Typhoid Fever

Epidemiology:

  • Median age: 24 y/o
  • Chronic carriers: median age >60 y/o/ M>F/ often have gallstones (S. Typhi lives in stones)
  • Peak areas: Mexico/ India/ Pakistan/ Egypt/ Indonesia/ Chile
  • Incidence in travelers is 1/10th that of HAV

Etiology

  • Salmonella Typhi
  • Salmonella Paratyphi A and B
  • Salmonella Typhimurium

Physiology

  • Acquired from contaminated food/water or by person-to-person transmission from a carrier
  • Incubation period: 10 days (range: 3-60 days)
  • Ingestion of organism that invades upper small bowel causing transient asymptomatic primary bacteremia (replication in mononuclear phagocytes)
  • Secondary bacteremia and invasion of gallbladder, Peyer’s patches of gut

Diagnosis

  • CBC:
    • Leukopenia (usually 4-5k with left shift)
    • Anemia (due to GI loss/ chronic disease)
  • Stool/ urine C/S:
    • Negative during first week, positive in 75% by third week (but in 10% by eighth week)
  • Blood c/s
    • 90% recovery during first week, 50% recovery during third week
  • Bone Marrow Bx: culture-posi-tive early in course
  • Serology (less reliable than culture)
  • Widal Test: positive

Clinical

(may be mild or severe)

Constitutional Manifestations

  • Fever/Chills: step-like daily increase in temperature (with prolonged course up to 8 weeks) with pulse-temperature dissociation
  • Malaise
  • Anorexia

Dermatologic Manifestations

  • Morbilliform Rash/Rose Spots (see Exanthems, [[Exanthems]]): blanching macules on chest/abdomen during first week

Gastroenterologic Manifestations

  • Mild Hepatosplenomegaly/Hepatitis
  • Constipation/Mild Diarrhea
  • Abdominal Pain
  • Necrotizing Cholecystitis
  • Intestinal Perforation
  • GI Bleeding

Pulmonary Manifestations

Neurologic Manifestations

  • Headache/Meningitis (see [[Meningitis]])

Other Manifestations

  • Nephritis
  • Myocarditis
  • Arthritis
  • Osteomyelitis (see Osteomyelitis, [[Osteomyelitis]])
  • Orchitis
  • Parotitis

Treatment

  • Chloramphenicol (PO) for 2 weeks
    • Fever decreases after day 5
    • Alternatives: amox/ bactrim/ cipro/ ceftriaxone
    • Relapse rate is 20% in patients treated early (5-10% in untreated patients)
    • Chronic carriers: treat for 6 weeks with bactrim + rifampin (or amox, amp + probenecid)
  • Steroids (for CNS manifestations)
  • Cholecystectomy: for carriers with gallstones
  • Typhoid Ty21 vaccine (PO live-attenuated):
    • Indications: travel to most developing countries, travel with exposure to unsanitary food
    • Contraindications: pregnancy, immunocompromised hsot
    • Vaccine efficacy is diminished by concurrent use of chloroquine or proguanil

Prognosis

  • 3-5% of cases become long-term carriers

References

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