Respiratory

Acute bronchitis: when not to prescribe antibiotics

Clinical Overview and When to Suspect Acute Bronchitis

— Influenza A/B, RSV, parainfluenza, coronaviruses (including SARS-CoV-2), rhinovirus, human metapneumovirus, adenovirus

— Bacterial causes are rare in immunocompetent adults; Bordetella pertussis, Mycoplasma pneumoniae, and Chlamydia pneumoniae account for <5–10%

— Cough >5 days, often productive (clear, yellow, or even green sputum — color does not predict bacterial etiology)

— Mild URI prodrome (sore throat, coryza, low-grade fever early)

— Chest wall soreness from coughing, occasional wheeze, normal mental status, no tachypnea

— One of the top 10 reasons for outpatient visits in the US

— Drives a disproportionate share of inappropriate antibiotic prescribing — a CMS quality measure and Choosing Wisely target

Board pearl: Purulent (yellow-green) sputum in acute bronchitis reflects sloughed tracheobronchial epithelium and neutrophils, not bacterial infection — it is not an indication for antibiotics. This is among the most repeatedly tested misconceptions in Step 3 ambulatory blocks.

Step 3 management framing: The "correct answer" in nearly every uncomplicated acute bronchitis vignette is symptomatic care + patient education + delayed-prescription or no prescription for antibiotics — and counseling the patient on why antibiotics will not shorten the illness or prevent complications.

Definition: Self-limited inflammation of the large airways (trachea/bronchi) in a patient without underlying chronic lung disease, lasting <3 weeks, dominated by cough ± sputum.

Etiology is overwhelmingly viral (>90%):

When to suspect on Step 3: Otherwise healthy adult presenting to clinic or urgent care with:

Epidemiology context for the ambulatory exam:

Diagnosis is clinical and one of exclusion — confirm absence of pneumonia, asthma exacerbation, COPD exacerbation, heart failure, and pertussis exposure.

Presentation Patterns and Key History

— Onset typically follows a viral URI prodrome by 1–3 days

— Median duration ~18 days; up to 25% of patients still cough at 4 weeks

— Initially dry, often becomes productive after several days

— Worse at night and with cold air; chest wall pain from intercostal strain is common

— Low-grade fever early (high fever >38.5°C should prompt reconsideration — think influenza, pneumonia, or COVID-19)

— Myalgias, headache, rhinorrhea, sore throat

— Substernal burning with cough; mild wheeze/dyspnea on exertion possible from transient bronchial hyperreactivity

— Duration of cough (>3 weeks → reconsider diagnosis: pertussis, post-infectious cough, asthma, GERD, ACE-inhibitor cough, TB)

— Smoking status and pack-years (a smoker with chronic cough is not acute bronchitis — think chronic bronchitis/COPD)

— Vaccination history: influenza, COVID-19, Tdap (pertussis), pneumococcal

— Sick contacts, daycare, school exposures, recent travel

— Occupational/environmental: wood smoke, dust, e-cigarette/vaping (EVALI), birds (psittacosis), farm animals

— Medications: ACE inhibitors (cough in 5–20%), immunosuppressants

— Red-flag symptoms: hemoptysis, weight loss, night sweats, drenching sweats, focal chest pain, orthopnea, PND

Key distinction: Acute bronchitis vs community-acquired pneumonia — pneumonia features focal exam findings, fever >38°C, tachycardia >100, tachypnea >24, and hypoxemia. Presence of any of these on history-exam should trigger a chest x-ray before you commit to "no antibiotics."

Board pearl: A cough lasting 2–8 weeks is termed subacute cough — pertussis tops the differential in adults regardless of vaccination history.

Hallmark symptom — cough:

Associated symptoms (usually mild):

Critical history elements to extract on the exam:

Pertussis clues: paroxysmal cough, post-tussive emesis, inspiratory whoop, incompletely vaccinated, outbreak setting, cough >2 weeks

Physical Exam Findings (and Vital Sign Assessment)

— Temperature usually <38°C; high fever should redirect workup

— Heart rate <100; pulse oximetry ≥95% on room air

— Respiratory rate <24

— Heckerling/Diehr rule: absence of all of (HR >100, RR >24, T >38°C, focal exam findings) makes pneumonia very unlikely → no chest x-ray needed

— Should be largely normal, possibly with diffuse coarse rhonchi or scattered wheezes that clear with cough

— No focal crackles, no egophony, no bronchial breath sounds, no dullness to percussion — any of these → obtain chest x-ray to evaluate pneumonia

— Prolonged expiratory phase may reflect transient bronchial hyperreactivity

Step 3 management: When the vignette gives you a healthy adult with cough × 1 week, T 37.6°C, HR 88, RR 16, SpO₂ 98%, and scattered wheezes that clear with cough — the correct next step is symptomatic therapy and reassurance, not chest x-ray, not sputum culture, not antibiotics.

Board pearl: The combination of normal vital signs + normal lung exam + cough <3 weeks has a negative predictive value >95% for pneumonia in healthy adults — imaging adds cost, radiation, and false positives without changing management.

