Pneumonia Diagnosis & Management for NEET PG — Complete Guide 2026
Master pneumonia for NEET PG 2026: CAP vs HAP vs VAP vs aspiration, typical vs atypical pathogens, CURB-65 and PSI scoring, sputum and urinary antigen workup, empirical antibiotics, duration of therapy, non-resolving pneumonia, and vaccination (PCV, PPSV).
Version 1.0 — Published February 2026
Quick Answer
Pneumonia contributes 2–3 NEET PG questions per paper across medicine, pulmonology, and ID. Master these 10 high-yield anchors:
- Classification — CAP (outside hospital or <48 h of admission), HAP (>=48 h after admission), VAP (HAP in a patient ventilated >=48 h), aspiration pneumonia (macroaspiration — anaerobes, right lower lobe)
- Typical CAP organisms — S. pneumoniae (most common), H. influenzae, Moraxella, Klebsiella (alcoholic, upper lobe, currant-jelly sputum), S. aureus (post-influenza)
- Atypical CAP organisms — Mycoplasma (young adults, cold agglutinins, bullous myringitis), Chlamydophila, Legionella (water, hyponatraemia, diarrhoea, transaminitis, severe), Coxiella
- CURB-65 — C (confusion), U (urea >7 mmol/L ≈ BUN >19 mg/dL), R (RR >=30), B (SBP <90 or DBP <=60), 65 (age >=65); 0–1 outpatient, 2 ward, >=3 ICU consideration
- PSI (PORT) — 20-variable, Class I–V; more accurate but complex; Class IV–V admit
- Workup — CXR (first-line); sputum Gram + culture; blood culture × 2; urinary antigen (pneumococcus & Legionella serogroup 1) in severe/ICU CAP; viral PCR; procalcitonin (selective)
- Outpatient CAP — amoxicillin 1 g TID OR doxycycline OR macrolide (IDSA prefers amox/doxy — high macrolide resistance)
- Inpatient non-severe CAP — beta-lactam + macrolide OR respiratory fluoroquinolone monotherapy (levo, moxi)
- Severe CAP / ICU — beta-lactam + macrolide (mortality benefit) OR beta-lactam + respiratory fluoroquinolone; add anti-MRSA (vanco/linezolid) and anti-pseudomonal if risk factors
- Duration — 5–7 days CAP (minimum 5 + 48–72 h clinical stability); 7 d HAP/VAP; 7–14 d Legionella; 4–6 weeks lung abscess
Pneumonia is a high-yield NEET PG chapter with predictable question patterns — CURB-65 cut-offs, atypical clues (hyponatraemia = Legionella, cold agglutinins = Mycoplasma), urinary antigen indications, empirical antibiotic tables, and vaccination schedules. This guide covers classification, severity scoring, workup, empirical regimens, duration, non-resolving pneumonia, and vaccination. Pair with the medicine subject hub, the asthma and COPD complete guide, and the tuberculosis diagnosis and treatment guide for complete pulmonology ID coverage.
Classification — CAP, HAP, VAP, aspiration
Pneumonia is an infection of the lung parenchyma classified by where it was acquired and predominant pathogen profile — correct classification drives empirical antibiotic choice.
| Type | Definition | Common pathogens |
|---|---|---|
| CAP (community-acquired) | Acquired outside hospital OR within <48 h of admission | S. pneumoniae, H. influenzae, Moraxella, atypicals (Mycoplasma, Chlamydophila, Legionella), viral (influenza, RSV, SARS-CoV-2), S. aureus (post-flu) |
| HAP (hospital-acquired) | Develops >=48 h after admission, not incubating at admission | Gram-negatives (P. aeruginosa, Klebsiella, Acinetobacter, E. coli, Enterobacter), S. aureus (often MRSA), rarely S. pneumoniae |
| VAP (ventilator-associated) | HAP in a patient intubated >=48 h | Same as HAP with higher resistance rates; early VAP (<5 days) — lower resistance; late VAP (>=5 days) — MDR gram-negatives and MRSA |
| Aspiration pneumonia | Follows macroaspiration of oropharyngeal or gastric contents | Gram-negatives, anaerobes (if poor dentition, alcoholism, severe periodontal disease); right lower lobe (gravity dependent), right upper lobe if supine |
| Immunocompromised pneumonia | Underlying HIV, neutropenia, post-transplant, immunosuppressive therapy | PCP (Pneumocystis), CMV, fungal (Aspergillus, Mucor, Cryptococcus), Nocardia, mycobacterial |
Note: HCAP (healthcare-associated pneumonia) as a separate category is no longer recommended (IDSA/ATS 2016) — pathogen profiles overlap CAP; risk stratify individually.
