Pneumonia & tuberculosis flashcards
26 high-yield MRCP Part 1 cards from the Intellect Medicos Infectious Diseases course. Try to answer each question before you open it — then study them properly with spaced repetition, which brings each card back just before you would forget it.
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What is the commonest cause of community-acquired pneumonia in the UK?
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Streptococcus pneumoniae.
Why? Classically sudden fever, pleuritic pain, rust-coloured sputum and lobar consolidation; cold sores (HSV reactivation) may appear.
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Which organism classically causes a severe, cavitating pneumonia shortly after influenza?
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Staphylococcus aureus.
Why? Flu damages the airway lining. Panton–Valentine leucocidin (PVL)-producing strains cause necrotising pneumonia with high mortality.
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Which organism causes pneumonia with "currant jelly" sputum in alcohol-dependent or diabetic patients?
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Klebsiella pneumoniae.
Why? It is linked to aspiration and often forms upper-lobe cavities.
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What is the most important organism in ventilator-associated pneumonia?
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Pseudomonas aeruginosa.
Why? VAP (≥48 h after intubation) is dominated by resistant Gram-negatives and MRSA, so empirical cover must include anti-pseudomonal agents.
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What does each letter of CURB-65 stand for?
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Confusion; Urea >7 mmol/L; Respiratory rate ≥30/min; BP systolic <90 or diastolic ≤60 mmHg; age ≥65.
Why? One point each. 0–1 low risk, 2 intermediate, 3–5 high risk of death. NICE NG250 (2025) says clinical judgement takes precedence over the score.
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What is the first-line antibiotic for low-severity community-acquired pneumonia in adults (NICE 2025), and for how long?
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Oral amoxicillin for 5 days.
Why? Low-severity CAP is mostly pneumococcal. NICE recommends stopping after 5 days unless cultures suggest otherwise or the patient is not stable.
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What is the first-line antibiotic regimen for high-severity community-acquired pneumonia (NICE)?
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Co-amoxiclav plus clarithromycin (erythromycin in pregnancy) for 5 days.
Why? The macrolide covers atypical organisms, including Legionella; give within 4 hours of presentation.
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Which adjunct treatment does NICE now suggest for adults with high-severity CAP, and which drug is preferred?
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Corticosteroids for 4–7 days (or until discharge); IV hydrocortisone is the preferred option.
Why? Steroids damp the excessive inflammatory response in severe pneumonia.
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What is the first-line antibiotic for non-severe hospital-acquired pneumonia in a patient not at higher risk of resistance?
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Oral co-amoxiclav.
Why? Early-onset HAP is caused by community-type organisms. Severe HAP or higher risk of resistance (e.g. onset >5 days after admission) needs IV cover such as piperacillin–tazobactam; add vancomycin or teicoplanin if MRSA is suspected (linezolid only if vancomycin cannot be used).
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What is the first-line diagnostic test for suspected Legionella pneumonia?
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Legionella urinary antigen test.
Why? It gives a rapid result; culture of respiratory samples on special media is also sent.
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A 50-year-old returns from a hotel holiday with fever, dry cough, diarrhoea and confusion. Na⁺ is 126 mmol/L and ALT is raised. He has not improved on amoxicillin. What is the first-line treatment?
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A macrolide (clarithromycin or azithromycin); alternative doxycycline or levofloxacin.
Why? Legionella is intracellular and does not respond to penicillins. It is caught from contaminated water aerosols (air-conditioning, hot tubs), not person to person.
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Which antibody causes haemolysis in Mycoplasma pneumoniae infection?
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Cold agglutinins (IgM).
Why? Mycoplasma triggers cold IgM autoantibodies against red cells.
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Which atypical pneumonia follows exposure to parrots or pigeons?
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Chlamydia psittaci (psittacosis).
Why? Classic clues are bird contact, severe headache and sometimes hepatosplenomegaly.
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How is Pneumocystis jirovecii pneumonia (PCP) confirmed?
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By detecting Pneumocystis (immunofluorescence, histochemical e.g. silver stain, or PCR) in induced sputum or bronchoalveolar lavage; bronchoscopy with BAL if induced sputum is negative.
