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Related Subjects: Asthma |Acute Severe Asthma |Exacerbation of COPD |Pulmonary Embolism |Cardiogenic Pulmonary Oedema |Pneumothorax |Tension Pneumothorax |Respiratory (Chest) infections Pneumonia |Fat embolism |Hyperventilation Syndrome |ARDS |Respiratory Failure |Diabetic Ketoacidosis

About

• Acute Infection of the lungs with inflammation in alveoli spaces
• Infection can be lobar, diffuse, bronchopneumonia
• Infective causes are bacterial, viral, fungal
• Other causes are aspiration, or radiotherapy or allergic mechanisms

Classification

• CAP: Community-acquired (Strep. pneumoniae)
• HAP: Hospital-acquired (Gram-negative bacteria)
• VAP: Ventilator-associated (multiple organisms, e.g. Pseudomonas, Klebsiella and Acinetobacter).

Pathological changes

Microbiological causes

Clinical

• Cough, purulent sputum/haemoptysis, pleuritic chest pain
• Shortness of breath, pyrexia, confusion, anorexia.
• Increased resp rate, tachycardia, low SpO2, dullness to percussion
• Bronchial breathing, unequal/reduced air entry
• Reduced expansion, crackles on auscultation.

Types

• community acquired (most common), hospital acquired (recent discharge/ inpatient?)
• aspiration (Hx stroke/? GCS/oesophageal pathology/neuro history including dementia, MS, Parkinson's/OGD, NG tube, bronchoscopy)
• ventilation (ITU admission/recently on ventilator.)

CURB 65 severity 1 point for each:

• Confusion
• Urea > 7 mmol/L
• Respiratory rate >30
• Blood pressure (SBP <90, DBP <60)
• 65 or older
• Score
  • 0-1 can go home with oral antibiotics if no other reason to be admitted. Treat as outpatient
  • 2 – Admit to hospital
  • 3+ – Often require ICU care

Other severity markers

• CXR – more than one lobe involved
• PaO2 <8 kPa
• Low albumin (<35 g/L)
• WCC (<4 × 109/L or high >20 × 109/L)
• Blood culture – positive

Investigations

• FBC: WCC, U+Es, CRP, blood cultures if CURB 65 >2. Serology for atypical and viral if suspected.
• Sputum: cultures if CURB65 >3 or CURB65 = 2 and not had Antibiotics.
• Urine: if CURB 65 >2 test for pneumococcal antigen, if >3 or suspicion test for legionella antigen.
• ABG:may see ↓ PaO2 (+/- ↑ PaCO2 due to hyperventilation but not if tiring/COPD.)
• CXR:look for focal consolidation. May have pleural effusions. May have pneumothorax as result of coughing or underlying lung disease (e.g. COPD (bullae) + coughing.)

Management

• ABCDE assessment.
• Sit up and give O2 as required. Give IV Fluids if dehydrated (likely in infection as abnormal ongoing losses due to fever/tachypnoea). Give antibiotics, see table below.
• Chest Physiotherapy
• Give antibiotics as soon as possible within 1 hour of diagnosis, either in A&E or CDU, as mortality rises with every hour of delay with antibiotics given. (See table below).
• Remains hypoxic consider CPAP or if ↑ CO2 then NIV
• Liase with ITU if hypoxia/hyperbarbia, acidosis continues

Antibiotics

• Sepsis RTI/UTI: Amoxicillin 1g TDS IV + Gentamicin as per policy. Pen allergy Clarithromycin 500mg BD IV/PO+ Gentamicin as per policy
• CURB Score <2: Doxycycline 200mg PO STAT then 100mg PO BD OR Amoxicillin 1g TDS PO for 5-7 days or Pen allergy: Clarithromycin 500mg PO BD
• CURB65 score >2 Amoxicillin 1g TDS IV + Clarithromycin 500mg BD IV OR PEN RASH Cefuroxime 1.5g TDS IV + Clarithromycin 500mg BD IV OR ANAPHYLAXIS: Levofloxacin 500mg BD IV
• Hospital Acquired Pneumonia (HAP) <5 days admission Evidence of consolidation on CXR >5 days admission or after ventilation: Mild HAP Amoxicillin 500mg TDS PO + Metronidazole 400mg TDS PO
• Severe HAP Co-amoxiclav 1.2g TDS IV for 5-7 days (IV to PO switch: co-amoxiclav 625mg TDS PO) OR Cefuroxime 1.5g TDS IV (rash) OR Levofloxacin 500mg BD IV/PO (anaphylaxis) for 5-7 days. If risk of aspiration add: Metronidazole 500mg TDS IV (IV to PO switch option: Doxycycline 200mg PO STAT, then 100mg BD +/- metronidazole 400mg TDS PO) Cefuroxime 1.5g TDS IV (rash) OR Levofloxacin 500mg BD IV/PO (anaphylaxis) If risk of aspiration add: Metronidazole 500 mg TDS IV
• Aspiration Pneumonia Amoxicillin 500mg TDS IV + Metronidazole 500mg TDS IV Clarithromycin 500mg BD IV + Metronidazole 500mg TDS IV

Refer for ITU and Mechanical Ventilation if

• PaO2 <8 kPa on 60% O2
• PaCO2 >6.4 kPa
• Patient exhausted, drowsy or unconscious
• Shock
• Hypotension or circulatory failure

References