Aspiration pneumonia vs aspiration pneumonitis:
- Pneumonitis (Mendelson) — chemical injury from gastric acid; hours after event; supportive care; antibiotics not routinely required
- Pneumonia — bacterial superinfection 48–72 h later; antibiotics needed
Typical vs atypical organisms
Atypical pneumonia is a clinical-pathogen category of organisms that lack a cell wall or are intracellular — they do not respond to beta-lactams and require macrolides, doxycycline, or fluoroquinolones.
| Feature | Typical | Atypical |
|---|---|---|
| Classic pathogens | S. pneumoniae, H. influenzae, Moraxella, Klebsiella, S. aureus | Mycoplasma, Chlamydophila, Legionella, Coxiella |
| Onset | Acute | Subacute |
| Fever | High (>39°C) | Low-grade |
| Cough | Productive, purulent sputum | Dry, non-productive |
| Pleuritic pain | Common | Uncommon |
| Chest X-ray | Lobar consolidation | Patchy / interstitial |
| WBC | High (neutrophilic) | Normal / mildly elevated |
| Respiratory response to beta-lactam | Yes | No |
Typical organism clues (NEET PG vignettes):
| Pathogen | Clue |
|---|---|
| S. pneumoniae | Rusty-coloured sputum, single rigor, lobar consolidation |
| Klebsiella | Alcoholic, diabetic, upper lobe, "currant jelly" sputum, bulging fissure sign on CXR |
| S. aureus | Post-influenza, cavitation, abscess, empyema, pneumatocoeles (children) |
| H. influenzae | COPD exacerbation |
| Pseudomonas | Bronchiectasis, CF, neutropenia |
| Anaerobes | Aspiration, poor dentition, foul-smelling sputum, right lower lobe |
Atypical organism clues:
| Pathogen | Clue |
|---|---|
| Mycoplasma | Young adult, "walking pneumonia", cold agglutinins → haemolytic anaemia, bullous myringitis, erythema multiforme |
| Chlamydophila pneumoniae | Hoarseness, pharyngitis preceding pneumonia |
| Chlamydophila psittaci | Bird exposure (parrots); severe systemic |
| Legionella | Water exposure (air-conditioner cooling tower, spa); hyponatraemia, diarrhoea, transaminitis, confusion, severe disease |
| Coxiella burnetii (Q fever) | Cattle / sheep / placental exposure; hepatitis; endocarditis of native valves in chronic |
| Francisella tularensis | Rabbit / tick exposure; regional lymphadenopathy |
Viral pneumonia:
- Influenza (H1N1 pandemic), RSV, adenovirus, parainfluenza, SARS-CoV-2
- Diffuse bilateral interstitial infiltrates; ground-glass on CT
- Post-influenza bacterial superinfection is a NEET PG favourite — S. aureus (MSSA or MRSA), S. pneumoniae
CURB-65 and PSI severity scoring
CURB-65 and PSI are complementary CAP severity scores — CURB-65 is bedside and fast, PSI is more accurate and comprehensive. Both guide outpatient vs inpatient vs ICU triage.
CURB-65 — 0 to 5 points:
| Letter | Criterion |
|---|---|
| C | Confusion (new onset) — AMTS <=8 or disorientation |
| U | Urea >7 mmol/L (> BUN 19 mg/dL) |
| R | Respiratory rate >=30 |
| B | BP — SBP <90 OR DBP <=60 |
| 65 | Age >=65 |
Interpretation:
| Score | 30-day mortality | Disposition |
|---|---|---|
| 0 | 0.7% | Outpatient |
| 1 | 3.2% | Outpatient (consider short stay) |
| 2 | 13% | Ward admission |
| 3 | 17% | Ward; consider ICU |
| 4–5 | 41% | ICU |
CRB-65 (without urea) — suitable for primary care where labs aren't available; scores 0 outpatient, 1–2 consider admission, 3–4 admit.
