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
- Pneumonia (see Pneumonia, [[Pneumonia]])
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
- xxx