Typhus vs Typhoid fever
How to tell Typhus and Typhoid fever apart when a board question makes them look alike.
Typhus is arthropod-borne rickettsial vasculitis; typhoid is fecal-oral Salmonella Typhi systemic enteric fever.
Side by side
Typhus is rickettsial disease spread by lice, fleas, or chiggers with fever, severe headache, myalgias, rash, and epidemic/crowding or flea exposure clues.
Typhoid fever is systemic Salmonella Typhi infection from contaminated food/water with stepwise fever, abdominal pain, constipation or diarrhea, rose spots, hepatosplenomegaly, and possible chronic carriage.
Rickettsial organisms infect vascular endothelium, causing vasculitis and rash after arthropod exposure.
Salmonella Typhi invades intestinal lymphoid tissue and disseminates through macrophages and bacteremia, with gallbladder carriage possible.
Arthropod exposure, rash with headache/fever, thrombocytopenia or transaminitis, and response to doxycycline support typhus.
Travel or poor sanitation exposure, blood culture with Salmonella Typhi, relative bradycardia, rose spots, leukopenia, and intestinal complications support typhoid fever.
The trap
The names sound alike, but vectors and organism class separate them: lice/fleas/chiggers rickettsia versus contaminated food/water Salmonella.
The repair move
For typhus versus typhoid, ignore the similar names and map vector, organism, and GI pattern.
Try a free question
CoreA traveler develops sustained fever, abdominal pain, constipation, rose-colored trunk macules, hepatosplenomegaly, and blood cultures grow Salmonella Typhi. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Typhoid fever. Enteric fever with rose spots, GI symptoms, travel/sanitation exposure, and Salmonella Typhi bacteremia supports typhoid fever.
Why the other choices are tempting
- B. Typhus is arthropod-borne rickettsial vasculitis.
- C. RMSF is a tickborne rickettsial disease with wrists/ankles-to-palms/soles rash.
- D. Brucellosis causes undulant fever after unpasteurized dairy or animal exposure.
- E. Lyme disease is Ixodes-borne Borrelia disease.
Flashcards
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What organism group causes typhus?
Rickettsial organisms cause typhus fevers.
What vectors spread typhus?
Lice, fleas, or chiggers can spread typhus depending on the syndrome.
Quick answers
What is the fastest way to tell Typhus from Typhoid fever?
Typhus is arthropod-borne rickettsial vasculitis; typhoid is fecal-oral Salmonella Typhi systemic enteric fever.
What is the key clue for Typhus?
Typhus is rickettsial disease spread by lice, fleas, or chiggers with fever, severe headache, myalgias, rash, and epidemic/crowding or flea exposure clues.
What is the key clue for Typhoid fever?
Typhoid fever is systemic Salmonella Typhi infection from contaminated food/water with stepwise fever, abdominal pain, constipation or diarrhea, rose spots, hepatosplenomegaly, and possible chronic carriage.
What is the common trap with Typhus vs Typhoid fever?
The names sound alike, but vectors and organism class separate them: lice/fleas/chiggers rickettsia versus contaminated food/water Salmonella.