PSI (Pneumonia Severity Index / PORT score):
- 20 variables: demographics, comorbidity, vitals, labs, imaging
- Classes I–V
- Class I — <50, no comorbidity, normal vitals → outpatient
- Class II–III (<=90 points) → outpatient or short stay
- Class IV (91–130) → admit
- Class V (>130) → ICU
- Validated in ~14,000 patients; more accurate than CURB-65
Clinical judgment: Both scores supplement — not replace — clinical judgement. Hypoxia (SaO2 <90%), social concerns (homelessness, alcoholism, no home support, unreliable follow-up), and unstable comorbidities may warrant admission irrespective of score.
IDSA/ATS severe CAP criteria (ICU threshold):
- Major (1 qualifies): mechanical ventilation, septic shock needing vasopressors
- Minor (3 qualify): RR >=30, PaO2/FiO2 <=250, multilobar infiltrates, confusion, uraemia (BUN >=20), leukopenia (<4000), thrombocytopenia (<100 × 10^9/L), hypothermia (<36°C), hypotension requiring aggressive fluids
Diagnostic workup
Workup of pneumonia confirms the clinical diagnosis, identifies the pathogen when possible, and establishes severity — chest radiography is the cornerstone with adjuncts selected by severity.
Imaging:
| Modality | When to use |
|---|---|
| Chest X-ray PA + lateral | First-line for all suspected pneumonia; lobar, multilobar, bronchopneumonic, interstitial patterns |
| CT chest | Non-resolving pneumonia, suspected complication (abscess, empyema, bronchiectasis, malignancy), HRCT for interstitial disease |
| Lung ultrasound | Increasingly used bedside; consolidation, effusion; high sensitivity |
Microbiology (severity-guided — not everyone needs all):
| Test | When |
|---|---|
| Sputum Gram stain and culture | Inpatient, especially if resistant organism risk (prior antibiotics, chronic lung disease, immunosuppression); collect before antibiotics |
| Blood cultures × 2 | Severe CAP, neutropenia, abnormal vitals, suspected bacteraemia |
| Urinary antigen — pneumococcus | Severe CAP, ICU admission; 70% sensitivity |
| Urinary antigen — Legionella pneumophila serogroup 1 | Severe CAP, travel, outbreak, hyponatraemia, suspected Legionella; detects only serogroup 1 (~70–90% of clinical Legionella) |
| Respiratory viral PCR | Winter, influenza/SARS-CoV-2 suspicion, immunosuppressed |
| Procalcitonin | Selective use; helps distinguish bacterial from viral; guides discontinuation |
| MRSA nasal swab | Negative swab has high negative predictive value for MRSA pneumonia — allows de-escalation of vancomycin |
| Bronchoalveolar lavage (BAL) | Severe, non-resolving, immunocompromised, VAP; quantitative cultures |
Labs:
- CBC, CRP, procalcitonin
- Urea, creatinine, electrolytes (hyponatraemia → think Legionella, SIADH)
- LFT (transaminitis → Legionella, Coxiella)
- ABG or SpO2
- HIV test in first adult CAP (low threshold)
Severity criteria trigger broader microbiology:
- Outpatient healthy — empirical, no microbiology needed
- Inpatient non-severe — blood cultures + sputum if available
- Severe / ICU — all above plus urinary antigens
Empirical antibiotic regimens
Empirical antibiotic choice for pneumonia depends on setting (outpatient vs inpatient vs ICU), comorbidity, local resistance, and risk factors for MRSA or Pseudomonas — and the IDSA/ATS 2019 CAP guideline is the NEET PG reference standard.