Key distinction: Wheezes that clear with cough suggest mobile mucus (bronchitis); fixed wheezes localized to one area suggest foreign body or endobronchial lesion.

Vital signs — the central decision driver:

General appearance: Non-toxic, comfortable, conversing in full sentences, no accessory muscle use.

HEENT: Erythematous oropharynx, clear or mucoid rhinorrhea, no exudates, no sinus tenderness; conjunctival injection suggests adenovirus.

Neck: Mild anterior cervical lymphadenopathy may accompany viral URI; significant lymphadenopathy warrants reconsideration.

Pulmonary exam — the highest-yield section:

Cardiac exam: Normal S1/S2; no JVD, no S3, no peripheral edema (rule out CHF mimicking bronchitis with cough).

Skin/extremities: No cyanosis, no clubbing.

Diagnostic Workup — Initial Studies (and When to *Not* Order Them)

— HR >100, RR >24, T >38°C, or O₂ sat <95%

— Focal pulmonary exam findings (crackles, egophony, dullness)

— Age >75 with cough (mounting evidence supports lower threshold)

— Mental status changes, particularly in elderly

— Hemoptysis, unexplained weight loss, immunocompromise

— Suspected heart failure or PE

— Procalcitonin has been studied as an antibiotic stewardship tool; a value <0.25 ng/mL supports withholding antibiotics. Not standard outpatient practice for bronchitis but is fair game on stewardship-themed Step 3 items.

— Influenza PCR/antigen during influenza season if symptoms <48 hours and antiviral therapy is being considered, or in high-risk patients

— SARS-CoV-2 PCR/antigen per local epidemiology

— Pertussis PCR on nasopharyngeal swab if cough >1–2 weeks with paroxysms, whoop, or post-tussive emesis — especially with infant exposure

— RSV PCR in elderly or immunocompromised

Board pearl: Procalcitonin-guided therapy reduces inappropriate antibiotic use in lower respiratory tract infections without worsening outcomes — a classic stewardship MCQ answer.

CCS pearl: In a CCS-style case, ordering "CBC, BMP, blood cultures, sputum culture, chest x-ray" on a healthy 28-year-old with 6 days of cough and normal vitals will lose efficiency/cost points. Order pulse oximetry, document the exam, and counsel.

Acute bronchitis is a clinical diagnosis — routine labs and imaging are not indicated in immunocompetent adults with classic presentation. The Step 3 trap is over-ordering.

Chest x-ray — order ONLY if:

CBC, BMP, procalcitonin, CRP — not routinely indicated in outpatient acute bronchitis.

Sputum Gram stain/culture — do NOT order for outpatient acute bronchitis. Yield is low and results misleading (colonization).

Targeted microbiologic testing when clinically indicated:

Pulse oximetry is the one universally appropriate bedside test.

Diagnostic Workup — Advanced or Targeted Studies

— Treat per CAP guidelines; consider sputum and blood cultures if hospitalized

— Repeat imaging in 6–8 weeks for smokers >40 or those with persistent symptoms to evaluate for post-obstructive pneumonia from malignancy

— Pertussis PCR (most sensitive in first 3 weeks); serology later

— Spirometry with bronchodilator to evaluate for asthma or cough-variant asthma

— PPD or interferon-gamma release assay if TB risk factors (foreign-born, immunocompromise, homelessness, incarceration, healthcare exposure)

— HIV testing if risk factors

— Sinus imaging if upper airway cough syndrome (postnasal drip) suspected

— Empiric trial for GERD-related cough (PPI 8 weeks) or upper airway cough syndrome (first-gen antihistamine-decongestant)

— Review medication list: stop ACE inhibitors as a diagnostic trial — cough resolves in 1–4 weeks

— Top 3 causes in non-smoking immunocompetent adults: upper airway cough syndrome, asthma, GERD

— Add HRCT chest, bronchoscopy, ENT/pulmonary referral as indicated

Step 3 management: A patient on lisinopril with 6 weeks of dry cough, normal exam, normal chest x-ray → discontinue the ACE inhibitor and switch to an ARB; reassess in 4 weeks. This is one of the most heavily tested patterns.

Key distinction: A persistent productive cough in a smoker for ≥3 months/year × 2 years defines chronic bronchitis (COPD phenotype) — not acute bronchitis — and triggers spirometry plus smoking-cessation counseling.

When initial evaluation suggests an alternative diagnosis, escalate as follows:

Chest x-ray abnormal or suggestive of pneumonia:

Persistent cough >3 weeks (subacute) — workup ladder:

Persistent cough >8 weeks (chronic) — formal chronic cough algorithm:

Specialty testing when indicated: D-dimer/CT-PA for PE, BNP/echo for HF, methacholine challenge for asthma when spirometry equivocal.

