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For further information, see CMDT Part 33-17: Salmonellosis

Key Features

Essentials of Diagnosis

  • Gradual onset of headache, sore throat, cough, and either diarrhea or constipation

  • Rose spots, relative bradycardia, splenomegaly, and abdominal distention and tenderness

  • Leukopenia; blood, stool, and urine cultures positive for Salmonella

General Considerations

  • Can be caused by any Salmonella species, including S typhi (typhoid fever) and non-typhoidal strains, especially S paratyphi subtype A in the United States

  • Infection begins when organisms breach the mucosal epithelium of the intestines

    • Having crossed the epithelial barrier, organisms invade and replicate in macrophages in Peyer patches, mesenteric lymph nodes, and the spleen

    • Serotypes other than typhi usually do not cause invasive disease, presumably because they lack the necessary human-specific virulence factors

    • Bacteremia occurs, and the infection then localizes principally in the lymphoid tissue of the small intestine

    • Peyer patches become inflamed and may ulcerate, with involvement greatest during the third week of disease

    • The organism may disseminate to the lungs, gallbladder, kidneys, or central nervous system

  • May have a long incubation period (6–30 days)

Clinical Findings

Symptoms and Signs

Prodromal stage

  • Increasing malaise, headache, cough, and sore throat

  • Abdominal pain and constipation are often present while the fever ascends in a stepwise fashion

  • During the early prodrome, physical findings are few

  • There may be marked constipation

Later stage

  • After about 7–10 days, the fever reaches a plateau and the patient is much more ill, appearing exhausted and often prostrated

  • Marked constipation may develop into "pea soup" diarrhea

  • Splenomegaly, abdominal distention and tenderness, relative bradycardia, dicrotic pulse, and occasionally meningismus appear

  • The rash (rose spots) commonly appears during the second week of disease

    • The individual spot, found principally on the trunk, is a pink papule 2–3 mm in diameter that fades on pressure

    • It disappears in 3–4 days

Differential Diagnosis

  • Brucellosis

  • Tuberculosis

  • Infective endocarditis

  • Q fever and other rickettsial infections

  • Other causes of acute diarrhea

  • Viral hepatitis

  • Lymphoma

  • Adult Still disease

  • Malaria


Laboratory Tests

  • Best diagnosed by isolation of the organism from blood culture, which is positive in the first week of illness in 80% of patients who have not taken antibiotics

  • Cultures of bone marrow occasionally are positive when blood cultures are not

  • Stool culture is not reliable because it may be positive in gastroenteritis without typhoid fever



  • Ciprofloxacin, 500 mg twice daily orally or 400 mg twice daily intravenously for 5–7 days (10–14 days for severe typhoid)

  • Azithromycin, 500 mg once daily orally for 7 days (for uncomplicated disease; not recommended for severe ...

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