Infectious Diseases
Core concepts
Build a systematic approach to fever: source, host factors (immunosuppression, devices, travel), and severity (sepsis criteria). Know the management of common infections - community-acquired pneumonia, urinary tract infection, meningitis, endocarditis, tuberculosis - and the principles of antimicrobial stewardship: culture before antibiotics when feasible, narrow based on sensitivities, and review duration. Understand HIV: testing, staging by CD4, opportunistic infection prophylaxis, and antiretroviral principles. Recognise tropical and travel-related infections.
Traps
Questions test empirical versus targeted therapy, and the timing of lumbar puncture in suspected meningitis (CT first if focal signs, seizures, or immunocompromise - but do not delay antibiotics). Distinguish culture-negative endocarditis (HACEK, Coxiella, Bartonella) from typical streptococcal disease. In TB, remember that a negative smear does not exclude disease. Do not treat asymptomatic bacteriuria except in pregnancy or before urological procedures.
Rule of thumb
In suspected bacterial meningitis, give dexamethasone with or before the first antibiotic dose, and do not delay antibiotics for imaging unless there are contraindications to immediate LP.
Worked example
A returning traveller with fever and thrombocytopenia after visiting a malaria-endemic area: send thick and thin films urgently and start treatment for severe malaria if there are danger signs, without waiting for confirmation.