Enteric Fever (Typhoid Fever)

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

Diagnosis

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

Treatment

Medications

• 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 disease)

• Ceftriaxone, 2 g once daily intravenously for 10–14 days for severe ...