Risk Stratification and the Antibiotic Decision

— Healthy adults with classic acute bronchitis regardless of sputum color or duration up to 3 weeks

— Patients pressuring for antibiotics — use shared decision-making and "delayed prescription" strategy

— Confirmed or strongly suspected pertussis → macrolide (azithromycin)

— Community-acquired pneumonia (infiltrate on CXR or strong clinical suspicion)

— COPD exacerbation with increased dyspnea + sputum volume + sputum purulence (Anthonisen criteria — ≥2 cardinal symptoms)

— Suspected bacterial superinfection with new fever after initial improvement

— Immunocompromise, frailty, age >80 with concerning trajectory

— Oseltamivir within 48 h of symptom onset for influenza, especially in high-risk patients (age ≥65, pregnancy, chronic comorbidity, immunocompromise)

— Nirmatrelvir-ritonavir for high-risk COVID-19 outpatients within 5 days of symptom onset

— Give a dated prescription with instructions to fill only if symptoms worsen or fail to improve in 3–5 days

— Reduces antibiotic use ~60% vs immediate prescribing while preserving satisfaction

Board pearl: Inappropriate antibiotic prescribing for acute bronchitis is a HEDIS quality measure (Avoidance of Antibiotic Treatment for Acute Bronchitis/Bronchiolitis, AAB) — used in pay-for-performance contracts.

Step 3 management: Default answer for uncomplicated acute bronchitis = no antibiotics + symptomatic therapy + patient education + return precautions.

The central Step 3 teaching: In immunocompetent adults with acute bronchitis, antibiotics do not meaningfully shorten illness, reduce activity limitation, or prevent complications — Cochrane data show ~½-day benefit at the cost of resistance, C. difficile, drug reactions, and cost.

Patient groups where you should still NOT prescribe antibiotics:

Situations where antibiotics ARE appropriate (i.e., the diagnosis is no longer acute bronchitis or there's a specific pathogen-driven indication):

Antivirals (not antibiotics) when indicated:

Delayed (back-pocket) prescription strategy:

Pharmacotherapy — Symptomatic Management

— Dextromethorphan 10–20 mg PO q4h or 30 mg q6–8h — first-line OTC; avoid with SSRIs/MAOIs (serotonin syndrome risk)

— Guaifenesin 600–1200 mg PO q12h — expectorant; modest evidence

— Benzonatate 100–200 mg PO TID — peripheral antitussive; warn against chewing/sucking (oral anesthesia, fatal pediatric ingestions reported — FDA boxed warning context)

— Codeine or hydrocodone-containing cough syrups — generally avoided; limited benefit, opioid risk; contraindicated in children <12 and breastfeeding mothers (FDA)

— Albuterol MDI 2 puffs q4–6h PRN — consider only if wheezing or bronchial hyperreactivity is present; not routine. Modest reduction in cough duration in wheezing subset; tremor and tachycardia common.

— Acetaminophen 650–1000 mg q6h (max 3–4 g/d; lower in liver disease/alcohol use)

— Ibuprofen 400–600 mg q6–8h with food; avoid in CKD, peptic ulcer, late pregnancy

— Hydration, honey 1–2 tsp (adults and children ≥1 year; never <1 year — botulism risk), humidified air, smoking cessation, hand hygiene, mask in shared spaces

— Oseltamivir 75 mg PO BID × 5 days for influenza within 48 h; renal dose-adjust

— Nirmatrelvir-ritonavir 300/100 mg BID × 5 days for COVID-19; screen for drug interactions (statins, calcineurin inhibitors)

Board pearl: Honey has the strongest evidence for nocturnal cough relief in children ≥1 year and is endorsed by the AAP — a frequently tested pediatric ambulatory answer.

Key distinction: Albuterol helps only the wheezing subset; reflexively prescribing it for every bronchitis patient is a stewardship and side-effect error.

Symptomatic therapy is the cornerstone. Evidence for most agents is modest; choose by predominant symptom and patient comorbidity.

Cough suppression (when cough disrupts sleep/function):

Bronchodilators:

Inhaled or oral corticosteroids: Not recommended for uncomplicated acute bronchitis in patients without asthma/COPD.

Analgesia/antipyresis:

Supportive measures (always recommend):

Targeted antivirals:

When Antibiotics ARE Indicated — Targeted Regimens

— Azithromycin 500 mg PO day 1, then 250 mg daily days 2–5 (preferred)

— Alternatives: clarithromycin 500 mg BID × 7 days; TMP-SMX DS BID × 14 days if macrolide-intolerant

— Primary goal: reduce transmission, not to shorten symptoms (most benefit if started <3 weeks from cough onset)

— Postexposure prophylaxis with the same regimen for high-risk close contacts: infants <1 year, third-trimester pregnancy, household contacts of infants, healthcare workers in neonatal units

— Mandatory public health reporting in all US states

— Amoxicillin 1 g PO TID × 5 days ± macrolide/doxycycline, or doxycycline 100 mg PO BID (per 2019 ATS/IDSA)

— With comorbidities (chronic heart/lung/liver/renal disease, DM, alcoholism, malignancy, asplenia): β-lactam + macrolide or respiratory fluoroquinolone (levofloxacin/moxifloxacin)

— Azithromycin, doxycycline, or amoxicillin-clavulanate × 5 days

— Oseltamivir 75 mg BID × 5 d; reduce to 30 mg BID if CrCl 30–60; further reductions if lower

CCS pearl: A patient who returns at day 7 of "bronchitis" with new fever, rigors, and focal crackles — order chest x-ray, pulse oximetry, CBC, and treat as CAP; do not just refill cough medicine.

