Microbiology · Year 2 · from Microbiology
Case 2: Typhoid Fever
Presentation
A 32-year-old man presents with 2 weeks of progressively worsening fever, headache, and abdominal discomfort. He returned from a trip to South Asia 3 weeks ago. The fever has been rising in a stepwise pattern over the past week, now reaching 40°C. He reports constipation rather than diarrhea, and significant fatigue. Physical examination reveals a toxic-appearing patient with relative bradycardia (pulse 80 bpm despite high fever), hepatosplenomegaly, and faint salmon-colored maculopapular lesions on the trunk.
Clinical Image
Rose spots - faint salmon-colored maculopapular lesions on the trunk representing bacterial emboli in the skin, characteristic of typhoid fever.
Image Source: Lecture image - typhoid fever clinical findings
Questions
- What is the most likely diagnosis based on the clinical presentation?
- What is the most sensitive diagnostic test during the first week of illness?
- What complications may develop if this condition is left untreated?
- What is the appropriate antibiotic treatment, and what resistance patterns should be considered?
Answers
- Most likely diagnosis: This presentation is classic for typhoid fever caused by Salmonella typhi. Key features include the stepwise rising fever, relative bradycardia (pulse-temperature dissociation), hepatosplenomegaly, rose spots on the trunk, and travel to an endemic region. The incubation period of 1-3 weeks and constitutional symptoms with abdominal discomfort (often constipation rather than diarrhea early in disease) are characteristic.
- Most sensitive diagnostic test: Blood culture is most sensitive during the first week of illness, when bacteremia is most prominent. However, bone marrow culture has the highest overall sensitivity (>90%) and remains positive even after antibiotic initiation. Stool cultures become positive in the second and third weeks. The Widal test (serologic) has limited sensitivity and specificity and is not recommended for diagnosis in endemic areas.
- Untreated complications: Without treatment, complications develop during the third week and include intestinal hemorrhage and perforation from necrosis of Peyer's patches in the terminal ileum. These are surgical emergencies with high mortality. Other complications include myocarditis, meningitis, osteomyelitis, and chronic carriage (colonization of the gallbladder leading to fecal shedding for more than one year).
- Treatment and resistance: First-line treatment options include fluoroquinolones (such as ciprofloxacin), third-generation cephalosporins (ceftriaxone), and azithromycin. However, increasing fluoroquinolone resistance, particularly in South Asia, is a major concern. Susceptibility testing should guide therapy. Treatment duration is typically 10-14 days. Chronic carriers may require prolonged antibiotic courses or cholecystectomy.