Why? CXR may be normal early (do HRCT if suspicion is high); serum beta-D-glucan and LDH are supportive but not specific. A positive PCR without respiratory symptoms should not by itself trigger treatment.
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What is the first-line treatment for Pneumocystis jirovecii pneumonia?
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High-dose co-trimoxazole for 21 days.
Why? Alternatives: IV pentamidine (nebulised pentamidine is not used for treatment), or clindamycin plus primaquine (check G6PD); atovaquone for mild disease.
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In PCP, at what PaO₂ should corticosteroids be added to antimicrobial treatment?
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PaO₂ <9.3 kPa on air (or SpO₂ ≤92% at rest, or falling by ≥3% on exercise) — i.e. moderate to severe disease.
Why? Give within 72 hours of starting anti-Pneumocystis treatment: killing the organisms causes a burst of lung inflammation, and steroids reduce respiratory failure and death.
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What is the first-line investigation for suspected pulmonary TB, and which test confirms it?
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First-line: chest X-ray. Confirmation: three sputum samples (one early morning) for acid-fast bacilli smear and mycobacterial culture.
Why? Culture remains the gold standard and gives drug sensitivities but takes weeks. NICE NG33 also recommends a rapid NAAT when the person has HIV, when a rapid result would change management, or when a large contact-tracing exercise is being considered.
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Why can a Mantoux test be falsely positive while an IGRA is not?
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Previous BCG vaccination causes a positive Mantoux; IGRAs use antigens absent from BCG.
Why? This is why IGRA is used when Mantoux is positive or unreliable.
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What is the standard regimen for drug-sensitive pulmonary TB?
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2 months of rifampicin, isoniazid, pyrazinamide and ethambutol, then 4 months of rifampicin and isoniazid (6 months total).
Why? The 4-drug phase kills the bulk of bacteria and prevents resistance; the continuation phase sterilises.
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How long is TB treated when the CNS is involved (e.g. TB meningitis), and what is added?
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12 months (2 months RIPE, then 10 months RI) plus an adjunctive corticosteroid (dexamethasone or prednisolone) at the start.
Why? Steroids reduce inflammation-related complications such as hydrocephalus and vasculitic infarcts.
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What are the NICE treatment options for latent TB infection?
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3 months of isoniazid + rifampicin, or 6 months of isoniazid alone — each with pyridoxine.
Why? Treating latent infection prevents later reactivation. Pyridoxine prevents isoniazid neuropathy.
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Which anti-TB drug causes peripheral neuropathy, and how is it prevented?
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Isoniazid; give pyridoxine (vitamin B6).
Why? Isoniazid depletes pyridoxine. Risk is higher in slow acetylators, diabetes, alcohol excess, HIV and malnutrition.
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Which anti-TB drug causes optic neuritis, and what should be checked before starting it?
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Ethambutol; check visual acuity and colour vision (and renal function).
Why? Red–green colour vision loss is often the first sign; stop the drug if vision changes.
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Why must a woman on the combined pill be warned when she starts rifampicin?
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Rifampicin is a strong liver enzyme (CYP450) inducer and makes hormonal contraception unreliable.
Why? It speeds the metabolism of many drugs (e.g. COCP, warfarin, steroids, many antiretrovirals). It also turns urine and tears orange-red.
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Which first-line TB drug commonly causes hyperuricaemia and gout?
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Pyrazinamide.
Why? It reduces renal urate excretion. It is also hepatotoxic (as are isoniazid and rifampicin).
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What is the classic chest X-ray appearance of miliary TB?
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Numerous tiny (1–3 mm) "millet seed" nodules spread evenly through both lungs.
Why? Miliary TB is haematogenous spread; it can also cause pancytopenia from marrow infiltration.
More Infectious Diseases topics
- Microbiology & antimicrobials
- Skin, soft tissue & Gram-positive infections
- Meningitis & encephalitis
- Gastrointestinal infections
- Viral infections & hepatitis
- HIV & opportunistic infections
- Zoonoses & rickettsial infections
- Malaria & tropical infections
- Worms & helminths
- Sexually transmitted infections
- Vaccines, PEP & asplenia