Board pearl: Macrolide resistance in S. pneumoniae now exceeds 30% in many US regions — azithromycin monotherapy is no longer adequate empiric CAP coverage in healthy outpatients per 2019 guidelines.

Step 3 management: Document the specific reason antibiotics were prescribed (e.g., "infiltrate on CXR consistent with CAP") to protect against quality-measure flags.

Pertussis (confirmed or high clinical suspicion):

Community-acquired pneumonia (outpatient, previously healthy, no comorbidities):

COPD exacerbation meeting Anthonisen criteria:

Influenza (antiviral, not antibiotic):

Mycoplasma/Chlamydia pneumoniae — generally not treated in acute bronchitis even when suspected; reserve macrolide/doxycycline for atypical pneumonia.

Special Populations — Elderly and Renal/Hepatic Impairment

— Atypical presentation: minimal fever, anorexia, weakness, delirium, falls; cough may be muted

— Lower threshold for chest x-ray even with normal vitals — sensitivity of physical exam drops

— Higher prevalence of CAP, HF exacerbation, aspiration pneumonitis, and influenza masquerading as "bronchitis"

— Verify pneumococcal (PCV20 or PCV15+PPSV23), influenza annually, RSV (≥60 with shared decision-making, ≥75 universally per 2024 ACIP), Tdap, COVID-19 vaccination status at every encounter

— Oseltamivir: reduce dose with CrCl <60; significant adjustment <30

— Amoxicillin, amoxicillin-clavulanate: dose-adjust at CrCl <30

— Levofloxacin: adjust at CrCl <50

— TMP-SMX: avoid or dose-reduce when CrCl <30; monitor K⁺

— NSAIDs (ibuprofen): avoid in CKD stage ≥3, volume depletion, concurrent ACEi/ARB+diuretic ("triple whammy" AKI)

— Acetaminophen: cap at 2 g/day in cirrhosis; avoid in active alcohol use

— Azithromycin, macrolides: caution with cholestatic hepatitis; QT prolongation

— Nirmatrelvir-ritonavir: contraindicated in Child-Pugh C; avoid with statins, amiodarone, many immunosuppressants

Board pearl: In a frail 82-year-old with new confusion and cough, "acute bronchitis" should rarely be the final answer — order CXR, CBC, BMP, UA, pulse oximetry, and assess for delirium etiologies.

Step 3 management: Use every acute respiratory visit in older adults as a vaccination opportunity — a high-yield ambulatory care theme.

Older adults (≥65, especially ≥75):

Renal impairment dosing pearls:

Hepatic impairment:

Polypharmacy/QT risk: Combining macrolides or fluoroquinolones with QT-prolonging drugs (ondansetron, methadone, antipsychotics, SSRIs) — check ECG and review interactions.

Special Populations — Pregnancy, Pediatrics, and Immunocompromise

— Acute bronchitis is still viral and antibiotics are still not indicated for uncomplicated disease

— Influenza in pregnancy is high-risk (ICU, mortality): give oseltamivir empirically if suspected, regardless of trimester or symptom duration

— Tdap in every pregnancy at 27–36 weeks to passively protect the newborn from pertussis — a high-yield prevention answer

— RSV maternal vaccine (Abrysvo) at 32–36 weeks during RSV season

— Avoid: NSAIDs after 20 weeks (oligohydramnios, premature ductus closure), codeine (neonatal sedation if near term), doxycycline and fluoroquinolones

— Safe symptomatic options: acetaminophen, dextromethorphan, guaifenesin, honey, saline rinses

— Most childhood "acute bronchitis" is viral; antibiotics not indicated

— OTC cough/cold medications are not recommended in children <4 years (FDA); honey ≥1 year is the AAP-endorsed option

— Codeine and hydrocodone contraindicated <12 years

— Distinguish bronchiolitis (<2 years, RSV, wheeze, retractions) — supportive care only; no routine albuterol, no steroids, no antibiotics

— Pertussis in infants can present with apnea without cough — high mortality, hospitalize

— Lower threshold for chest imaging and microbiologic workup

— Broader differential: PCP, CMV, aspergillus, TB, atypical mycobacteria

— Coordinate with the patient's specialty team before starting any antibiotic that interacts with immunosuppressants (azithromycin, fluoroquinolones, nirmatrelvir-ritonavir)

Board pearl: Tdap at 27–36 weeks of every pregnancy is the single most testable pertussis-prevention fact on Step 3.

Key distinction: Bronchiolitis (infant, wheeze, RSV) ≠ acute bronchitis (adult/older child, large airway cough) — management differs but both avoid antibiotics.