Community-acquired pneumonia
Outpatient — healthy, no comorbidity, no prior antibiotics (90 days):
| Option | Dose |
|---|---|
| Amoxicillin | 1 g PO TID (preferred in areas of high macrolide resistance — India) |
| Doxycycline | 100 mg PO BD |
| Macrolide (if local pneumococcal macrolide resistance <25%) | Azithromycin 500 mg day 1, 250 mg days 2–5; clarithromycin 500 mg BD × 7 d |
Outpatient — comorbidity (chronic lung, heart, liver, renal, diabetes, malignancy, asplenia, alcoholism):
| Option | Components |
|---|---|
| Combination | Amoxicillin-clavulanate 875 mg BD OR cefpodoxime 200 mg BD OR cefuroxime 500 mg BD PLUS azithromycin or doxycycline |
| Monotherapy | Respiratory fluoroquinolone — levofloxacin 750 mg OD or moxifloxacin 400 mg OD |
Inpatient non-severe CAP:
| Option | Components |
|---|---|
| Combination | IV beta-lactam (ceftriaxone 1–2 g OD, cefotaxime, ampicillin-sulbactam) PLUS macrolide (azithromycin 500 mg OD) |
| Monotherapy | Respiratory fluoroquinolone |
Inpatient severe / ICU CAP:
| Option | Components |
|---|---|
| Preferred | Beta-lactam (ceftriaxone or ampicillin-sulbactam) PLUS macrolide (azithromycin) |
| Alternative | Beta-lactam PLUS respiratory fluoroquinolone |
| Add anti-MRSA if risk | Vancomycin or linezolid |
| Add anti-pseudomonal if risk | Piperacillin-tazobactam, cefepime, meropenem, ceftazidime |
MRSA and Pseudomonas risk factors:
- Prior isolation
- Hospitalisation + IV antibiotics within 90 days
- Structural lung disease (bronchiectasis, CF)
- Immunosuppression
- Post-influenza (MRSA)
- Cavitary / necrotising pneumonia
Hospital-acquired and ventilator-associated pneumonia
Empirical (IDSA 2016):
- Cover S. aureus (including MRSA in high-risk units) and gram-negatives including Pseudomonas
- Preferred: piperacillin-tazobactam OR cefepime OR meropenem PLUS vancomycin or linezolid
- In units with >10% gram-negative resistance: dual anti-pseudomonal (e.g., pip-tazo + aminoglycoside or fluoroquinolone)
- De-escalate based on cultures
Aspiration pneumonia
- Community-acquired aspiration: amoxicillin-clavulanate or ampicillin-sulbactam
- Hospital-acquired aspiration: piperacillin-tazobactam or meropenem
- Severe periodontal disease / alcoholic / foul sputum → anaerobic coverage (clindamycin or metronidazole added)
- Pure chemical pneumonitis → supportive; antibiotics only if superinfection evident after 48–72 h
Duration of therapy
Duration of antibiotic therapy in pneumonia has shortened over the last decade — the rule of thumb is 5 days for uncomplicated CAP provided clinical stability, 7 days for HAP/VAP, and longer for specific organisms or complications.
| Scenario | Duration |
|---|---|
| Uncomplicated CAP | Minimum 5 days, with clinical stability for 48–72 h; typical 5–7 days |
| CAP with bacteraemia | 7 days |
| Legionella pneumonia | 7–14 days (azithromycin 7–10 d; fluoroquinolone 7–14 d) |
| Staphylococcus aureus bacteraemic pneumonia | 2–4 weeks |
| Pseudomonas pneumonia | 10–14 days |
| HAP / VAP | 7 days (shorter than traditional 14, per IDSA 2016) |
| Aspiration bacterial pneumonia | 7 days |
| Lung abscess / necrotising pneumonia | 4–6 weeks, guided by imaging and cultures |
| Empyema | 2–6 weeks + drainage |
| TB pneumonia | 6 months (HRZE 2 m + HR 4 m) per RNTCP/NTEP |
Clinical stability criteria:
- Temperature <=37.8°C
- HR <=100
- RR <=24
- SBP >=90
- SpO2 >=90% on room air
- Tolerating oral intake
- Normal mental status
IV to oral switch as soon as clinical stability achieved — same agent or equivalent class.
Non-resolving pneumonia
Non-resolving pneumonia is failure of clinical or radiographic improvement despite 7–10 days of appropriate antibiotics, OR worsening after initial response — it triggers a structured differential that separates wrong bug, wrong drug, wrong diagnosis, and host factors.
