Cough and chest infection in OPD
Count the breathing rate, check SpO₂, use CRB-65. Most acute coughs are viral. A cough over 2 weeks needs a TB test.
Two patients in a row.
First: a 38-year-old man has had a cough for 6 days with yellow sputum and a mild fever. RR 18, SpO₂ 98%, chest clear. He asks for "a strong antibiotic, like last time".
Second: a 45-year-old woman has had a cough for 5 weeks, with evening fevers, night sweats and 4 kg weight loss. Her brother had TB last year.
Who needs an antibiotic, and who needs a TB test today?
- Look for pneumoniaFever, fast breathing, low SpO₂, focal crackles. Count RR for 30 seconds. Use CRB-65.
- Cough for 2 weeks or moreSputum GeneXpert for TB, especially with weight loss, night sweats, fever or contact.
- Most acute coughs are viralNo antibiotic. They last about 3 weeks.
- Antibiotic if pneumonia or high riskAmoxicillin first. Doxycycline or clarithromycin if allergic.
- Red flagsHaemoptysis, weight loss, smoker over 40: chest X-ray.
- Symptom careHoney (over 1 year), warm drinks, paracetamol, stop smoking.
- Safety-netReturn if breathless, chest pain, confusion, or not better in 3 weeks.
- SpO₂ below 94%
- RR 30 or more
- New confusion
- Low BP
- Haemoptysis
- Very unwell, pregnant or immunosuppressed
- Pneumonia
- Tuberculosis
- Lung cancer in an older smoker
- Heart failure
- Pulmonary embolism
- Asthma or COPD
- Pertussis
- Foreign body (children)
| CRB-65 0 | Low risk, usually home |
| CRB-65 1–2 | Consider hospital assessment |
| CRB-65 3–4 | Urgent admission |
| SpO₂ | Below 94% (88% in COPD) needs hospital whatever the score |
| Amoxicillin | 500 mg 3 times daily for 5 days (1 g if more severe) |
| Doxycycline | 200 mg on day 1, then 100 mg daily, 5 days in total |
| Clarithromycin | 500 mg twice daily for 5 days |
| TB testing | Cough 2 weeks or more: sputum GeneXpert (free through the national TB programme) |
Check every dose against a current drug reference and your hospital protocol.
On this page
Why it matters
Most acute coughs are viral and last about 3 weeks. Antibiotics don't shorten them, cause side effects and drive resistance, which is already very high in Pakistan. Your job is to pick out the few who need more: pneumonia, TB, cancer, heart failure, PE.
History
- How long? Under 3 weeks (acute), 3–8 weeks (subacute), over 8 weeks (chronic).
- Sputum (colour alone doesn't mean bacteria), fever, breathlessness, chest pain, haemoptysis.
- TB features: weight loss, night sweats, evening fever, poor appetite, TB contact, previous TB.
- Smoking (cigarettes, huqqa, sheesha), occupation, dust.
- Asthma, COPD, heart failure, diabetes, HIV, immunosuppression.
- ACE inhibitors (dry cough), reflux, post-nasal drip.
- Children: paroxysms, whoop, vomiting after coughing (pertussis); sudden onset (foreign body).
Examination
- RR counted for 30 seconds, SpO₂, pulse, BP, temperature, confusion.
- Chest: focal crackles, bronchial breathing, dullness (consolidation or effusion), wheeze.
- Weight, lymph nodes, clubbing.
- Heart failure signs: raised JVP, oedema, bibasal crackles.
Viral, pneumonia, TB or something else?
- Viral bronchitis
- Advice, no antibiotic
- Pneumonia
- CRB-65, amoxicillin or admit
- Tuberculosis
- Sputum GeneXpert, chest X-ray
- Lung cancer
- Chest X-ray urgently
- Asthma or COPD
- Inhalers, steroid if flare
CRB-65
| Feature | Point |
|---|---|
| Confusion (new) | 1 |
| Respiratory rate 30 or more | 1 |
| BP systolic below 90 or diastolic 60 or less | 1 |
| Age 65 or over | 1 |
CRB-65 doesn't include oxygen. Low SpO₂ needs hospital whatever the score. Social circumstances and frailty also matter.
Who gets an antibiotic?
- Well, not high riskNo antibiotic; self-care; return if worse.
- Higher risk (older, heart or lung disease, diabetes, immunosuppressed)Consider immediate or delayed antibiotic.
- Pneumonia or systemically very unwellAntibiotic now; CRB-65 to decide home or hospital.
Differential diagnosis
| Condition | Clues |
|---|---|
| Viral bronchitis | Cough, mild fever, no focal signs, improving slowly |
| Pneumonia | Fever, fast breathing, focal crackles, low SpO₂ |
| Tuberculosis | Cough 2 weeks or more, weight loss, night sweats, haemoptysis, contact |
| Asthma or COPD | Wheeze, previous episodes, smoker |
| Heart failure | Orthopnoea, oedema, bibasal crackles |
| Pulmonary embolism | Sudden breathlessness, pleuritic pain, risk factors |
| Lung cancer | Smoker over 40, haemoptysis, weight loss, persistent cough |
| Pertussis | Paroxysms, whoop, vomiting after coughing |
| ACE inhibitor cough | Dry cough, started after the drug |
| Post-nasal drip or reflux | Chronic, worse lying down |
TB in Pakistan
- Pakistan has one of the highest TB burdens in the world.