Pregnancy:

Pediatrics:

Immunocompromised (transplant, chemotherapy, HIV with CD4 <200, biologics):

Complications and Adverse Outcomes

— Post-bronchitic cough (transient bronchial hyperreactivity) — cough lingers 3–8 weeks; reassure, consider short-acting bronchodilator if wheezing

— Secondary bacterial pneumonia — suspect with biphasic illness: improvement then new fever, focal exam, increased work of breathing

— Sinusitis or otitis media as part of the viral syndrome

— Asthma exacerbation in undiagnosed asthmatics — viral URIs are the #1 trigger

— COPD exacerbation in patients with underlying disease

— Rib fracture or musculoskeletal chest pain from forceful cough (especially elderly, osteoporotic, chronic steroid users)

— Cough syncope, urinary incontinence, hemoptysis (usually minor, from mucosal disruption)

— C. difficile colitis — risk highest with fluoroquinolones, clindamycin, broad β-lactams

— Anaphylaxis and Stevens-Johnson syndrome (sulfas, β-lactams)

— QT prolongation and torsades (azithromycin, fluoroquinolones, especially with other QT-prolonging drugs)

— Tendinopathy and aortic dissection (fluoroquinolones — FDA boxed warnings; avoid in elderly, those on steroids, aortic aneurysm)

— Peripheral neuropathy, dysglycemia (fluoroquinolones)

— Drug interactions (azithromycin–warfarin, macrolides–statins → rhabdomyolysis)

— Selection for antimicrobial resistance at population level

— Cost, AE-related ER visits, and patient expectation reinforcement for future visits

— Untreated pertussis spreading to infants; missed PE, HF, lung cancer, TB

Board pearl: The number needed to harm with antibiotics for acute bronchitis (rash, GI upset, candidiasis) is roughly 1 in 5 — better than the number needed to benefit.

Step 3 management: Always document return precautions: high fever, dyspnea, hemoptysis, persistent fever >3 days, or worsening after initial improvement → return for reassessment.

Of the illness itself (uncommon in healthy adults):

Of inappropriate antibiotic prescribing — the real Step 3 morbidity:

Of missed alternative diagnoses:

When to Escalate Care — Triage, Consult, Admission

— Hypoxemia (SpO₂ <92% on RA, or <88% in known COPD)

— Respiratory distress: RR >24, accessory muscle use, inability to speak full sentences

— Hemodynamic instability: HR >120, SBP <90, signs of shock

— Altered mental status, severe dehydration, intractable vomiting (can't tolerate PO meds)

— Suspected PE, HF, MI, or pneumothorax uncovered during workup

— Hemoptysis more than blood-streaked sputum

— CURB-65 ≥2 or PSI Class IV–V if pneumonia identified

— Failure of outpatient therapy at 48–72 h or clinical deterioration

— Inability to care for self at home / unsafe discharge environment

— Pulmonology: cough >8 weeks unexplained, suspected asthma/COPD, abnormal spirometry, recurrent bronchitis (≥3/year), abnormal imaging

— ENT: suspected upper airway cough syndrome refractory to empiric therapy, chronic sinusitis

— Gastroenterology: suspected GERD-related cough refractory to PPI trial

— Infectious disease: suspected TB, atypical mycobacteria, immunocompromise with unexplained cough

— Cardiology: cough with orthopnea/PND/edema → HF workup

CCS pearl: In a CCS case, deterioration on day 3 with new hypoxemia → admit, obtain CXR, ABG, blood cultures, start empiric CAP therapy (ceftriaxone + azithromycin or respiratory fluoroquinolone), and update the patient/family. Don't "continue current management."

Board pearl: Smoker >40 with persistent localized infiltrate or non-resolving "bronchitis" after antibiotics → CT chest to evaluate for post-obstructive pneumonia from bronchogenic carcinoma.

Step 3 management: Set an explicit 48–72 h follow-up for any borderline patient discharged from clinic; document the safety net.

Send to ED / consider admission when:

Specialist referral indications:

Public health notification: Pertussis (reportable), TB (reportable), measles, novel respiratory pathogens.

Key Differentials — Same-Category (Respiratory) Causes

— Focal crackles, fever >38°C, tachycardia, hypoxemia, infiltrate on imaging

— Requires antibiotics; outpatient management with amoxicillin or doxycycline if healthy and no comorbidities

— Abrupt onset of fever, myalgias, headache, prostration; cough often dry

— Oseltamivir within 48 h of symptom onset; vaccinate annually

— Cough, fever, anosmia/ageusia, dyspnea; check pulse oximetry (silent hypoxia)

— Nirmatrelvir-ritonavir for high-risk outpatients within 5 days

— Paroxysmal cough, post-tussive emesis, inspiratory whoop, >2 weeks duration

— Azithromycin + isolation + public health report + contact prophylaxis

— Known COPD, increased dyspnea + sputum volume + sputum purulence (Anthonisen)

— Short-acting bronchodilators, systemic steroids 5 days, antibiotics if ≥2 cardinal symptoms

— Wheeze, nocturnal cough, allergic history, response to bronchodilator; spirometry confirms

— Inhaled SABA + ICS; oral steroids if moderate-severe

Key distinction: "Cough + fever + focal exam/infiltrate" = pneumonia. "Cough + diffuse normal exam + normal vitals" = bronchitis.

Board pearl: Always reassess the diagnosis when antibiotic-treated "bronchitis" fails — the diagnosis was likely wrong, not the antibiotic.