Definitions:
- Slow-resolving: radiographic improvement lags behind clinical (normal at 4 weeks in 60%, 8 weeks in 85%)
- Non-resolving: absence of clinical improvement in 7–10 days
- Progressive: clinical or radiographic deterioration
Differential — the classic 4 buckets:
-
Wrong bug / wrong drug (resistance)
- MRSA, MDR gram-negatives
- Atypicals not covered (no macrolide or fluoroquinolone)
- Tuberculosis
- Fungal (Aspergillus, Mucor, Cryptococcus, endemic mycoses)
- PCP in immunocompromised
- Viral (influenza, SARS-CoV-2)
- Parasitic (rare — amoebic, paragonimus)
-
Wrong diagnosis
- Pulmonary embolism
- Pulmonary oedema / heart failure
- Lung cancer / obstructive post-obstructive pneumonia
- Vasculitis (GPA, EGPA)
- Organising pneumonia (COP/BOOP)
- Eosinophilic pneumonia
- Hypersensitivity pneumonitis
- ARDS
- Pulmonary haemorrhage
- Drug-induced pneumonitis (amiodarone, bleomycin, methotrexate)
-
Complication
- Parapneumonic effusion / empyema
- Lung abscess
- Metastatic infection (endocarditis, meningitis)
- Pneumothorax
-
Host factors
- HIV / immunosuppression
- Neutropenia
- Malnutrition
- Non-adherence
Workup:
- Repeat CT chest (more sensitive than CXR)
- Sputum AFB × 3 + mycobacterial culture + GeneXpert
- HIV test
- Autoimmune workup (ANA, ANCA, RF)
- Eosinophil count
- Bronchoalveolar lavage (BAL) — cell differential, cultures (bacterial, mycobacterial, fungal, PCP, viral), cytology, galactomannan
- Lung biopsy (transbronchial or surgical) — for unexplained persistent disease or suspected malignancy / COP / vasculitis
Pneumonia prevention — vaccination
Vaccination is the single highest-impact preventive intervention for pneumonia — pneumococcal, influenza, COVID-19, Hib, measles, and pertussis vaccines each reduce pneumonia incidence.
Pneumococcal vaccines:
| Vaccine | Type | Serotypes |
|---|---|---|
| PCV13 | Conjugate | 13 |
| PCV15 | Conjugate | 13 + 22F + 33F |
| PCV20 | Conjugate | PCV15 + 5 more |
| PPSV23 | Polysaccharide | 23 |
Adult recommendations (CDC/ACIP 2022, simplified):
- All adults >=65
- Adults 19–64 with chronic conditions (chronic heart, lung, liver disease, diabetes, alcoholism, smoking), immunocompromise, asplenia, CSF leak, cochlear implants
- Two strategies:
- PCV20 alone (single dose)
- PCV15 → PPSV23 >=1 year later (8 weeks in immunocompromised)
Children (Indian UIP since 2021):
- PCV13 (or PCV15) at 6, 14 weeks, 9 months (2+1 schedule)
- PCV introduced nationally after staged rollout
Influenza vaccine:
- Annual inactivated or live attenuated (LAIV — for age 2–49 healthy)
- Reduces pneumonia incidence, hospitalisation, mortality
- Critically important in elderly, chronic disease, pregnancy, healthcare workers
COVID-19 vaccination:
- Primary series + boosters as per national policy
- Reduces severe disease and pneumonia
Hib vaccine:
- Routine in UIP (with pentavalent vaccine at 6, 10, 14 weeks)
- Protects against H. influenzae type b — invasive disease (meningitis, epiglottitis, pneumonia)
Other:
- Measles, pertussis, varicella — reduce primary viral pneumonia and bacterial superinfection
- Smoking cessation — essential adjunct
Sources and references
- Harrison's Principles of Internal Medicine, 21st Edition (Loscalzo et al., 2022) — Chapter on Pneumonia.
- Metlay JP et al. Diagnosis and Treatment of Adults with Community-Acquired Pneumonia. An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America. Am J Respir Crit Care Med 2019; 200:e45-e67.
- Kalil AC et al. Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia: 2016 Clinical Practice Guidelines by the Infectious Diseases Society of America and the American Thoracic Society. Clin Infect Dis 2016; 63:e61-e111.
- Lim WS et al. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax 2003; 58:377-382 (CURB-65).
