Infectious Diseases: Sepsis, Meningitis, TB, HIV and Tropical Infection
Core concepts
Infectious diseases require a syndromic approach: sepsis, endocarditis, meningitis, pneumonia, urinary infection, tuberculosis, HIV, malaria and other travel-related infections. Obtain cultures before antibiotics when this does not delay treatment. Know common organisms, empiric regimens and infection-control precautions. Sepsis management includes early recognition, oxygen, fluids, cultures and broad-spectrum antibiotics within one hour for septic shock. TB requires airborne isolation, notification and adherence support. HIV care includes CD4 count, viral load, opportunistic infection prophylaxis and antiretroviral therapy.
Traps
Do not perform lumbar puncture before excluding raised intracranial pressure or coagulopathy. In bacterial meningitis, give dexamethasone with or before the first antibiotic. Blood cultures should be taken before antibiotics but must not delay them in sepsis. Malaria can present with nonspecific fever; repeated thick and thin films are needed. Beware of treating colonisation rather than infection, especially in urinary catheters and wounds.
Worked example / rule of thumb
A young adult has fever, neck stiffness and photophobia. Start empiric ceftriaxone plus vancomycin and dexamethasone immediately; arrange CT before LP only if focal signs, seizures or immunosuppression raise concern for raised intracranial pressure. Rule: in suspected bacterial meningitis, antibiotics and dexamethasone are not delayed for imaging or lumbar puncture.