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The serious complications of paratyphoid fever generally occur after 2–3 weeks of illness and may include intestinal hemorrhage or perforation, which can be life threatening. | The serious complications of paratyphoid fever generally occur after 2–3 weeks of illness and may include intestinal hemorrhage or perforation, which can be life threatening. | ||
==Physical Examination== | ==Diagnosis== | ||
===Physical Examination=== | |||
In paratyphoid fever, liver and spleen enlargement can be seen. | In paratyphoid fever, liver and spleen enlargement can be seen. | ||
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Paratyphoid fevers or Enteric fevers are a group of enteric illnesses caused by strains of the bacterium Salmonella paratyphi. There are three species of Salmonellae that cause paratyphoid: Salmonella paratyphi A, S. paratyphi B ( or S. schotmulleri) and S. paratyphi C (S. hirschfeldii). They are transmitted by means of contaminated water or food. Typhoid fever is an acute, life-threatening febrile illness caused by the bacterium Salmonella enterica serotype Typhi. Paratyphoid fever is a similar illness caused by S. Paratyphi A, B, or C. The paratyphoid bears similarities with typhoid fever, but its course is more benign.
Pathophysiology
Paratyphoid fever starts when the bacterium Salmonella typhi is passed from another person due to bad hygiene such as lack of washing hands after using the restroom. Eventually the bacteria passes down to bowel, then penetrating the intestinal mucosa (lining) to the underlying tissue. If the immune system is unable to stop the infection here, bacteria multiplies and spread to the bloodstream, after which the first signs of disease are observed in the form of fever. Bacteria can penetrate further to the bone marrow, liver and bile ducts, and are excreted into the bowel contents. In the second phase of the disease, bacteria penetrates the immune tissue of the small intestine, and the initial symptoms of small-bowel movements begin.
Causes
Paratyphoid fever is caused by any of three strains of Salmonella paratyphoid: S. paratyphoid A; S. schottmuelleri (also called S. paratyphoid B); or S. hirschfeldii (also called S. paratyphoid C).[1]
Epidemiology and Demographics
Infections with S. Paratyphi A are common in Africa, they follow a course similar to typhoid but rose spots are more abundant and larger. Paratyphoid B is more frequent in Europe. Paratyphoid C is a rare infection, generally seen in the Far East. An estimated 22 million cases of typhoid fever and 200,000 related deaths occur worldwide each year; an additional 6 million cases of paratyphoid fever are estimated to occur annually. Approximately 300 cases of typhoid fever and 150 cases of paratyphoid fever are reported each year in the United States, most of which are in recent travelers. The risk of typhoid fever is highest for travelers to southern Asia (6–30 times higher than for all other destinations). Other areas of risk include East and Southeast Asia, Africa, the Caribbean, and Central and South America. The risk of paratyphoid fever is also increasing among travelers to southern and Southeast Asia. Travelers to southern Asia are at highest risk for infections that are nalidixic acid–resistant ormultidrug-resistant (resistant to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole). Travelers who are visiting friends and relatives (VFRs) are at increased risk. Although the risk of acquiring typhoid or paratyphoid fever increases with the duration of stay, travelers have acquired typhoid fever even during visits <1 week to countries where the disease is endemic.
Risk Factors
Paratyphoid fever can occur in any age group as it is food and water borne. Humans are the only source of these bacteria; no animal or environmental reservoirs have been identified. Typhoid and paratyphoid fever are most often acquired through consumption of water or food that has been contaminated by feces of an acutely infected or convalescent person or a chronic, asymptomatic carrier. Transmission through sexual contact, especially among men who have sex with men, has rarely been documented.
Natural History, Complications and Prognosis
The serious complications of paratyphoid fever generally occur after 2–3 weeks of illness and may include intestinal hemorrhage or perforation, which can be life threatening.
Diagnosis
Physical Examination
In paratyphoid fever, liver and spleen enlargement can be seen.
Laboratory Findings
A single blood culture is positive in only half the cases. Stool culture is not usually positive during the acute phase of the disease. Bone marrow culture increases the diagnostic yield to about 80% of cases. The Widal test is an old serologic assay for detecting IgM and IgG to the O and H antigens of salmonella. The test is unreliable but is widely used in developing countries because of its low cost. Newer serologic assays are somewhat more sensitive and specific than the Widal test but are infrequently available. Because there is no definitive serologic test for typhoid or paratyphoid fever, the diagnosis often has to be made clinically.
Medical Therapy
Empiric treatment in most parts of the world would use a fluoroquinolone, most often ciprofloxacin. However, resistance to fluoroquinolones is highest in the Indian subcontinent and increasing in other areas. Injectable third-generation cephalosporins are often the empiric drug of choice when the possibility of fluoroquinolone resistance is high. Patients treated with an appropriate antibiotic may still require 3–5 days to defervesce completely, although the height of the fever decreases each day. Patients may actually feel worse when the fever starts to go away. If fever does not subside within 5 days, alternative antimicrobial agents or other foci of infection should be considered.
References
- ↑ Frey, J. Rebecca. Paratyphoid Fever 1999. Encyclopedia of Medicine. 28 Oct 2008<http://findarticles.com/p/articles/mi_g2601/is_/ai_2601001024>