Typhoid fever

Dr Daniel J Bell et al.

Typhoid fever or just typhoid is an infectious disease caused by the Salmonella enterica serovar Typhi bacterium, usually spread by the orofecal route. The condition is characterized by severe fever, acute systemic symptoms, with occasionally serious enterocolic complications.

Do not confuse typhoid with typhus which is a different disease, caused by an entirely different organism. Typhoid fever and paratyphoid fever are both enteric fevers. Paratyphoid fever is caused by a related serotype of Salmonella enterica, and is very similar to typhoid fever clinically, but usually less severe.

Most hospital presentations with typhoid fever are in those aged 5 to 25 years. Evidence from the primary care setting however shows that many patients, especially infants under 5 years old, may not be medically-recognized as typhoid due to the non-specific nature of their presentation. From 60-90% of typhoid sufferers are either managed wholly as outpatients, or do not engage with medical services at all.

It is usually contracted by consuming contaminated food or water and therefore the provision of safe food sources and clean water in the developed world means that typhoid is now unusual. On the other hand, the absence of safe food and water in the developing world means that typhoid prevalence remains high.

  • incubation period lasts 7 to 14 days after the Salmonella enterica serotype Typhi bacterium is ingested
    • as little as 3 days and as much as 60 days has been seen
  • prodrome of fever and malaise: indicates start of bacteremia 
    • typically quotidian, i.e. daily
    • starts as low-grade but by week 2 tends to be high (39-40°C)
  • within a week of the onset of symptoms:
    • flu-like illness
      • chills (rigors rare)
      • frontal headache
      • malaise
      • loss of appetite
      • generalized abdominal ache
      • dry cough
      • myalgia
  • confusion
  • relative bradycardia is classic, but often is not seen
  • constipation 
    • diarrhea more common in infants and adults with HIV
  • absence of bowel symptoms in sick patients is atypical
  • hepatosplenomegaly
  • rose spot rash is classic, but <30% patients
    • occasional 2-4 mm red maculopapular blanching spots
    • chest and abdomen predominantly

Complications are seen in up to 15% affected patients. Acute GI bleeding is the most common serious sequela, in as many as 10% cases; its pathogenesis is necrotic adenopathy in a Peyer patch eroding through a small bowel blood vessel 1. Generally fortunately it is mild, but in 2% it is massive, and potentially fatal without rapid resuscitation.

Perforation of the bowel, usually ileal, is the gravest sequela, and may be seen in up to 3% hospital inpatients with typhoid. 

It is caused by Salmonella enterica serotype Typhi and most patients are infected by the consumption of contaminated food or water. Unlike all the other Salmonella species, serovar Typhi is not a zoonosis, and humans are their only host. Once it has invaded the GI epithelium it spreads to the regional nodes, where it multiplies before dispersing throughout the reticuloendothelial system

Gastrointestinal and hepatobiliary manifestations are the commonest findings on imaging of typhoid fever.

Cardiac, pulmonary, GU and CNS imaging abnormalities may be seen 3

  • fluoroquinolone antibiotics are the mainstay of successful treatment, e.g. ciprofloxacin
    • if resistance is a problem, third-generation cephalosporins, e.g. ceftriaxone, may be tried
  • supportive measures

Chronic asymptomatic carriage of typhoid is a well-recognized sequela, 10% excreting the bacteria in their feces for three months and as many as 4% do so for over a year.

With effective treatment the mortality rate is <1%.

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Article information

rID: 66221
Synonyms or Alternate Spellings:
  • Typhoid

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