- Fine MJ et al. A prediction rule to identify low-risk patients with community-acquired pneumonia. N Engl J Med 1997; 336:243-250 (PSI).
- CDC Advisory Committee on Immunization Practices (ACIP) 2022 pneumococcal vaccine recommendations.
Frequently asked questions
How many pneumonia questions appear in NEET PG?
Pneumonia contributes 2-3 direct questions per NEET PG paper across medicine, pulmonology, pediatrics and infectious disease. The most tested subtopics are CAP vs HAP vs VAP definitions, CURB-65 scoring, atypical vs typical pathogens, urinary antigen tests for Legionella and pneumococcus, empirical antibiotic choice by setting, duration of therapy, and vaccination schedules based on 2019-2025 pattern analysis.
What is the difference between CAP, HAP, VAP, and aspiration pneumonia?
CAP (community-acquired pneumonia) is pneumonia acquired outside hospital or within 48 hours of admission — common pathogens are Streptococcus pneumoniae, Haemophilus influenzae, atypicals (Mycoplasma, Chlamydophila, Legionella), and viral. HAP (hospital-acquired pneumonia) develops greater than or equal to 48 hours after admission — gram-negatives (Pseudomonas, Klebsiella, E. coli) and MRSA dominate. VAP (ventilator-associated pneumonia) is HAP in a patient intubated for greater than or equal to 48 hours — similar pathogens with high resistance rates. Aspiration pneumonia follows macroaspiration of oropharyngeal or gastric contents — anaerobes (in dentate patients or severe periodontal disease) and gram-negatives; right lower lobe is classic.
What is CURB-65 and how is it used?
CURB-65 is a 5-point bedside severity score for CAP. C — Confusion (new onset), U — Urea greater than 7 mmol/L (greater than 19 mg/dL BUN), R — Respiratory rate greater than or equal to 30, B — Blood pressure (SBP less than 90 OR DBP less than or equal to 60), 65 — Age greater than or equal to 65. Score 0-1 outpatient, Score 2 short-stay / ward admission, Score greater than or equal to 3 ICU consideration. 30-day mortality: 0 — 0.7 percent, 1 — 3.2 percent, 2 — 13 percent, 3 — 17 percent, 4-5 — 41 percent. CRB-65 omits urea and is useful in primary care.
What is the Pneumonia Severity Index (PSI)?
PSI (PORT score) is a 20-variable prognostic score stratifying CAP into 5 risk classes. Class I (age less than 50, no comorbidity, normal vitals) is very low risk — outpatient. Classes II-III low-moderate risk — mostly outpatient or short-stay. Class IV moderate-high risk — admit. Class V (greater than 130 points) high risk — ICU consideration. PSI is more accurate than CURB-65 but complex; CURB-65 is easier at bedside. Use PSI when you have labs; CURB-65 when triage is urgent. Neither replaces clinical judgment.
What are atypical versus typical organisms in CAP?
Typical CAP organisms are Streptococcus pneumoniae (most common overall), Haemophilus influenzae (COPD), Moraxella catarrhalis, Klebsiella pneumoniae (alcoholics, diabetics — currant jelly sputum, upper lobe), Staphylococcus aureus (post-influenza). Atypicals are Mycoplasma pneumoniae (young adults, walking pneumonia, cold agglutinins, bullous myringitis), Chlamydophila pneumoniae and Chlamydophila psittaci (bird exposure), Legionella pneumophila (water exposure, hyponatremia, diarrhea, transaminitis, severe disease), Coxiella burnetii (Q fever — cattle, sheep). Atypicals do NOT grow on standard media, do NOT respond to beta-lactams, require macrolide, doxycycline, or fluoroquinolone.
What is the empirical antibiotic regimen for CAP?
Outpatient healthy adult CAP — amoxicillin 1 g TID OR doxycycline 100 mg BD OR macrolide (azithromycin 500 mg day 1 then 250 mg days 2-5) — IDSA prefers amoxicillin or doxycycline due to high macrolide resistance. Outpatient with comorbidity — amoxicillin-clavulanate OR cephalosporin PLUS macrolide OR doxycycline; OR respiratory fluoroquinolone (levofloxacin 750 mg, moxifloxacin 400 mg). Inpatient non-severe — IV beta-lactam (ceftriaxone 1-2 g daily or ampicillin-sulbactam) PLUS macrolide, OR respiratory fluoroquinolone monotherapy. Inpatient severe/ICU — beta-lactam PLUS macrolide OR beta-lactam PLUS respiratory fluoroquinolone. Cover MRSA (vancomycin or linezolid) and Pseudomonas if risk factors present.