Community-acquired pneumonia:

Influenza:

COVID-19:

Pertussis:

Acute exacerbation of COPD:

Asthma exacerbation / cough-variant asthma:

Bronchiolitis (pediatric, <2 y): RSV, wheeze, retractions — supportive care, no antibiotics, no routine bronchodilators or steroids

Aspiration pneumonitis/pneumonia: Witnessed event, dependent lobe infiltrate, dysphagia/stroke risk factors

Tuberculosis: Risk factors, weight loss, night sweats, hemoptysis, upper lobe cavitation; AFB smear + NAAT + culture; isolation

Pulmonary embolism: Pleuritic pain, tachycardia, hypoxemia, unilateral leg swelling, risk factors — Wells score, D-dimer, CT-PA

Lung cancer: Cough >8 weeks in smoker, hemoptysis, weight loss — CT chest; assess LDCT screening eligibility (age 50–80, ≥20 pack-year, current or quit <15 y)

Key Differentials — Non-Respiratory and Systemic Mimics

— Orthopnea, PND, peripheral edema, S3, JVD, bibasilar crackles

— BNP, CXR (cephalization, Kerley B lines, effusions), echo; treat with diuretics and guideline-directed therapy

— Postprandial cough, nocturnal symptoms, hoarseness, retrosternal burning

— Empiric PPI trial × 8 weeks, lifestyle modification; manometry/pH study if refractory

— "Tickling" sensation, throat clearing, cobblestone posterior pharynx

— First-generation antihistamine-decongestant trial (older patients: caution with anticholinergic burden, BPH, glaucoma); intranasal steroid for allergic component

— Dry, persistent cough; onset days–months after initiation; 5–20% of users

— Resolves with discontinuation in 1–4 weeks; switch to ARB

— Intranasal steroid, saline irrigation, allergen avoidance

— Sudden choking event, focal wheeze or atelectasis, especially in children/elderly with dysphagia

— Absent during sleep, present only when awake; diagnosis of exclusion

— Vaping history, bilateral infiltrates, GI symptoms; diagnosis of exclusion; supportive care ± steroids

— Atypical features (hemoptysis, sinus disease, renal involvement, eosinophilia) → escalate workup

Step 3 management: A patient on lisinopril, hydrochlorothiazide, and atorvastatin presenting with 6 weeks of dry cough → stop the lisinopril, switch to losartan, follow up in 4 weeks.

Board pearl: Chronic cough in non-smoking, non–ACEi-using adults: the "big three" — upper airway cough syndrome, asthma, GERD — account for >90% of cases.

Heart failure (cough as presenting symptom):

GERD-related cough:

Upper airway cough syndrome (postnasal drip):

ACE-inhibitor cough:

Postnasal drip from chronic rhinosinusitis or allergic rhinitis:

Foreign body aspiration:

Psychogenic/habit cough:

EVALI (e-cigarette/vaping-associated lung injury):

Eosinophilic bronchitis, sarcoidosis, vasculitis (GPA, EGPA):

Anxiety/somatic cough, anticholinergic-induced dry airways — consider after ruling out organic causes

Secondary Prevention / Discharge Plan / Counseling

— Influenza: annually for all ≥6 months

— COVID-19: per current ACIP guidance

— Pneumococcal: PCV20 alone, or PCV15 + PPSV23, for all adults ≥65 and younger adults with risk factors (chronic heart/lung/liver disease, DM, smoking, immunocompromise, CSF leak/cochlear implant)

— Tdap: every 10 years; once during weeks 27–36 of every pregnancy

— RSV: ≥75 universally; 60–74 with risk factors (per 2024 ACIP); maternal vaccine 32–36 weeks

— Use 5As: Ask, Advise, Assess, Assist, Arrange

— Combine behavioral counseling + pharmacotherapy (varenicline first-line, or nicotine replacement combination, or bupropion); reassess at 2–4 weeks

— Counsel on e-cigarettes/vaping — not endorsed as a cessation tool

— "Antibiotics don't kill viruses, and your cough is from a virus."

— "Sputum color doesn't tell us bacteria are there."

— "Most coughs last 2–3 weeks even with the best treatment."

— Document the counseling in the chart — relevant to HEDIS AAB quality measure

Board pearl: The most heavily tested vaccine teaching points on Step 3 ambulatory blocks: Tdap in every pregnancy, annual influenza, pneumococcal for ≥65, RSV for ≥75.

Step 3 management: End every acute respiratory visit with: vaccination review, smoking cessation if applicable, written return precautions, and explicit follow-up timing.

