Typhoid Fever Pathophysiology and Schematic Diagram

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Typhoid Fever Pathophysiology and Schematic Diagram Powered By Docstoc
					                            Common Complications of Typhoid Fever

       Intestinal bleeding or perforation
       Sepsis
       Myocarditis
       Meningitis
       Osteomyelitis
       Pneumonia
       Pancreatitis
       Delirium, psychosis

                                  Schematic Diagram of Typhoid Fever

        Predisposing Factors:                                          Precipitating Factors:

Age: Infants and youths/ elderly                                Improper food handling and
Prevalent in temperate climates
                                                                Contaminated water supply
High incidence in fall
                                                                Living in overcrowded areas/ poor

                                                                Poor hygiene/ hand washing

                                                                Low gastric acidity (Use of antacids)

                                  Ingestion of food or water
                                contaminated with Salmonella

                                   The bacteria adheres and
                                  invades the gut wall of the
                                     gastrointestinal tract

                                It enters the distal ileum (Peyer
   S.typhi has a Vi capsular
antigen that avoids neutrophil-
based inflammation. It induces
 host macrophages to attract
     more macrophages.

    The bacteria co-opt the
     macrophage’s cellular
   machinery for their own
 reproduction which is carried
    through the mesenteric
         lymph nodes.

It enters the thoracic duct then
the lymphatic system and then
through the tissues of the liver,
   spleen, bone marrow, and
          lymph nodes.

    The bacteria continue to
   multiply until it reached a
  critical density (1,000,000 to
        cause an infection).

  It then induces apoptosis of
 the macrophages and leaking
      into the blood stream
  (bacteremia) and to the rest
           of the body.
                   TYPHOID FEVER

                  The gallbladder is infected
                     through extension of
                  infection of bacteria or via

                     S.typhi reinvades the
                    gastrointestinal tract as
                      well as the Peyer’s

 The bacteria that does                    The bacteria that remained
not re- infect the host is              present in the system of the host
   shed into the stool                  pauses and continuos to multiply
                                        which makes the host as “carrier”
                                                 for a long time.