- Anyone with cough for 2 weeks or more should have sputum sent for GeneXpert (detects TB and rifampicin resistance).
- Especially with fever, night sweats, weight loss, haemoptysis, TB contact, diabetes or HIV.
- Diagnosis and treatment are free through the national TB programme. Refer to the local TB centre.
- Avoid fluoroquinolones (levofloxacin, moxifloxacin, ciprofloxacin) for chest infections where TB is possible: they partly treat TB and delay diagnosis.
Investigations
| Test | When |
|---|---|
| Usually none | Simple acute cough in a well person |
| Chest X-ray | Pneumonia, TB, cancer suspected, or not improving |
| Sputum GeneXpert (2 samples) | Cough 2 weeks or more |
| CBC, CRP | Unwell, or deciding on antibiotics |
| SpO₂ | Everyone with a chest infection |
Treatment
- Honey (over 1 year old), warm drinks, rest, fluids.
- Avoid codeine cough syrups: little benefit, dependence risk.
- Stop smoking: cigarettes, huqqa, sheesha.
Common mistakes
- Giving antibiotics for every yellow sputum.
- Not counting the respiratory rate.
- Missing low SpO₂ because CRB-65 was 0.
- Giving levofloxacin or moxifloxacin for a cough that could be TB.
- Not sending sputum for GeneXpert in a 3-week cough.
- Forgetting heart failure in an older breathless patient.
Follow-up
Come back if breathless, chest pain, coughing blood, confused, or the cough lasts more than 3 weeks. Recheck a chest X-ray at 6 weeks in smokers over 50 with pneumonia.
Frequently asked questions
Does a chest infection need antibiotics?
Most acute coughs and bronchitis are viral and don't need antibiotics. Pneumonia and high-risk patients do.
When should a cough be tested for TB?
In Pakistan, any cough lasting 2 weeks or more, especially with fever, night sweats, weight loss or haemoptysis, should be tested with sputum GeneXpert.
Which antibiotic is used for pneumonia at home?
Amoxicillin 500 mg three times daily for 5 days. Doxycycline or clarithromycin if allergic to penicillin.
How long does a viral cough last?
About 3 weeks. Antibiotics don't make it shorter.
Test yourself
Exam-style questions on this guide, from our two question banks. Choose an answer to see why each option is right or wrong.
1. A man has a 6-day cough with yellow sputum, normal observations and a clear chest. What is the best management?
Answer: Advice and no antibiotic. Acute bronchitis is usually viral; sputum colour doesn't mean bacteria.
- Ciprofloxacin: Not needed and resistance risk.
- Chest X-ray: Not needed.
- Inhaled steroid: Not needed.
- Amoxicillin for 10 days: Not needed.
2. A patient has had a cough for 5 weeks with weight loss and night sweats. Which test is most important?
Answer: Sputum GeneXpert. In Pakistan, cough for 2 weeks or more with these features needs TB testing.
- ASO titre: Not useful.
- Throat swab: Not useful.
- Spirometry: Not first.
- Allergy test: Not useful.
3. Which antibiotic is first choice for community-acquired pneumonia treated at home?
Answer: Amoxicillin. Amoxicillin 500 mg three times daily for 5 days; doxycycline or clarithromycin if allergic.
- Nitrofurantoin: Urinary only.
- Meropenem: Far too broad.
- Metronidazole: Wrong spectrum.
- Ciprofloxacin: Poor pneumococcal cover.
4. Which bacterium has no cell wall, so it is not affected by penicillins?
Answer: Mycoplasma pneumoniae. Mycoplasma lacks a cell wall (its membrane contains sterols), so it does not Gram stain and beta-lactams do not work. It causes atypical pneumonia in young adults, with cold agglutinins (IgM) that can cause haemolysis. Treat with macrolides or doxycycline.
- Streptococcus pneumoniae: Has a cell wall; penicillin works.
- Haemophilus influenzae: Has a cell wall.
- Klebsiella pneumoniae: Has a cell wall.
- Legionella pneumophila: Has a cell wall, though treated with macrolides as it is intracellular.
5. A young man with sore throat, fever, cervical lymphadenopathy and splenomegaly develops a widespread maculopapular rash after taking an antibiotic. Which antibiotic was given?
Answer: Amoxicillin. In infectious mononucleosis (EBV), aminopenicillins cause a maculopapular rash in most patients; it is not a true penicillin allergy. Avoid amoxicillin when glandular fever is suspected. Diagnose with heterophile antibody (Monospot) and atypical lymphocytes. Advise avoiding contact sports for several weeks (splenic rupture risk).
- Azithromycin: Not typical.
- Ciprofloxacin: Not typical.
- Doxycycline: Not typical.
- Clindamycin: Not typical.
References and dose sources
- NICE NG120 — Cough (acute): antimicrobial prescribing
- Amoxicillin dosing: Drugs.com: Amoxicillin dosage (see also our amoxicillin dose page)
- Doxycycline dosing: Drugs.com: Doxycycline dosage (see also our doxycycline dose page)
- Clarithromycin dosing: Drugs.com: Clarithromycin dosage (see also our clarithromycin dose page)
- Paracetamol dosing: Drugs.com: Acetaminophen (paracetamol) dosage (see also our paracetamol dose page)
International guidance is linked where it reflects good practice. Where your hospital’s protocol differs, follow your hospital.