Vaccination — the highest-yield prevention bundle (review at every visit):

Smoking cessation — the single most impactful intervention:

Environmental: Avoid secondhand smoke, wood smoke, occupational dust/fumes; consider home air quality

Hand hygiene, masking when ill, staying home from work/school — patient education on reducing transmission

Asthma/COPD optimization for patients with underlying lung disease (controller therapy, inhaler technique check, action plan)

Antibiotic stewardship counseling — the conversation:

Lung cancer screening eligibility check in smokers/former smokers age 50–80 with ≥20 pack-years

Follow-Up, Monitoring, and Counseling Cadence

— As-needed return if no improvement in 1 week, worsening symptoms, new fever after initial improvement, hemoptysis, dyspnea, or chest pain

— Telephone or portal check-in at 5–7 days for higher-risk or anxious patients

— Cough persisting >3 weeks → in-person reassessment; consider pertussis testing, spirometry, CXR

— Cough >8 weeks → formal chronic cough workup

— Smoker >40 with any abnormal imaging → repeat imaging at 6–8 weeks to ensure resolution; CT chest if not resolved

— Pertussis-confirmed patient → public health follow-up for contact tracing and prophylaxis

— Influenza/COVID treated outpatient → reassess if not improving by day 5

— Expected illness duration (median ~3 weeks of cough)

— Why antibiotics weren't prescribed

— Specific return precautions: fever >38.5°C lasting >3 days, RR >24, SpO₂ drop (if home pulse oximeter), chest pain, hemoptysis, confusion, dyspnea

— Smoking cessation discussion if applicable

— HEDIS AAB measure tracks % of acute bronchitis visits without antibiotic dispensing within 3 days

— Document the diagnosis precisely — "acute bronchitis" vs "URI" vs "acute sinusitis" — to avoid measure misattribution

— Most patients return to work when fever-free for 24 h and able to control cough; healthcare workers with confirmed influenza or pertussis follow occupational health protocols

Board pearl: A patient who calls on day 10 still coughing but feeling gradually better with normal vitals needs reassurance, not antibiotics, not imaging.

CCS pearl: Schedule a defined follow-up event (clinic visit, telephone call) in the case orders — leaving a case open-ended costs efficiency points.

Routine follow-up for uncomplicated acute bronchitis:

Mandatory follow-up scenarios:

Counseling content (document):

Quality and value-based monitoring:

Rehabilitation/return-to-work:

Ethical, Legal, and Patient Safety Considerations

— Inappropriate prescribing is a system-level harm (resistance, C. difficile outbreaks) and an individual harm (AEs, anaphylaxis)

— The Joint Commission and CMS mandate antimicrobial stewardship programs in hospitals; ambulatory programs increasingly required

— Use shared decision-making: acknowledge concerns, explain natural history, offer delayed prescription as a compromise

— Document the discussion in the chart

— Patient satisfaction does not decrease when antibiotics are appropriately withheld if counseling is performed

— A patient who insists on antibiotics has the right to be informed of risks and benefits and to refuse alternative management — but the clinician is not obligated to prescribe non-indicated antibiotics. Document refusal of recommended management.

— Pertussis, tuberculosis, novel influenza strains, measles, COVID-19 (per state) — reportable to public health

— Healthcare workers with pertussis or influenza follow occupational restrictions

— Patient discharged from urgent care or ED with "acute bronchitis" diagnosis: ensure PCP follow-up plan, written return precautions, and medication reconciliation

— Avoid prescribing fluoroquinolones in the elderly on warfarin or steroids without a compelling indication (FDA boxed warnings: tendon rupture, aortic dissection, hypoglycemia, neuropathy, QT)

— Reconcile with the patient's outpatient medication list — drug-drug interactions are the most common post-discharge adverse event

— Avoid presuming antibiotic-seeking behavior based on demographics; the same evidence-based standard applies to every patient

— Ensure language-appropriate counseling materials; use professional interpreters

Board pearl: A clinician is never ethically required to prescribe a non-indicated antibiotic to satisfy a patient — but is required to counsel, document, and offer alternatives.

Step 3 management: When the vignette features a patient demanding "a Z-pak," the correct answer is education + delayed prescription or symptomatic care, not capitulation.

Antibiotic stewardship as a patient-safety issue:

Navigating patient pressure for antibiotics:

Informed consent / refusal edge cases:

Mandatory reporting:

Transition-of-care safety:

Equity and access:

High-Yield Associations and Rapid-Fire Clinical Facts

Board pearl: When the stem describes a healthy adult with 1 week of productive cough, normal vitals, and demands a "Z-pak" — the answer is patient education and symptomatic care, period.

Acute bronchitis is >90% viral — antibiotics offer ~½-day symptom benefit at the cost of harm

Median cough duration: ~18 days; up to 25% cough at 4 weeks — set expectations

Purulent sputum ≠ bacterial infection — color reflects neutrophils and sloughed epithelium

HEDIS AAB measure: ambulatory quality indicator tracking antibiotic avoidance in acute bronchitis

Heckerling criteria for ruling out pneumonia: absent HR >100, RR >24, T >38°C, and focal exam → CXR not needed

Pertussis: cough >2 weeks + paroxysms/whoop/post-tussive emesis → PCR + azithromycin + report

Tdap at 27–36 weeks of every pregnancy — protects newborn from pertussis

ACE-inhibitor cough in 5–20%; switch to ARB, resolves in 1–4 weeks

Honey ≥1 year for nocturnal cough — AAP-endorsed; never <1 year (botulism)

Codeine/hydrocodone cough syrups contraindicated <12 years and in breastfeeding — FDA

