

• oxygen

• IV fluids

• antibiotics according to local guidelines

• analgesia if pleurisy

​

💡 Specific causes of pneumonia

• Streptococcus pneumoniae

  • most common bacterial cause

  • “fever + pleurisy + herpes labialis”

​

• Haemophilus influenzae

  • most common cause of pneumonia in COPD patients

​

• Staphylococcus aureus

  • most commonly occurs following influenza infection

​

• Klebsiella pneumoniae

  • “elderly + alcoholic + diabetic + red-currant jelly sputum”

  • upper lobes usually affected

​

• Mycoplasma pneumoniae

  • tends to affect the young

  • associations: erythema multiforme, cold autoimmune haemolytic anaemia, Gullian-barre syndrome, Stevens-Johnson syndrome

​

• Legionella pneumophilia

  • in the vignette, the patient may be going on holiday and is staying in a hotel with water tanks kept at < 60 degrees Celsius

  • colonises water tanks kept at < 60 degrees Celsius

  • associations: hyponatraemia, lymphopenia, derranged LFTs

​

• Chlamydia psittaci

  • contact from infected birds

​

• Pneumocystis jiroveci

  • “immunocompromised (e.g. HIV) + dry cough + exercise-induced desaturation”

  • prophylaxis is indicated if the CD4 count < 200 x 10^6

​

• common organisms causing hospital-acquired pneumonia (HAP)

  • gram-negative enterobacteria

  • Staphylococcus aureus

  • Pseudomonas