Community-Acquired Pneumonia vs Influenza
Community-Acquired Pneumonia and Influenza are easy to mix up on the boards. Here's a side-by-side comparison — presentation, workup, imaging, and first-line treatment — drawn from our full outlines.
Community-Acquired Pneumonia vs Influenza at a glance
- Community-Acquired Pneumonia: Lower respiratory tract infection acquired outside of healthcare settings.
- Influenza: Acute viral respiratory illness from influenza A or B with seasonal epidemics and pandemic potential.
Keep comparing — start your free trial
You've used your 2 free previews. Create your free account to see the full Community-Acquired Pneumonia vs Influenza comparison — plus all 514 diagnosis outlines, 6,400+ board-style questions, and an AI tutor. Your 7-day free trial includes everything, no credit card required.
Side-by-side comparison
| Feature | Community-Acquired Pneumonia | Influenza |
|---|---|---|
| At a glance | Lower respiratory tract infection acquired outside of healthcare settings. | Acute viral respiratory illness from influenza A or B with seasonal epidemics and pandemic potential. |
| Classic presentation | Lobar consolidation with bronchial breath sounds and egophony classically points to S. pneumoniae; bullous myringitis with patchy infiltrates suggests Mycoplasma.; Cough (productive purulent sputum, or dry), fever, chills, rigors; Pleuritic chest pain, dyspnea; Constitutional: fatigue, myalgia, anorexia; Elderly may present atypically:… | Abrupt onset (over hours) of fever, chills, myalgia, headache, fatigue; Respiratory: dry cough, sore throat, nasal congestion/rhinorrhea; GI symptoms (vomiting, diarrhea) more common in children; Severe prostration disproportionate to other URI causes; Usually self-limited 3-7 days, but cough and malaise may linger 1-2 weeks; Fever,… |
| Workup / key labs | CBC (leukocytosis with left shift), BMP, lactate, procalcitonin (helps de-escalate antibiotics); Blood cultures × 2 if severe, ICU admission, immunocompromise, or cavitary disease; Sputum Gram stain and culture if severe or specific pathogen suspected; Urine antigens: S. pneumoniae and Legionella (severe CAP, Legionella outbreak,… | Often clinical diagnosis during peak season in otherwise well outpatients; Rapid influenza diagnostic tests (RIDT) — point-of-care, modest sensitivity (~50-70%), high specificity; Rapid molecular assays (NAAT/PCR) — higher sensitivity, preferred when treatment decision or hospitalization at stake; RT-PCR — gold standard; multiplex… |
| Imaging | Chest radiograph (PA and lateral) — REQUIRED to diagnose pneumonia; lobar consolidation, interstitial infiltrate, or cavitation; CT chest if non-resolving, complicated (abscess, empyema), or unclear; Bedside lung ultrasound — increasingly used in EDs | Chest radiograph if hypoxia, focal findings, or worsening symptoms — to exclude primary viral pneumonia or secondary bacterial pneumonia; CT chest if diagnosis uncertain or complicated |
| First-line treatment | Outpatient, no comorbidities, no recent antibiotics: amoxicillin 1 g TID OR doxycycline 100 mg BID OR macrolide (azithromycin, clarithromycin) if local pneumococcal resistance <25%; Outpatient with comorbidities (heart, lung, liver, renal, diabetes, alcohol, malignancy, asplenia): beta-lactam (amoxicillin-clavulanate 875 mg BID or… | Antivirals — start ASAP for symptomatic patients (ideally within 48 h of onset):; Oseltamivir 75 mg BID × 5 days (oral; renal dose adjust) — most widely used; Zanamivir 10 mg (2 inhalations) BID × 5 days — avoid in asthma/COPD (bronchospasm risk); Peramivir 600 mg IV × 1 dose — for those unable to tolerate PO; Baloxavir marboxil 40-80… |
Drill Community-Acquired Pneumonia vs Influenza questions on FirstPassPA
Turn this comparison into retention. 6,400+ board-style questions with an AI tutor that explains every answer — free to start, no card required.
Start studying free → Try today's free questionEducational use only. This outline is a study aid for PA students and is not medical advice or a substitute for clinical judgment. FirstPassPA is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCCPA or PAEA. PANCE® and PANRE® are registered trademarks of the National Commission on Certification of Physician Assistants; End of Rotation™ is a program of the Physician Assistant Education Association.