What is the duration of antibiotic therapy in pneumonia?
Minimum duration for CAP is 5 days provided clinical stability criteria are met for 48-72 hours (afebrile, stable vitals, tolerating oral, normal mental status). Typical course is 5-7 days for most CAP. Legionella pneumonia requires 7-14 days (azithromycin 7-10 days; fluoroquinolone 7-14 days). Bacteremic Staphylococcus aureus pneumonia requires 2-4 weeks. Lung abscess or necrotizing pneumonia requires 4-6 weeks (often guided by cultures). HAP/VAP requires 7 days in most cases (shorter than the traditional 14 days — IDSA 2016). Aspiration pneumonia (bacterial) is 7 days.
What vaccines prevent pneumonia?
Pneumococcal vaccines include PCV13 (13-valent conjugate), PCV15 (adds 22F and 33F), PCV20 (adds 5 more serotypes), and PPSV23 (polysaccharide). In adults in India and globally, current CDC/ACIP recommendation (2022) is: age greater than or equal to 65 or younger with immunocompromise/chronic disease — PCV20 alone OR PCV15 followed by PPSV23 greater than or equal to 1 year later. Influenza vaccine (annual — inactivated or live) reduces pneumonia risk and post-flu bacterial pneumonia. Children receive PCV13/PCV15 in infancy (6, 10, 14 weeks in Indian UIP since 2021). Adults with HIV, asplenia, sickle cell, CKD, transplant — PCV plus PPSV23.
What is the workup of non-resolving pneumonia?
Non-resolving pneumonia is failure of clinical or radiographic response despite 7-10 days of appropriate antibiotics (no improvement) OR worsening after initial response (deterioration). Differential includes wrong antibiotic (resistant organism, atypical, viral, fungal, TB), wrong diagnosis (pulmonary embolism, vasculitis, BOOP/COP, organizing pneumonia, eosinophilic pneumonia, lung cancer, heart failure, ARDS), complications (empyema, lung abscess), immunosuppression (HIV, malignancy). Workup includes repeat imaging (CT chest), sputum AFB and mycobacterial culture, HIV test, ANA/ANCA/eosinophils, BAL with differential cell count and cultures (fungal, mycobacterial, nocardia), and biopsy if needed (transbronchial or surgical lung biopsy).
What are the IDSA criteria for severe CAP?
IDSA/ATS severe CAP criteria — 1 major OR 3 minor criteria qualify for ICU admission. Major criteria: mechanical ventilation, septic shock requiring vasopressors. Minor criteria: respiratory rate greater than or equal to 30, PaO2/FiO2 less than or equal to 250, multilobar infiltrates, confusion/disorientation, uremia (BUN greater than or equal to 20 mg/dL), leukopenia (WBC less than 4000), thrombocytopenia (platelets less than 100,000), hypothermia (less than 36 C), hypotension requiring aggressive fluid resuscitation. Important because severe CAP mandates combination therapy (beta-lactam plus macrolide or respiratory fluoroquinolone) and ICU-level monitoring.
Convert this guide into exam marks — revise the asthma and COPD complete guide, cross-check with the tuberculosis diagnosis and treatment guide, and use the AI tutor to drill empirical antibiotic choice.
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This content is for educational purposes for NEET PG exam preparation. It is not a substitute for professional medical advice, diagnosis, or treatment. Clinical information has been reviewed by qualified medical professionals.
Written by: NEETPGAI Editorial Team Reviewed by: Pending SME Review Last reviewed: February 2026
This article is reviewed by qualified medical professionals for clinical accuracy and exam relevance. For corrections or updates, contact the editorial team.
This content is for educational purposes for NEET PG exam preparation. It is not a substitute for professional medical advice, diagnosis, or treatment. Clinical information has been reviewed by qualified medical professionals.
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