Dextromethorphan + SSRI/MAOI → serotonin syndrome risk

Benzonatate — never chew/suck; pediatric ingestion can be fatal

Oseltamivir within 48 h of influenza onset; empiric in pregnancy

Nirmatrelvir-ritonavir within 5 days for high-risk COVID-19; Child-Pugh C contraindication; many drug interactions

Albuterol helps only the wheezing subset of acute bronchitis patients

Procalcitonin <0.25 ng/mL supports withholding antibiotics in lower respiratory infections

Chronic bronchitis = productive cough ≥3 months/year × 2 consecutive years — COPD phenotype, not acute bronchitis

Big three causes of chronic cough: upper airway cough syndrome, asthma, GERD

Smoker >40 + non-resolving infiltrate → CT chest for malignancy

Lung cancer screening LDCT: age 50–80, ≥20 pack-years, current or quit <15 years

Fluoroquinolones: tendon rupture, aortic dissection, QT, neuropathy, hypoglycemia, C. diff — avoid for bronchitis

Board Question Stem Patterns

— Answer: Reassurance, symptomatic therapy, return precautions. Not azithromycin, not chest x-ray, not sputum culture.

— Answer: Nasopharyngeal PCR for pertussis, start azithromycin, report to public health, postexposure prophylaxis for household contacts.

— Answer: Chest x-ray → likely CAP → outpatient amoxicillin + macrolide or doxycycline (or respiratory fluoroquinolone if comorbidities), assess CURB-65.

— Answer: Discontinue lisinopril, switch to losartan, follow up in 4 weeks.

— Answer: Empiric oseltamivir regardless of testing; supportive care; verify Tdap planned at 27–36 weeks.

— Answer: No OTC cough/cold meds <4 years, honey >1 year, hydration, supportive care.

— Answer: Short-acting bronchodilators, systemic steroids × 5 days, antibiotic (azithromycin/doxycycline/amoxicillin-clavulanate × 5 days).

— Answer: CT chest for malignancy; assess LDCT eligibility going forward.

Board pearl: Look for the vital sign normality clause — if all vitals normal and exam non-focal, the answer is almost never "antibiotics" or "chest x-ray."

Step 3 management: The phrase "previously healthy" + classic bronchitis features = symptomatic management.

Pattern 1 — The "Z-pak demand": 32-year-old presents with 7 days of productive cough, T 37.4°C, HR 80, RR 14, SpO₂ 98%, scattered wheezes clearing with cough. Requests azithromycin because "it worked last time."

Pattern 2 — The pertussis whoop: Unvaccinated 22-year-old with 3 weeks of paroxysmal cough, post-tussive emesis, exposure to newborn niece.

Pattern 3 — The pneumonia pivot: 68-year-old with cough × 5 days, T 38.6°C, HR 108, RR 22, SpO₂ 93%, focal right-base crackles.

Pattern 4 — The ACE-inhibitor cough: 58-year-old on lisinopril × 3 months with dry cough × 6 weeks, normal CXR, normal exam.

Pattern 5 — The influenza window: 45-year-old pregnant patient (28 weeks) with abrupt fever, myalgias, cough × 36 hours during flu season.

Pattern 6 — The pediatric cough syrup trap: 3-year-old with cough × 4 days, parent asking for cough syrup.

Pattern 7 — The COPD exacerbation: Known COPD with increased dyspnea + sputum volume + purulence.

Pattern 8 — The lingering cough: 55-year-old smoker, "bronchitis treated 6 weeks ago," persistent cough and 10-lb weight loss.

One-Line Recap

Acute bronchitis is a self-limited, predominantly viral large-airway illness whose correct Step 3 management in immunocompetent adults is symptomatic therapy and patient education — not antibiotics — reserved exceptions being confirmed pertussis, influenza/COVID-19 within the antiviral window, COPD exacerbations meeting Anthonisen criteria, and pneumonia identified by abnormal vitals, focal exam, or imaging.

Board pearl: When in doubt on a Step 3 ambulatory respiratory vignette featuring a healthy adult with productive cough and normal vitals, the correct answer combines reassurance, symptomatic therapy, and vaccination/cessation counseling — and explicitly avoids antibiotics, advanced imaging, and microbiologic testing.

Default answer: Healthy adult + cough <3 weeks + normal vitals + non-focal exam → no antibiotics, no chest x-ray, no sputum culture — just symptomatic care, vaccination review, smoking cessation, and return precautions.

Exceptions that DO get treated: pertussis (azithromycin + report), influenza within 48 h (oseltamivir), high-risk COVID-19 within 5 days (nirmatrelvir-ritonavir), COPD exacerbation with ≥2 cardinal symptoms (antibiotic + 5-day steroid), and confirmed CAP (amoxicillin or doxycycline outpatient).

Highest-yield ambulatory prevention bundle: influenza annually, pneumococcal ≥65, Tdap at 27–36 weeks of every pregnancy, RSV ≥75, COVID-19 per ACIP, and smoking cessation with varenicline-first pharmacotherapy.

Quality and stewardship anchor: The HEDIS AAB measure rewards withholding antibiotics in acute bronchitis; document counseling, offer delayed prescription if needed, and use shared decision-making to manage patient expectations without yielding to non-indicated prescribing.