Infectious Diseases
The infectious disease domain tests sepsis, pneumonia, urinary infection, sexually transmitted infections, HIV, tuberculosis, and vaccination, focusing on early treatment and appropriate diagnostic testing.
Core rules
- Sepsis is life-threatening organ dysfunction from infection. Obtain cultures, measure lactate, give broad-spectrum antibiotics, and provide fluids. In septic shock, antibiotics should be given within one hour.
- Community-acquired pneumonia: start empiric antibiotics based on severity and comorbidities; do not delay for sputum results in a sick patient.
- Gonorrhea and chlamydia: treat gonorrhea with ceftriaxone and chlamydia with doxycycline when coinfection is possible or not excluded. Test partners.
- HIV: start antiretroviral therapy for all patients regardless of CD4 count, after baseline resistance testing and screening for opportunistic infections.
Worked example
A 70-year-old has fever, hypotension, and a lactate of 4 mmol/L. This is septic shock until proven otherwise. Draw blood cultures, give broad-spectrum antibiotics immediately, and start isotonic fluids. Do not wait for imaging or culture results before treating.
Traps
- Delaying antibiotics in septic shock to obtain imaging.
- Missing tuberculosis in a patient with night sweats, weight loss, and apical infiltrates.
- Treating asymptomatic bacteriuria in older adults.
- Prescribing antibiotics for a viral upper respiratory infection.