General Medicine
Pneumonia
Pneumonia for MBBS: classification by setting, common organisms, CURB-65 severity, empirical antibiotics and complications, mapped to NMC codes IM3.1 to IM3.19.
MedNext Academy | 3 min read
Clinically reviewed by Dr Shameer Deen, MBBS, MS, MRCS
Pneumonia
Pneumonia for MBBS: classification by setting, common organisms, CURB-65 severity, empirical antibiotics and complications, mapped to NMC codes IM3.1 to IM3.19.
This chapter covers the diagnosis and management of pneumonia across its settings, from community-acquired to ventilator-associated disease. It emphasises severity scoring, chest imaging, rational empirical antibiotic selection with de-escalation, and the recognition of complications such as effusion and empyema.
High-yield: Pneumonia
- Pneumonia is classified by setting into community-acquired, hospital-acquired, ventilator-associated and aspiration types, which guides likely organisms and therapy.
- Streptococcus pneumoniae remains the commonest cause of community-acquired pneumonia.
- The CURB-65 score uses confusion, urea, respiratory rate, blood pressure and age 65 or over to guide the site of care.
- A chest X-ray showing new consolidation supports the diagnosis but a normal early film does not exclude pneumonia.
- Atypical organisms such as Mycoplasma and Legionella cause pneumonia with prominent extrapulmonary features and normal Gram stain.
- Legionella is classically associated with hyponatraemia, diarrhoea and deranged liver tests.
- Empirical antibiotics should be started promptly and then de-escalated according to culture results.
- A parapneumonic effusion that is loculated, low in pH or frankly purulent needs drainage.
- Klebsiella pneumonia classically causes an upper-lobe cavity with a bulging fissure in alcoholics and diabetics.
- Aspiration pneumonia targets dependent lung segments and involves anaerobic and oral flora.
- Sputum Gram stain and culture help direct therapy but should not delay the first antibiotic dose.
- Hospital-acquired and ventilator-associated pneumonia require broader cover for resistant Gram-negative organisms and MRSA.
- Pneumococcal and influenza vaccination reduce the incidence and severity of pneumonia in at-risk groups.
- Failure to improve by 48 to 72 hours should prompt review for complications, resistance or an alternative diagnosis.
- Oxygen, fluids and early mobilisation are core supportive measures alongside antibiotics.
Pneumonia essentials
- Classify by setting: Community, hospital, ventilator-associated or aspiration, which predicts likely organisms.
- Severity: CURB-65 (confusion, urea, respiratory rate, blood pressure, age 65 or over) guides the site of care.
- Commonest organism: Streptococcus pneumoniae in community-acquired disease; atypicals cause extrapulmonary features.
- Treatment: Prompt empirical antibiotics, de-escalate on culture, and drain a complicated effusion.
NMC competencies in this chapter
- IM3.1: Types of pneumonia: community, hospital, ventilator-associated and aspiration
- IM3.2: Aetiology and microbiology by setting and host immunity
- IM3.3: Pathogenesis, natural history and complications
- IM3.7: Diagnostic tests in pneumonia
- IM3.12: Empirical antimicrobial selection and prescription
- IM3.13: Culture-directed therapy, de-escalation and treatment failure
- IM3.15: Criteria for hospitalisation and intensive care
- IM3.19: Pneumococcal, influenza and respiratory vaccination counselling
Frequently Asked Questions
How is the severity of community-acquired pneumonia assessed?
The CURB-65 score adds one point each for confusion, raised urea, respiratory rate of 30 or more, low blood pressure and age 65 or over, and a higher score indicates a need for hospital or intensive care.
What is the commonest cause of community-acquired pneumonia?
Streptococcus pneumoniae is the commonest organism; atypical organisms such as Mycoplasma and Legionella cause disease with prominent extrapulmonary features.
When should a pleural effusion in pneumonia be drained?
A parapneumonic effusion that is loculated, has a low pH, or is frankly purulent (empyema) should be drained rather than managed with antibiotics alone.
How does this chapter help for NEET-PG?
Organism-setting associations, severity scoring, atypical clues such as Legionella and empirical antibiotic choice are frequently tested, so this framework maps directly to exam questions.
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