What is the initial workup and treatment for a suspected typhoid case?

Workup of a Suspected Typhoid Case

Blood cultures are the most critical diagnostic test for typhoid fever, with up to 80% sensitivity in the first week of illness, and should be obtained from any patient with suspected typhoid. 1

Initial Clinical Assessment

• Key symptoms to evaluate:

  • Fever (almost invariable in typhoid)
  • Headache
  • Constipation or diarrhea
  • Dry cough
  • Meningism (may be present)
  • Duration of symptoms (complications more likely if >2 weeks)

• Important travel history:

  • Recent travel to endemic areas (South Central Asia, Southeast Asia)
  • Consumption of potentially contaminated food or water
  • Contact with known typhoid carriers

Diagnostic Workup Algorithm

Step 1: Rule out malaria

• Malaria must be excluded first in any febrile traveler from endemic regions 2
• Perform blood smear or rapid diagnostic test for malaria

Step 2: Blood cultures

• Collect blood cultures immediately (highest yield within first week of illness)
• Sensitivity: 40-80% in first week 2
• Multiple sets may increase yield

Step 3: Additional cultures

• Stool cultures (become positive after first week, sensitivity 35-65%)
• Urine cultures (become positive after first week, sensitivity 0-58%)
• Bone marrow cultures if diagnosis uncertain (higher sensitivity than blood)

Step 4: Laboratory tests

• Complete blood count (may be normal or show any pattern of abnormality)
• Liver function tests (may show various patterns of abnormality)
• Renal function tests

Step 5: Antibiotic sensitivity testing

• Critical for guiding therapy
• Test for nalidixic acid resistance (indicates potential fluoroquinolone resistance)
• Note: Ciprofloxacin disc testing alone is unreliable for determining sensitivity 2

Treatment Approach

First-line treatment:

• Ceftriaxone 2g IV once daily for 7-14 days for adults 1
• For children: 50-75 mg/kg/day IV in divided doses 3, 4

Alternative treatments based on sensitivity:

1. Azithromycin (preferred for uncomplicated cases, children, and pregnant women)

   • 20 mg/kg/day for 7 days 1

2. Ciprofloxacin (if organism is sensitive)

   • 500 mg PO twice daily for 10 days 5
   • Not recommended for cases from South Asia due to high resistance rates 6

Treatment selection based on resistance patterns:

• Fully sensitive strains: Azithromycin (preferred) or fluoroquinolones
• Multidrug-resistant strains: Ceftriaxone or azithromycin
• Quinolone-resistant strains: Azithromycin or ceftriaxone 1

Monitoring and Follow-up

• Monitor for clinical response (defervescence typically occurs within 4-8 days)

• Watch for complications (10-15% of cases), including:

  • Gastrointestinal bleeding
  • Intestinal perforation
  • Typhoid encephalopathy

• Consider changing antibiotics if no improvement within 2 days 1

• Follow-up testing not routinely needed after symptom resolution except for:

  • Food handlers
  • Healthcare workers
  • Childcare providers

Important Considerations

• Vaccination history: Previous typhoid vaccination does not exclude diagnosis (incomplete protection) 2
• Widal test: Not recommended due to poor sensitivity and specificity 2
• Newer rapid serological tests: Have shown mixed results, not reliable enough for definitive diagnosis 2
• Antibiotic resistance: Over 70% of S. typhi isolates imported to the UK are resistant to fluoroquinolones 2
• Duration of therapy: Flexible duration based on clinical response may be appropriate (continue for 5 days after defervescence) 3

Prevention for Contacts

• Evaluate household contacts for asymptomatic carriage 1
• Consider selective vaccination for close contacts of documented carriers 2
• Emphasize proper hand hygiene, especially after toilet use and before food preparation 1